Машиностроение и техносфера XXI века. Том 4, 2009 г. by Донецкий политехник (Донецкий национальный технический университет)

Министерство образования и науки Украины Донецкая областная и городская администрации Международный союз машиностроителей Фонд поддержки прогрессивных реформ Национальная металлургическая академия Украины (НИИСТ) Донецкий и Севастопольский национальные технические университеты Брянский государственный технический университет Московский государственный университет инженерной экологии Таганрогский технологический институт Южного федерального университета Жешувский, Остравский, Силезский, Ясский технические университеты Политехника Любельская, Технический университет Молдовы, Политехника Ченстохова, Магдебургский, Портсмутский, Тульский университеты Бухарестская военно-техническая академия Институт международного сотрудничества, Российско-Украинский университет Институт механики и сейсмологической стабильности АН РУ Севастопольский центр профессионально-технического образования Донецкий институт холодильной техники Ассоциация металловедов и термистов Украины Научно-технический союз машиностроения Болгарии Научный центр проблем механики машин НАН Беларуси Издательство «Машиностроение», ОАО НИИ «Изотерм», ОАО «ДЗГА» АО «НОРД», ЗАО «НКМЗ», ЧП «Технополис», Снежнянский машзавод ООО Никитовский машзавод «Кераммаш»

МАШИНОСТРОЕНИЕ И ТЕХНОСФЕРА XXI ВЕКА Сборник трудов

XVI

МЕЖДУНАРОДНОЙ НАУЧНО-ТЕХНИЧЕСКОЙ КОНФЕРЕНЦИИ Том 4 14 - 19 сентября 2009 г. в городе Севастополе

2009

Донецк-2009

ББК К5я54 УДК 621.01(06) Машиностроение и техносфера XXI века // Сборник трудов XVI международной научно-технической конференции в г. Севастополе 14-19 сентября 2009 г. В 4-х томах. – Донецк: ДонНТУ, 2009. Т. 4. – 290 с. ISBN 966-7907-25-2 В сборник включены материалы XVI международной научнотехнической конференции «Машиностроение и техносфера XXI века», отражающие научные и практические результаты в области обработки изделий прогрессивными методами, создания нетрадиционных технологий и оборудования. Представлены современные достижения и перспективные направления развития технологических систем, металлорежущего инструмента и оснастки. Освещены современные проблемы материаловедения в машиностроении. Рассмотрены вопросы механизации и автоматизации производственных процессов, управления качеством и диагностики технических систем. Приведены сведения об особенностях моделирования, экономических проблемах производства, вопросах инженерного образования и других актуальных проблемах техносферы. Предназначен для научно-технических работников, ИТР и специалистов в области машиностроения и техносферы. Издается при содействии Международного союза машиностроителей Адрес международного организационного комитета: Украина, 83001, г. Донецк, ул. Артема, 58, ДонНТУ, кафедра ТМ. Тел.: +38 (062) 305-01-04, факс: +38 (062) 305-01-04 E-mail: tm@mech.dgtu.donetsk.ua http://www.dgtu.donetsk.ua

ISBN 966-7907-25-2

 Донецкий национальный технический университет, 2009 г.

BELASTUNGSANALYSE DER GABEL EINES GABELSTAPLERS Adamczyk J., Kaliński W. (Schlesische Technische Hochschule, Gliwice, Polen) In der Bearbeitung, wurden die Ergebnisse der Analyse von Gabelbelastung eines Gabelstaplers vorgestellt, verursacht durch Schwingungen der transportierten Ladung und Querbelastung der Gabelenden, auf Grund des uneigentliches Nutzen des Gabelstaplers der für den Ladungstransport auf Paletten bestimmt ist. Der analysierte Gabelstapler ist für den Transport von zwei arten Ladung bestimmt, von welchen die Bezeichnung des Aufbaumaßes und die Lage auf den Gabeln auf Zng. 1. gezeigt wurde. Die erste Ladungsart i = 1, bildet eine Palette mit vier Sackpakete, je 1000 kg Ladung auf der Palette. Ausmaß der ganzen Ladung und die Koordinatenwerte sind folgende: a 1 = 1,15 m, s 1 = 1,55 m, h 1 = 0,375 m, l 1 = 2,3 m, w 1 = 0,75 m. Die Massenparameter der Ladung sind folgende: Masse m 1 = 4000 kg, der Massenträgheitsmoment ist J S1x = 992 kgm2. Die zweite art. der Ladung, i = 2, bilden zwei Paletten mit zwei Sackpakete, je 1200 kg Ladung auf einer Palette Die belasteten Paletten, jede auf einem Arm der Gabel, sind zusammen gedrückt in einer Vertikalebene, welche durch die Teilungsebene führt, gezeigt auf der linken Seite der Zng. 1. Ausmaß der ganzen Ladung und die Koordinatenwerte sind folgende: a 2 = 1,5 m, s 2 = 1,15 m, h 2 = 0,5 m, l 2 = 1,85 m, w 2 = 1,0 m. Die Massenparameter der Ladung sind folgende: Masse m 2 = 2400 kg, J S 2 x = 885 kgm2.

Zng. 1. Bezeichnung des Ladungsdimension und seine Anordnung, b = 0,09 m, c = 0,65 m

Zng. 2. Schema der Gabel belastet mit Einheitskraft und Einheitsmoment 3

Auf Zng. 2 wurde der Gabelarm gezeigt, für die Bestimmung der Einflusszahlen, des angenommnes Schwingungsmodell. Die Einflusszahlen sind gleich: δ11 =

a2 6 EI x

δ 22 =

(a + 3b + c),

1 6 EI x

(3a + 3b + c),

δ12 =

a 12 EI x

(3a + 6b + 2c)

Die Differentialgleichungen freien Querschwingungen der Gabel sind beschrieben durch Grundgleichungen  ⋅ δ y = −my ⋅ δ11 − J Sxβ x 12  ⋅ δ β = −my ⋅ δ − J β x

Sx x

 , 22  

(1)

welche nach unterstellen der Lösung In form einer harmonischen Funktion und ihren Ableitungen y = y0 cos ωt → y = − y0ω2 cos ωt  ,  = −β ω2 cos ωt  β x = β0 cos ωt → β x 0 

(2)

und einem Ordnungsvorgang kann man wie folgt ausdrücken:

y0 (1 − mω2 ⋅ δ11 ) + β0 (− J Sx ω2 ⋅ δ12 ) = 0  , y0 (−mω2 ⋅ δ12 ) + β0 (1 − J Sx ω2 ⋅ δ22 ) = 0

(3)

dagegen die Zustandsgleichung nimmt folgende Gestalt an: 4





ω δ11 ⋅ δ 22 − ( δ12 )  ⋅ m ⋅ J Sxω − ω ( J Sx ⋅ δ 22 + m ⋅ δ11 ) + 1 = 0 



(4)

Querschnitt des Gabelarmes wurde gezeigt auf Zng. 3. Widerstandsmoment fürs Biegen und Trägheitsmoment sind gleich wie folgt: Wx =

s ⋅ h 2 0,2 ⋅ 0,052 s ⋅ h3 0,2 ⋅ 0,053 = = 8,333 ⋅ 10− 5 m3, I x = = 2,083 ⋅ 10− 6 m4 = 6 6 12 12

Zng. 3. Querschnitt des Gabelarmes

Für die Belastung bezeichnet als i = 1, sind die Einflusszahlen gleich: −6

−6

δ11 = 1,043 ⋅10 m/N , δ 22 = 1,665 ⋅10 1/Nm, δ12 = δ 21 = 1,159 ⋅10 1/N ,

(5)

dagegen für die Belastung bezeichnet als i = 2 haben wir −6

−6

δ11 = 2,075 ⋅10 m / N , δ 22 = 2,065 ⋅10 1/Nm , δ12 = δ 21 = 1,812 ⋅10 1/N

(6)

Es wurden folgende Werte für die Frequenz der naturellen, vertikalen Ladungsschwingung bezeichnet: für die Variante i = 1 – ω11 = 13,42 s-1 (f 11 = 2,13 Hz), ω12 = 59,58 s-1 (f 12 = 9,48 Hz), sowie für i = 2 – ω21 = 14,56 s-1 (f 21 = 2,32 Hz), ω22 = 47,31 s-1 (f 22 = 7,53 Hz). Die Staplergabel, welche eine länge des horizontales Armteil von 2,2 m hat, gefertigt ist aus Stahl dessen mechanische Eigenschaften übereinstimmen mit Eigenschaften des Stahls 40 H, welche nach der Wärmebehandlung - dem Härten und Anlassen sind folgende: Zugfestigkeit – R m = 1000 MPa; Minimum, Dehngrenze – R e = 800 MPa; Minimum, Härte – 217 HB. Ein vereinfachter Smith-Diagramm konstruiert fürs Biegen [1] bei Z go = 600 MPa; Z gj = 800 MPa; Q g = 850 MPa , wurde auf Zng. 4 gezeigt. Die Normalspannungen, hervorgerufen vom Biegen, auf Grund der Gabelbelastung der befestigten auf der Palette Ladung. Den größten Wert erreichen sie im Schnitt, in welchem der Maximale Wert des Biegemoments der Gabel auftretet, di. in der Zone des eingebogenen Gabelarms. Die Spannungen betragen: für Belastungsvariante bezeichnet als i = 1, σ1max = σ1m =

M g1max Wx

0,5 ⋅ 4000 kg ⋅ 9 ,81 ms −2 ⋅ 1,15 m = 270,76 MPa , 8,333 ⋅ 10-5 m3

dagegen für Variante i = 2 σ1max =

M g 2 max Wx

0,5 ⋅ 2400 kg ⋅ 9,81 ms −2 ⋅ 1,5 m = 211,9 MPa 8,333 ⋅ 10-5 m3

Zng. 4. Vereinfachter Smith - Diagramm für Stahl 40H

Die Fahrt mit einem belasteten Gabelstapler im, welche ungleichen Gelände, erzeugt eigene Schwingungen, welche die Ursache der Änderung vom Mittelwert der Spannung in jedem Punkt der Gabel sind. In der untersuchten oberen schicht der Armbiegezone ändern sich die Spannungen, welche aus der statischen Belastung stammen. Die Änderung kann man mit einer quasi festgelegten harmonischen Funktion von Amplitude σ m beschreiben. Für die Amplitude der Verschiebung von Schwingungen der

Ladungsmassenmitte S i y = 0,04 m, kann man das Wert der statischen Kraft berechnen, welche dieses Wert der Verschiebung des Gabelpunktes der sich unterhalb der Ladungsmassenmitte befindet, aufruft: 2  1  2   1  2  Py a1 (a1 + 3b + c ) , y Py = Pz δ11 =  a1a1  a1  + [a1b](a1 ) +  a1c  a1  = 2 ⋅ EI x  2  3   2  3  6 EI x

( )

(7)

die statische Kraft, welche dieser Durchbiegung entspricht ist gleich: Py =

6 EI x ⋅ y

⋅ (a + 3b + c )

2 ⋅ 1312290 ⋅ 0,04 2

(

1,15 ⋅ 1,15 + 3 ⋅ 0 ,09 + 0 ,65

)

N = 38348 N

(8)

Die amplituidale Spannung ist gleich:

σ 1a =

M g1

38348 ⋅ 1,15 Nm −5

2 ⋅ 8,333 ⋅ 10 m

= 264 ,62 MPa

(9)

Der maximale Spannungswert beträgt diesmal: σ1 max = σ1m + σ1a = 270,76 + 264,62 = 535,38 MPa

(10)

Bei der Behandlung eines Falles der dynamischen Belastung des Gabelarms, wurde das Modell das auf Zng. 5. gezeigt ist angenommen. Es wurde angenommen, dass das vertikale teil des Armes in der unteren Führung befestigt ist, punkt B. Das maximale Wert der normalen Spannung In der äußeren gebogenen Schicht, im Punkt der Gabelbiegung mit Kraft vom Wert F x ist gleich [11]

σ ( Fx ) = 2

wo: Wy =

s ⋅h 6

Fx ⋅ a = Wy

k zast . ⋅ m ⋅ υ x2 ⋅ a , Wy

0 ,2 ⋅ 0 ,05

= 3,333 ⋅ 10

−4

m3, Ersatzsteifigkeit der Gabel k zast . =

(11) k g ⋅ kϕx kg + k

Zng. 5. Verschiebung des Gabelschlagpunktes auf Grund ihrer Torsion und Durchbiegung 6

kg =

3⋅ E ⋅ I y 3

= 1972000

, k

k zast = 151600

k a

= 6565744

I0 = I x + I y =

N m

h s

, k = 2

G I0 b

= 31778200

Nm rad

−5

( h + s ) = 3,541 ⋅10 m4

– m 12 Polarträgheitsmoment vom Querschnitt des Gabelarms, m = 10160 kg – die Masse vom belasteten Stapler, υ x - die Komponente des Geschwindigkeitsvektor vom Schlag des Gabelende in das Hindernis, es wurde angenommen υ = 3,0 m = 10,8 km . Im Resultat der x s

Berechnung hat man erhalten:

σ ( Fx ) =

Fx ⋅ a = Wy

151600

N m ⋅ 10160kg ⋅ (3,0 ) 2 ⋅ 2,2m m s ≅ 777,1MPa −4 3 3,333 ⋅ 10 m

Wenn man annehmt die Variante i =2 der Gabelbelastung des Staplers, die maximale, normale Spannung aufgerufen durch das Biegen in zwei Ebenen, tretet auf in der Ecke des Rechteckigen Querschnitt der Gabel und ist gleich:

σ max = σ 1 max + σ ( Fx ) = (211,9 + 777,1) MPa = 989MPa

(12)

In der analisierten Variante der Belastung, erreichen die Spannungen in der Ecke des Gabelquerschnittes den Wert, der sich dem Katalogwert von R m nähert, für Stahl aus welcher die Gabel gefertigt wurde. Wenn man berücksichtigt die berechneten Spannungswerte (10) und (12), kann man beobachten, dass die Ursache des zerplatzen der Gabel, nur der ungehöriger Betrieb des Gabelstaplers sein kann, was seinen Grund im schrägen anfahren auf quere Hindernisse hat oder die quere Verschiebung der Ladung im vergleich zu der Fahrtrichtung. Literatur: 1. Adamczyk J., Kaliński W. Analiza przyczyn pękania wideł wózka widłowego. Gliwice, 2008, 30 s. (praca niepublikowana). 2. Niezgodziński M. E., Niezgodziński T. Wzory wykresy i tablice wytrzymałościowe. Wyd. VIII, WN-T, Warszawa 1996.

INFLUENCE OF LIQUID LAYER ON ENERGY LOSS AT GRANULE IMPACT Antonyuk S., Dosta M., Heinrich S. (Hamburg University of Technology, Hamburg, Germany) The influence of the thickness and the viscosity of the liquid layer at the contact as well as impact velocity on the energy dissipation during the normal impact of spherical granules was investigated. Using a free-fall device the restitution coefficients of γ-Al 2 O 3 granules impacted on a steel wall with a liquid layer were measured. With increasing liquid viscosity the restitution coefficient and the critical thickness of liquid layer at which the granule sticks decreased. With decreasing impact velocity the restitution coefficient greatly decreases. A rational explanation of obtained effects was given by results of numerically solved energy balances. 7

Introduction The moisture content in fluidized beds during spray bed granulation has a great influence on the inter-particle collision properties and hence on the flow behavior [1]. During this process the most important mechanisms of granule collisional energy loss are the micro processes of coating of the particle surface with a liquid film or droplets and the particle wetting [2-3]. In this work, we study the effects of the thickness and viscosity of the liquid layer as well as impact velocity on the energy dissipation during normal impact of a spherical granule on the wall with a liquid layer. Based on the measurements and simulations the influence of these parameters on liquid layer height at which the granule sticks was obtained. Force balance of the impact With relation to the forces acting on the particle the full period of the impact can be divided into four intervals, Fig. 1. In the first period, the particle penetrates into the liquid layer and displaces the liquid from contact area. The particle-wall contact takes place during the second period. After loss of the contact the particle moves upward through the liquid up to the liquid layer surface (the third period). During the last period a liquid bridge is formed. This bridge will be stretched up to a critical length, where its rupture occurs.

I - penetration IV - rebound Fig. 2. Forces acting on the particle during the penetration and rebound

Fig. 1. Schematic representation of impact intervals

The equation of motion of a particle impacted on a liquid layer on a wall can be written as:         d2x  m p 2 = Fp,g + Ft + Fb + FD + Fc + Fvis + Fcap + Fl,g , dt

(1)

with the forces (Fig. 2): F p,g , F l,g - gravitational forces of the particle and the liquid film on the particle, F t - surface tension force, F b - buoyancy force, F D - drag force, F c contact force between the particle and the wall, F vis - viscous force, F cap - capillary force. The surface tension force F t was determined for a liquid bridge under static conditions by Orr et al. [4], calculated and measured by many authors [5]-[6] as: Ft = ±γ la π d p sin α sin(Θ + α),

(2)

where γ la is the liquid-air surface tension and α is a half of central angle (Fig. 2). The dynamic contact angle Θ depends on the wetting conditions of the particle. In investigated cases the buoyancy force is relative small and can be neglected. The drag force F D can be calculated by the following equation: 8

1 FD =± π c D ρl d p2 sin 2 (α) v 2 , 8

(3)

where v is the particle velocity, c D is the drag coefficient and ρ l is liquid density. The contact force F c can be expressed as a sum of an elastic force (first term in Eq. (5) according to Hertz [8]) and a damping force (second term in Eq. (5) according to Tsuji [9]): Fc k ′el x 3/2 + α d m* k ′el x1/4 =

dx , dt

(4)

with the effective mass of both contact partners m*= (1/m p +1/m w )-1 ≈ m p . (w is the wall). The Hertzian constant k/ el in Eq. (4) can be given by the following expression: k ′el =

4 Ep 3 1-ν 2p

R* ,

(5)

where ν p is the Poisson ratio of the particle, E p is the modulus of elasticity. The energy dissipation in the model is controlled by a damping parameter αd which depends on the restitution coefficient. The viscous resistance arises due to the liquid shear flow between granule and wall. For a Newtonian fluid the viscous force F vis was found as [10], [11]: 6 π η R 2p dx Fvis = ± , h s − x dt

(6)

where η is the liquid viscosity and (h s -x) is the particle-wall separation distance. The capillary force in the liquid bridge depends on the Laplace hydrostatic pressure difference across the fluid surface and on the cross-section area of the neck:

 1 1  2 2 − Fcap = −γ la   πR p sin α,  R1 R 2 

(7)

where R 1 and R 2 are the local radii of the curvature (Fig. 2). Here a minus is written before the radius R 2 due to concave meridional curvature of the bridge. The energy loss E diss,tot during particle collision can be described using the restitution coefficient which is equal to the square root of the ratio of elastic energy E kin,R released during the restitution to the initial kinetic impact energy E kin : vR E E e =kin,R = 1 − diss,tot = . Ekin Ekin v

(8)

Testing method and material Fig. 3 illustrates the used experimental free-fall setup. Before the granule is dropped, it is being held at a predetermined height h above the target (steel flat wall) with the aid of a vacuum nozzle that releases the granule with zero initial velocity and rotation. From Eq. (8) it follows that the restitution coefficient is a ratio of relative rebound velocity v R (at the bridge rupture) to that before the impact v (at the contact with the liquid). These velocities were determined from impacts captured using with a high-speed video camera (4.000 fps). 9

As test material the spherical γ-Al 2 O 3 granules produced by SASOL were chosen. The properties of these granules are given in Table 1 [8, 12]. Table 1. Characteristics of the examined granules Property Value granule size d p in mm 1.75 ± 0.05 granule density in kg/m3 1040 modulus of elasticity E p in 14.62 ± kN/mm2 0.3 Hertzian constant k/ el in 592 ± 40 MN/m1.5 Normal restitution coefficient 0.735 ± 0.02 The borders for the liquid layer forms a polymer ring film attached to the wall surface. The water solutions of the hydroxypropyl methylcellulose Pharmacoat® 606 with different concentrations (3-10 mass-%) for variation of viscosity were used.

Fig. 3. The free-fall device for measurements of granule impact on a wall with a liquid layer

The impact behavior was studied by varying the viscosity of the liquid layer in the range of 1-300 mPas and the layer thickness from 40 µm to 1 mm. The measurements were carried out at two impact velocities of 1.0 m/s and 2.4 m/s. Experimental results The results of fall tests are shown in Fig. 4. The restitution coefficient becomes smaller with increasing thickness and viscosity of the liquid layer, when the amount of the energy absorption by adhesion increases. The maximum of the restitution coefficient corresponds to the impact without the liquid layer [12]. The minimum of the restitution coefficient equals to zero, i.e. the granule sticks. The corresponding layer thickness h s,st depends on the viscosity and the impact velocity. With larger binder viscosity this sticking thickness decreases. Thus, to increase the agglomeration rate of particles, either the viscosity or the thickness of the binder layer should be increased. 1

viscosity η in mPa . s:

velocity v in m/s:

1.0

0.8

en(h s = 0)

4.5 15.0

0.6

50.0 0.4

sticking en(h s,st ) = 0

0.2

restitution coefficient e n

0.8

2.36 en(h s = 0)

1.00 0.6

0.4

0.2

sticking en(h s,st ) = 0

0 0

200

400

600

800

1000

layer thickness hs in µm

Fig. 4. Influence of viscosity and thickness of the liquid on restitution coefficient (v=2.36m/s) 10

200

400

600

800

1000

layer thickness hs in µm

Fig. 5. Influence of the impact velocity on restitution coefficient

The experimental results (Fig. 5) showed that the decrease of the impact velocity can greatly reduce the restitution coefficient and the sticking height. Therefore, a smaller restitution coefficient is caused by the longer time for energy absorption during penetration in the layer and stretching of the bridge. In contrast to wet conditions, the restitution coefficient of γ-Al 2 O 3 granules for the impact without a liquid layer is independent of the velocity in this range [12]. Simulation results The numerical calculations of the equation of motion (1) were performed for the particle impact velocity of 2.36 m/s and the viscosity of η = 4.5 mPa⋅s which correspond to the conditions of the performed free-fall experiments. The properties of the granules and the liquid were used as material parameters of the model. The damping parameter αd was assumed to be 0.23 according to the restitution coefficient (Table 1). The diagram in Fig. 6 compares the experimental obtained and calculated restitution coefficients at different liquid layer thicknesses. A good agreement of the calculated values with experimental data can be seen in Fig. 6. 100 %

56.4 %

Ediss,tot

26.9 % 0.8

0.6

simulation experiment

0.4

energy in µ J

restitution coefficient en

12.4 %

Ekin Evis Ec,d ED

4.7 %

Et 0.75 %

0.1

Emg

0.2

0 0

200

400

600

800

0.01 100

layer thickness hs in µm

Fig. 6. Experimental and calculated normal restitution coefficients versus liquid layer thickness (η = 4.5 mPa⋅s, γ la = 43.6 mN/m, Θ R = 25°, Θ = 175° and v = 2.36 m/s)

300

500

layer thickness hs in µm

700

Fig. 7. Kinetic impact energy (v = 2.36 m/s) and dissipated energy parts versus liquid layer thickness (η =4.5 mPa·s). The plotted values show the contribution of different energies at the sticking point

Fig. 7 shows the influence of different forces on the total energy dissipation E diss,tot which increases with the layer thickness and arrives the initial kinetic energy E kin at the sticking point. The most important influence on the energy absorption during the penetration and rebound are caused by the viscous (E vis ) and drag forces (E D ). Hence, the drag force becomes a significant effect only at the thick layers (h s /R p > 0.3). The surface tension (E t ) should also be considered in the case of small liquid viscosity and particle velocity when the contribution of the drag and viscous forces become smaller. The deformation energy loss (E c,d ) has the same order of magnitude as the viscous dissipation due to the liquid. References: 1. M. S. van Buijtenen, N. G. Deen, S. Antonyuk, S. Heinrich and J.A.M. Kuipers, Proc. of 9th Int. Conf. on Circulating Fluidized Beds, 2008, pp. 227-232. 2. P. Müller, S. Antonyuk, J. Tomas and S. Heinrich, In Micro-Macro-Interactions in Structured Media and Particle Systems, Springer, Berlin, 2008, pp. 235-243. 3. B. Ennis, G. Tardos and R. Pfeffer, Powder Technology 65, 1991, pp. 251-272. 4. F. M. Orr, L. E. Scriven and P. Rivas, J. Fluid Mech. 67, 1975, pp. 723-742. 5. H. Schubert. Powder Technology 37, 1984, 11

pp. 105-116. 6. C. D. Willet, M. J. Adams, S. A. Johnson and J. P. K. Seville. Powder Technology 130, 2003, pp. 63-69. 7. A. A. Kaskas, Doctoral dissertation, Technical University of Berlin. 1970. 8. S. Antonyuk, Doctoral dissertation, University of Magdeburg, 2006. 9. Y. Tsuji, T. Tanaka and T. Ishida, Powder Technology 71, 1992, pp. 239-250. 10. A. Cameron, “Basis lubrication theory”, Ellis Harwood, Chichester, 1981. 11. G. Lian, Y. Xu, W. Huang and M. J. Adams. J. Non-Newtonian Fluid Mech. 100, 2001, pp. 151-164. 12. S. Antonyuk, S. Heinrich, J. Tomas, N. G. Deen, M. S. van Buijtenen and J. A. M. Kuipers. Submitted in Granular Matter, 2009.

SOME METHODS OF PRINCIPAL STRESS SEPARATION IN PHOTOSTRESS MEASUREMENTS Bakšiová Z. (Technical University of Kosice, Kosice, Slovakia) PhotoStress is a widely used technique for visualizing stress distribution. PhotoStress method provides quantitative stress measurement at any selected point or points on the coated surface of the test object. The paper describes a method of making the required additional measurement for determining the separate principal stresses from the photoelastically derived stress difference. The procedure uses a specially designed strain gage (stress-separator gage). The measurement is performed on coated beam. 1. Introduction to Stress Analysis by the PhotoStress Method PhotoStress is a widely used full-field technique for accurately measuring surface strains to determine the stresses in a part or structure during static or dynamic testing. With the PhotoStress method, a special strain-sensitive plastic coating is first bonded to the test part. Then, as test or service loads are applied to the part, the coating is illuminated by polarized light from a reflection polariscope. When viewed through the polariscope, the coating displays the strains in a colorful, informative pattern which immediately reveals the overall strain distribution and pinpoints highly strain areas (Figure1). With an optical transducer (compensator) attached to the polariscope, quantitative stress analysis can be quickly and easily performed. Permanent records of the overall strain distribution can be made by photography or by video recording [3].

Fig. 1. Full-Field Interpretation of Strain Distribution

PhotoStress testing provides an accurate and economical means for stress analysis of any part or structure, regardless of the part’s complexity or material composition. With PhotoStress you can: • Instantly identify critical areas, highlighting overstressed and understressed regions. • Measure principal stress directions and principal stress magnitudes. • Accurately measure peak stresses and determine stress concentrations around holes, notches, fillets, and other potential failure sites. • Optimize the stress distribution for minimum weight and maximum reliability. • Test repeatedly under varying load conditions, without recoating the part. • Make stress measurements in the laboratory or in the field — unaffected by humidity or time. • Detect yielding, and measure assembly and residual stresses [7]. 2. Relationships between Fringe Orders and Magnitudes of Strain and Stress The fringe orders observed in PhotoStress coatings are proportional to the difference between the principal strains in the coating (and in the surface of the test part). This simple linear relationship is expressed as follows:

ε1 − ε 2 = N

λ 2 tK

=N f

(1)

Where:

ε 1 , ε 2 = principal strains in coating, N = normal-incidence fringe order, λ = wavelength of yellow light (575 nm), t = thickness of PhotoStress coating, K = strain-optic coefficient of coating, f = λ/2tK = fringe value of coating. Assuming the strains in the coating precisely replicate those in the test-part surface, and assuming the part is stressed below its proportional limit, Hooke’s law can be applied as follows to determine the difference of principal stresses:

σ1 − σ 2 = Where:

E (ε 1 − ε 2 ) 1+ µ

σ 1 , σ 2 = principal stresses in test part,

E = elastic modulus of test material, µ = Poisson’s ratio of test material. Equations (1) and (2), which are the primary relationships used in photoelastic coating stress analysis, give only the difference in principal strains and stresses, not the individual quantities. To determine the individual magnitudes and signs of either the principal strains or stresses generally requires, for biaxial stress states, a second measurement, such as the sum of the principal strains [5]. 3. Strain Gage Separation Method In addition to its unique capability as a full-field technique for visualizing stress distribution, the PhotoStress method provides quantitative stress measurement at any selected

(2)

point or points on the coated surface of the test object. At interior locations, removed from a free edge, the stress state is commonly biaxial; and it is sometimes necessary to determine the separate principal stresses, as well as their difference. This paper describes a method of making the required additional measurement for determining the separate principal stresses from the photoelastically derived stress difference. The procedure uses a specially designed strain gage (stress-separator gage) which is applied to the coating surface after the normalincidence reading has been made. The PhotoStress Separator Gage embodies a number of special features designed for ease of use and optimum performance in PhotoStress applications. First in importance, of course, is that the gage does not require any particular angular orientation. It is simply bonded at the point where separation measurements are desired. Separator Gauges must be used with a specially designed interface module in conjunction with the Measurements Group P-3500 Strain Indicator. The Model 330 Interface Module is a four-channel switch-and-balance unit with precision resistive circuits for reducing gauge excitation voltage to minimize self-heating effects, supplying bridge-completion for the 200-Ohm Separator Gauge and attenuating the gauge output so that the P-3500 Strain indicator reads out in units of 10 microstrain. As noted earlier, a normal-incidence photoelastic measurement on the PhotoStress coating provides the difference in principal strains at the test point. If the sum of the principal strains can be measured at the same point, then the separate principal strains are obtainable by simply adding and subtracting the two measurements [4]. Representing the gage output signal by the symbol S G , for convenience in algebraic manipulation: SG =

ε1 + ε 2 2

(3)

And

ε 1 + ε 2 = 2 SG .

(4)

Adding and subtracting with Equation (1),

ε1 = SG +

Nf , 2

(5)

ε 2 = SG −

Nf 2

(6)

4. Principal Stress Separation on Coated Beam The following example is provided to illustrate the calculating the separate principal stresses from the combined photoelastic and separator strain gage measurements. Beam of steel ( E = 2,1 . 10 5 MPa , µ = 0,3 ) have been coated with Type PS-1 photoelastic sheet, 3,1mm thick. For plane surfaces, premanufactured flat sheets are cut to size and bonded directly to the test part. The fringe value f for the coating is 605µε / fringe . Using the Model 040 reflection polariscope, the normal-incidence measurement at a point of interest on the coating yields a reading of 0,69 fringes ( N ) (Figure 2). 14

Fig. 2. Model 040 Reflection Polariscope and Coated Beam The load is then removed from the beam, and a PhotoStress Separator Gage is installed on the coating at the same point. Gage orientation is arbitrary, since the sum of any two perpendicular strains is equal to the sum of the principal strains. The strain gage is connected to a portable strain indicator through the Model 330 Interface Module and the instrument is balanced to zero indication for the no-load condition (Figure 3).

Fig. 3. The Model 330 Interface Module in conjunction with the P-3500 Strain Indicator and PhotoStress Separator Gage For example, with the multiplier switch of a P-3500 set to X1, the same load is reapplied to the beam, after which the indicated strain ( ∑ ε =10 times the display reading) is

ε1 + ε 3 = − 210 µε . In this case, it is not corrected either N or strain-extrapolation errors. Substituting N , f and

∑ε

for reinforcement or

into Equations (5) and (6):

SG + N f − 210 + 0,69 . 605 = = 104 µε , 2 2 S − N f − 210 −0,69 . 605 ε3 = G = = − 314 µε . 2 2

ε1 =

These principal strains are then substituted into the biaxial Hooke’s law to determine the principal stresses: 15

(7) (8)

(

))

2,1.10 5 E ( ) ε + µ ε = 104.10 −6 + 0,3. − 314.10 −6 = 2,262 MPa 1 3 2 2 1− µ 1 − 0,3 E 2,1.10 5 ( ) σ3 = ε + µ ε = − 314.10 −6 + 0,3.104.10 −6 = − 65,262 MPa 3 1 2 2 1− µ 1 − 0,3

σ1 =

(

)

(9) (10)

Conclusions This paper describes a unique method of making the required additional measurement for determining the separate principal stresses from the photoelastically derived stress difference. The procedure uses a specially designed strain gage (stress-separator gage) which is applied to the coating surface after the normal-incidence reading has been made. Practical experience with the method demonstrates that it offers several advantages over obliqueincidence measurements. It is quick, easy to use, and it completely eliminates the need for highly developed photoelastic skills. In most cases, it is also more accurate than obliqueincidence determinations. Bibliography: 1. Instruction Bulletin S-116-H: Photoelastic Materials. Raleigh: Measurements Group, 1996. 2. Instruction Bulletin S-127-F: PhotoStress Separator Gage. Raleigh: Measurements Group, 1996. 3. Tech Note TN-702-2: Introduction to Stress Analysis by the PhotoStress Method. Raleigh: Measurements Group, 1996. 4. Tech Note TN-708-2: Principal Stress Separation in PhotoStress Measurements. Raleigh: Measurements Group, 1996. 5. TREBUŇA, F.: Princípy, postupy, prístroje v metóde photostress: Košice: Typopress, 2006. 360 s. ISBN 80-8073-670-7. 6. Strain Measurment with the 040-Serie Reflection Polariscope: Raleigh: Measurements Group, 1996. 7. www.vishay.com.

LOGICAL CONDITION REPLACEMENT IN COMPOSITIONAL MICROPROGRAM CONTROL UNIT WITH CODE SHARING Barkalov A. A., Kovalyov S. A., Krasichkov A. A., Miroshkin A. N. (The University of Zielona Gora, 2Donetsk National Technical University, Zielona Gora, Donetsk, Poland, Ukraine) The new design method for compositional microprogram control units with code sharing is proposed. The method targets on reduction in the number of PAL macrocells in the combinational part of control unit with the help of logical condition replacement. Some additional control microinstructions containing codes of the classes of pseudoequivalent chains are used for operational linear chains modification. Proposed method is illustrated by an example. Introduction One of the most important blocks of any digital system is its control unit [1] responsible for interplaying of all other system blocks. If an interpreted control algorithm is a linear one, it can be interpreted using the model of compositional microprogram control unit (CMCU) [2]. Recently, the complex programmable logic devices (CPLD) are widely used for implementation of logic circuits [3, 4]. One of the important tasks connected with control unit design is minimization of hardware amount. In case of CPLD, this task can be solved due to decrease of the number of Programmable Array Logic (PAL) macrocells. To solve this problem, the number of terms in sum-of-products (SOP) should be diminished for address 16

functions of CMCU [3, 4]. Some development of this approach is proposed in our article, based on the logical condition replacement [2]. The aim of the work is the optimization of CMCU combinational part due to introduction a field with codes of POLC classes, as well as use of the logical condition replacement. The task of the work is development of CMCU synthesis method, allowing decrease for the number of PAL macrocells in comparison with known methods of CMCU synthesis [4]. A control algorithm is represented by a graph-scheme of algorithm (GSA)[8,9]. Background of CMCU with code sharing Let a control algorithm to be interpreted be represented by a graph-scheme of algorithm (GSA) Γ [5].Let this GSA be characterized by the set of vertices B = {b0 , bE } ∪ E1 ∪ E2 and the set of arcs E, where b 0 is an initial vertex, b E is a final vertex, E 1 is a set of operator vertices, and E 2 is a set of conditional vertices. Each operator vertex bq ∈ E1 contains a collection of microoperations Y (bq ) ⊆ Y , where Y = { y1 , ..., y N } is a set of data-path microoperations. Each conditional vertex bq ∈ E 2 contains some element xl ∈ X , where X = {x1 , ..., x L } is a set of logical conditions (input signals). A GSA Γ is named a linear GSA [2] if the number of its operator vertices exceeds 75% of the total their number in GSA. Let the set C = {α 1 , ..., α G } be constructed for GSA Γ , where α g ∈ C is an operational linear chain (OLC) [2]. Any component bg i of OLC α g ∈ C belongs to the set E1 (i = 1, ..., Fg ) . Each pair of adjacent components bg i , bg i +1 corresponds to the arc

< bgi , bgi +1 >∈ E , where i = 1, ..., Fg − 1 , g = 1, ..., G . Each OLC α g ∈ C has only one output

Og and the arbitrary number of inputs. Formal definitions of OLC, its input and output can be

found in [2]. Each vertex bq ∈ E1 corresponds to microinstruction MI q kept in the cell of control memory (CM) with address Aq . It is enough R = log 2 M 

(1)

bits for microinstruction addressing, where M = E1 . Let each OLC α g ∈ C include Fg components and Q = max( F1 , ..., FG ) . Let each OLC α g ∈ C be encoded by binary code K (α g ) having

R1 = log 2 G 

(2)

bits and variables τ r ∈ τ be used for such encoding, where τ = R1 . Let each component bq ∈ E1 be encoded by binary code K (bq ) having

R2 = log 2 Q 

(3)

bits and variables Tr ∈ T be used for this encoding, where T = R2 . Encoding of components is executed in such a manner that condition

K (bgi +1 ) = K (bgi ) + 1

(4)

takes place for each OLC α g ∈ C (i = 1, ..., Fg − 1 ) . If condition

R1 + R2 = R

(5)

takes place, then the model of CMCU with code sharing U 1 can be used (Fig. 1,a). In CMCU U 1 , a block of microinstruction addressing (BMA) implements the system of input memory functions for counter CT and register RG: Φ = Φ(τ,X); Ψ = Ψ(τ , X).

(6)

Let us point out that in the case of CMCU U 1 an address of microinstruction is represented as the following one: A(bq ) = K(α g )*K(bq ) ,

(7)

where bq is a component of OLC α g ∈ C and “*” is a sign of concatenation. The CMCU U 1 operates in the following order. If Start=1, then an initial address is loaded into RG and CT. A flip-flop TF is set up which causes Fetch=1, then microinstructions can be read out of control memory. Each cell of CM keeps microoperations y n ∈ Y and special variables y0 and yE . If y 0 = 1 , then a current content of CT is incremented, otherwise both CT and RG are loaded from BMA. If y E = 1 , then flip-flop TF is reset, signal Fetch=0 and operation of CMCU is terminated. It corresponds to transition from the vertex bq ∈ E1 , where < bq , bE >∈ E . Pulse Clock is used for timing of CMCU. Let us point out that OLC α i , α j ∈ C are pseudoequivalent OLC [2] if their outputs are connected with input of the same vertex of GSA Γ . The hardware amount in logic circuit of BMA can be decreased due to introduction of a special block for transforming the OLC codes into the codes of the classes of pseudoequivalent OLC (POLC) named as a code transformer (TC) [2]. But TC consumes some resources of the chip in use. In this article , we propose to decrease the complexity of code transformer due to using of free resources of EMB. The logical condition replacement is proposed for decrease of the number of PAL macrocells in the logic circuit of BMA. Main idea of proposed method Let α g ∈ C1 if α g ∈ C and its output is not connected with the final vertex bE . Let us find a partition Π C = {B1 ,...,BI } of the set C1 on the classes of POLC. Let us encode the classes Bi ∈ Π C by binary codes K ( Bi ) having RB bits, where RB = log 2 I 

(8)

Let us use variables vr ∈ V for encoding of the classes, where V = RB . Let the number t of the outputs of EMB belongs to the set TF = { 1,2 ,4 ,8 } . Let the following condition take place if t = 1 18

q≥M

(9)

In (9), q is the number of words of EMB when t = 1 . The control memory contains M collections of microoperations having N + 2 bits. The value 2 takes into account the variables y0 and y E . It is possible to have RF free outputs of EMB, forming the control memory, where  N + 2 RF =  *t − N − 2  t 

(10)

These free outputs can be used for representation of the codes K ( Bi ) if the following condition takes place:

RF ≥ RB

(11)

Obviously, there is a field FY in the microinstruction format, containing hot-one encoded collections of microoperations and variables y0 and y E . If condition (11) takes place, then the block BCT is absent. Let X ( Bi ) be a set of logical conditions xl ∈ X determining transitions from the output of OLC α g ∈ Bi , where X ( Bi ) = Li . Let L0 = max (L1 ,..,LI ) and L0 << L . In this case, the method of logical condition replacement [9] can be used, when the logical conditions xl ∈ X are replaced by some new variables p q ∈ P , where P = L0 . In this article a model o CMCU U 2 is proposed based on instruction of the field K ( Bi ) in the microinstruction format, as well as the logical condition replacement. The structural diagram of CMCU is shown in Fig. 1,b.

Fig. 1. Structure diagram of CMCU U 1 (a) and U 2 (b) In the CMCU U 2 , a block of logical conditions (BLC) implements functions 19

P = P(V , X )

(12)

These functions are used for logical condition replacement. The block BMA implements functions Φ = Φ(V , P ); Ψ = Ψ(V , P )

(13)

whereas the control memory implements the truth table for functions y 0 = y 0 (T ,τ ); y E = y E (T ,τ ); V = V (T ,τ ); Y = Y (T ,τ )

(14)

The following method of CMCU U 2 synthesis is proposed in this article: 1. Construction of the sets C , C1 , and Π C for a GSA Γ . 2. Encoding of OLC, their components and classes Bi ∈ Π C . 3. Replacement of logical condition xl ∈ X . 4. Construction of CMCU transition table. 5. Construction of the content of control memory. 6. Synthesis of CMCU logic circuit. In CMCU U 2 logic circuit for blocks BLC and BMA are implemented with PAL macrocells, whereas the control memory is implemented as a collection of EMB. Conclusions The proposed method of CMCU logic circuit optimization uses three following factors: existence of the classes of pseudoequivalent OLC (it allows decrease for the number of CMCU transitions in comparison with it’s base model [4]); existence of the free output of EMB forming the control memory (it permits representation of the codes of POLC classes without the special block of code transformer); logical condition replacement permitting decrease for the number of required inputs for the block BMA (it can result in decrease for the number of macrocells in the logic circuit of BMA). Obviously, the block BLC adds some delay in the time of cycle in comparison with the CMCU U 1 . Therefore, the proposed approach can be applied if it results in the less hardware amount than for equivalent CMCU U 1 . Besides, even in this case we can apply the method if it gives required timing characteristics for a resulting digital system. The scientific novelty of proposed method is determined by use of the classes of pseudoequivalent OLC and free resources of EMB for decreasing the number of macrocells in block of microinstruction addressing with the help of logical condition replacement. The practical importance of the method is determined by decrease for the number of macrocells and EMB in CMCU logic circuit. The future development is in trying to use proposed method for the basis of Field Programmable Gate Arrays (FPGA) and in design of CAD system for synthesis of CMCU. References: 1. De Micheli G. Synthesis and Optimization of Digital Circuits. – NY: McGraw-Hill, 1994. – 636 pp. 2. Баркалов А.А. Синтез устройств управления на программируемых логических устройствах. Донецк: ДНТУ, 2002. – 262 с. 3. Macrocell Configurations in CoolRunner XPLA3 CPLDs. Режим доступа: www.xilinx.com/support/documentation/application_notes/xapp335.pdf 4. Грушвицкий Р.И., Мурсаев А.Х., Угрюмов Е.П. Проектирование систем с использованием микросхем программируемой логики. – СПб: БХВ. – Петербург, 2002. – 608 с. 5. Barkalov A., Titarenko L. Logic Synthesis for Compositional Microprogram Control Units – Berlin : Springer, 2008. – 272 pp. 6. Barkalov A.A., Kovalyov S.A., Bieganowski J., 20

Miroshkin A.N. Synthesis of control unit with code sharing and modified linear chains. Машиностроение и техносфера XXI века // Сборник трудов XV международной научно-технической конференции в г. Севастополе 15-20 сентября 2008 г. В 4-х томах. – Донецк: ДонНТУ, 2008г. Т. 4. – С. 54-59. 7. Баркалов А.А., Красичков А.А., Мирошкин А.Н. Синтез устройства управления с разделением кодов и модификацией операторных линейных цепей. Наукові праці Донецького національного технічного університету. Серія "Інформатика, кібернетика і обчислювальна техніка". Випуск 9 (132) – Донецьк: ДонНТУ. – 2008. – С. 183-187. 8. Соловьев В.В. Проектирование цифровых схем на основе программируемых логических интегральных схем. – М.: Горячая линия-ТЕЛЕКОМ, 2001. – 636 с. 9. Baranov S. Logic Synthesis for Control Automata – Boston: Kluwer Academic Publishers, 1994 – 312 pp. 10. Maxfield C. The Design Warrior’s Guide for FPGA – Amsterdam: Elseteir, 2004. – 541 pp.

OPTIMIZATION OF COMPOSITIONAL MICROPROGRAM CONTROL UNITS WITH CPLD Barkalov A. A., Zelenyova I. Y., Kovalev S. A., Lavrik A. S. (The University of Zielona Gora, Donetsk National Technical University, Zielona Gora, Donetsk, Poland, Ukraine) The method of hardware reduction is proposed oriented on compositional microprogram control units and CPLD chips. The method is based on a wide fan-in of PAL macrocells allowing using more than one source of microinstruction address. Such approach permits to minimize the number of PAL macrocells used for transformation of microinstruction address. Conditions for this method application are given. The results of experiments are shown. Introduction It is known, that peculiarities of a control algorithm to be interpreted, as well as logic elements in use should be taken into account to optimize the logic circuit of a control unit. In this article, there is discussed a problem of control unit implementation when a control algorithm is represented by the linear graph-scheme of algorithm (GSA). The complex programmable logic devices (CPLD) with programmable array logic (PAL) macrocells are used for implementation of the logic circuit [2, 3]. In the case of linear GSA, the model of compositional microprogram control unit (CMCU) can be used [4]. In this article the following peculiarities are: existence of pseudoequivalent operational linear chains (OLC) in the linear GSA, and the wide fan-in of PAL macrocells [4, 5, 6]. This feature of PAL can be used for having more then one soure of codes of the classes of pseudoequivalent OLC [7, 8]. We propose to use these peculiarities together with the encoding of the fields of compatible microoperations [9]. The aim of research is hardware amount reduction in logic circuit of CMCU due to simultaneous use of more than one source of codes for classes of pseudoequialent OLCs and encoding of the fields of compatible microoperations. The task of research is developments of synthesys method permitting reduction of the number of PAL macrocells and programmable read-only memory (PROM) chips in CMCU with transformer of microinstruction adreses. Background of CMCU with address transformer Let GSA Γ be represented by sets of vertices B and arcs E. Let B = {b0 , bE } ∪ E1 ∪ E2 , where b 0 is an initial vertex, b E is a final vertex, E 1 is a set of operator vertices, where E1 = M, and E 2 is a set of conditional vertices. A vertex bq ∈ E1 contains a microinstruction 21

( )

Y bq ⊆ Y , where Y = {y1 ,..., y N } is a set of data-path microoperations [1]. Each vertex bq ∈ E 2

contains a single element of a set of logical conditions X = {x1,..., xL } . Let GSA Γ be a linear GSA, that is a GSA with more than 75% of operator vertices. Let us form a set of operational linear chains (OLC) C = {α1 ,..., α G } for GSA Γ , where each OLC α g ∈ C is a sequence of operator vertices and each pair of its adjacent components corresponds to some arc of the GSA. Each OLC α g ∈ C has only one output O g and arbitrary number of inputs. Formal definitions of OLC, its input and output can be found in [2]. Each vertex bq ∈ E1 corresponds to microinstruction MIq kept in a control memory (CM) of CMCU and it has an address A bq . The microinstructions can be addressed

( )

using R = log 2 M 

(1)

bits, represented by variables Tr ∈ T = {T1 ,..., TR }. Let OLC α g ∈ C include Fg components and the following condition takes place: A(bgi +1 ) = A(bgi ) + 1 ,

(2)

In equation (2) b gi is the i-th component of OLC α g ∈ C , where i = 1,..., Fg − 1 . If outputs Oi , O j are connected with an input of the same vertex, then OLC

α i ,α j ∈ C

are pseudoequivalent OLC (POLC) [2]. Let us construct the partition

Π C = {B1,..., BI }

of the set C1 ⊆ C on the classes of POLC. Let us point out that α g ∈ C1 if Og , BE ∉ E . Let us encode the classes Bi ∈ Π C by binary codes K (Bi ) with R1 = log 2 I 

{

(3)

}

bits and use the variables τ r ∈ τ = τ 1 ,...,τ R1 for the encoding. In this case a GSA Γ can be interpreted using the model of CMCU U 1 with address transformer (Fig. 1). The pulse Start causes loading of the first microinstruction address into a counter CT and set up of a fetch flip-flop TF. If Fetch = 1, then microinstructions can be read out the control memory CM. If a current microinstruction does not correspond to an OLC output, then a special variable y 0 is formed together with microoperations Yq ⊆ Y . If y 0 = 1, then content of the CT is incremented according to the addressing mode (2). Otherwise, block of microinstruction address BMA generates functions

Φ = Φ (τ , X )

(4)

to load the next microinstruction address into the CT. In the same time, a block of address transformer BAT generates functions

τ = τ (T ) 22

(5)

If the output of OLC α g ∉ C1 is reached, then yE = 1 . It causes cleaning of TF and operation of CMCU U 1 is terminated. Such organization of CMCU permits decrease of the number of terms in functions Φ from H 1 till H 0 , where H 1 , H 0 is the number of terms for equivalent finite state machines (FSM) Moore and Mealy respectively. But block BAT consumes some macrocells or cells of PROM used for implementation of CM. In this article we propose some CMCU U 2 , where H 2 = H 0 and block BAT consumes less hardware than its counterpart in U 1 . Here H 2 means the number of terms in functions Φ for CMCU U 2 . In the same time, we propose to use the method of encoding of fields of compatible microoperstions to decrease the number of PROM chips in CMCU control memory. Main idea of proposed method Let us point out that logic circuits for BMA, CT, TF and BAT are implemented as the parts of CPLD. To implement the CM one should use PROM chips with t outputs, where t = 1, 2, 4, 8, 16 [3, 4]. Let us address the components of OLC α g ∈ C1 in such a manner that condition (2) takes place and maximal possible amount of classes Bi ∈ Π C was represented by a single generalized interval of R-dimensional Boolean space. Such addressing needs a special algorithm which should be developed. Let Π C = Π A ∪ Π B , where Bi ∈ Π A if this class is represented by one interval, and Bi ∈ Π B otherwise. The counter CT is a source of the codes for Bi ∈ Π A . If condition

Π B = 0/

(6)

takes place, then block BAT is absent. Otherwise, only output addresses for OLC from classes Bi ∈ Π B should be transformed. It is enough R2 = log 2 (I B + 1)

(7)

bits for such encoding, where I B = Π B and 1 is added to take into account the case when Bi ∈ Π A . Let us point out that some part of these codes can be implemented using free outputs of PROM. Let us use the strategy of the encoding of fields of compatible microoperstions, which can be explained as the following [9]. Microoperations yi , y j ∈ Y are compatible microoperations, if they are never written

{

}

in the same vertices of initial GSA. Let us find the partition Π Y = Y 1 ,, Y J , where Y j is a

(

)

class of compatible microoperations Y ∈ Y . Let N j = Y , then each microoperation j

y n ∈ Y j can be encoded by a binary code K ( y n ) having R j bits, where

(

)

R j = log 2 N j + 1 

(8)

The unit is added to N j in (8) to take into account the case when microoperations

( )

yn ∈ Y j are absent in a set Y bq ⊆ Y . The decoder DC j is used to generate microoperations yn ∈ Y . The set of decoders DC j ( j = 1,, J ) form a block of microoperation decoding (BMD). j

This block has RY inputs, where 23

RY =

∑R

(9)

j =1

These inputs are controlled by a block of microoperation coding (BMC). The BMC is implemented using PROM chips, having t outputs. If each POM has not less than M words, then it is enough R0 chips for implementation of the BMC logic circuit, where  R + 2 R0 =  Y   t 

(10)

The number 2 is added to RY to take into account additional variables y 0 and y E , formed by the BMC. Obviously, there are K 0 free outputs in PROMs of the BMC, where K 0 = R0 * t − RY − 2

(11)

These outputs can be used to represent some bits of codes K (Bi ) . If condition K 0 ≥ R2 ,

(12)

takes place, then the block BAT is absent, because all bits of K (Bi ) are generated by BMC. Outputs of CT represent codes of classes Bi ∈ Π A . This approach results in CMCU U 2 (Fig. 2), where functions z r ∈ Z are used for microoperations encoding and Z = RY .

Fig. 1. Structural diagram of CMCU U 1

Fig. 2. Structural diagram of CMCU U 2

In the CMCU U 2 , codes of classes Bi ∈ Π A are represented by variables Tr ∈ T , whereas codes of lasses Bi ∈ Π B by variables v r ∈ V , where V = R2 . In contrast to CMCU U1 , the block BAT is absent, the block BMA implements functions Φ = Φ (T , V , X ) ,

(13)

V = V (T ); y0 = y0 (T ); y E = y E (T ); Z = Z (T ),

(14)

block BMC implements functions

and the block BMD implements functions 24

Y = Y (Z )

(15)

The following synthesis method for CMCU U 2 is proposed in this article: construction of sets C , C1 , Π C for GSA Г; addressing of microinstructions; construction of sets Π A and Π B ; encoding of classes Bi ∈ Π B ; encoding of microoperations and specifications of block BMD; construction of CMCU transition table; specification of the block BMC; synthesys of CMCU logic circuit. Conclusion There are three factors in the base of proposal method, such as: existence of the classes of pseudoequvalent OLC’s tht permits decrease of CMCU transition table length in comparison with its base model [4]; wide fan-in of PAL macrocells, that allows using up to three sources of codes of the classes; encoding of the fields of compatible micooperations, allowing decrease for the number of PROM chips in comparison with CMCU U 1 . The drawback of proposed method is increase for the cycle time due to using of additional block for microoperation decoding. Therefore, the method can be used if it satisfies to timing requirements of a project. Otherwise, other models of CMCU [4] should be appled for interpretation of a particular linear GSA. The scientific novelty of proposed method is determined by simultaneous use the PLA macrocells wide fan-in and logical condition replacement. It leads to hardware amount decrease for blocks BMA and BAT. If condition (12) takes place, then the block BAT is absent. The practical significance of this method is determined in decrease for the number of macrocells in CMCU logic circuit. It allows getting logic circuits with less hardware than for control units known from literature. Our investigation shows that the number of macrocells is decreased up to 10% for CMCU U 2 (Γ j ) in comparison with equivalent CMCU U1 (Γ j ) . There are two directions of our further research. The first, we should develop an algorithm permitting decrease for the number of OLC with outputs addresses to be transformed. The second, we should try this approach for CPLD based on programmable logic arrays [9], as well as on FPGA [10]. References: 1. Baranov S. Logic Synthesis for Control Automata. – Kluwer Academic Publishers, 1994. – 312 pp. 2. Грушвицкий Р.И., Мурсаев А.Х., Угрюмов Е.П. Проектирование систем с использованием микросхем программируемой логики. – СПб: БХВ. – Петербург, 2002. – 608 с. 3. Соловьев В.В. Проектирование цифровых схем на основе программируемых логических интегральных схем. – М.: Горячая линияТЕЛЕКОМ, 2001. – 636 с. 4. Barkalov A., Titarenko L. Logic Synthesis for Compositional Microprogram Control Units. – Berlin: Springer, 2008. – 272 pp. 5. http://www.altera.com/products/devices/common/dev-family_overview.html 6. http://www.xilinx.com/products/silicon_solutions/cplds/index.htm. 7. Баркалов А.А., Зеленёва И.Я., Лаврик А.С. Использование особенностей ПЛИС для оптимизации схемы устройства управления. / Наукові праці ДонНТУ. Серія «Інформатика, кібернетика і обчислювальна техніка» Випуск 9 (132) – Донецьк: ДонНТУ. – 2008. С. 178-182. 8. Баркалов А.А., Ковалёв С.А., Красичков А.А., Лаврик А.С. Оптимизация устройства управления с преобразователем адреса микрокоманд. /Материалы Девятого Междунардного научно-практического семинара. Таганрог. 2008. С. 12-20. 9. http://www.xilinx. com/support/documentation/coolrunner-ii.htm 10. Maxfield C. The Design Warrior’s Guide to FPGAs. – Amsterdam: Elseveir, 2004. – 541 pp.

КОМПЬЮТЕРНАЯ ПОДДЕРЖКА ПРОЕКТНЫХ РАБОТ Bernat Р. (Państwowa Wyższa Szkoła Zawodowa w Nysie, Nysa, Polska) The article presents possible applications of information solutions to facilitate the construction of large groups of similar parts. 3D model generator of collars and the database for their storing have been prepared. Введение В статье представлены возможности применения информационных решений, совершенствующих выполнение конструкторских работ для больших групп деталей подобного типа. Подготовлен генератор 3D моделей фланцев и база данных для их сохранения. Это было ответом на потребности конструкторского отдела производственного предприятия. Подбор программного обеспечения для создания этих инструментов явился следствием информационных средств, имеющихся на предприятии, для которого было разработано программное обеспечение. Постановка задачи Фланцы клапанов имеют множество конструктивных решений. Кроме того, отдельные типы фланцев отличаются между собой способом уплотнения. Большое количество потенциальных конструкционных решений вызвало необходимость разработки метода, позволяющего осуществить быструю подготовку необходимого конструктивного решения и его архивизацию. Целью проводимых работ была разработка инструментов для генерирования трехмерных моделей фланцев, предполагая уровнень автоматизации процесса создания отдельной модели, который можно получить. В результате появилапсь необходимость создания базы данных, дающей возможность сохранения генерированных моделей. Достижение вышеуказанной цели требовало реализации следующей процедуры: 1. выбор информационных инструментов, 2. проектирование генератора моделей, 3. выполнение моделей 3D, 4. проектирование базы для архивизации моделей. Задачей проекта генератора фланцев была возможность создания моделей как стандартных фланцев, так и фланцев нестандартных размеров. Для базы данных предполагалась - кроме функции архивизации - возможность поиска моделей, а также добавления новых групп стандартных фланцев. Генератор подготовлен для группы деталей типа фланец, описанных в следующих стандартах: EN 1092-1:2001 в интервале номинальных давлений от PN 6 до PN100 и номинальных диаметров от DN 10 до DN 3600 для типов фланцев: 01, 02, 03, 04, 05, 11, 12, 13, 21, 32, 33 и 34 с учетом вариантов профиля торца типа: А-Н, DIN 2501 в интервале номинальных давлений от PN 6 до PN 320 и диаметров от DN 10 до DN 2000 только для типа со сварочным наконечником, ANSI Bl6.5 в интервале номинальных давлений от 1125 до 2500 lbs и номинальных диаметров от 0,5 до 24 дюймов. Выбор стандартов из интервалов номинальных давлений PN и диаметров DN следовал из потребностей предприятия. Для элементов промышленной арматуры введены последовательности номинальных диаметров и давлений. Стандартизация этих значений упростила процесс подбора типа фланца для заданных условий работы. Это, в свою очередь, дало возможность компьютерной поддержки проектных работ по 26

подбору фланца. Номинальное давление PN и номинальный диаметр DN можно считать параметрами, которые позволяют подобрать фланец соответствующего размера и прочности. Процедура расчета прочности фланца содержится в [4]. Реализация проекта Процессу генерирования трехмерной модели сопутствует обмен информации между отдельными элементами, которыми являются: таблицы для введения данных, таблицы обработки данных, таблицы для сохранения значения размеров и таблица экспортирующая данные, которая непосредственно соединена с программой CAD 3D. Поток информации в соответствии с работами, ведущимися в [2], представлен на рис. 1.

Рис. 1. Ход создания 3D модели После выбора информационных инструментов разработан генератор моделей 3D фланцев. Была разработана панель пользователя в форме электронной таблицы, которая помогает пользователю определить основные параметры фланца, а также просматривать соответствующие им стандартные значения. Внешний вид генератора представлена на рис. 2.

Рис. 2. Генератор моделей фланцев На рис. 2. представлен вид генератора 3D моделей фланцев для стандарта EN 1092-1:2001. По такому же принципу подготовлены генераторы для стандартов DIN 2501 и ANSI В 16.5. После подтверждения выбранных при помощи меню в панели пользователя (рис.2) параметров фланца в графической программе генерируется 27

трехмерная модель детали. Пример такой 3D модели представлен на рис. 3.

Рис. 3. 3D модель фланца Очередным шагом в проводимых работах было проектирование базы данных. Разработанная база данных (рис. 4.) позволяет архивизировать выбранные 3D модели, а также позволяет предоставлять модели другим пользователям и обмениваться моделями между собой членам рабочей группы.

Рис. 4. Главная панель базы данных Был подготовлен также стандартный установочный файл, дающий возможность простой установки разработанного пакета инструментов (рис.5). После установки автоматически включается программа с уровня, с которого пользователь имеет доступ к каждому элемент)' пакета инструментов.

Рис. 5. Установочная программа и окно сокращения программы Фланец навигатор Подготовленная апликация может использоваться в каждом предприятии, если будут выполнены следующие программные требования:  для файлов электронных таблиц требуется профамма, считывающая файлы с 28

расширением xls, созданные в MS Excel 2003,  для просмотра 3D моделей будет применена программа для просмотра файлов, обслуживающая расширение ipt,  для генерирования моделей будет применена программа Autodesk Inventor,  для базы данных требуется программа, считыфвающая файлы баз данных, созданные в MS Access 2003. Лучшей программой для управления проектными данными, чем примененная, является программа Autodesk Vault. Однако выбор информатических инструментов должен был учитывать программы, которыми располагает предприятие. Заключение В результате проведенных работ созданы 64 основных модели, соответствующих разным конструкционным вариантам фланцев, 3 файла электронных таблиц, управляющих размерами основных моделей, а также база данных для ввода и предоставления трехмерных моделей фланцев. В связи с существенными конструкционными различиями между отдельными типами фланцев не было возможности подготовить одну универсальную 3D модель фланца, которую можно было бы считать основной для всех типов фланцев. В задачах для проведенных работ была принята возможность записи в базе данных каждой новой созданной 3D модели фланца. Поэтому была необходима подготовка такого метода создания отдельной модели, чтобы время, необходимое для получения 3D модели было как можно короче. Это удалось благодаря тому, что файлы электронных таблиц были дополнены таблицами стандартных значений. Одновременно была уставлена возможность ручного ввода каждого параметра. Подготовленное решение усовершенствовало процесс проектирования фланцевого присоединения. Сократилось время доступа к стандартным данным, а в результате - время, необходимое для генерирования трехмерной модели фланца. Отход от концепции записи всех моделей в базе данных изменил ее предназначение База уже не должна быть предназначена для хранения всех разработанных материалов, а для предоставления возможности доступа к данным и - в результате - к выбранным 3D моделям всем пользователям сети LAN. Поэтому разработанная база данных выполняет вспомогательную роль в процессе предоставления 3D моделей фланцев пользователям рабочей группы. Сама база содержит ряд функций, облегчающих поиск данной позиции (данной модели), а также формы для ввода данных. Она может являться платформой обмена данных трехмерных моделей деталей после добавления данных очередных групп деталей. Предложенное решение можно развивать, используя разработанный метод создания моделей для очередных групп деталей. Таким образом, будут возможны генерирование 3D моделей деталей, а также составляющих сложного элемента, эффективный обмен данных и работа в коллективе. Список литературы: 1. Bernat Р.: Komputerowe wspomaganie w zakresie technicznego przygotowania produkcji, [w:] Technologiczne Systemy Informacyjne w Inżynierii Produkcji i Kształceniu Technicznym, Monografia pod red. Antoniego Świcia, Wydawnictwa Uczelniane Politechniki Lubelskiej. Lublin 2009. 2. Bartkowicz Ł.: Biblioteka modeli 3D przyłączy kołnierzowych jako narzędzie usprawniające proces projektowy. Praca dyplomowa inżynierska. Nysa: Instytut Zarządzania PWSZ, 2008. 3. Bemat P.: Komputerowe wspomaganie przygotowania produkcji, [w:] Racjonalność w funkcjonowaniu organizacji. Gospodarka-Społeczeństwo, Monografia pod red. Piotra Bernata, Oficyna Wydawnicza PWSZ, Nysa 2009. 4. Mazanek Eugeniusz Przykłady obliczeń z podstaw konstrukcji maszyn T. 1., wyd. 1., Warszawa: Wydawnictwa Naukowo-Techniczne. 2005. 29

PREDICTING THE THICKNESS OF THE SURFACE LAYER SUBJECTED TO THERMO-CHEMICAL TREATMENT APPLYING EDI USING MODELING THROUGH THE METHOD OF NEURONAL MODEL Besliu V., Topala P., Ojegov A. (State University „Alecu Russo”, Baltsy, Moldova Republic) This paper contains a comparison of experimental and theoretical results using modeling through the method of neural model aiming at predicting theoretically the thickness of the surface obtained during the process of hardening by means of electric discharges in impulse. Acceleration of the technical scientific progress that may be gained by technical reutilization and introduction of new progressive techniques and technologies in modern production constitutes an important factor for the increase of production efficiency and quality improvement. A possibility of solving the problem of reutilizing materials is the application of no conventional technologies in general and of electric discharges in impulse (EDI) in particular. Different materials that conduct electricity, such as copper, graphite, nickel etc. that influence the physical chemical and mechanic properties of the piece under treatment (modifying its durability, resistance to wear, roughness) are being used as anode toolelectrode to process the surface in conformity with this method. To considerably increase the micro hardness of the piece surface without melting the material when the thickness of the white layer is of µm character in papers [1-5] electric discharges in bipolar impulses are applied if the tool-electrode is made of graphite and the steel piece is overdone. Nowadays, to decrease the number of attempts different methods of theoretic analysis are being used, one of them being modeling by means of the method of neuronal model [6] which gives the possibility to predict some experimental results without their integral realization. In order to predict the thickness of the superficial layer formed by applying EDI we used the software of neuronal model NNMODEL3.1. The values of the thickness in the superficial layer were first determined experimentally as a result of investigating the transversal micro section of the samples that had been processed with electric discharges in bipolar impulses as it was described in [4, 5, 7]. The method of neuronal model gives the possibility to work out a dynamic model of treating thermo chemically the piece surface by electric discharges in impulse. Having got a trained neuronal model and using real cases we can apply this net aiming at predicting the thickness of the superficial layer for a new set of parameters white treating thermo chemically the piece surface processed by applying EDI. We established experimentally 21 cases which represent sets of values for entrance and exit parameters during the processing. The entrance parameters of the processing are: W c [J] - the energy on the condenser battery, S[mm] – the size of the interstice, n- the number of passes, W [J] the energy in the interstice (counted taking into account the efficiency of the experimental installation), also the exit parameters that show the obtained results, h[µm]thickness of the superficial layer makes the matrix of data from the neural net (table 1). The neuronal model indicates the entrance and exit variables to realize the connections between entrance and result data. The variables stated as exit are those that will be calculated by the neuronal model algorithm to predict its values, also for the entrance data that are not in their training interval (fig.1). For example, the variation intervals of variables are as follows: : W c (J)-[0,64 – 1,40], S (mm)-[0,5-2,0], n-[1,0-4,0], W (J)-[0,26-0,65], H (Pa)[12,0-175,2], h (µm)-[4,0-14,0]. 30

Table 1. Matrix of data from the neuronal model

Fig. 1. Creation of the neuronal model The neuronal model has six variables possessing the following significations: V2-W c (J), V3-S (mm), V4-n (number of passes), V5-W (J), V6-H (Pa), V7-n (Âľm). To obtain the predicted values of exit values with small errors the interrogation values of the neuronal model NNMODEL3.1 should belong to the intervals of training mentioned above. To determine the thickness of the superficial layer by thermo chemical treatment with electric discharges in impulse one can preliminarily consult the neuronal model. The latter may estimate values V7 when one of the entrance variables V2-V5 possesses a value that is different from the trained ones but is in the experimentally determined interval. Fig.2 presents the variation of the white layer for the experimental case (red line) and the one obtained as a result of using the neural net (blue line) for a matrix of 21 experimental cases. This shouts that the results obtained experimentally and those predicted with the help of the neuronal model are subjected approximately to the same regulations while the deviation of the predicted values does not go beyond a few per cents and because of this we can affirm with confidence that the use of the neuronal model ensures the prediction of results that will be obtained; it also provides a decrease of number of attempts. Thus, having the neuronal model that represents a dynamic model we can test the net with values different from the experimental ones, but which are found in the interval of variation of variables. Fig.3 31

represents the dependence of the thickness of the superficial layer on the energy accumulated on the condenser battery (or is emitted in the interstice if the efficiency of the installation is taken into account). When the energy on the condenser battery rises we can notice an increase of the thickness of the superficial layer. The increase of this parameter reflects the variation character of the emitted energy in the interstice when the quantity of energy accumulated on the condenser battery in the generator of current impulses increases and consequently the depth of diffusion of alloying elements increases too.

Exp

Teor

Fig. 2. Comparison of measured values and those predicted by using the neuronal NNMODEL3.1 for parameter h (the thickness of the superficial layer)

Fig. 3. Dependence of thickness of the superficial layer h on the value of energy in the condenser battery W c

Fig. 4. Variation of thickness in the superficial layer depending on the energy value on the condenser battery for different values of number of passes 32

The effect the other variables on the dependence V2-V6 and V2-V7 is presented in the figures below. The superficial layer thickness depending on the energy value on the condenser battery for different values of the number of passes has an approximately linear character which means that the processing energetic regime is one of the main factors that determine the productivity of the process which corresponds to the experimental data, in order to obtain layers with prescribed thickness it is more convenient to use more superior energetic regimes to reach the desired effect at a single pass.

Fig. 5. Variation of thickness in the superficial layer depending on the energy value on the condenser battery for different values of energy emitted in the interstice Thus, in order to obtain layers with prescribed thickness it is more convenient to use more superior energetic regimes to reach the desired effect at a single pass. Fig.5 presents the thickness variation of the superficial layer depending on the energy value from the condenser battery for different values of the energy emitted in the interstice. This shows that the higher the energy emitted in the interstice, the thicker, the superficial layer but this increase is not directly proportional because of the causes of energy tosses on the reactive elements of discharging contours. These modifications of losses of energy for the analyzed case are not revealed well because the quantity of energy emitted in the interstice was modified also for different periods of duration of the discharging impulse. Conclusions: Judging by the comparison of the theoretical results with the experimental ones we can affirm with confidence that the application of the neuronal model gives the possibility quite exactly to describe and to predict the obtained effects due to which it is beneficial and allows us to essentially decrease the number of necessary experimental attempts to work out technologies of thermo chemical treatment of surfaces by applying electric discharges in impulse. Bibliography: 1.Topala P., Beshliu V. Graphite deposits formation on innards surface on adhibition of electric discharges in impulses. Bulletin of the Polytechnic Institute of Iaşi, 2008, T.LIV. p.105-111. 2.Topala, P., Stoicev, P., Epureanu, A, Beshliu, V. “The hardening of steel surfaces on the sections for electrosparkle alloyage. International Sientific and Technical conference Machine building and technosphere of the XXI centry. Donetk 2006. p.262-266. 3. Besliu V. Research on cementing the superficial stratum of steel piece surfaces by applying electrical discharges in pulses. Physics and Technicks: Processes, models, experiments. 2008.N1.p.90-96. 4. Besliu V. The influence of thermo chemical treatment by applying electrical discharges with bipolar impulses on the micro hardens and thickness of the superficial surface. “UASM, Scientific International Symposium Modern Agriculture – Realizations and Perspectives”, Chisinau.p.175-178. 5. Besliu V. Research on the thermal and thermo chemical treatment of piece surfaces by means of electrical discharges in 33

impulse/Summary of the Doctoral Thesis, Galaţi, 2008, 56p. 6. Rusnac V. Modeling the process of modification of the micro geometry of metal pieces applying electrical discharges in impuls UASM, Scientific International Symposium Modern Agriculture – realizations and Perspectives. Chisinau 2008. p.75-82. 7. Besliu Vitalie. Structure and Properties of Surface Layers of Pieces Cemented when Interacting with the Plasma Channel ofElectric Discharges in Pulse. The annals of “Dunarea de Jos” University of Galati, Fascicle V, Technologies in machine bulding. Vol.1, Year XXIV(XXIX), 2008, p.75-82.

THEORETICAL ASPECTS CONCERNING THE ELASTIC BEHAVIOR ON A BEAM UNDER THE ACTION OF THE CUTIING FORCE IN THE TURNING PROCESS Boca M., Nagîţ, G., Manole I. (Techn. Univ. “Gh. Asachi.”, Iasi, Romania) The aim of this paper is to show the influence of cutting force on a behaviour bar fixed between lathe chuck and the tailstock. Also it is necessary to specify the connetion between deformations and rigidity of the technological system. For this achievement are presented fiew considerations about the cutting tool problem in order to show how to compensate critical values for this. The study focuses on a description, in a first phase, of a theoretical model for calculating the cutting force presented in a study undertaken and in the second analysis, the experimental results collected and interpreted of another study. Introduction In the turning processes, as in the other case of the cutting processing, it follow to obtain parts without deflections from proposed surface to be processed. Besides the errors caused by imperfections of the MTDW system (machine-tool-device-workpiece) which have influence both the accuracy and the final form of the workpiece machined, another cause of their appearance is due to elastic sdeflections produced by the influence of cutting force on the workpiece material. Source of such errors are represented by different depths of cut. Average amplitude and the elastic deflections arising due to turning the influence of cutting force on the part processing, involves a model calculation. Besides these factors influence a significant and temperature are generated in part during processing.Another problem is related to the rigidity of the workpice because, it has a small value and it exist possibility to appear thevibrations in the system increases, leading to failure initial conditions imposed geometric. This considerations have been conducted to various studies including [12]which measure, calculate and compensate the effect of deflections due to action of the cutting forces. Preliminary analysis Until now, Kops [4], based on analytical model developed by Armarego [armarego, 2000], made a study of processing on slender bars that establishes a relationship between deflections and depth of cutting. By this characterization, with reference to the drawing of such models, there are developed studies using devices [4,12], for measuring the force, or theoretical methods calculate the deflections using the FEM analysis [6,7,10]. Beside the studies presented it is highlight also the researches undertaken for this purpose by Jiangling[3] which present a united model for predicted the diametral error of slender bar, beside a series of experiments which verify the prediction accuracy of the proposed model and a good agreement between the predicted and measured data is found. Another author, Polini[9] compare three models for calculating the cutting force. From another point of view, after some authors [7,11], the dynamic stiffness of processing that can predict deflections of the workpiece is in close touch with all the 34

knowledge rigidity spindle-tailstock-workpiece. This stiffness can be characterized by resistance to the opposing force applied indirectly by lathe tool and processed bar. Also, the deflections of the system leading to a real depth of processing that differs from that originally proposed. All these specifications are necessary to obtain a suitable quality of surface and geometry of the part processed. Geometric analysis of diametral deflections In the turning process, the diametral error it is defined as the relative movement between tool and the workpiece processed, resulting in the radial direction of the workpiece. Thus, the workpiece will have the initially center position of rotation (before processing) moved from the final centre of the workpiece (during and after implementation turning). The stablishment and approximation of elastic deviation of workpieces implies a theoretical model calculation. For this, we will consider a cylindrical bar (Fig. 1) caught at one in the chuck machine and supported on tailstock to the other end. To see the connection between the strength and rigidity of the system is required firstly to define the system rigidity. Thus, in the case of a normal lathe, the literature recommends calculation formula: JM =

Fig. 1. Schema with deflection of the workpiece

Fz yM

(1)

J M -is the rigidity of machine tools, F z - size force acting on the bar, and y M -deformation force on the direction bar.The force consists of next factors:

Fz = CFz â&#x2039;&#x2026; t X Fz â&#x2039;&#x2026; f YFz

(2)

where C is the constant of the cutting force which account by quality (prelucrabilitatea)of processed material, t is the depth of cutting, f is feed, X Fz and Y Fz exponents.Knowing the approximate amount of the force and the static rigidity of the lathe, we can anticipate the resistance bar like answer to these interactions. Therefore, a relevant study in this regard is made Segonds [Segonds, 2006] in which was chosen opted a cutting depth of 0.5 mm, an feed with value of 0.05 mm/rev and a speed of 500 m / min. In measuring the deflections were used two sensors placed on each of axes X, Y and were calibrated at the begining of processing (Fig.2).

Fig. 2. Workpiece machined [11] 35

Fig. 3. The.representation of the theoretical and the real surface machined [11]

After processing data from sensors placed on the two axes, drawn graph (Fig.4) approximates movements of the workpice. It is noted that the Y axis movement is more significant in comparison with the results on the X axis. Result as cutting force, the component was described by the direction of the unit vector of X axis, on middle line direction of the workpiece, describes the biggest movement. If we assume that the force F is aplicated at the end bar caught on top of the tailstock, then we have a torsional moment M (x) which tends to deforme the bar with

a force at least equal to that of the middle bar.

Fig. 4. Deflections for the C part machined

Based on the study undertaken by Vosniakos[13],that following the action of force F over a deformation δ2, resulted, according theorems of Castigliano II for the elastic line of a beam subject to elastic deformation, the calculated deformations for the 2nd segment using relations: δ2 =

∂U 2 ∂F2

= δ ( x) δ M ( x) + δ F ( x)

Um =

32 F 2 32 F 2 3 l1 {[ x ( l l l )] } {[ x − (l1 + l2 + l3 )]3 }ll11 +l2 + − + + + 1 2 3 0 3π Ed 24 3π Ed 24

32 F 2 {[ x − (l1 + l2 + l3 )]3}ll11 ++ll22 +l3 + 3π Ed 24

(1) (2)

(3)

In the same way, the energy of deformations can be calculated also:

∂U F 2 χ F 2 2χ F 2 2χ F 2 l1 + l2 3l1 [( ) ( ) ( x)ll11 ++ll22 +l3 UF = x x = + + 0 l1 2 2 2 π Gd1 π Gd 2 π Gd3 ∂F δM =

∂U M 64 F 64 F {[ x − (l1 + l2 + l3 )]3}l01 + {[ x − (l1 + l2 + l3 )]3}ll11 +l2 + = 4 3π Ed1 3π Ed 24 ∂F

64 F {[ x − (l1 + l2 + l3 )]3 }ll11 ++ll22 +l3 + 4 π Ed3 ∂U F 4χ F 4χ F 4χ F δF = [ x]l01 + [ x]ll11 +l2 + [ x]l1 +l2 +l3 = 2 2 π Gd1 π Gd 2 π Gd32 l1 +l2 ∂F

(4)

(5)

(6)

Relations (5) and (6) allowed calculation of diplacements made by force and torsional moment: Conclusions By this study which presents the influence of the force on technological elements, can anticipate and calculate both theoretically and practically deflections that may arise in workpice machined. Depending on the rigidity of the lathe it can process small diameters for workpieces which respect the elastic characteristics of the technological systemMany authors have researched and developed methods of calculation and compensation the effect of cutting forces on the work piece material. Also it was agreed that the cutting force acting perpendicular to the axis of workpiece, which has a decisive influence under the processing. The stages followed show the possible ways to performe a research. Is very important to find the best way to calculate, with a mathematical model the deflections of the workpiece, and then to interpret the results and put them in line. This study remain a open front to develop methods for reduce, as much as possible, the influence of cutting force on the accuracy of the workpieces machined considered. Acknowledgments The authors would like to express the gratitude to the BRAIN-POSTDRU-doctoral fellowships program. References: 1. Armarego E., The unified generalized mechanics of cutting approach a step towards a house of predictive performance models for machining operations, Machining Science and Technology, 4/3 , 2000, aviable from http://www.sciencedirect.com, 24/02/09. 2. Fan, S.; Wang, T.; Wang, W. & Leng, Y. Prediction of diameter errors compensation in bars turning, J. Cent. South.Univ.Techno., vol.12/2, 2005, 268pp. 3. Jiangling, G., Rogondi, H., A united model of diametral error in slender bar turning with follower rest, Int Machining Tools Manufacturing, 2006, 1002pp. 4. Kops L., Gould M., Mizrach M., Improved analysis of the accuracy in turning, based on emerging diameter error, Journal of Engineering for Industry 115, 1993, 253pp. 5. Liu, Z. X., Repetitive measurement and compensation to improve workpiece machining accuracy, IN: Adv. Manuf. Tech., 1999, 85pp. 6. Mayer, R.; Phan, A. & Cloutier G., Prediction of diameter errors in bar turning: a computationally effective model, Applied Mathematical Modelling 24, 2000, 943pp. 7. Phan, A. V., Baron, L., Mayer, R.R. J., and Cloutier, G., Finite element and experimental studies of diametral errors in cantilever bar turning, Applied Mathematical Modeling 27, 2003, 221pp. 8. Picos O., Tehnologia constructiilor de masini, EDP, 1984.9. Polini, W. & Prisco, U., The estimation of the diameter error in bar turning: a comparison among three cutting force models, International Journal Advanced Manufacturing Technology, No.22, 2003, 465pp. 10. Quiang, Liu Zhan., Finite difference calculaions of the deformations of mult-diameter workpieces during turning, Journal of Materials Processing Technology 98, 2000, 310pp. 11. Segonds S., Cohen G., Landon Y., Monies F., Lagarrigue P., Characterising the behaviour of workpieces under the effect of tangential cutting force during NC turning, Application to machining of slender workpieces, Journal of Materials Processing Technology 171, 2006, 471pp. 12. Topal S. A cutting force induced error elimination method for turning operations, Journal of Materials Processing Technology 170, 2005, 192pp. 13. Vosniakos G.C., Benardos P.G., Mosialos S., Prediction of workpiece elastic deflections under cutting forces in turning, Robotics and Computer-Integrated Manufacturing 22, 2006, 505pp.

INTRODUCTION TO SYTHESIS AND TRANSFORMATIONS OF MECHATRONICS SYSTEMES Buchacz A., Galeziowski D. (Silesian University of Technology, Gliwice, Poland) The main purpose for this paper is to introduce problem of mechatronics systems 1 synthesis. Piezo elements in form of stack 2actuators can be applied to mechanical subsystem, and by connection to external LRC network work as vibrations dampers or absorbers. Synthesized by distribution into partial fraction or widened method cascade structures must comply with the dynamical properties in the form of resonant and anti-resonant frequencies. Due to complexity of electrical and mechanical concerns non dimensional transformations has been used. 1. Introduction At the beginning of 80’s Gliwice Research Centre3 started to expand currently known problem of synthesis of mechanical and electrical systems [1,2,3,4,5]upon synthesis and designing of mechanical continous [6,7], discrete [8,9] and continous-discrete systems [10,11]. Lack of publications related to reverse task and projecting of mechatronics systems has given cause for this paper. Mechatoronics systems built from mechanical discrete sub-systems with “n” degree of freedom connected to piezo actuators and external electrical network has been never investigated before. In papers [12,13] possibility of using piezo stack as a damper was presented but only as an example of structure with one degree of freedom. This paper basing on [1-14] is focused on designing of mechatronics systems with “n” degree of freedom. It presents all cascade structures that can be derived from solving the reverse task: piezo in function of passive damper or semi-active damper and variations of them. For practical point of view, all mechanical systems received from synthesis has been transformed to non dimensional time model. By these transformation all parameters of external network L x , Rx , C x can be determined easily. These case highlights originality of this paper. 2. Piezo actuator configurations Piezo actuators configurations strictly depends on parameters of external LRC network. It is possible to receive passive damping (L x , L x Rx ) function or semi active (L x C x, L x Rx C x ), fig. 1. For each configuration it is important to determine current flow in a circuit i p

and voltage u p which is a function of

i p = f (e, x )

(1)

u p = f (e, F pe )

(2)

where: e – piezoelectric constant, F pe – electrical part of force coming from piezo, x displacement derivative.

implied as mechanical discrete system connected to piezo element and external LRC network. piezo stack – type of piezo actuator, monolithic structure, formed from large number of single piezo layers called wafers. 3 Institute of Engineering Processes Automation and Integrated Manufacturing Systems at Silesia University of Technology. 2

A Fpe Fpm

Fpe

ip iz ic

up q

Fpm Cps

ip iz ic

up q

cpm

Cps

cpm Cx Fpe

Fpm

ip iz ic

Fpe

Lx Fpm

up q

Cps

ip iz ic

Cps

cpm

B D Fig. 1. Representation of piezo stack in electrical and mechanical path for passive damping A, B and semi-active C, D

Semi active function can be obtained using negative capacitance circuit made according to Fukada, Kimura and Date remarks [15]. 3. Synthesis of cascade systems Regarding cascade systems, reverse has been solved by two methods: distribution into partial fractions and widened method. For each case dynamical characteristics are examined as slowness function U (s) = H

d l s l + d l −1 s l −1 + ... + d 0 c k s k + c k −1 s k −1 + ...c1 s

(3)

where: l– odd degree of numerator, k– degree of denominator, l − k = 1 , H – any positive real number, or mobility function: c s k + c k −1 s k −1 + ...c1 s (4) V (s) = H k l d l s + d l −1 s l −1 + ... + d 0 where: k – odd degree of numerator, l – degree of denominator, k − l = 1 , H – any positive real number. 4. Non dimensional transformations Non dimensional transformation simplify the issue of calculation of investigated system parameters. Fig. 2 present chosen structure that can be received from solving reverse task.

c3 c1

c2 m2

F(t)

Fig. 2. Chosen structure that can be received from synthesis Dynamical equation after transformation to non dimensional time for presented structure can be read as

α 0   0

0 0   x1′′ 0 0 0   x1′  1 + β 0   x1   x0 cos(ητ ) −β          (5) 1 0   x 2′′  + 0 0 0   x 2′  +  − χ 1 + γ + χ − γ   x 2  =  0  0 λ   x3′′  0 0 2 D   x3′   0 1 + δ   x3   0 −1 

Equation (5) has been presented as mechatronics structure with dynamical behavior in form of

 m1 0  0 

0 m2 LC ps

  c1 + c 2  +  − c2    0 

  0   x1  0   x  + 0 0  2   εs LC ps  up  0 RC ps  e  0 0

− c2 c 2 + c3 + c 4 C ps C

    x1    x 2  +   εs RC ps  u p  e  0 0

  0   x   F (t )  1   eA p  −   x2  =  0  lp  u   0    p   C εs  ps  1 +  e  C 

(6)

Figure 3 present other examples of structures that has been achieved from synthesis. Additionally, different settings of parameters L x R x C x. has been applied. 4. Conclusions It is possible to receive mechatronics structures4 from synthesis that will comply with required dynamical properties in form of resonant and antiresonant frequencies. Non dimensional transformation allow to simplify and connect mechanical and electrical concerns. If using different method of synthesis such as distribution into continued fraction it is possible to get branched structures too. 4

built from mechanical discrete sub-system with „n” degree of freedom connected to piezo stacks and LRC networks

c1 c2 m1

c3 m2

.. .

...

Lx c1 c2 m1

c3 m2

...

B Cx Lx

Fig. 3. Cascade mechatronics systems with 1 piezo element: A – passive function, B semiactive function However, these structures and practical examples shall be presented in further research works. References: 1. Arczewski K.: Analiza i synteza drgających układów mechanicznych metodą liczb strukturalnych. Praca doktorska, Politechnika Warszawska, Warszawa 1974, 2. Bellert S., Wojciechowski J.: Analiza i synteza układów elektrycznych metodą liczb strukturalnych: WNT, Warszawa 1968, 3. Białko M. [red]: Filtry aktywne RC. WNT, Warszawa, 1979, 4. Heinlen W.E., Holmes W. H.: Active filters for integrated circuits, fundamentals and design methods. Oldenbourg Verlag Munchen, Wien 1974, 5. Soluch W. [red.]: Filtry piezoelektryczne. WKiL, Warszawa 1982, 6. Buchacz A.: Synteza drgających układów prętowych w ujęciu grafów i liczb strukturalnych, Zeszyty Naukowe Politechniki Śląskiej, Mechanika z. 104, Gliwice 1991, 7. Buchacz A. [red.]: Komputerowe wspomaganie syntezy i analizy podzespołów maszyn modelowanych grafami I liczbami strukturalnymi. Zeszyty Naukowe Politechniki Śląskiej, Mechanika z. 127, Gliwice 1997, 8. Dymarek Dymarek.: Odwrotne zadanie dynamiki tłumionych mechanicznych układów drgających w ujęciu grafów i liczb strukturalnych, Praca doktorska, Politechnika Śląska, Gliwice 2000, 9. Dymarek A.: Komputerowo wspomagana synteza dyskretnych układów mechanicznych z tłumieniem. Zeszyty Naukowe Katedry Automatyzacji Procesów Technologicznych i Zintegrowanych Systemów Wytwarzania, z. 1, Gliwice 2003, s. 15-22, 10. Dzitkowski T.: Odwrotne zadania dynamiki dyskretno-ciągłych układów mechanicznych w ujęciu grafów i liczb strukturalnych, Praca doktorska, Politechnika Śląska, Gliwice 2001, 11. Dzitkowski.: Komputerowo wspomagana synteza dyskretno-ciągłych układów mechanicznych z tłumieniem. Zeszyty Naukowe Katedry Automatyzacji Procesów Technologicznych i Zintegrowanych Systemów Wytwarzania, z. 3, Gliwice 2003, s. 23-32, 12. H. Ahlers: Passive Dampfung reibungsinduzierter Bremsgerausche mit Piezoelementen. VDI Verlag GmbH, Dusseldorf 2002. 13. M. Neubaer, R. Oleskiewicz, K. Popp, T. Krzyżynski: Optimization of damping and absorbing performance of shunted piezo elements utilizing negative capacitance, “Journal of sound and vibration”, vol. 298, no1-2, pp. 84-107, 2006. 14. E. Fukada, M. Date, K. Kimura and others: Sound Isolation by Piezoelectric Polymer Films Connected to Negative Capacitance Circuits, IEEE Transactions on Dielectrics and Electrical Insulation Vol. 11, No. 2; April 2004. 41

EQUATIONS OF MOTION OF THE VIBRATING MECHATRONIC SYSTEM WITH THE GLUE LAYER Buchacz A., Płaczek M. (Silesian University of Technology, Gliwice, Poland) This paper is connected with the analysis of mechatronic systems including piezoelectric materials used as sensors or actuators for stabilization and damping of mechanical vibration. The main aim of this paper is to show the development of equations of motion of such kind of systems. 1. Introduction Piezoelectric transducers with external electric circuit can be applied in many mechanical systems such as a beam or a shaft in order to obtain required dynamic characteristic of designed system. Only very precise mathematical model of the mechatronic system enables the engineer to design a system with the required dynamic characteristic. Piezoelectric transducers used as sensors or actuators in mechatronic systems require an application of a glue layer attached to a mechanical system. The omission of the influence of this connection layer on the dynamic characteristic of the system results in an inaccuracy in the analysis of the system [1,2]. So, the purpose of the mechatronic system’s mathematical model development is to make the analysis of this system more precise. 2. The considered mechatronic system The considered mechatronic system is the cantilever beam which has a rectangular constant cross-section, length l and Young’s modulus E b with the piezoelectric transducer of length l p and thickness h p . The external RC electric circuit is adjoined to the transducer’s clamps. This system is loaded with force F(t). The beam’s vibrations affect the piezoelectric transducer which generates electric charge and produces additional stiffness of electromechanical nature, dependent on the capacitance of the transducer and adjoined external circuit. The external circuit introduces electric dissipation resulting in electronic damping of vibration. [1] The considered system is shown below (see Fig.1).

Fig. 1. The considered mechatronic system The transducer is bonded on the beam’s surface by the glue layer of finished thickness h k and Kirchhoff’s modulus G. The connection layer has homogeneous properties in overall length. 2. The assumption about pure shear of the glue layer In all of previous authors’ works the analysis of the considered flexural vibrating onedimension mechatronic system was supported on the assumption about the uniaxial, homogeneous strain of the transducer and pure shear of the connection layer. The dynamic equation of beam’s motion was assigned on the basis of the dynamic equilibrium of the 42

elementary beam and transducer’s section and assigned in agreement with d’Alembert’s principle [1-4].

Fig. 2. The pure shear of the connection layer The dynamic equation of the beam’s motion can be marked as an equation: ∂2 y − EI ∂ 4 y 1 ∂ F (t ) = − ⋅ τ ⋅ [H ( x − x1 ) − H ( x − x 2 )] + 2 4 ρ b hb b ∂x 2 ρ b ∂x ρ b hb bl ∂t In equation of the beam’s motion the Heaviside’s function H(x) was introduced to curb the working space of the transducer to partition from x 1 to x 2 . The transducer’s interaction including pure shear of the connection layer can be marked as:

τ=

G ⋅lp hk

(ε

−εp)

The upper beam’s surface and the piezoelectric transducer’s strains can be described by the following equations:

εb = −

hb ∂ 2 y hb ⋅ 2 = ⋅ Ak 2 sin (kx ) cos(ωt ) , 2 ∂x 2

εp =

d 31 ⋅U hp

where U denotes externally applied voltage and d 31 is the transducer’s piezoelectric constant. The dynamic equation of the transducer’s motion with external circuit was expressed as an equation of linear RC circuit with harmonious voltage source, where Q(t) denotes the electric charge on the surface of the transducer and C p is a total transducer electric capacitance, R z and C z are externally applied resistance and capacitance [1]:

RZ CZ

dU C (t ) Q(t ) + U C (t ) = . dt Cp

The dynamic flexibility of the considered system was assigned on the basis of the approximate Galerkin’s method. The solution of the beam’s differential motion’s equation was defined as a product of time and displacement’s eigenfunctions which meet the defined boundary conditions: 43

∞

k = (2n − 1)

y ( x, t ) = A∑ sin[k ⋅ x ]⋅ cos(ωt ) , n =1

y (l ,0 ) = A

y (0, t ) = 0 ,

π 2l

n = 1,2,3...

4. The assumption about the eccentric tension of the glue layer In the further authors’ work the discrete – continuous mathematical model of the considered mechatronic system was improved. There was no the assumption about the pure shear of the connection layer but the glue layer’s deformation - the assumption about the eccentric tension of the glue layer was taken into account. The considered mechatronic system was modelled as the combined beam made up of the beam with the glue layer and the piezoelectric transducer. The beam’s influence on the glue layer and the piezoelectric transducer was replaced by the couple of forces F b . The piezoelectric transducer’s influence was described as a force F p . Fig. 3 shows this force system.

Fig. 3. The eccentric tension of the glue layer The substitute cross-section of considered mechatronic system was introduced to unify material parameters. The glue layer’s cross-section area was reduced – width of the glue layer was reduced to the value of the converse of the parameter n equals the quotient of the beam and glue’s Young’s modulus. There was still the assumption about the uniaxial, homogeneous strain of the transducer.

Fig. 4. The substitute cross-section of the beam with the glue layer The area and moment of inertia of the substitute cross-section was introduced as follows:

AC = b ⋅ hb + b ⋅ 44

1 ⋅ hk , n

h  1 h  b ⋅ hb ⋅  hk + b  + hk ⋅ b ⋅ ⋅ k 2 n 2  , yC = AC

b⋅ IC =

1 3 2 2 ⋅ hk 3 hk  b ⋅ hb hb 1    n + b ⋅ ⋅ hk ⋅  y C −  + + b ⋅ hb ⋅  hk + − yC  12 n 2  12 2   

Using well known equations the stress on the substitute cross-section’s upper surface was assigned and in agreement with the Hooke’s law the strain of this surface was assigned. This strain is equal to the piezoelectric transducer real strain described as follows: hb ∂ 2 y R ⋅ 2 ⋅ d 2 ∂x S − 31 U . εp = E p Ap ⋅ P ⋅ R E p Ap ⋅ T h p 1− + S ⋅ Eb Eb −

where symbols P, R, S and T are parameters depending on the beam and glue layer’s geometrical parameters. 5. Conclusions In both mathematical models of the considered mechatronic system the dynamic equations of the beam and the piezoelectric transducer’s motion ware assigned on the same way but the second model is more precise because, as it was proved, the true piezoelectric transducer’s strain depends on the glue and beam’s material and geometrical parameters. So it is indispensable to take into account geometrical and material parameters of all system’s components because the omission of the influence of one of them results in inaccuracy in the analysis of the system. Acknowledgements This work was supported by Polish Ministry of Science and Higher Education as a part of the research project No. N501 118036 (2009-2010). References: 1. Buchacz A., Płaczek M.: Damping of Mechanical Vibrations Using Piezoelements, Including Influence of Connection Layer’s Properties on the Dynamic Characteristic, Solid State Phenomena Vols. 147-149 (2009), Trans Tech Publications, Switzerland, p. 869-875. 2. Pietrzakowski M.: Influence of glue layers on vibration damping of composite plates, Proceedings of XVIIIth Symposium Vibrations in Physical Systems, Poznań-Błażejewko, 1998, s. 225-226. 3. Przybyłowicz, P.M.: Torsional Vibration Control by Active Piezoelectric System, Journal of Theoretical and Applied Mechanics, 33(4), 1995, s. 809-823. 4. Tylikowski, A.: Stabilization of Beam Parametric Vibrations, Journal of the Theoretical and Applied Mechanics, 31(3), 1993, s. 657-670.

REPLACEMENT OF PROCESSING METHODS FOR ADVANCED OPERATIONS Bunga G., Pikurs G. (RTU, Riga, Latvia) Research results, which show that grinding process of sealing surfaces of compatible joints at finishing stage should be replaced with turning and milling with cubic boron nitride tools. There was necessity to research governed laws and make analysis, whose can provide high precision and surface quality and thereby durability of involved parts. Very important surface characteristic, which determine workability of compatible joint is portance of roughness, and it is very relevant during exploitation of compatible details. Workability of various machines and equipment depends from surface resistance to wearing, surface resistance to adhesion, wearing intensity reduction and increasing of joint sealing. Grinded surfaces with penetrated grinding stone parts intensively wear sealing and make dehermetisation. Wherewith is necessary to replace grinding process with more productively turning and milling together. Introduction Science and technology development requires for new, most advanced equipment and machinery, which are able to work in heavy operation conditions, and high precision, surface quality, reliability and economy are the parameters which characterize these machinery. Thereby there are necessary preliminary studies and analysis of conformity to physical laws, which will provide high precision and surface quality and as follows durability of associated details. For reaching advanced exploitation of moving joined details there is necessity to study contact processes of surfaces. Nowadays theory of contact processes is based on thesis, that surface contact of moving details is discrete and it depends from macro roughness, waveness , micro roughness and seismic roughness deformations. One of most important surface characterizing values, which determine workability of coupling is portance of roughness, and it is very important during designing, technological drafting and exploitation stages [1]. Actual surface contact value is one of surface geometrical characterizing values, which allows solving above mentioned tasks, especially problems, which are involving with prime cost of joined details and exploitation qualities. Research character and subjects are chosen like this, because nowadays such type of tasks is very urgent, and these requirements are requested for coupled details of various unitsâ&#x20AC;&#x2122; exploitation. The work capacity of equipment depends from surface resistance to wear, resistance to adhesion, wear intensity reducing and joint connection compression reinforcement. Joint connection during exploitation becomes loose, and as is find in researches the loosening becomes because during last grinding operations there in surface is pressed shiver parts of grinding stones. The shiver parts of grinding stone which are pressed in surface actively acts on packing material, thereby wear it and to develop depressurizing and emergency situations. Most important surface geometry characterizing criteria is value, which characterize surface load carrying capacity. Criteria is characterized by sum of surface profile sections lengths, which is obtained by plane laminating of surface profile in investigated approximation, which is related to base length. The surface micro roughness resistance ability to load capacity characterizes portance of roughness, and it express material distribution in profile depth for detail surface roughness layer. This is also functionally relevant with several exploitation qualities and embodies surface roughness forms and profile height characteristics. 46

Analysis Major method for slip packing and harden coupled rolling surfaces is grinding [2]. As shows experimental investigations, during grinding, shiver parts of grinding stone presses in to detail surface. Wherewith, these abrasive parts start to act to packing and packing material. By the specific efficacy partial packing depressurizes and additional technological environment leaks as well as emergency situations take part. The research assignment and target was to find technological opportunities for replacing grinding operation with precise equal value machining operation [3]. Accordingly to rapid inspection results, additionally research was done for turning and milling possibilities to replace grinding operations. In this case machined surface is free of abrasive parts. Wherewith packing and material of packing are not under additional wear conditions. There was necessity to perform turning and milling of preparation, which was previously under heat treatment, during research. In order to assure it, there was examined possibility to carry out turning and milling of these preparations by cubic boron nitride (CBN HV=7800, t=1400°C) cutters and mill cutters. In this case was necessity to provide same surface characterizing parameters, which was obtained before by grinding. Turned, milled and grinded surfaces were compared by using various processed surface characterizing parameters: Ra, Rq, Rt, Rz, Rc and RSm, as well as to weight up portance of roughness and frequencies of districts of roughness accordingly to International ISO 4287, Japanese JIS B0601 and American ASME B.46.1 standards. All machined surfaces were profilographed and established their characterizing parameters, including portance of roughness and frequencies districts of roughness. Research of machined surface geometry was performed by multilateral and compact surface roughness device Rugosurf 10 from Swiss company Tesa technology. Characterizing values of processed surfaces are interpreted in figure. Condition of surface substantially is characterized by train of parameters. Ra, μm (1) average roughness, arithmetic mean deviation of the profile is the area between the roughness profile and its mean line or the integral of the absolute value of the roughness profile height over the evaluation length. Rq, μm (2) root mean square roughness deviation of the assessed profile or root mean square value of the ordinate values Z(x) within a sampling length: l

1 2 Rq = Z ( x )dx , l ∫0

(1)

where l – sampling length; Z – ordinate values. Rt, μm – maximum, total height of the profile, it is vertical distance between the highest and lowest points of the profile within the evaluation length. Rz, μm – average maximum height of the profile points on ten point height of irregularities. Rc, μm – mean height of profile irregularities or is the distance between the average of all peak heights from the mean line and the average of all valley depths from the mean line: Rc =

1 m ∑ Zt i , m i =1

where m – number of profile peaks; Zt i – height of the i-th profile element. 47

(2)

RSm, Îźm mean spacing between profile irregularities or mean width of the profile elements is equal to the mean wavelength of the peak valley cycles. Besides all before mentioned parameters there is portance of roughness and frequencies districts of roughness also. Surface condition characteristics, which are shown in figure, indicates that grinding surface condition might be equally substituted. Larger value of mean spacing of profile irregularities even make better oil involving of profile.

Fig. 1. Portance R charts and parameter values of turned, milled and grinded surfaces in consecutive order Conclusion Research shows that portance of roughness is associated with surface geometry and its exploitation quality. Researches indicate that portance of roughness should be indicated and provided mandatory, during designing and technological drafting, because it is important and indispensable geometrical parameter. Surface is characterized not only by micro topographical surface roughness parameters: arithmetic mean deviation of the profile, ten point height of irregularities, total height of profile and mean spacing of profile irregularities, but also root mean square deviation of profile â&#x20AC;&#x201C; Rq, mean peak to valley height of profile â&#x20AC;&#x201C; Rc and frequencies districts of roughness. Grinding stone smithereens, which are penetrated in to details surface, activate wearing and dehermetisation during exploitation. Wherewith is necessary at finishing stage to perform turning or milling with cubic boron nitride tools for tempered surfaces. Processing methods, which are mentioned above with three included figures provide equivalent surface geometry and characteristics as well as portance of roughness and frequencies districts of 48

roughness. Thereby turning and milling equivalently substitute grinding, which almost have one and half times lower productivity. References: 1. Fritz A.H., Schulze G. Fertigungstechnik. – Berlin, Heidelberg, New York: Springer – Verlag, 2004. – S.479. 2. König W., Klocke F. Fertigungsverfahren. – Berlin, Heidelberg, New York: Springer – Verlag, 1999. – S.471. 3. Bunga G., Geriņš Ē. Apstrādes ar atdalīšanu tehnoloģijas. – Rīga: RTU, 2007. – 85 lpp. CUTTER ROTATIONAL SPEED OPTIMIZATION IN HIGH PERFORMANCE CUTTING OF ALUMINUM ALLOYS Burek J., Ostrowski R., Szular A. (PRz, Rzeszow, Poland) In the paper, results of research on high performance cutting (HPC) process are presented, concerning in particular optimization of parameters for high speed cutting (HSC) of aluminum alloys used in the aerospace industry. Introduction The purpose of HPC process design consists in selection of optimum process parameters ensuring maximum possible material removal rate. Research on HPC revealed that an important issue consists in proper selection of spindle rotational speed [1]. In fact, the quantity determines to a considerable degree the dynamic characteristic of the MachineFixture-Tool-Workpiece (MFTW) system. Therefore, it is very important in high performance cutting that the so-called “stability lobe” effect is utilized and, by appropriate selection of the material penetration frequency, the stable process is realized also above the limiting cutting depth [2]. To this end one has to find such spindle rotational speed values at which variations of machined layer thickness and related variations of cutting forces can be minimized. Alternating load on a cutter results in vibrations and deflections of the tool. Fig. 1 shows a simplified analysis of that process for cutting with full cutter diameter at which there is a deflection of the cutter edge in feed direction. The motion results in larger (+u) and smaller (–u) thickness of machined layer that in turn generates variable cutting forces. If in the end-milling process, the frequency corresponding to tooth entrance into the material f E differs from the chatter frequency (cutter’s self-vibrations) f A or its submultiples, a phase shift occurs between consecutive penetrations of material by a cutter tooth. The result consists in strongly oscillating cutting forces and self-excited vibrations that make the process unstable [3]. If the frequency at which a tooth enters the material corresponds to the cutter selfvibration frequency or its submultiples, then the tool displacement crosses its zero value always at the same contact angle and there is no phase shift between consecutive material penetrations. Cutter deflection and the resulting thickness of machined material layer are the same at each penetration. There are no significant variations of cutting forces in that case. One has to bear in mind that the chatter frequencies can be situated in the vicinity of the machine’s proper vibration frequencies that can excite the MFTW system. If this is the case, it is necessary to select rotational speeds located in the vicinity of identified chatter minimums in order to prevent resonance vibrations. In order to design a HPC end-milling process in supercritical range of the stability lobe plot, it is necessary to analyze the vibration characteristic of the system composed of machine tool, spindle, tool fixture, and the tool itself. Purpose of such analysis consists in identification of appropriate spindle rotational speeds at which f E = f A /k. That is the primary task of the any process design procedure. 49

Tooth 1 vf +u

Chatter frequency fA Cutter path after

n fE = n ∙ z/60 -u TA=1/fA

Cutter path without deflektion

Deflektion u

-u

Tooth 2

Unstable process-chattering Stable process fE = fA fE ≠ fA

Stable process fE =2∙fA

Fig. 1. Origin of the chatter phenomenon in milling Selection of process parameters by means of the specific spindle power The above-described studies on the specific spindle power e s revealed suitability of that quantity for characterization of high performance end milling. The next question arising therefore is whether it is possible to determine parameters of HPC of such type by means of analysis of that quantity. Numerous studies on the stability lobe effect allow to draw a conclusion that the dynamic characteristics of a milling process can be described in terms of the spindle power and appropriate spindle rotational speeds as well as tooth-material contact frequencies can be identified that way. When spindle rotational speed varies, tool vibration frequencies occurring in the course of end milling show very good correlation with values calculated from the stability lobe plot. In case of the depth of cut a p being set to a value exceeding the limiting depth of cut a p,crit characteristic for the process, then vibration amplitudes observed in instability intervals are much larger than those occurring in stable regions (Fig. 2). End milling n

Vibration amplitude ap > ap crit Theoretical stability limit

vf ae ap

Cutting depth ap

Vibration amplitude

Unstable process - chattering

Vibration amplitude ap < ap crit Spindle rotational speed n

Fig. 2. Vibration amplitude versus spindle rotational speed 50

Also at cutting depths less than the limiting value, unstable intervals of the stability lobe plot manifest themselves through slightly increased vibration amplitudes. The effect can be used for identification of appropriate spindle rotational speeds.When working within an unstable range of the stability plot, surfaces with large undulation generated by vibrations may occur. Moreover, such process conditions result in significant increase of dynamic cutting forces related to large variations in thickness of the machined layer. Consequently, the spindle torque increases and causes in turn an increase of the consumed power. Machining at constant depth of cut in a stable range makes it possible to obtain high quality surfaces at much less cutting forces than those occurring in instability regions. Increase of the spindle power can be therefore caused by two overlapping phenomena. Firstly, slight deflection of the tool towards direction of feed results in increased friction at the tool-material contact surface related to vibrations occurring in the course of machining with amplitudes ranging from 10 to 50 μm. That causes increase of cutting forces and additional demand for power. Secondly, because of undulated structure of workpiece surface, thickness of the machined layer varies and results in occurrence of strongly varying and increased cutting forces. These phenomena cause increase of spindle driving torque that in turn induces increase of consumed power. Analysis of specific spindle power e s makes possible to assess effectiveness of a cutting process. Calculations are based on the portion of consumed power used by the process (P – P L ) divided by current material removal rate Q w . The share of consumed power used by the process can be divided into the cutting power P c and a fraction ∆P R necessary to overcome dynamical oscillations of cutting forces resulting from deflection of the tool:

es =

P − PL PC + ∆PR = = ec + ∆eR Qw Qw

(1)

The specific spindle power e s is thus composed of the specific cutting power e c and another quantity characteristic for end milling, i.e. the specific energy loss ∆e R .Tracing the specific spindle power e s allows to draw some conclusions important for assessment of functional characteristics and stability of a HPC process. As variability of cutting speed within the considered range (v c > 1000 m/min) produces virtually no changes in specific cutting energy for different spindle rotational speeds, changes in specific spindle power e s must be explained by variations of the specific energy loss ∆e R . At low values of the specific spindle power e s one may therefore expect a very good operational characteristics of an end mill with small power loss, while higher values of e s represent evidence of unfavorable course of the process with high account of dynamical cutting forces. The procedure to be followed when designing a HPC process based on the specific spindle power analysis is presented in Fig. 3. The method can be used for identification of optimum spindle rotational speed as well as for determination of maximum possible endmilling material removal rate. The first step consists in determination of spindle rotational speed stability intervals. To identify them, tests are carried out with varying spindle rotational speed n at constant feed per tooth f z and the depth of cut a p as close as possible to its limiting value a pcrit . The spindle power P is recorded in the course of machining by means of the controller’s “Servo-Trace” function. Then, specific spindle power e s is calculated from the measured data. Appropriate spindle rotational speeds can be precisely identified at locations where the specific spindle power function has its minimums. Then, using spindle rotational speed 51

n determined that way, the stability limits are calculated in order to identify the maximum material removal rate.

Target: maximum material removal rate / max ap

Cutting depth ap

Unstable process ap max

ap max = f(n) Stable process Test number Spindle rotational speed n

ap critical

b) Determination of maximum material removal rate ap1 Specific spindle power es

Specific spindle power es

a) Determination of rotational speed n Specific energy loss ∆eR ∆eR min

∆eR ec

ap2

fz max

ap2 > ap1

instability

Feed per tooth fz

Fig. 3. Cutting process analysis through specific spindle power control Technological studies Fig. 4 presents results of practical application of the above-described method to determination of appropriate spindle rotational speeds by means of the specific spindle power. To limit the number of tedious tests, this is accomplished in two steps. First, after determination of the spindle power characteristics, a range of rotational velocities to be examined is determined. Within that range, spindle rotational velocity is changed with relatively large number of steps n = 1000 min–1. Tests for cutting with full cutter diameter were carried out at constant feed per tooth f z within the limiting cutting depth a p , crit . 1) Range narrowing

2) Range identification

Specific power consumption es

kW × min dm3

[

es min

5 0 8

1/min

10,5

15 0 12,5 1/min

]

Specific power consumption es

[kWdm× min]

Spindle rotational speed n × 1000

Fig. 4. Determination of appropriate spindle rotational speed by means of spindle power analysis; process parameters: f z = 0,14, a p = 5 mm, a e = 20 mm., n = var. 1/min, cutting compound: emulsion, tool parameters : z = 3, D = 30 mm, r ε = 4 mm Appropriate spindle rotational speed range can be identified in a region where the 52

specific spindle power has its minimum. In the next step, the spindle rotational speed is controlled in smaller steps in order to identify the specific spindle power minimum e s,min . That is the point determining the spindle optimum rotational speed selected by means of the minimum specific spindle power method.. To complete selection of process parameters, the maximum material removal rate is determined in the third step. The method used to achieve that is presented in Fig. 5.

[kWdm× min] Power consumption P

20 16

ap= 6mm

ap=8 mm

Qw max

Process instability

0,14

0,16

0,18

0,20

[mm]

0,24

Feed per tooth fz

Fig. 5. Determination of the maximum material removal rate; process parameters: f z = var, a p = var, a e = 30 mm., n = n opt 1/min, cutting compound: emulsion, tool parameters : z = 3, D = 30 mm, r ε = 4 mm Starting from a constant setpoint limiting depth of a p , crit , the feed per tooth value is increased up to a predetermined limit. That limit must be defined for a given tool in such a way that its breakage at too high feed rates will be avoided. Because of reduction of specific cutting force with increasing thickness of machined layer at higher feed per tooth, the specific spindle power decreases. After reaching the predefined limiting feed rate, the depth of cut is being increased and the feed per tooth is increased accordingly. Such procedure is continued up to a point at which increase of feed per tooth will result in increase of specific spindle power. That means that the process stability limit was reached. Summary Large cross sections of machined material layer result in high cutting forces and large volumes of chips to be removed. Because of high loads, the process becomes unstable and the result consists in increased spindle power consumption. The point of lowest specific spindle power determines optimized setpoint parameters ensuring reliable end milling at maximum possible material removal rate. Transfer of process parameters calculated that way onto other machining tasks, such as cutting with a portion of tool diameter, proved that observing that stability limit can guarantee reliability of HPC processes. Acknowledge: Financial support of Structural Funds in the Operational Programme Innovative Economy (IE OP) financed from the European Regional Development Fund Project No POIG.0101.02-00-015/08 is gratefully acknowledged. References : 1. Andrae P.: High-Efficiency Machining, Manufacturing Engineering 125 (2000) 4, s. 82-96. 2. Groppe M.: Optimierung der Hochleistungszerspanung von Aluminium – Struktur-bauteilen, Begleitband zum Seminar “Neue Fertigungstechnologien für die Luft- und Raumfahrt”, Hannover 2003. 3. Tönshoff H.K.: High-Speed or HighPerformance Cutting - a Comparison of New Machining Technologies, Production Engineering Vlll/1 (2001), s. 5-8. 53

HIGH PERFORMANCE CUTTING OF ALUMINUM ALLOYS Burek J., Ostrowski R., Szular A. (PRz, Rzeszow, Poland) In the paper, a study is presented concerning specific spindle power in high performance cutting (HPC) operations using high speed cutting (HSC) of aluminum alloys used for construction components in the aerospace industry. Introduction The high performance machining is specially desirable in production of aerospace parts out of solid material. Despite continuous increase of number of passenger planes manufactured, the process must be still considered a piece production. For that reason machining of aluminum parts, usually very complex in shape, is carried out in very short series (3–30 pieces). That generates a need for elaboration of appropriate production method that would be effective and flexible at the same time. Taking into account the costeffectiveness of such production, even in case of possible increase of demand, it is necessary to exclude production operations that are difficult to automate, such as e.g. riveting of components. Thanks to homogenous design of a part, usually machined out from a cuboidal aluminum blank, it is possible to manufacture it in a more flexible and automated way by means of milling. As the amount of removed material reaches is as high as 90% of the blank in case of some parts, the cutting process must be configured with use of extreme machining parameters ensuring high material removal rates [1]. In case of conventional milling, especially when end milling is considered, such process is highly energy- and timeconsuming. Only with use of up-to-date machine tools and high material removal rates, i.e. when the HPC machining is employed, it is possible to achieve economically feasible production of parts of homogenous solid design. Advantage of HPC with respect to conventional cutting process consists in significantly enlarged feed rates making possible multiplication of material removal rates and reduction of machining times. Thanks to HPC it is possible to reduce production costs of some parts by more than 50%, with additional advantage of reducing their weight by as much as 25% [2]. Implementation of HPC machining to production practice still involves very high research costs. To design and implement an economically feasible process, it is necessary to match up all elements of the Machine-Fixture-Tool-Workpiece (MFTW) system. In order to implement a high performance cutting process effectively, it is necessary to select properly the tools to be used and appropriate machining parameters [3]. Conditions of the study In the framework of the study, AlZn6MgCu aluminum alloy was machined widely used in the aerospace industry (R m = 450–520 N/mm2, 150 HB). The research work was carried out on 5-axis machining center DMU 80P duoBlock of DMG brand (Fig. 1). Power measurements were performed by means of Siemens 840 D controller equipped with the so-called “Servo-Trace” function. The feature allows to trace drive signals and different operational states of the machine.

Technical data: Travel: X – 800 mm Y – 800 mm Z – 800 mm B/C Speed: vx,y,z = 60 m/min Acceleration: ax,y,z = 7 m/s2 Spindle: P = 28 kW, M = 121 Nm, n = 18000 1/min Fixture: HSKA63 CNC Control: Sinumerik 840D Powerline Blum Laser and Renishaw MP700 touchprobe

Fig. 1. The 5 axis machining center Technological research The purpose of HPC consists in maximization of the material removal rate Q w . Therefore the target is to utilize as much of the main spindle power as possible and transform it to the cutting power. That is the main purpose of any HPC process design. For that reason a new parameter is being introduced — the specific spindle power e s , by means of which it is possible to calculate the effect of setpoints on the high performance end-cutting process. The specific spindle power e s is defined as the ratio of power consumed by main spindle drive to the material removal rate Q w . The power used for the end-cutting process can be calculated in general as a difference between the total consumed power P and the loadindependent idle power P L , thus

es =

P − PL Qw

(1)

The quantity e s is a measure of the cutting process efficiency, allowing at the same time to recognize what material removal rate Q w can be achieved at given spindle power P. In the framework of technological trials, effect of process parameters essential for HPC-type end-milling was determined. An important operational parameter of any cutter is the spindle rotational speed n. It determines the cutting speed and has a prevailing effect on dynamics of the whole MFTW system. Other important quantities are here also: feed per tooth f z , depth of cut a p , and width of cut a e , These parameters affect the material removal rate Q w and thus determine productivity of the process.

Qw = v f ⋅ ae ⋅ a p

(2)

All tests were carried out in the stable range of the, below the limiting cutting depth. As an assessment criterion, measured power consumed by spindle in the course of machining was used, as well as the specific spindle power e s calculated on that basis. For purpose of consecutive measurements, two grooves 400 mm long were milled each time with full cutter 55

diameter and the corresponding two maximum consumed power values were averaged. In the course of studies concerning the machining rate, the spindle rotational speed was changed in its upper range of n = 14000–18000 rpm. At varying spindle rotational speed, feed per tooth f z and depth of cut a p were kept constant. As a result, both feed rate and material removal rate increased with higher rotational speeds. Fig. 2 shows measured spindle power P and calculated specific spindle power e s as functions of spindle rotational speed n. Additionally, idle power P L consumed by spindle is plotted. As a result of higher spindle rotation speeds and keeping the machined layer transverse cross-section constant, higher material removal rates are achieved, resulting in turn in increased cutting power. The effect consists in increase of consumed power with increasing material removal rate. In case of machining of the material used, reduction of cutting forces, and thus also power consumption resulting from increase of cutting speed, occurs only up to v c = 1000 m/min, that is outside the examined range. Oscillations of power consumption in the examined rotational speed range can be explained by means of end mill dynamic characteristics that varies with the rotational speed. That results in varying depth of machined layer, affecting in turn the spindle power consumption. Calculation of specific spindle power e s consumed by spindle allows to select the most favorable rotational speed ranges.

[kWdmx min ] 3

Specific power consumption eε

14 12

Power consumption P 22

2 0

[1/min]

Specific power consumption eε

Power consumption P

[kW]

FFp p

aaee ap

FFf f Ff N

FfN

vVff

Spindle rogate n/1000

Fig. 2. Power consumption versus spindle rotational speed; process parameters: f z = 0,14 mm, a p = 6 mm, a e = 30 mm, n = var., cutting compound: emulsion, tool parameters : z = 3, D = 30 mm, r ε = 4 mm Cutting width a e at end milling is determined by cutter contact angle φ. In practice, when a workpiece is machined, not always the full cutter diameter a e = D is employed, but sometimes only a part of it. For that reason, effect of the cutting width on spindle power P and the resulting specific spindle power e s . was also examined. The experiment was carried out with cutting width increasing from half to full cutter diameter (a e = 15–30 mm). On the grounds of test results (Fig. 3) it can be concluded that the spindle power P increases almost linearly with increasing cutting width a e . The increase is however less than increase of the material removal rate at larger cutting width. That results in reduction of specific spindle power e s . Cutting with full cutter diameter (a e = D) is therefore a more energetically favorable case and should be considered the target. The reason for that consists in the fact that increase of cutting width results in relatively small increase of cutting force as the machined layer cross section remains constant in the whole cutting process. Moreover, at a e > D (0) the share of idle running power in the whole consumed power becomes more 56

important and load-dependent, while it is not related to any major changes when the width of cut varies. On the other hand, the material removal rate increases in proportion to cutting width. When designing a HPC roughing process, one should therefore select the largest possible cutting width a e , with account for the spindle power remaining at the disposal. To examine the effect of feed rate v f , values of feed per tooth f z were incremented in a stable range of f z = 0.14–0.25 mm. Spindle rotational speed n and depth of cut were constant. 28

[ kWdmx min]

Power consumption P

[kW]

Power consuptions P 22

Specific power consumption eε

[mm]

The width of cutting ae

Fig. 3. Spindle power consumption versus width of cut; process parameters: f z = 0,18 mm, a p = 10 mm, a e = var., n = 18000 1/min, cutting compound: emulsion, tool parameters: z = 3, D = 30 mm, r ε = 4 mm Fig. 4 presents plots of measured spindle power P and calculated specific spindle power e s . Increased thickness of machined layer related to increased feed per tooth results in increased cutting forces that in turn causes an increase of power consumed by spindle. On the other hand, specific spindle power decreased with increasing feed rate. The cause here consists in smaller specific cutting forces related to larger thickness of machined layer. It follows from the above that in case of HPC machining one should try to achieve as large feed per tooth as possible in order to use effectively the spindle power remaining at disposal. However, the resulting increase of cutting forces should be kept in mind.

[ kWdmx min] 3

Power consumption P

[kW]

Specific power consumption eε

22 0 0

0,14

0,16

0,18

0,20

0,22

[mm]

Specific power consuption eε

Power consumption P

Feed per tooth fz

Fig. 4. Spindle power consumption versus rate per tooth; process parameters: f z = var, a p = 10 mm, a e = 30 mm., n = 18000 1/min, cutting compound: emulsion, tool parameters : z = 3, D = 30 mm, r ε = 4 mm 57

Fig. 5 shows results of research concerning effect of the depth of cut a p on the consumed power. In that case, examined depth of cut a p increases in the stable range, while other setpoints are kept on a constant level. Consumed power increases almost linearly with increasing depth of cut. That effect is related to proportional increase of cutting forces at increasing width of cut a e corresponding to increasing width of cut a p . At constant machining speed, that results in proportional increase of consumed power. On account of increase of the material removal rate with increasing cutting depths one should expect that the specific spindle power will remain unchanged, however the quantity decreases at larger depths of cut. 14

[kW]

Specific power consumption eε

Power consumption P

0 0

[mm]

0 12

[ kWdmx min] 3

Specific power consumption eε

Power consumption P

Cutting depth ap

Fig. 5. Power consumed versus depth of cut; process parameters: f z = 0,14 mm, a p = var, n = 18 000 1/min, cutting compound: emulsion, tool parameters : z = 3, D = 30 mm, r ε = 4 mm A possible reason consists in large cutter edge radius (r ε = 4 mm). At cutting depths up to a p < 4 mm, such geometry in combination with different deformation processes results in machining at less depths of cut being less effective than cutting with the cutter’s cylindrical surface (a p > 4 mm). For that reason, the specific spindle power decreases with increasing cutting depth in the range under consideration. Summary The results presented above allow to draw several conclusions concerning selection of parameters for a HPC process. First of all, selection of spindle rotational speed affects strongly the specific spindle power. As for setpoints decisive for the material removal rate it should be concluded that the most favorable values involve as large cutting width as possible and high feed rate per tooth. Increase of feed per tooth turns out to be more favorable compared to increase of cutting depth also from the energetic point of view. In case of tools with large edge radius it would be advisable to check additionally the power consumption for larger depths of cut. Acknowledge: Financial support of Structural Funds in the Operational Programme Innovative Economy (IE OP) financed from the European Regional Development Fund Project No POIG.0101.02-00-015/08 is gratefully acknowledged. References : 1. Andrae P.:High-Efficiency Machining, Manufacturing Engineering 125 (2000) 4, s. 82-96. 2. Groppe M.: Optimierung der Hochleistungszerspanung von Aluminium – Strukturbauteilen, Begleitband zum Seminar “Neue Fertigungstechnologien für die Luft- und Raumfahrt”, Hannover 2003. 3. Tönshoff H.K.: High-Speed or High-Performance Cutting - a Comparison of New Machining Technologies, Production Engineering Vlll/1 (2001), s. 5-8. 58

NEW ON SYNOPTICAL REALIGNMENT CARS FROM THE ECONOMIC - FINANCIAL Chirugu M., Timofte G., Paraschiv Dr., Rotaru M. (Tehnical University of Iassy, Iassy, Romania) A particular problem in the machine building industry is realignment motor vehicles. Of size they all depend on economic factors. The overall objective of this work is to study a new method of realignment of vehicles. The specific objectives of the project which aims to achieve the general objective are the following: 1) Tracking the flow of vehicle technology on the band to FINISHING WORKSHOP; 2) Developing a new synoptic of realignment. 1. Theme proposed by resolution In this paper I have proposed to analyze a problem related to how come the pieces necessary for realignments in finishing workshop. • We have defined a procedure under which to establish the route realignments necessary new parts. To initiate this project we have taken information from the field on the departments directly involved in this issue. If problems are found in a vehicle in the areas mentioned above to retouch is needed. Once the issue is resolved, move the vehicle in an area of stress plus electronic verification - suitcase (parameters of the vehicle is checked).[4] After the vehicle passes into the issue (strains, locksmiths, paint). If it finds one of these violations are rectified on the spot in the workshop. After this vehicle pass inspection in the area where MADC is the final approval before it is made available for the customer. The control consisting of the general appearance of the vehicle (engine compartment for controller has 2 minutes to check, for the outside of the vehicle are at 2 minutes and 1 minutes for the inside).[7] If the inspector finds a defect you check the schedule on the motor vehicle and go to the workshop for remedy the defect.[5] If not found any irregularity, the vehicle goes to the park where the sale is taken to prepare the documents necessary for delivery to the customer. Evaluation of defects occurring during production are evaluated according to Standard Car Assessment Alliance.[1] Aves - a reference developed by Renault and Nissan to measure the quality of the final manufacturing of posture “customer vision”. Aves aims to evaluate the quality of a vehicle at the time of delivery and detection of defects visible to the customer. For this precise method was developed based on 3 main axes: 1) Means; 2) Check-list; 3) Place of evaluation.[3] 2. Experimental research

TCM

(piste)

ASSEMBLY - Fiche nocompliance

FINISHING - fiche signals incident

MADC

SHED PIECES LOGISTICS

VEHICLE FLEET SHIPPING

-collecting -transport organization

Fig. 1. Departments directly involved in this issue First I went from a pre-flow technology in the analysis to the problem. LEGEND -

TCM - tombe chaine machine MADC - mise a disposition client

SUPPLY REQUIRED = ( Program auto x tehnical coefficient) - STOCKS DACIA First I started with the work taking information from the location where finishing Workshop held realignment vehicle itself.[6] Finishing workshop is part of the Department of General Assembly and where vehicles are checked and made available to the client (MADC). Once you do track the vehicle in which to verify the dynamic, noise, brakes, speed come in finishing workshop and if find problems after verifications, the car come in the area which will remedy the problem.[2] Therefore the workshop is divided into:

- UEL MECHANICAL - UEL PAITING - UEL ELECTRICAL

3. Results of research Realignment process Flow management realignment plant

Issue request for retouch

Ticket copy of the consumer

Warehouse

Workshop

Copy application retouch (information, check stock)

Bon copy of the consumer

Issue : Ticket consumer NOTE SPOILAGE

Area transit

Fig. 2. Realignment process 61

After realingment Workshop retouch return receipt consumption stream manager where supplements: quantity realingment; index evolutionary time. Warehouseman is responsible for transferring songs from workshop to retouch magazie. Entry in the shed is made under the note and reject voucher consumption. 4. Conclusions Following the study conducted on the theme proposed for solving we reached the following conclusions: 1) The pieces in the shed is made under the note and reject voucher consumption; 2) The warehouseman is responsible for transferring parts from the warehouse workshop finishes parts; 3) Waste recovery and transferred to the scrap warehouse will be the physical flows; 4) Recovery Workshop finishing parts of the warehouse of trash to carry out planned. Acknowledgements I wish to thank for its support in making this work to Doctoral training BRAIN – “Investment in Intelligence”, to the dean faculty of Machine Manufacturing and Industrial Management professor Gheorghe Nagîţ and last but not least the scientific coordinator professor Dragoş Paraschiv.

References : 1. Aragon, A.,-Financial Management, International Student Edition, SUA, 1990, pag.15-32. 2. Intra-net Dacia Group Renault, accessed : 05.05.2009-02.06.2009. 3. Laurentie, J.,-Logistique: Demarche et technique, Ed. Afnor, Paris, Franţa, 1994, pag.54-69. 4. Luca, G.,-Planificare resurselor necesare producţiei, Rev.”Tribuna Economică”, nr.35, 1995, pag.112-125. 5. Luca, G.,-Sisteme flexibile şi logistică industrială, Ed.Gh.Asachi, Iaşi, 2000, pag.63-98. 6. Reni, R.,-Sistemi esperti e sistemi di valutazione, Rev.”Sistemi e impresa” Italia, 1990, pag.123-135. 7. Verzea, I.; Luca G.,Managementul logisticii industriale şi comerciale, Ed.Performantica, Iaşi, 2006, pag.67-89.

APPLICATION OF THE EDDY CURRENT METHOD FOR MEASUREMENTS OF GEOMETRICAL DIMENSIONS IN TWO-LAYER STRUCTURES Dziczkowska M. (Silesian University of Technology, Gliwice, Poland) If an examined object is made of a conductive material and then covered with a thin foil that is also capable to conduct electric current and finally the entire structure is coated with a non-conductive protecting film then the eddy current method can be applied to simultaneous measurements of thickness demonstrated by the both layers. The presented study comprises calculation of possible errors when two parameters are determined at a time and is attempt to establish application limits for the eddy current method. To make the analysis simpler a contact coil was substituted with a model one with all its n turns encapsulated by a circle with the radius of r 0 positioned within the distance of h over surface of the examined structure. The examined component is made of nonferromagnetic metal with its conductance σ p . Surface of the structure is covered with a conductive film, with its thickness of d and conductance of σ i . The mutual location of the coil 62

with respect to the structure under test is shown in Figure 1. If the alternating current with the angular frequency of ω flows through the coil, the electromagnetic field generated by that coil shall induce eddy currents in the examined material. These eddy currents shall generate their own counteracting field aimed to reduce the field within the confines of the coil. Finally, the coil impedance shall be altered by ΔZ [1], Fig. 1. A contact coil positioned over a conductive two-layer structure

[2] and [3]. ∆Z = n 2ωπµ 0 r0 Q(α , β , ρ , s )

(1)

where: ∞

Q(α , β , ρ , s ) = jβ ∫ c(α , β , ρ , s ) ⋅ J 12 ( β y )e −αβy dy

(2)

The function c(α,β,ρ,s) is defined by the following formula:

c(α , β , ρ , s) =

( y 2 + js + y 2 + j )( y 2 + j − y) + ( y 2 + js − y 2 + j )( y 2 + j + y) ⋅ e −αβ ( y 2 + js − y 2 + j )( y − y 2 + j ) ⋅ e −αβ

y2 + j

− ( y 2 + js + y 2 + j )( y + y 2 + j )

However, use of generalized parameters seems to be more convenient:

Variations of impedance components can be calculated by means of the following equations: r = ∆R = R − R0 = n 2ωπµ 0 r0φ (α , β , ρ )

(7)

l = ∆L = L0 − L = n πµ 0 r0 χ (α , β , ρ )

(8)

where:

ϕ (α , β , ρ , s ) = Re Q(α , β , ρ , s ) χ (α , β , ρ , s ) = − Im Q(α , β , ρ , s )

(9) (10)

R 0 and L 0 stand for the resistance and inductance of the coil positioned in air, while R and L represent the resistance and inductance of the coil approached to the structure under tests. Application of the sensitivity model [3] makes it possible to find out coefficients that define how the distance h and the thickness d affect impedance components of the measuring coil.

∆r 2n 2 πβ 2 ∂ϕ ∆r 2n 2 πβ 2 ∂ϕ ∆rh = = = (11) ∆rd = ∆h ∆d r02σ i ∂α r02σ i ∂ρ ∂χ ∂χ ∆l ∆l (13) ∆ld = ∆lh = = 2n 2 πµ 0 = 2n 2 πµ 0 ∆h ∂α ∆d ∂ρ 63

(12) (14)

Assuming that conductance of materials that make up the both conductive layers is known (σ i = const and σ p = const), the eddy current method can be used to check both the thickness d of the conductive outer layer and the distance h. For the assumed mathematic model the distance h is meant as a distance of the model coil form the surface of the structure under test. However, if the scaling procedure described in [1] is applied to the coil, it proves possible to efficiently measure distance between the actual coil and the examined surface. When the structure is coated with non-conductive film of varnish or foil, the method enables trustworthy investigation of the film thickness. For the case when the both geometrical parameters: thickness of the conductive layer d and thickness of the non-conductive film h are unknown, only a single measurement is sufficient to determine the both impedance components of the coil and to calculate the both unknown dimensions. Errors for simultaneous determination of two parameters can be estimated after application of the superposition rules and equations (11), (12), (13) and (14). 2n 2 πβ 2 ∂ϕ 2n 2 πβ 2 ∂ϕ ⋅ ∆d ⋅ ∆h + ∆r = r02σ i ∂ρ r02σ i ∂α

(15)

∂χ ∂χ ⋅ ∆h + 2n 2 πµ 0 ⋅ ∆d ∂α ∂ρ

(16)

∆l = 2n 2 πµ 0

After resolving the system of equations (15) and (16) for the unknown variables Δh and Δd the following result can be obtained: ∆h =

r02σ i ∂ϕ ∂χ 1 ⋅ ∆ + ∆r l 2 2 2 2n πµ 0 M (α , β , ρ , s ) ∂ρ 2n πβ M (α , β , ρ , s ) ∂ρ

(17)

∆d =

r02σ i ∂ϕ ∂χ 1 l ⋅ ∆ + ∆r 2 2 2 2n πµ 0 M (α , β , ρ , s ) ∂α 2n πβ M (α , β , ρ , s ) ∂α

(18)

If the error for resistance measurements for the contact coil is Δr and the error for measurements of inductance is Δl, the errors for determination of the both geometrical parameters shall never exceed the values defined by formulas (17) and (18).

Fig. 2. Coefficients that define effect of the thickness parameters for the non-conductive film and the outer conductive layer onto variations of the coil resistance and inductance 64

Figure 2 presents coefficients that define how the thickness of the non-conductive film located between the coil and the conductive material affects variations of the coil resistance and inductance parameters depending on the β for several selected values of the s parameter provided for the assumption that σ i =15 MS/m. The same figure comprises also the impact coefficients for the thickness of the outermost conductive layer, i.e. explains how its thickness influences variations of the coil resistance and inductance. Variations of parameters for the measuring coil increase in pace with the frequency of eddy currents, i.e. higher frequencies of eddy currents result in larger variations of measuring coil caused by repositioning of he measuring coil against the conductive material. On the other hand, the effect of the thickness for the outermost conductive layer is the highest for a defined frequency bandwidth that depends also on the distance h, thickness d and conductance of the both layers. It is also important that there are specific frequencies of eddy currents for which the effect of the thickness d variations onto the coil resistance or inductance is nil. For such frequencies the errors defined by formulas (17) and (18) are extremely large. Figure 3 presents graphs for those errors calculated under the assumption that the error for measurements of the coil resistance is 0.1 mΩ and the error for measurements of the coil inductance is 1 μH.

Fig. 3. Errors for simultaneus determination of the both geometrical parameters References : 1. L.Dziczkowski, M.Dziczkowska, A useful mathematical model for analysis of non magnetic thin foil on the grounds of the eddy current method. Машиностроение и Техносфера XXI века. Сборник Трудов XIV Международной Конференции, Донецк-2007, T.5, стр.26-31. 2. L.Dziczkowski, An Attempt to Find Out Optimum Conditions for Conductance Measurements by Means of the Eddy-Current Method in Multi-Layered Structures, Машиностроение и Техносфера XXI века. Сборник Трудов XV Международной Научно-Технической Конференции, Донецк-2008, Т.4. стр. 100104. 3. L.Dziczkowski, Errors in Conductance Measurements of Two-Layer Structures, Автоматизация: Проблемы, Идеи, Решения. Материалы Международной НаучноТехнической Конференции, Севастополь-2008, стр. 138-141.

ERRORS IN CONDUCTANCE MEASUREMENTS OF MATERIALS THAT ARE USED FOR CONSTRUCTION OF THICK PLATES Dziczkowski L. (Silesian University of Technology, Gliwice, Poland) The paper deals with problems related to non-destructive tests of large conductive structures with use of eddy currents. Application of a mathematical model that explains effect of a conductive half-space onto alteration of impedance components attributable to a measurement contact coil made it possible to propose a general sensitivity-based model suitable to find out the optimum frequency of eddy currents. The plate presents a conductive structure that is -Z subject to examinations by means of a contact coil, r where the plate thickness is much large than the σ h 0 penetration depth of eddy currents. It is why, for the purpose of the mathematical model that explains effect +Z of parameters attributable to the examined structure onto the coil impedance, it can be substitutes with a half space [1], [2]. The real coil is substituted with a model one with all its n turns encapsulated by a circle with the radius of r 0 positioned within the distance of h over Fig. 1. The contact coil surface of the examined structure. Conductance of the approached to a conductive material of the examined structure is denoted as σ. structure Alteration of the coil impedance is defined by the following formula: 0

∆Z = jωπr0 µ 0 µ r n 2 β ⋅ Q(α , β )

where:

∞

Q(α , β ) = jβ ∫ 0

λ − λ2 + j λ + λ2 + j

⋅ J12 ( βy )e −αβy dy

(1) (2)

However, it is convenient to use the following generalized parameters: α=

(3)

2h r0

β = r0 ωµ 0σ i

(4)

Alteration of the coil impedance components can be found by calculation of its real and imaginary parts of (1). r = ∆R = R − R0 = n 2ωπµ 0 r0φ (α , β ) l = ∆L = L0 − L = n 2πµ0 r0 χ (α , β )

where: ϕ (α , β ) = Re Q(α , β ) χ (α , β ) = − Im Q(α , β )

(5) (6) (7) (8)

R 0 and L 0 stand for the resistance and inductance of the coil positioned in air, while R and L represent the resistance and inductance of the coil approached to the structure under tests. The method of total differential shall be applied to equations (5) and (6). Alterations of 66

the coil resistance and inductance shall depend respectively on variations of the functions φ(α,β) and χ(α,β). ∆r = n 2π

β2 ⋅ ∆ϕ r0σ

(9)

∆l = n 2πµ0 r0 ⋅ ∆χ

(11)

∆χ (α , β ) =

(10)

where: ∆ϕ (α , β ) =

∂ϕ ∂ϕ ⋅ ∆α + ⋅ ∆β ∂α ∂β

∂χ ∂χ ⋅ ∆α + ⋅ ∆β ∂α ∂β

(12)

Variations of the generalized parameters depend on alterations to the conductance σ and the distance h: ∆α =

(13)

2 ⋅ ∆h r0

∆β =

β 2σ

∆σ

(14)

Figure 2 presents a diagram that is useful and convenient for calculations. Equations (9-14) are included in boxes. To calculate a differential at the output of a box it is necessary to multiply the input function by the box content. It is the easy way to calculate impact coefficients for all the measured parameters and determine how these coefficients affect alterations of the coil resistance and inductance.

∆h

∆σ

∆α 2 r0

β 2σ

∆β

∂ϕ ∂ϕ ⋅ ∆α + ⋅ ∆β ∂α ∂β

∂χ ∂χ ⋅ ∆α + ⋅ ∆β ∂α ∂β

∆ϕ

∆χ

n 2π

β2

∆r

r0σ

n 2 π µ0 r0

∆l

Fig. 2. The flow chart for calculations of the impact coefficients how variations of the coil distance from the examined structure and material conductance affect alterations of resistance and inductance hibit d b th i il The flow chart from Figure 2 makes it easy to calculate impact coefficients that define effect of variations in the distance between the coil and the examined surface as well as in conductance of the examined material onto alterations of resistance and inductance exhibited by the measuring coil.

∆r 2n 2πβ 2 ∂ϕ ∆rh = = r02σ ∂α ∆h ∆l ∂χ ∆lh = = 2n 2πµ0 ∆h ∂α

∆r n 2πβ 3 ∂ϕ ∆rσ = = ∆σ 2r0σ 2 ∂β

(15)

∆l n 2πµ0 r0 β ∂χ ∆lσ = = 2σ ∆σ ∂β

(17)

(16) (18)

Fig. 3. Impact coefficients that define effect of material conductance for the examined structure and the distance between the measuring coil and the examined surface onto resistance and inductance of the coil. Curves are plotted for the generalized parameter of β as the argument and for several values of the α parameter. Equations (15) and (18) can be considered as theoretical sensitivities of the eddy current method to measurements of the material conductance and to distance of the coil from the examined surface. Therefore they can be used for adjustment of the eddy current frequency and coil dimensions for the needs of a specific measuring instrument or a specific test. As dimensions of the examined structure are usually known and its expected (rated) conductance can be predicted, the optimum frequency of eddy currents can be calculated. Figure 3 exhibits graphs for impact coefficients as a function of the β parameter and for several values of α. Effect of the coil distance from the surface of examined structure onto impedance components variations of the coil is extremely large as compared to the similar effect onto the same coil parameter but exerted by conductance variations within the examined structure. It is the major reason that presents hindrances to conductance measurements and enforces the need to carry out thorough analysis prior to design eddy current conductometric gauges and selection of the measuring head (probe). It is also the reason that restricts accuracy of conductometric gauges. The mechanism that defines dependence on the distance between the coil and the measured structure is equivalent to the effect of surface roughness onto results of the conductance measurements. Increase of the β parameter and, consequently, increase of the eddy current frequency, brings on growth of the Δrh and Δlh factors. It is why selection of lower frequencies of eddy currents is more beneficial for conductance measurements. However, in case of a flaw detector, application of higher frequencies my be much beneficial. Figure 3 presents effect of conductance onto electric parameters of the coil with purposefully distinguished values of the generalized parameter β m (α) for which the function φ(α=const,β) reaches its extremum. The sensitivity value, defined as alteration of the coil resistance caused by variations of conductance for the frequency of f m that corresponds to β m , equals to zero. In such a case, alteration of the coil resistance depends only on the distance h. For frequencies lower than f m the considered sensitivity is positive, so conductance growth results in increase of the coil resistance. For frequencies higher than f m the sensitivity is negative, therefore even slight increases of conductance value leads to drops of the coil resistance. The higher frequencies are applied the stronger effect of conductance variations onto alterations of the coil resistance is visible. On 68

the other hand, conductance growth always results in decrease of the coil inductance. The higher sensitivity occurs for frequencies slightly lower than f m . It is important to add that growth of the frequency much above f m only insignificantly diminishes sensitivity of the measuring instrument. References: 1. L. Dziczkowski, A mathematic model to determine optimum conditions for measurements of material conductance by means of the eddy current method applicable to large structures, Машиностроение и Техносфера XXI века. Сборник Трудов XVI Международной Научно-Технической Конференции, Донецк-2009. 2. L. Dziczkowski, Examination of eddy current properties suitable for application in conductometric technology, Машиностроение и Техносфера XXI века. Сборник Трудов XVI Международной Научно-Технической Конференции, Донецк-2009. 3. L. Dziczkowski, Errors in the simultaneous determination of conductivity and foil thickness by the eddy curent method based on a single measurement, Автоматизация: Проблемы, Идеи, Решения. Материалы Международной Научно-Технической Конференции, Севастополь-2007, стр. 137-140. 4. M. Dziczkowska, A mathematic model to determine optimum conditions for measurements of conductivity exhibited by multi-layer structures with use of the eddy-current method. Машиностроение и Техносфера XXI века. Сборник Трудов XV Международной Научно-Технической Конференции, Донецк-2008. A MATHEMATIC MODEL TO DETERMINE OPTIMUM CONDITIONS FOR MEASUREMENTS OF MATERIAL CONDUCTANCE BY MEANS OF THE EDDY CURRENT METHOD APPLICABLE TO LARGE STRUCTURES Dziczkowski L. (Silesian University of Technology, Gliwice, Poland) The paper deals with problems related to non-destructive tests (NDT) that are carried out with use of eddy currents. The major objective is to present mathematic model that defines effect of a conductive half-space onto variations of impedance components attributable to the measuring coil. The completed calculations enabled to draw up guidelines to find out the optimum frequency of eddy currents. When the contact coil fed with alternating current is approached to the surface of a conductive material, the electromagnetic field around the coil induces eddy currents in the tested material. The currents generate their own electromagnetic field oriented, in accordance with Lenz’s law, opposite to the exciting field. Eventually, the field around the coil will be reduced, leading to changes in the coil -Z impedance. By measuring the coil r impedance components of the coil it is possible to calculate the parameters of the σ h tested conductive material. Analytic 0 calculations for the effect of eddy currents onto variations of the contact +Z coil impedance that take account for mechanical design properties if the coil are rather sophisticated. In general, the obtained formulas are hardly clear, Fig. 1. A contact coil placed over a thick difficult for analysis and consequently conductive plate offer limited applicability. It is why 0

application of some simplification makes things more convenient. Let us assume that the contact coil has n turns encapsulated by a circle with the radius of r 0 positioned within the distance of h in parallel to a smooth surface of the examined structure made of conductive material with conductance (specific conductivity) of σ and relative magnetic permeability μ r =1. Dimensions of the structure are sufficiently large that its edges present no obstacles to conductivity of eddy currents. For simplification let us also assume that the structure adopts the form of a half-space. Fig. 1 presents the arrangement of the coil positioned over a conductive half space. It is also convenient to use the following substitutions:

α=

2h r0

β = r0 ωµ 0σ

(1)

(2)

The generalized parameter α is the normalized distance of a model contact coil where the coil distance from surface of the examined structure is referred to the coil radius. The dimensionless parameter β depends on conductance of the examined material and the angular frequency ω (pulsation) of eddy currents. After approaching the measuring head (probe) to the distance of h to the non-magnetic surface of the plate made of a material with its conductance σ the complex impedance of the coil shall be altered by the following value: ∆Z = jωπr0 µ 0 µ r n 2 β ⋅ Q(α , β )

(3)

where: Q(α,β) is the normalized alteration of the coil impedance: ∞

Q(α , β ) = ∫ c(λ ) ⋅e

−αβλ

J (βλ )dλ 2 1

c (λ ) =

(4)

λ − λ2 + j

(5)

λ + λ2 + j

Alterations of the coil resistance and inductance can be calculated by determination of the real and imaginary part of the total impedance. r = R − R0 = n 2ωπµ 0 r0ϕ (α , β )

(6)

where:

ϕ (α , β ) = Re Q(α , β )

(7)

l = L0 − L = n 2πµ0 r0 χ (α , β )

(8)

where:

χ (α , β ) = − Im Q(α , β )

(9)

Calculations for alterations of the inductance assumes a rule that is convenient for non-ferromagnetic materials. As the coil inductance decreases and the resistance increases due to the influence of a conductive medium, it is convenient to define the alterations in such a way to maintain their positive values. R 0 and L 0 shall be considered as resistance and inductance of the coil when it is positioned within a distance from the examined surface, whereas R and L stand for resistance and inductance of the coil approached closely to the structure under investigation. Values of the functions φ(α,β) and χ(α,β) can be determined by means of numerical methods with any required accuracy. It has also turned out that values of these functions can be determined with sufficient accuracy by means of modern measuring instruments directly during execution of tests. To investigate those properties of eddy currents that are useful for non-destructive tests (NDT) it was necessary to carry out numerical calculations where results of them are exhibited in the form of diagrams in Fig. 2. Graphs for the functions φ(α,β) and χ(α,β) are plotted for various values of the parameter α and with the 70

parameter β as an independent variable. When tracing the course of the function φ(α,β) one can notice that the function reaches its maximum for a specific value of β. The generalized parameter β is the only variable that occurs in equations for alterations of the contact coil impedance caused by presence of a conductive medium and that depends on conductance of the material. Therefore, for the value of β for which the function φ(α,β) reaches its maximum, variations of conductance to no extent shall affect variation of the measuring coil resistance. Attention should be paid to the fact that the generalized parameter of β is directly proportional to the square root of the product made up by the conductance σ of the examined material and the eddy current ω frequency f = . Therefore the 2π Fig. 2. Diagrams of the functions φ(α,β) and χ(α,β) for sevaral values of the parameter α and with the task to find out the optimum frequency of eddy currents, the most parameter β as an independent variable suitable for specific application, is equivalent to calculation of the optimum value for the β parameter. It is why the symbol β m was used to denote this value of β argument, for which the function φ(α,β) achieves its maximum. This optimum value depends on the distance between the coil and the surface of the examined structure. This distance is proposed to be expressed by the generalized parameter α. The less α is, i.e. the closer the coil is positioned against the examined structure, the higher value is achieved by the β m (α) parameter. The value β m (α) is unambiguously associated with a specific characteristic frequency:

β m2 (α ) f m (α ) = 2πr02 µ 0σ

Fig. 3. 3D graphs for the functions φ(α,β) and χ(α,β) depending on variations of α and β parameters 71

(10)

that depends also on the coil radius and conductance of the investigated material. It should be noted here that for the argument β = β m (α) the function χ(α,β) is steeply inclined with respect to the X-axis, therefore the derivative of this function by the β variable is of a large value. It confirms strong effect of conductance onto alterations of inductance. One can cay that for the eddy current frequency that corresponds to β m , variations of

conductance are irrelevant to the coil resistance but they substantially alter its inductance. This maximum is rather ‘flat’ thus it may be pretty difficult to find it out under specific circumstances and determination of its value may be associated with a significant error. For the arguments β > β m the function χ(α,β) is really flat, hence variations of Fig. 4. 3D graphs for function r(α,β) that conductance shall result in only small describes variations of the measuring coil alterations of inductance. Therefore it resistance as well as the function l(α,β) for seems reasonable that for determination variations of the coil inductance l(α,β) with of conductance on the basis of regard to the course of α and β parameters inductance measurements the frequency of eddy currents should be selected very close or possibly slightly below f m . Conductance can be also determined by measurements of the variations exhibited by the coil resistance. Alterations of the functions φ(α,β) are clearly higher for frequencies below f m . Therefore this frequency range seems to be more interesting for investigations. Although, in order to guarantee monotonous properties of the scale it is indispensable to select frequency of eddy currents substantially lower or higher than f m , taking also account for diameters of all the applicable coils and the entire range of measured conductance values. Attention must be paid to the fact that values of the considered functions strongly depend on the distance between the coil and the examined surface, which is expressed by the generalized parameter α. Fig. 3 present 3D graph for the functions φ(α,β) and χ(α,β) depending on variations of the both their arguments, i.e. α and β. The effect of the distance expressed by the parameter of α onto the values of the analyzed functions increases in pace with the value of the β parameter and in the inverse proportion to the coil distance of from the examined surface, i.e. the higher values the β parameter adopts and the shorter distance is between the coil and the structure under test, the stronger the α parameter affects alterations of the function values. Graphs in Fig. 2 and 3 are plotted as a function of the generalized parameter of β that is associated by means of the relationship (2) with conductance σ of the material that makes up the examined structure as well as with frequency ω of eddy currents. Formulas (6) and (8) that define variations of resistance and inductance of the contact coil comprises the conductance parameter only in the confounding form, i.e. as a constituent of the β parameter. Therefore the nature of variations exhibited by the functions φ(α,β) and χ(α,β) in pace with increase of β reflects effect variations of the conductance but not the frequency. To make readers aware how the coil parameters defines by formulas (6) and (8) vary in the 3D space the graphs for the function r(α,β) that defines resistance variations of the measuring coil and for the function l(α,β) that corresponds to the inductance variations have been plotted in a 3D space with regard to the course of α and β parameters. These graphs are exhibited in Fig. 4. One has to pay attention that the coil resistance grows at increasing rates with the rise of the eddy current frequency as it is proportional to the product of the analyzed function φ(α,β) and the frequency ω. During measurements, the actual distance between the coil and surface of the examined structure is usually unknown so it is necessary to measure two parameters at a time and to calculate the conductance parameter with simultaneous compensation of influence demonstrated by the varying distance. The completed analysis makes it possible to make one important conclusion. When the contact coil resistance is measured with the purpose to determine distance of the coil from the examined surface and the desired conductance values is determined in the basis 72

of the inductance measurements it seems more convenient to apply such frequency of eddy currents that is equal to the frequency of f m . Although one has to bear in mind that much higher sensitivity of measurements can be achieved when higher frequencies of eddy currents are applied. In such a case it is reasonable to determine conductance on the basis of measurements obtained for the contact coil resistance and use results from measurements of inductance variations to compensate influence of the coil distance from the examined surface. The latter method offers much higher sensitivity but the compensation mechanism is much less accurate. References: 1. L. Dziczkowski, Effect of eddy current frequency on measuring properties of devices used in non- destructive measurements of non-ferromagnetic metal plates, Archives of Materials Science and Engineering, Volume 32, Issue2, August 2008, pp. 77-84. 2. L. Dziczkowski, Selection of the frequency of eddy currents in non-destructive testing of non-ferromagnetic plates, Journal of Achievements in Materials and Manufacturing Engineering.Volume27, Issue1, March 2008, pp. 43-46. 3. L. Dziczkowski, M. Dziczkowska, A useful mathematical model for analysis of non-magnetic thin foil on the grounds of the eddy current method. Машиностроение и Техносфера XXI века. Сборник Трудов XIV Международной Научно-Технической Конференции, Донецк-2007. T.5, стр. 26-31. 4. L. Dziczkowski, The analysis of determining the conductance and thickness of thin nonmagnetic foil by the eddy current method, Машиностроение и Техносфера XXI века. Сборник Трудов XIV Международной Научно-Технической Конференции, Донецк2007. T.5, стр. 22-26. 5. L. Dziczkowski, Errors in the simultaneous determination of conductivity and foil thickness by the eddy current method based on a single measurement, Автоматизация: Проблемы, Идеи, Решения. Материалы Международной НаучноТехнической Конференции, Севастополь-2007, стр. 137-140. EXAMINATION OF EDDY CURRENT PROPERTIES SUITABLE FOR APPLICATION IN CONDUCTOMETRIC TECHNOLOGY Dziczkowski L. (Silesian University of Technology, Gliwice, Poland) The study refers to issues related to application of eddy currents to examine properties exhibited by large conductive structures. Use of the mathematical model that determines effect of the conductive half space onto variations of the impedance components demonstrated by a measuring coil has made it possible to carry out extensive analyses to establish application limits for the proposed method when two parameters of the examined structure are analyzed at a time. The study takes advantage of the mathematic model disclosed in [1]. When a contact coil approaches to a thick, non-ferromagnetic but conductive plate, coil impedance is altered by the value of: ∞

∆Z = jωπr0 µ 0 n β ⋅ Q(α , β ) 2

(1)

where:

Q(α , β ) = ∫

λ − λ2 + j

λ +j 0 λ + 2

⋅e −αβλ J 12 (βλ )dλ

(2)

The following generalized parameters are used as arguments of the above equations:

α=

2h r0

β = r0 ωµ 0σ

(3)

(4)

The generalized parameter α is the distance h of a model contact coil with n turns, where the coil distance from surface of the examined structure is referred to the coil radius r 0 . The dimensionless parameter β depends on conductance σ of the examined material and the angular frequency ω (pulsation) of eddy currents. Variations of the coil resistance and inductance can be found by calculation of the real and imaginary parts of the coil impedance. r = R − R0 = n 2 ωπµ 0 r0ϕ (α , β )

(5)

where:

ϕ (α , β ) = Re Q(α , β )

(6)

l = L0 − L = n 2 πµ 0 r0 χ (α , β )

(7)

where:

χ (α , β ) = − Im Q(α , β )

(8)

R 0 and L 0 stand for the resistance and inductance of the coil positioned within a distance from a conductive medium while R and L represent the resistance and inductance of the coil approached to the examined surface. Pretty few properties of eddy currents can be spotted when analyzing graphs for normalized coil components plotted on the complex plane. Fig. 1 presents such graphs for the functions φ(α,f) and χ(α,f) defined by formulas (6) and (8). However, it is not the generalized ω β2 . parameter β that is used for the plots but directly the frequency f = = 2π 2πr02 µ 0σ The graphs were plotted for six values of the α parameter: α=0.01, α=0.05, α=0.1, α=0.2, α=0.5 and α=1. Selected values for frequencies, i.e. f=20kHz, f=40kHz, f=60kHz, f=80kHz, are marked on each curve that represents alterations of normalized impedance components as a function of the eddy current frequency. The marked points have been then connected to make up a continuous curve. When a measuring instrument is tuned to one of the foregoing frequencies, the point that correspond to alterations of impedance components shall ‘travel’ down that curve. Therefore it is possible to trace variations of normalized impedance components caused by movements of the coil towards and outwards the surface of the examined structure. If operation of a conductometer is the matter of analysis it is reasonable to plot similar curves

Fig. 1. Diagrams for the functions φ(α,f) and χ(α,f) depending on frequancy variations plotted for several values of the α parameter. The frequency ranges from 0 to 100 kHz, conductance 74 of the material is constant and amounts to σ=15MS/m

for variations of conductance. For the analysis formulas (6) and (8) are used but the expression (2) β = r0 ωµ 0σ is substituted instead of the β argument. Numerical calculations were carried out for the constant value of angular frequency (pulsation) ω = 2πf whereas the conductance value σ served as independent variable. Fig. 2 present example plots for calculation results for six values of frequency from 1 kHz to 0.5 MHz. For each case the conductance was incremented by 0.01MS/m per each step up to the threshold of 60 MS/m. A ‘large dot’ on each plot was used to mark six values of conductance that correspond to metals: σ=10 – 60 MS/m. All these curves are superposed one to another and make up a single trajectory but the higher frequency is associated with eddy currents the later (time-delayed) segment of the trajectory is plotted. Distances between ‘large dots’ correspond to normalized alterations of the coil impedance caused by variations of conductance attributable to material of the examined structure. The larger distance is between ‘large dots’ the higher sensitivity to conductance variations is exhibited by the measuring instrument. The presented diagram clearly demonstrates how frequency of eddy currents affects the nature of the coil impedance variations, what are the shares of resistance and inductance in the total impedance alterations. For instance, when a very low frequency of eddy currents is applied, e.g. f=1 kHz one can notice that variation of conductance within the range from 20 to 60 MS/m results in no alterations of the coil resistance whilst its inductance changes significantly. On the other hand, when higher frequencies are applied, share of resistance in overall alterations of impedance is definitely higher. For the frequency of f=500 kHz alterations of inductance become really low as compared to resistance changes. However, the visual evaluation of distances between ‘large dots’ marked on the graphs with normalized increments is misleading. Despite of the fact that such a graph is very useful for selection of eddy current frequency and design feature of the coil, accurate evaluation of the coil sensitivity is possible only after calculations for alterations of the parameters measured directly during experiments with due account to all the associated circumstances. For instance, if the purpose is to directly measure resistance and inductance one has to use equations (5) and (7) to calculate absolute variations of resistances and inductances. Calculations were carried out for a large coil with the diameter r 0 =1cm and with turns. Calculation results are exhibited in Fig. 3. Curves that represent trajectories of the functions Δl(α=const,σ), Δr(α=const,σ) were plotted by variations of conductance σ with the constant frequency ranging from f=1kHz to 0.5MHz. Similarly to Fig. 2 ‘large dots’ were used to distinguish those points on each trajectory that correspond to the selected conductance values from the range σ=10 – 60 MS/m.

Fig. 2. Normalized alterations of impedance components demonstrated by a contact coil caused by presence of a conductive medium. The graphs are plotted on the complex plane for α=0.1 and several frequencies of eddy currents. Distances between ‘large dots’ on these graphs correspond to actual sensitivities of the measurement method. Due to the fact that alteration of the coil resistance is directly proportional to the product of the function φ and the frequency of eddy currents, the coil sensitivity defined as the effect of conductance onto variations of the coil resistance clearly increases in pace with the frequency growth. Unfortunately, the effect of the conductance onto variations of the coil inductance is still less and less when the conductance is growing. Therefore the problem of frequency selection for eddy currents becomes a crucial issue to guarantee satisfying metrological properties of measuring equipment. This problem must be considered in a more extensive context. Alterations of the coil impedance are affected not only by the conductance but also by the distance from the surface of the examined structure. 76

Fig. 3. Curves for variations of resistive and inductive components of a contact coil impedance caused by presence of a conductive medium. The curves are plotted on the complex plane for α=0.1 and several frequencies of eddy currents.

However, that distance is frequently unknown. If so, simultaneous measurements of the both components of the coils impedance should enable determination of the conductance with the highest possible accuracy. Experience acquired during the course of measurements enforced application of a mechanism to compensate effect of the coil distance from the examined structure surface denoted by h. Therefore two-parameter measurement proved to be a must. Only an instruments sensitive to the both impedance components is capable to determine the conductance and the distance of h or at least to compensate variations of that distance.

References: 1. L.Dziczkowski, A mathematical model to determine optimum conditions for measurements of material conductance by means of the eddy current method applicable to large structures. Машиностроение и Техносфера XXI века. Сборник Трудов XV Международной Научно-Технической Конференции, Донецк-2008. 2. L. Dziczkowski, Effect of eddy current frequency on measuring properties of devices used in non- destructive measurements of non-ferromagnetic metal plates, Archves of Materials Science and Engineering, Volume 32, Issue2, August 2008, pp. 77-84. 3. L. Dziczkowski, Selection of the frequency of eddy currents in non-destructive testing of non-ferromagnetic plates, Journal of Achievements in Materials and Manufacturing Engineering.Volume27, Issue1, March 2008, pp. 43-46. 4. L. Dziczkowski, A definition of eddy current penetration depth useful for flaw detection and conductivity measurement, The Journal PAMM - Journal of Applied Mathematics and Mechanics, ISSN '1617-7061', Volume 8, Issue 1, Date: December 2008, Pages: 10205-10206. 5. M. Dziczkowska, A Mathematic Model to Determine Optimum Conditions for Measurements of Conductivity Exhibited by Multi-Layer Structures With Use of the Eddy-Current Method. Машиностроение и Техносфера XXI века. Сборник Трудов XV Международной Научно-Технической Конференции, Донецк-2008. Стр. 96-100. 6. L.Dziczkowski, An Attempt to Find out Optimum Conditions for Conductance Measurements by Means of the Eddy-Current Method in Multi-Layered Structures, Машиностроение и Техносфера XXI века. Сборник Трудов XV Международной Научно-Технической Конференции, Донецк-2008 T.4, стр. 100-104. 7. L.Dziczkowski, Errors in Conductance Measurements of Two-Layer Structures, Автоматизация: Проблемы, Идеи, Решения. Материалы Международной НаучноТехнической Конференции, Севастополь-2008, стр. 138-141.

CINETICS OF DRYING OF HIGH ALUMINIUM REFRACTORY CONCRETE MATRICS CONTAINING MICROSILICA Fröhlich L., Martončíková J. (Technical University of Košice, Košice, Slovak Republic) The paper presents knowledge gained from the experimental study of the effect of microsilica addition on the drying process, which takes place in a high alumina refractory concrete within the temperature range between 20 and 700°C. As microsilica can have multiplying effects in the mixture, which display themselves depending on its content, a wide range of its contents has been studied, namely from 0 to 20 % by weight. The results show that microsilica produces the most significant effect at the beginning of the drying process, when it participates in the formation of new structural formations even at the stage of the mixture mixing and solidification. Introduction The drying of aluminium silica refractory concrete monoliths is an energy and technologically intensive process which should result in a dry but mainly undamaged body. Its intensity is based on physical processes which take place in the substantially heterogeneous environment. This environment is affected not only by the essential components of the refractory concrete but also by a number of corrective additions. These may include microsilica (MS), which fulfils several functions in the mixture. Due to its presence and fineness it fills in micro-spaces in the matrix areas of the refractory concrete, and at the same time it participates in the changes of rheological properties of the mixture. It also contributes to the formation of the primary strength at the stage of setting and hardening of the monolith, and the mullite generated during the burn out process changes structural characteristics of the monolith. Due to its composition (about 98 % SiO 2 by weight ), the aggregate state (particles with the size less than 20 μm) and its crystallinity (predominantly the amorphous state) microsilica has puzzolano properties /1/. In contact with water and in the basic environment it can hydrate and generate new structural formations with bonding effects. However, these bonds are relatively weak, and they are not sufficient to generate a solid body, thus microsilica alone cannot be used as a bond. But in the stage of mixing the mixture and producing the monolith, when hydrated ions of Ca2+ and Al3+ from concrete components are present in batch water, it can participate in the production of C-S-H, C-S-A-H or A-S-H dispersions. Based on the stability conditions these systems produce gel structures. As the gel has the character of the spatial net structure, which binds a considerable amount of water, this structure prevents water from being freely released from the body. It creates a natural obstacle for its removal during the first stages of the drying process. Thus microsilica may have a direct effect on the drying process of the entire refractory concrete monolith. The present paper summarizes knowledge gained from the experimental study of some effects of microsilica on the kinetics of alumina refractory concrete bodies drying both in low and high temperature drying areas. Experimental part The study of effects of microsilica on the drying process of the refractory concrete monolith has been carried out on bodies made of the high alumina refractory concrete with the defined additions of microsilica, namely 5, 10, 15, and 20 % by weight. The bodies produced from microsilica without additions, i.e. from LC18 commercial refractory concrete and bodies from pure microsilica, i.e. 100 % MS by weight have been used as comparison samples. Their preparation consists in the thorough homogenisation of refractory concrete mixtures 78

mass loss (g)

with microsilica and batch water. The amount of water was changing depending on the coexistence of the substance. In general, with the increased amount of microsilica in the mixture it was necessary to increase the amount of batch water from 4 to 30 % by weight. Other factors of the processing were identical, including the time of vibrating and compacting of a relevant body. The drying kinetics has been carried out on the thermo scales. This method enabled to measure the temperature on the sample surface as well as the humidity removal from the heated area. The heating conditions of the experimental body were identical and the heating was performed in the dynamic mode with the temperature rise rate of 5°C/min. The samples were heated from 25°C to final 700°C. The stated temperature interval included both drying stages, namely the low temperature one with the free water release and the high temperature one with bound, hydrated water release. Due to the linear increase of the temperature depending on time it is possible to consider the obtained drying curves as the kinetic drying curves. Experimentally the loss of mass of a corresponding body was monitored in time as well as the effect of the microsilica addition on the drying conditions. Results and discussion Fig.1 shows the results of this experimental study. In spite of the fact that they are biased with a certain methodical error (different amounts of batch water), it is possible to define three areas on the given curves. The first is the area before reaching the temperature of 100°C, the second is the temperature range from 100 to 300°C and the third is the area of temperatures between 300 and 700°C. 2.0

LC18

0.0

5 % MS 10 % MS

-2.0

15 % MS

-4.0

20 % MS 100 % MS

-6.0 -8.0 -10.0 -12.0 -14.0 0

200

400

600

800

temperature (°C)

Fig. 1. Loss of mass of the test bodies The position of individual curves and their shape is naturally affected not only by the presence of microsilica, but also by the amount of batch water. As with the increased amount of microsilica in the mixture it was necessary to add more and more batch water to ensure processability of the mixture during the formation of the bodies, the correlation between microsilica and batch water has arisen. From the above mentioned it can be anticipated that the more water (microsilica) is added to the mixture, the greater the apparent porosity π a at the end of the drying process, which has been proved by the measurement. The measurement results are displayed in Fig.2.

apparent porosity (%)

80 70 60 50 40 30 20 10 0 0

100

amount MS (% )

Fig. 2. Apparent porosity Ď&#x20AC; a of the test bodies after the drying

In order to eliminate the effect of various amounts of batch water in individual bodies and to compare the obtained results, the relative mass losses have been calculated for each moment of the drying process. The processed results are shown in Fig.3. 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2

0 % MS

100

200

300

400

500

600

700

800

temperature (Â°C) 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2

5 % MS

100

200

300

400

500

temperature (Â°C)

600

700

800

0.5 0.4 10 % MS

0.3 0.2 0.1 0 -0.1 -0.2

100

200

300

400

500

600

700

800

temperature (°C) 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2

15 % MS

100

200

300

400

500

600

700

800

temperature (°C) 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2

20 % MS

100

200

300

400

500

600

700

800

temperature (°C) 0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2

100 % MS

100

200

300

400

500

600

700

800

temperature (°C)

Fig. 3. Rrelative mass losses of the bodies with 0, 5, 10, 15, 20, and 100 % of MS by weight in the mixture Based on the comparison of individual curves in Fig.3 it can be concluded that in the first area below 100°C the addition of microsilica results in the deceleration of the water 81

release, which is represented by the changing gradient of the initial curve parts. This phenomenon occurs probably due to the fact that based on microsilica physical effects the porosity character changes depending on the increase of its amount. In the body without its addition the structures with a higher amount of large pores can be anticipated at the expense of small pores. The release of free water from the surface layers is not obstructed. The stabilised state and thus the constant drying rate is achieved within the temperature range between 95 and 125°C, which is proved by the existence of “a retaining line”. With the increase of the microsilica content this area shifts towards the higher temperatures and with 20 % MS by weight the interval moves to the margin between 115 and 163°C. With the temperature increasing above 100°C the water release rate increases up to the maximum level, which is shown by the inflex point on the curve in Fig.1 in the second identified area of the temperature interval between 100 and 300°C. The maximum rate with the addition of microsilica is shifted towards the higher temperatures from 168 to 182°C Fig.3. During the drying of the body with 100% content of microsilica this maximal value is reached at the lower temperature, i.e. at 171°C, which corresponds to the effect of the body porosity. If the increasing content of microsilica results in the increased porosity of the top layers of the body (due to the effect of the microporosity formation which occurs after the increase of the amount of batch water), then the maximum rate should be reached at lower temperatures rather than at higher temperatures. As this does not happen, the direct influence of microsilica and its effects on the above mentioned shift exists. Gel structures could be formed in the interaction with the dissolved concrete components, which would be capable of retaining free water and thus shift the maximum rate towards higher temperatures. The third area of the drying within the temperature range from 300 to 700°C is characterized by the existence of several maximal values which correspond to the hydrate decomposition. It is the most distinctly expressed in case of the body made from the mixture without microsilica, where hydrates coming from concrete and reactive Al 2 O 3 are present in the structure. As in the other mixtures added microsilica changed the concentration of hydratable components, while microsilica itself hydrated only to a very limited extent (see Fig.3 100% MS), this effect was displayed also in the intensity of the above stated maximal values, which decrease gradually. Conclusion From the experimental study it is concluded that microsilica has the most significant effects during the first stages of the drying process, when reaction products along with other mixture components can be present in the monolith structure. When concrete is present too, C-S-H gels may be formed; otherwise A-S-H structures may be formed, which subsequently prevent water from being released. The presence of these structures helps to retain free water, and shifts the maximum rate of its removal to the temperatures close to 180°C. The paper has arisen within the VEGA 1/4135/07 project. References : 1. Vladislav Trefil: Vliv mikrosiliky na alkalicko-křemičitou reakci. Stavební technologie, 2002. 2. K.Ghambari Ahari, J.H.Sharp, W.E.Lee: Hydration of refractory oxides in castable bond systems-II: alumina-silica and magnesia-silica mixtures. Journal of the European Ceramic Society 23 (2003) 3071-3077. 3. Uta Telljohan, Karsten Junge, Drik Deppe: Sušení cihelních výliskú. Silika, č.3-4/2006, s. 85-88

EMISSIONS FROM COKE PRODUCTION Frล hlichovรก, M., Bรกlintovรก, Kuckovรก, A. (Technical University of Kosice, Kosice, Slovakia) The present paper focuses on the environmental impact of the coke production on the quality of the environment. The process of the coke production belongs to the technological processes which burden all components of the environment. Emissions arise from various sources which are required for the coking process during the coal processing, and used for the coking process itself, as well as for the coking gas purification. In the effort to eliminate these negative impacts on the air quality, new technologies and elements reducing the environmental burden are being launched. The environmental pollution problems have contributed to the development of new coke production technologies which result in the minimization of emissions and the maximization of coke production. 1. Introduction The coke production is considered a major source of the air pollution. It is connected with the rise of chemical substances and compounds which enter the air in the form of gases, steam and aerosol, and water and soil pollution occur as well. Solid polluting substances include coal and coke dust. Gaseous emissions are formed by CO 2 , SO 2 , NO x , CO, and ammonia along with steam labelled as other polluting substances, which include saturated and unsaturated hydrocarbons, aliphatic and aromatic hydrocarbons, e.g. tar, benzol, hydrogen sulphide, phenol, hydrogen cyanide, naphthalene, pyridine and others. Amounts of emissions are released into the environment continuously, or they occur fitfully with the different duration and variable intensity. The highest amount of emissions gets into the air during the coal carbonisation in coking chambers. During recent 25 years pressure has been put on coke plants to reduce emissions released into the air. Environmental investments in innovative technologies have contributed to the reduction of the long term monitored harmful substance emissions, mainly solid polluting substances (TZL), gaseous SO 2 , NO x , CO and other polluting substances. The decrease of emissions from coke plants in the European Union countries between 1980 and 2003 is shown in Fig. 1.

Older coke plants The most modern coke plants Fig. 1. Reduction of emissions in coke plants in the EU member states [3] The coke production technology used in classical coke plants does not to enable to eliminate the release of emissions totally [4]. The implementation of a number of technical 83

measures aiming at the environmental protection causes problems with meeting more stringent emission limits both in our country and abroad, which subsequently results in the coke production decrease due to the shutdown of many coking batteries. Problems with the environmental pollution have contributed to the development of new coke production technologies which result in the minimization of emissions and the maximization of coke production. For several decades advanced methods of coke production and processing have been designed and applied with the aim to improve conventional production methods, namely the so called technologies of the 2nd generation and technologies of the 3rd generation, which should solve the impact of the coke production on the environment. Reduction of emissions from coke production in Slovakia The production of metallurgical coke in Slovakia started in 1965, when the first coking battery VKB 1 was put into operation in the East Slovak Iron Works. It was a modern large scale battery with plenty of new equipment serving for the environmental protection and protection of workers from harmful substances. The second coking battery VKB 2, which had been producing coke from 1969, was identical with the first one. When constructing the third coking battery VKB 3 new technological knowledge was used again to enhance the environmental protection. At present coke is produced in two coking batteries in U. S. Steel KoĹĄice s.r.o. Along with the metallurgical coke also pitch coke was produced from coke tar in the iron works since 1966. However, neither modern technological equipment nor compliance with the technological discipline could eliminate increased emissions of organic polluting substances (PAU) into the air, mainly the increased amount of benzo(a)pyrene 3,4. Consistent application of environmental policy in the company has contributed to the fact that during recent 15 years significant progress has been made in the Coke plant in the area of air and water pollution prevention A substantial reduction of emissions was achieved due to the coke production cessation in the second coking battery VKB 2 in 1992. This battery was not innovated in order to improve the ecological situation since it had been put into operation. Another significant step in the area of the emission reduction was the cessation of the tar carbonisation based pitch coke production and the shutdown of the Pitch coke plant in 1995. Another environmentally friendly step was the construction of the biological waste treatment plant in 1998 and the shutdown of the Phenol plant, where dephenolization of phenol ammonia water was carried out in extraction columns using benzol. Recently enhanced technologies have been launched in the Coke plant for the capturing of emissions rising during the preparation of coal charge, filling chambers with coal, pressing, cooling and processing of coke, heating coking batteries and during the coking process itself. The completion of the project aiming at the implementation of emission-free filling of coking chambers in 2006 significantly contributed to the reduction of solid polluting substances compared with 2005; with the same production volume of unscreened coke it was about 62%. It is not possible to reduce the share of TZL in the coke production process to a zero level; however, it is possible to reduce it to the lowest possible value. This value may be reached provided that ecological equipment is maintained in operational condition, operational and technological parameters are met to the maximum extent and coking chambers are sufficiently maintained. The amount of TZL depends not only on the condition of equipment and its operation, but also on the quantity of coke produced. Another relatively significant source of the air pollution is the Chemicals plant, where in 2006 the process of hermetization of the chemical part of the coke plant, pressurization of the final coking gas cooling and recycling of the tar sludge was completed. The construction of the coking gas desulphurisation equipment is being prepared and it should be completed by 84

2009. All newly launched technologies contributed to some extent to the reduction of the total volume of emissions produced in the plant. Gaseous emissions are related mainly to the combustion of gas used to heat the batteries. Under standard heating conditions their amount is stable and it depends on the type and composition of the combusted gas as well as on the gas consumption per ton of produced coke. When ensuring the production of the required quantity of coke, it is not practically possible to affect the amount of generated emissions. This amount gradually and slightly increases in connection with the increasing operating time of the batteries, as the result of deteriorating conditions of the heating system masonry and the tightness of the coking chamber walls. The reduction of the emissions of other polluting substances, mainly emissions of tar, benzol, naphthalene, pyridine etc. was reached as the result of launching a series of environmental measures in the Chemicals plant. The most significant measures include the hermetization of the gas pipeline and collecting tanks. With almost identical levels of the coke production during the recent three years the volume of other polluting substances has dropped by more than 82 % compared with 2005. The total amount of emissions from the coke production in tons released into the air in individual years, as well as the efficiency of the newly launched technologies can be assessed based on Fig. 2. The high amount of emissions released in 2003 results from the increased coke production, and related amount of emissions released during the production process as well as from the increased breakdown rate of separating devices, Fig. 3.

Fig. 2. The amount of emissions from the Coke Plant Division, [t/year]

Fig. 3. The coke production in the Coke Plant Division, [t]

However, based on the above review it is not possible to assess the effects of new environmental measures launched in individual production sectors on the reduction of the emission volume. It results from the assessment of the quantity of individual types of harmful substances. The amount of emissions of solid polluting substances released into the air during the assessed years is shown in Fig. 4. The development of the amount of gaseous emissions is shown in Fig. 5.

Fig. 4. The amount of TZL emissions

Fig. 5. The amount of SO 2 and NO x emissions

[t/year]

The increase recorded before 2004 is related to the increasing production of coke. In 2005 new technologies of the emission-free filling of coking chambers and dry dedusting of guide carriages during the coke extrusion process were launched into operation. During the launching process original dust removal devices were shut down, which resulted in the increase release of emissions. The efficiency of new technologies is proved by the reduction of emission volumes in the following years by as much as 38 % at approximately equal level of the coke production. Conclusion To sum up, the environmental activities performed in the Coke plant represent a positive sign for the permanent improvement of the environment. A number of environmental technologies and measures launched in recent years in the Coke plant Division are of the utmost importance. The launching of various environmentally-friendly equipment can positively reduce the impact on the working and living environment, which represents a good result for practices used in the coking industry . Financially and technologically intensive technologies have brought the expected effect. The launching of environmentally-friendly technologies is reflected also in the charges paid for emissions released into the air, and significant savings have been achieved. The coke production in Slovakia complies with the emission limits defined by the European Union. The paper has arisen within the VEGA 1/0338/09 project. References : 1. Available on the internet: <http://ec.europa.eu/environment/climat/pdf/nap.sk.final.pdf> [cit.2007-10-6]. 2. Hawthorne, S.,Hullinger, J.P., Skubák, J.: Iron and steel engr. 74, č. 2, 1997, s. 54-58. 3. Buss, W.E., Toll, H., Worberg, R.: Cokemaking in Europe- Trends and Directions, AISE Steel Technology July/August 2003, s. 35-41. 4. Brockmeyer, E., Voges, B.: Visible emissions test report, No 92-275-026-034-09, Prepared forEPA by Radian Corporation, Research Triangle, March 1992. 5. Boltun, E.: Diplomová práca , Hutnícka fakulta TU v Košiciach, Košice 2008.

TECHNICAL-ECONOMICAL COMPETITIVENESS OF THE MANUFACTURING SYSTEMS Daschievici L., Ghelase D. (â&#x20AC;&#x153;Dunarea de Josâ&#x20AC;? Galati University, Galati, Romania) On world wide plan, enterprises are confronted with a dynamics more and more an accelerated and unpredictable of the changes. This is influenced by the technical and scientifically progress, dynamic requirements of the customers, science of management and mathematical economy [2]. These changes enforce an aggressive competition to the global scale what assume settlement of new equilibrium between economy, technology and society. This paper presents a new approach of technical-economical competitiveness for manufacturing systems, and a new type of competitive management of them, so that their technical-economical performance to be maximized. 1. Introduction On world wide plan, enterprises are confronted with a dynamics more and more an accelerated and the unpredictable changes. This is influenced by the technical and scientific progress, dynamic requirements of the customers, science of management and mathematical economy [2], [3]. These changes enforce an aggressive competition at the global scale what assumes the request of a new settlement equilibrium between economy, technology and society. This paper presents a new approach of technical-economical competitiveness for manufacturing systems, and a new type of competitive management of them, so that their technical-economical performance to be maximized. Through manufacturing system understand the technological systems ensemble, which are used for obtaining of particular product. Each of these technological systems is composed of machine tool, tools, appliance, parts, operator and manufactures one of technological process operation for realization of the product. The manufacturing system is composed when the product is started into manufacturing and stay in this structure just up to the completion execution produced respectively. After when another product is started, the problem of manufacturing system structure is rerun from begin. Thence, it follows at the current level the competitiveness is definite by the economical factors and indicators obtained. We can say as through competitiveness of the enterprises we understand the capacity (the potential) of enterprise operated comparative performant with other enterprises in the punctual mod context macro economical concrete to a given moment. The performance is measure in which the enterprise meet aim for which is creased.In this moment the algorithm for technical-economical competitiveness evaluation is not defined and, more the technical factors are not taken into account, also consumptions and expenses caused by the technological processes are generated by the technical actions. In this context, competitiveness notion has new valences, because it assembles the factors and politics which determine the enterprise capacity to occupy a favourable place on market, to keep that place and to improve the position. Unless the competitiveness characterizes synthetically and completely the viability of enterprise. 2. The algorithm of competitive management with application to the manufacturing systems Through application of the competitiveness management at manufacturing system of the mechanics buildings, can release a management of these systems. The authors of the paper propose a block scheme and on its base can elaborate a competitive management algorithm, figure 1. The manufacturing system receives contracts after auctions of the market. The competitive management system means the competitiveness evaluation and, on its base to 87

action on manufacturing system through instructions about caring on mode of manufacturing process to obtain maximum competitiveness [2], [3].

the

Fig. 1 Block scheme for competitive management On the other hand, in abaft the competitiveness evaluation, the management system must give the elaborate possibility of the competitive offers which will enter in auctions. To realise these two objects, the competitive management system uses reinforcement learning method to know the market and on-line unsupervised learning method to know the manufacture system. The next step is the comportamental modelling of the system for elaboration of the necessary adjustment instructions of the technological process and management politics. Watching each line from block scheme (figure 1), we can see the following: the modelling algorithm of the market-manufacturing system relation includes using the data base from economical environment (auctions), extraction of the knowledge through data mining and realisation the model through reinforcement learning; for obtaining of the punctual competitiveness indicators will be constituted the data bases from competition environment and will extract knowledge to evaluate the competitiveness; the offers from market enter in competition environment to generate contracts for manufacturing system; the modelling algorithm of the manufacturing system is realised leaving from the contract specifications and identifying the system. Using data mining, will be obtained data set about functional and economic parameters, the dates which will be used for development of the model through unsupervised learning methods. On base of above learning processes will be realised the comportamental modelling of the ensemble of the manufacturing system â&#x20AC;&#x201C; market and a possible implementation of the management system. The manufacturing system will receive instructions about the way of development of manufacturing processes to achieve the 88

maximum level of the efficiency (maximum profit). The algorithm follows conceptual and it will be materialized through the system of relations between the value measures of exogenous and endogenous factors of the manufacturing system come from reality through relation modeling manufacturing system â&#x20AC;&#x201C; economical environment and functional modeling of the manufacturing system. The modeling is based on the reinforcement learning and on-line learning. The stages of the algorithm are: the determination of the relations of the manufacturing system with economical environment through reinforcement learning; the determination of the relations results from functional modeling of the manufacturing system; the determination of the system of relations among the groups of endogenous and the exogenous factors of the manufacturing system. 3. Conception of a methodology of mathematical evaluation and the on-line identification of technical - economical competitiveness of manufacturing system For most industrial companies, the estimation method of the cost determines especially the performances of two strategic functions: product design and the offer (the price of product). In general, is commonly admitted that product design can engage up to 70-80% of the total product cost. The recent progress achieved in Integrated Engineering such as concurrent engineering or integrated design opens a new field for cost estimating during the design stage. In a competitive market, the incapacity of the company to quickly and adequately successful request for quotation can echo severely on its capacity to survive economically. Indeed, an underestimated cost will result in losses while an overestimated cost will prevent the company from remaining competitive. So, there is a strong need expressed by industry to have sound cost estimating solutions, both in terms of design and quotation, that can improve the performance of these strategic functions. In manufacturing, cost estimating is the art of predicting what it will cost to make a given product or batch of products. Various techniques exist for cost estimating. The manufacturing cost of a part can be estimated using one of four basic methods: intuitive, analogous, parametric and analytical. This mechanism is characterized by an ability to perceive the economical process environment and make real-time decisions about interactions among the manufacturing system and the economical environment. The comportamental approach is characterized by an ability to perceive the economical environment and make real-time decisions about tasks. The competitive management includes and bases on comportamental modelling and on-line learning, and it is necessary to know in every moment the manufacturing system state, namely the relation between its capacity to function at the performance optimum parameters and economical environment, suddenly, in a given situation. The answer at this necessity is generated by the mathematic evaluation methodology of the technical-economical competitiveness of a manufacturing systems in a given frame. In the concrete case of the manufacturing system, the performance can evaluate through profit rate P, given by the relation: P = (p-c )q[Euro/hour]

(1)

where p is the price, c is the cost and q is the productivity. This relation will be analysed in connection with other aspects, such as, investment amount and business efficiency, For identification of system state relation, is necessary to establish and multiply of some manufacturing system attributes â&#x20AC;&#x201C; productivity, quality, flexibility, saving, predictability both its with external environment attributes- owned market section, the evolution of client requirements dynamic, market price, concurrent systems. Mainly, the methodology of 89

mathematical evaluation and on-line identification of competitiveness will generate solutions for competitiveness measures knowledge, in a concrete mode above explained, and based online learning and give to the management disposal dates and solutions to elaborate the politics which follow to get, to keep and to increase the technical-economical competitiveness level. For the verification of the accuracy and applicability of the concept of competitive management of the manufacturing systems it is necessity to obtain results on a concrete case. In this sense, it is simulated and modeled a real manufacturing system of a pilot enterprise which works in the real conditions on a real market with values of parameters tacked from the economical reality. 4. Conclusions This paper proposes a modern approach about manufacturing system competitiveness because: manufacturing system competitiveness is approached in a new manner, original by using investigation modern methods, which are taken into account all the factors which influence the realisation, keeping and increasing of industrial enterprise competitiveness; it is proposed a mathematical evaluation methodology of technical-economical competitiveness of manufacturing system; it is proposed a new management concept of manufacturing systems, based on comportamental modelling of ensemble of manufacturing systems-market and management setting at the manufacturing system level, which is all levels applicable and proper to the actual market requirements. In this context, of competitive management can offer solutions for development and competitive enterprises. Through this type of management the technical phenomenon is associated with the economical phenomenon. Increase competitiveness is not a process of exploit of a short-time advantages but it appears as a complex process and constitutes the support of an economic structures based on capital investments, on scientific research, development and innovate. It is necessary to put in obvious the correlations among economical average (the market, competition) and the manufacturing system and to study the role which they have it in the acquirement and the increase of enterprise competitiveness. This becomes still more pressing due to the fact as the special literature consigns studies about competitiveness at least to the level of the enterprise and studies about process and technology of manufacturing system donâ&#x20AC;&#x2122;t connection between the two entities in the context of the technical economical competitiveness. The paper develops the notion of competitive management of the manufacturing system through comportamental modeling and on-line learning. References: 1. Christoph H. Loch, Stephen Chick and Arnd Huchzermeier (2007) Can European Manufacturing Companies Compete: Industrial Competitiveness, Employment and Growth in Europe, in European Management Journal, 251-265, Volume 25, Issue 4. 2. Epureanu A., Buruiana F., Ciuntu S., Susac F. â&#x20AC;&#x201C; (2007) Algorithm for Economical Characteristics Identification a Machining System, The Annals of Dunarea de Jos University of Galati, Fasc. V, 135-139, ISSN 1221-4566. 3. Falticeanu, C., Epureanu, A., Daschievici, L., Ghelase, D., Modern Approach of Techical-Economical Competitiveness for Manufacturing Systems, Proceedings of 3rd International Conference in Manufacturing Engineering ICMEN, 1-3 October, 2008, Thessaloniki, Greece, p. 821-826, ISBN 978-960243-649-3.

METHODS FOR IMPROVEMENT OF QUALITY Ghelase D., Daschievici L. (University “Dunarea de Jos”, Galati, Romania) The paper presents some aspects regarding continuous improvement of quality, such as: Kaizen strategy, Deming Cycle PDCA, the „5 S” Method and Quality Circles, methods which can be applied in order to drive a manufacturing process towards excellence. 1. Introduction TQM is focused on: a) Customer satisfaction: quality is meeting then exceeding customer requirements and expectations (for products, services or information and communication delivery), both stated and implied. b) Continuous improvement: the use of benchmarking should be a basic rule of the organization. Benchmarking is a process for rigorously measuring performances versus the best-inclass companies and for using the analysis to meet and surpass the best-in-class. c) Total organization involvement: in TQM it is strictly required to involve in the process everyone inside the organization. Each enterprise involved in a total quality process realizes a permanent effort to ameliorate its activity, in every sector, continuously and implicating every employee at every hierarchical level. Those principles gave birth to a model adopted in the economy (at first by the manufacturers, in Japan in the fifties, in USA in the seventies, in Europe in the eighties, later by other economic and social sectors, both private and public), together with the Quality Certification Systems introduced by ISO and spread all over the world through national organizations, responsible for the normation and accreditation in quality (e.g. ISO 9000 norms). TQM is more advanced than quality certification: it encompasses all organizations activities and human resources. TQM is promoted by means of “awards” like: Deming Quality Prize in Japan (1951), Malcom Baldrige Award in USA (1987), European Quality Award in the EU (1992), other minor quality awards elsewhere. 2. Kaizen Strategy The guidelines for services quality are basically in these two Japanese words, used by Maasaki Imai, one of the fathers of quality systems: Kaizen and Kairyo. The Kaizen approach and the Kairyo approach are compared according to their differences in the components of the activity concerned: the application to the services is evident, and we can choose the fitting approach in accordance with customers’ expectations [1]. Kaizen means continuous improvement. Kaizen is an efficient strategy to think and solve problems step by step with the contribution of all. It distinguishes itself from innovation which proposes breakthroughs that need important investments. Figure 1 and Table 1 show the essential differences between the two methodologies: Kaizen and Kairyo.

KAIZEN

KAIRYO

Fig. 1. Difference between Kaizen and Kairyo 91

Table 1. Differences between Kaizen and Kairyo ACTIVITY KAIZEN KAIRYO improvement reengineering Radical, sudden and not Level of the change Gradual and continual steady Starting point

Existing processes

Zero point

Continuous

Once

By little degrees Continuous and in progress

By great strides

Involvement

All

Few and selected

Participation

Bottom up

Top down

Style

Consent

Directive

Risk

Moderate

High

Rules

Adaptation and evolution

Conflicts and discussions

Forms of action

Maintaining and improvement

Dismantling and building

Approach

Collective, team working

Individuals’ efforts

Evaluation criteria

Process and striving for the best practices

Results and profits

Frequency of the change Speed Timing

Intermittent

Maasaki Imai says that in most cases the quality improvement can be reached through the Kaizen methodology, but some times it is necessary and compulsory to adopt the Kairyo methodology. Reengineering normally refers to a drastic, dramatic process improvement in certain areas of management or in certain phases of the product or service life cycle. However, reengineering addresses only a limited area of problems in the company and brings about limited improvement, no matter how dramatic. Reengineering probably will always have its place as an organizational change process. But it is relevant in limited circumstances because, ultimately, it produces short-term and static results. Reengineering is like innovation. We expect innovation to occur all the time, yet we know it doesn't happen. It's unrealistic to expect reengineering to be applicable all the time. That would cause chaos. Kaizen is a more lasting improvement process. 3. Deming Cicle (PDCA) Deming cycle is a method for continuous improvement and consists of following the PDCA philosophy, which is represented by four steps (Fig. 2): • Plan: establish what must be done; • Do: realizing what has been forecast; • Check: checking and demonstrating what has been realized; • Act: rectifying according to the results. After each cycle, it’s very important to steady realized improvement, to come back to the starting point and to restart another cycle, and so on. 92

Fig. 2. Deming Cycle (PDCA) For the Plan part, which can be separated in several steps, it is recommended to use different specific tools. For the step identify the problem, we will use the Brainstorming; for choose priorities, the Pareto law; for collect data, report sheet or histogram; for looking for the causes of non-quality, the Cause- Effect Diagram (Ishikawa), FMEA (Failure Mode and Effect Analysis). For the Do part we must first use the set of WWWWHHWF questions (What? Who? Where? When? How? Why? For whom?) and determine and choose the means. That can be done with the help of Poke-Yoke tool (simple and cheap anti-errors system. It allows to avoid errors as a preventive and can be implemented from the conception phase or as soon as a human mistake is discovered). Next, for the confirm solutions we will use the QFD tool (Quality Function Deployment, also known as “House of Quality). For the Check part we will use Statistical Process Control (SPC) in the Control step. For the interpreting and evaluating step we will use tools such as report sheets, histogram, SPC. For the Act part we have to use FMEA tool. 4. The “5S” The 5S method is it considered as an essential, very simple and efficient management technique and the first practice of total quality. This method is born and has been applied first in Japan, and has spread throughout Europe and America. Good managers know that in order to drive an enterprise to excellence we must begin with the 5S and applied it continually. The name 5S comes from the first letters of the Japanese words: seiri, seiton, seiso, seiketsu, shitsuke, which can be respectively translated by: clearing, tidying, cleaning, order and rigour. Their significations are detailed below: Seiri: Clearing what is useless means strictly keeping what is essential and clearing the rest. It’s a fight against human propensity to collect everything. Seiton: tidying things according to their usefulness. It supposes to place and order things in order to keep them easy of access and avoid useless movements and loss of time. Seiso: Cleaning ensures the neatness of the working place and allows malfunctions and defaults detection. Seiketsu: Order is not an activity according to the strictest definition of the term but it consists of maintaining a pleasant and long-lasting sight at the working place by the regular use of the first three steps. Shitsuke: Rigour consists in encouraging and motivating the employees in keeping their good habits in order to continuously improve the rules to reinforce the efficiency and adapt themselves to new situations. There’s no place for drifting, hierarchy must continue to explain the process and particularly what has been bad understood in order to work in a more welcoming, cleaner, safer and more pleasant quality environment. 93

The 5S method gives spectacular and undeniable results, contributing to productivity, safety and life quality improvement. Because this method physically transforms the working place, people work in better conditions. So it deeply modifies people frame of mind at every hierarchical levels, contributing to the growth of the personnel efficiency and wellness. 5. Quality Circles A quality circle is a volunteer group composed of workers who meet together to discuss workplace improvement, and make presentations to management with their ideas. Typical topics are improving safety, improving product design, and improvement in manufacturing process. Quality circles have the advantage of continuity, the circle remains intact from project to project. Quality Circles were started in Japan in 1962 (Kaoru Ishikawa [2] has been credited for creating Quality Circles) as another method of improving quality. The movement in Japan was coordinated by the Japanese Union of Scientists and Engineers (JUSE). Prof. Ishikawa, who believed in tapping the creative potential of workers, innovated the Quality Circle movement to give Japanese industry that extra creative edge. Quality circles are established with management approval and can be important in implementing new procedures. While results can be mixed, on the whole, management has accepted quality circles as an important organizational methodology. The operation of quality circles involves a set of sequential steps as under [3]: 1. Problem identification: Identify a number of problems; 2. Problem selection : Decide the priority and select the problem to be taken up first; 3. Problem Analysis : Problem is clarified and analyzed by basic problem solving methods; 4. Generate alternative solutions: Identify and evaluate causes and generate number of possible alternative solutions; 5. Select the most appropriate solution: Discuss and evaluate the alternative solutions by comparison in terms of investment and return from the investment. This enables to select the most appropriate solution; 6. Prepare plan of action: Prepare plan of action for converting the solution into reality which includes the considerations "who, what, when, where, why and how" of solving problems; 7. Present solution to management circle members present solution to management fore approval; 8. Implementation of solution: The management evaluates the recommended solution. Then it is tested and if successful, implemented on a full scale. Conclusions It is sensible to know, use and control the good quality methods/tools in order to reach an effective total quality management and, using continuous improvement, to stay in the road towards excellence. That must be known and applied by everyone (employees or managers) at their levels in each enterprise which wants to be a success. References: 1. Ghelase D. Sisteme de asigurare a calitatii: Ceprohart, 2002. 2. Ghelase D., Dogariu C., Daschievici L. Asigurarea calitatii prin cercurile de calitate. Conferinta Internationala de Comunicari stiintifice â&#x20AC;&#x153;Tehnologii Moderne, Calitate, Restructurareâ&#x20AC;? TMCR2005, Chisinau, Moldova, 2005. 3. Ghelase D., Daschievici L., Diaconescu I. Seven Management Computerized and Planning Tools: Modelling and Optimization in the Machines Building Field, Bacau, vol. 2, 2007. -275 p. 4. Campbell J. D., Reyes-Picknell J. Strategies for Excellence in Maintenance Management, Productivity Press, ISBN 978-1-56327-335-3, 2006. 94

CHARACTERISTIC’S OF TWO-PHASE GAS-LIQUID FLOW IN HEAT EXCHANGER WITH SEGMENTAL BAFFLES Guziałowska J., Ulbrich R. (Opole University of Technology, Opole, Poland) This paper presents hydrodynamics of two-phase gas-liquid flow in tube bundle space with segmental baffles. The influence of tube pitch on the characteristics of two-phase flow was investigated. The flow regime maps were determined using visual observation of flow structures. Introduction Two-phase flow in tube bundle space in shell-and-tube heat exchangers with segmental baffles is very complex phenomenon due to the geometry involving a multitude of parameters: arrangement of tubes, external diameters of tubes and baffle spacing. Hydrodynamic structures accompanying the flow of the two-phase gas-liquid mixture in tube bundle space of shell-and-tube heat exchanger greatly affect the operating parameters of the device. Their influence can determine not only the intensity of heat exchange but it also can be correlated to problems resulting from vibrations of the bank of pipes in the exchanger. Therefore, the identification and analysis of the two-phase flow structures can be regarded as a crucial element for the description of the phenomena occurring in the heat exchanger’s shell side [1]. The research in this paper applies an experimental study for the identification and analysis of two phase gas-liquid flow by means of image processing method. The process of two phase flow has been realized in test channel 1220×240×30mm (length × width × thickness) with changed arrangement of tubes. In experiments nineteen different geometry configurations were tested, changing baffle spacing, baffle cut out’s and tube pitch [6]. Experimental investigations has been conducted with digital high speed CMOS video camera with frequencies up to 2000 Hz and with accuracy of 1024 x 1024 pixels for each image. The images recorded with the CMOS camera were taken at the frequencies which depend on gas and liquid velocity. Adequate frequency selection prevent pictures being taken out of focus. Methodology and results analysis Flow regime maps provide valuable information about the characteristics of two-phase flow mixture in tube bundle space of shell-and-tube heat exchanger with segmental baffles. Flow structures were determined with the aid of visual observation for three different geometrical configurations, where tube pitch was changed (t/d=1,45; t/d=1,625; t/d=2) [2]. Whereas in order to define areas, where independently of tube pitch, the hydrodynamics of two-phase flow is similar, experimental results at one common regime map were matched. Before further analyses, symbol’s systematic which characterize structures was introduced (tab. 1). In this case, four different flow structures were distinguished on the basis of visual analysis: • B-bubble flow, • P-plug flow, • F-foam flow, • S-slug flow. In case, when for each tube pitch the flow regime was the same, structure’s symbol was painted (fig 2.).

Tabel 1. Symbol’s systematic FLOW STRUCTURE 3B

SYMBOL

FLOW STRUCTURE 2F1P

2P1F

2P1S

2F1S

2B1P

2S1F

2P1B

1B1P1F

b) liquid mean velocity [m/s]

liquid mean velocity [m/s]

gas mean velocity [m/s]

liquid mean velocity [m/s]

gas mean velocity [m/s]

Fig. 1. Characteristic of flow structures distinguished on the basis of visual analysis: a) t/d=2; b) t/d=1,625; c) t/d=1,45; where: □-bubbly flow, Δ –plug flow, ○- foam flow, ◊- slug flow 96

liquid mean velocity [m/s]

gas mean velocity [m/s]

Fig. 2. Geralized flow characteristic for three different tube pitch Above, on the figure 1 , characteristic’s of two-phase flow structures determined with the aid of visual observation for three different tube pitches is presented. Whereas on the figure 2, in order to comparison the tube pitch influence on the flow regime, all analyses are presented on the one generalized flow pattern map. On the basis of the figure above (fig. 2), it can be observed that for three tested tube pitches, the hydrodynamic’s of two-phase gas-liquid flow in tube bundle space is similar. The compatibility between the regime maps was equal 63,6%. It was observed too, that for the slug flow the compatibility is the highest and equal 92%, for another regimes this value varies between 42% (plug flow) and 55% (bubbly flow). Whereas the mean velocity is defined as geometric mean of two superficial velocities (v is ): the first (between baffles) - across tube bundle (v iop ) and the second (in baffle window) – along tube bundle (v iow ):

vis = viop ⋅ viow

(1)

where: i – relates to liquid phase (L) and gas phase (G) Subsequently to the stage of tube bundle space research was devoted to a comparison of authors’ own studies with the results gained by other scientists. Unfortunately, the compatibility between own results and Taitel’s [4], Ulbrich and Mewes [5] or Mishima and Ishii [3] was unsatisfactory at 30% level. So low compatibility was the main reason to propose our own flow regime map (fig. 3). 97

Fig. 3. Our own regime map Summary In this paper geometrical parameters influence on the hydrodynamic’s of two-phase gas liquid flow in tube bundle space with segmental baffles was tested. As result of analyses, it was found that the tube pitch hasn’t considerable influence on the hydrodynamic’s of two-phase flow. Baffle spacing and baffle cut have bigger influence on the velocity and circulation zones in heat exchanger than tube pitch. The compatibility between the regime maps for three different tube pitches was above 60%. This result is admitted as satisfactory. Whereas compatibility between own and another authors studies was very low and it was the main reason to create own flow regime map. References: 1. Chisholm D.: Two-phase flow in pipelines and Heat Exchangers. Georg Godwin Ed. London, 1983. 2. Guziałowska J., Ligus G., Ulbrich R.: Some problems of flow pattern recognition in complex geometry, 5th International Conference on Transport phenomena in Multiphase Systems, Bialystok, 2008. 3. Mishima K., Ishii M.: Flow regime transition criteria for upward two-phase flow in vertical tubes, International Journal of Heat and Mass Transfer, t.27, nr 5,s. 723-737, 1984. 4. Teitel Y., Barnea D., Dukler A.E.: Modelling flow pattern transitions for steady upward gas-liquid flow in vertical tubes, AIChE Journal, t.26, s. 345-354, 1980. 5. Ulbrich R., Meves D.: Vetical, upward gas-liquid twophase flow across a tube bundle, International Journal of Multiphase Flow, t. 20, s. 249-272, 1994. 6. Zając D., Guziałowska J., Ulbrich R.: The application of DPIV and DIP in the measurements of the flow along tube bundle, Sixth International Conference on Enhanced, Compact and Ultra-Compact Heat Exchangers: Science, Engineering and Technology, Potsdam, 2007.

PALLETIZATION WITH ROBOT OTC DAIHEN Hajduk M., Baláž V. (Technical university of Košice, Košice, Slovakia) This paper presents building of palletizatin cell with robot OTC Daihen with implementing camera system for parts classification and palletization. Palletization cell is then equipped by conveyor. The parts are moved by conveyor belt and the camera system recognizes them by shape, color and dimension. Paper also describes classification algorithm for the OTC Daihen robot and approach to processing and evaluating of visual area. Introduction At the present The Department of production system and robotics dispatches with two robotized cells. At one of them, the robot OTC Daihen is installed. This cell is aimed at palletization and electric welding. This article will deal with aplication for palletization. Palletization cell Palletization cell is equipped with OTC Almega AX-V6 robot with six laxity levels and carrying capacity of 6kg at the flange. Robot is operated by AX-C system, which enables to achieve repeatable accuracy 0,08 mm. Operating system works with Windows NT4 disc operating system and RTX upgrade, which enables to operate the robot in real-time mode. Robot is offset with effector for manipulation with components. Effector is constructed in such a way, that it can a) transmit the components by the help of a couple of suckers and b) manipulate with the second part with components by means of two-finger tentacle. Effector was designed and constructed at our department. Schema of the transmission of information in palletizational workplace is in the fig.1. Components are transported to the robot on a conveyor, which is operated by its own operating system. Programme is intelligent contactor and we can by means of analogue module operate frequency changer. That enables us to change the speed of engine rotation and by that to change also the shift of the conveyor according to robot´s operating system´s requirements.

Fig.1.Schema of communication at the palletization cell Components are laid on the conveyor at random and the robot´s task is to identify them by the help of camera. For the purpose of identification we used the camera MINTROM AVT Marlin F-033B. Camera is connected to PC via usb port. Resolution of this camera can be adjusted from 160x120 to 640x480 by 74 snapshots per second. Graphic chart of relative response of camera is on fig.2.Another attributes of camera: ● True partial scan (higher frame rates by smaller AOI) ● Format_7 support (flexible AOI, flexible speed) ● Optocoupled asynchronous image trigger ● Image preprocessing features: - Auto controlled gain, exposure, white balance - Real-time shading correction 99

- Programmable LUT … ● Smart frame grabber features: - Image FIFO memory (17 full frames) - Image mirror - Single-shot, multi-shot, free-run - 2 programmable inputs, outputs … ● B/w and color ● Very high frame rate ● Angled head and customized housings

Fig. 2. Relative Response of camera During the first stage it is necessary to teach the camera the pattern, according to which it will carry out the comparing of the objects on the conveyor. There may be more of such patterns (standards). After scanning of the picture below the camera, these information are sent to computer, which, on the basis of applied algorhythm evaluates the type of the component on the conveyor and at the same time the swing out of the object. These data are then sent to the robot´s operating system, which carries out the swing out of the effector to such a position, that it can do off that component from the conveyor and put it to a prepared palette, fig.3.

Fig.3. Palletization cell

100

Robot´s operating system can change the speed of the conveyor if the calculations of the object take longer time. Fig.4. is a caption of the classification, in which a picture of an object found in the scanned image is standardized with the objects saved in the database. Classification

Choice of identification

Type of an attribute SHAPE OF AN OBJECT

Type of an attribute COLOUR

Generation of a database The classes of objects Based on colour

Generation of a database The classes of objects Based on shape

Scanning of the object by camera and procession of the image

Classification of the objects by comparing Scanned and processed images with the DATABASE

Sending of the data to the robot operating system

Fig.4. Account for the classification Conclusion The introduced cell is in the process of construction. After completion of camera system, visualization of the cell and publication of the data on the internet are intended to take place. Palletization cell will then be enlarged and equipped with new modules of transmission of information towards the internet and gsm networks. References : 1. Hajduk M., Baláž V., Sukop M.: Sorting workstation with Colour Sensors, SAMI 2005, 3rd Slovakian-Hungarian Joint Symposium on Applied Machine Intelligence. 21.–22.1.2005 Herľany, Slovakia. p. 353–357. 2. Taranenko W., Czahor G.: Performance of adaptive control algorithm for machining processin the presence of computational delays, Sevastopol 2003,p. 161-164. 3. Zubrzycki J., Drachov O., Taranenko V., Taranenko G.: The device to processing of the deep holes, 9th, Int. Conference ROBTEP 2008, Tatranská Lomnica 9-11.6.2008, Slovakia, p. 757- 760. The contribution was worked out with reference to VEGA 9448 project solving.

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COAXIAL OTH SIDE MORE - OUTPUT GEARS Haľko J., Paško J. (FMT TU Košice, with the seat in Prešov, Slovakia) This grant is about principial solution of coaxial both side more-output gears, based on double step gear of internal rotary wheel, which is in together contact with more tooth gear outputs. Also it says about analysis of strength charging relations on this kind of gears. Introduction Objects of research work of Development of Technological Devices Department is also case of study of high accurate gears. Those gears manufactured in this time worked on base of rotating gear they use, by the way their quality, rather difficult transformation of transfer move from satellite move to centrical. It is also related with possibility of charge of those gears. The purpose of our solution was at simplifying of transformation of satellite move to centrical with the target of increasing life and increasing charge within the same accurate parameters. Double step gears by a wheel with internal and external tooth gear Developed double step gear with one internal tooth gear presents a double step gear of two gearings with internal and external tooth gear. At the same time the body of internal wheel gear by its teeth rings together with two wheels at the same time – with wheel 1. and 2. step of a gear, when also rotate around its own axis which is on excenters mount shaft. This solution presents an effort of simplifying of transfer satellite move to centrical, which is used for today high accurate gears. This solution type of gear gives an option to get a big gear relations in a wide spectre. It depends of a proper choice of a teeth number at all four teeth rings. With a proper suggestion is possible get a gear in consistent or reverse direction of rotation opposite to input direction of rotation. There is possibity to get more bigger gear relations as the known high accurate gears (for example: TEINJIN, SEIKI, SUMITOMO CYCLO, SPINEA, and lot of others…). Performantly is possible these gears resize for a similar values of performance and torques as have known high accurate gears. There is a real assumption to get a values of accuracy as they are ostensible at high accurate gears. It results from its construction. In opposite to, this solution is assumpting, in a wiew on simplifying of transfer satellite move to centrical, its increasing lifetime and stability of charging trough its lifetime. Lifetime is assumpting on a level of lifetime technological mechanical devices, so around 10 years in onetime and double time shift by keeping all rules of using devices including service of device (includes: changing parts as a bearings or other parts of device sized for a shorted lifetime). Handicap related for pitting have got a similiar character as a rotating gears which was described at chapters before. Design of these gears can be based on: Involute gear, cycloidal gear or gear with free designed face of tooth, friction gear. Gear relations of involute gear can get a values u max = 1000. By a cycloidal gear values of gear relations can get ten times more values as by involute, so u max = 10 000 and more. By a friction gear similar as by a friction gear of cardan mechanism, value of gear relation is depend of allowed smallest inequality diameters a friction wheels. Therefor maximum value of gear relation can be bigger as by epicycloidal gear, so u max ≥ 10 000. (In depend of technological concept). Assumpting of gear lubrication: - oil, fat (for lower performance till around 5 kW). Exact parameters of gearbox depends of concrete wanted design for concrete purpose, in rpm of gear, accuracy and also performance values. 102

Velocity relations, if output wheel include external gear On the next fig. no. 1, are shown velocity relations on double step reducer, if output shaft which is in the gear box putted by a wheel wit external tooth gear. External teeth have z 2 and z 3 putted on internal satellite rotation wheel no. 2, internal gearing z 1 have a central wheel and gearing z4 have an output wheel. z 1 , z 2 and z 3 , z 4 work – gear together. Gearing z 2 and z 3 are on the same body 2 of internal wheel. At the fig. 2 are shows velocity relation on internal wheel 2 in together work of z 1 , z 2 and z 3 , z 4 . These velocity are definitive for sizing - design of gearing and all next parts of gearing. Searching for value of functioning velocity and gear ratio for concrete design is on the base of known steps from mechanic and parts of machines. At the fig. 3 is wiewed principial solution of both side more (fine) output gear. At the fig. 4 is a photo from manufactured prototype reducer of both side three output alignment gear with one input and with two outputs on the opposite side and one output at the input side. Concrete sample relations: On the two shafts at the opposite side of input shaft is gear ratio u 1 = 5,1,…, u 2 = 840, 15…, At the side of output shaft is gear ratio on the shaft u 3 = 210, 13 As was told before, concrete solution of gearboxes is able to use in a big spectrum of a gear relations and also their outputs. The main limitation is given just by ability or by option of technical solution of gear design with maximum count of outputs.

Fig. 1. Double step gear with external tooth gear on a output shaft

Fig. 2. Velocyty relations – output shaft an with external gear

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Fig. 3. Scheme design of both side more output gear

Fig. 4. Both side more output gear

Conclusion Our suggestion of double step gear considerably reduce difficulty of transfer satellite move to centrical which is used by high accuracy gears. This solution gives an ability to get a big gear relations in a great spectrum, by this, is possible to get a bigger gear relations as by a high accuracy gears (as in chapter 3) by a relative lower weight of reducer. With a good designed project is possible to get a gear with consistent or opposite direction move. From this kind of gears will be manufacture functional model, which will be tested to base functionality, possibilities of performance charge, parameters of torsion toughness, effeciency and erosion. At the base of analyzed measurement and findings will be specified next requests for increase to better of design, functional and performance parameters of these gears. This paper is particular solution of VEGA č. 1/4156/07. References : 1. BLAGODARNY, Vladimir – PAVLENKO, Slavko – PAŠKO, Ján: Zrýchlené skúšky opotrebenia strojných súčastí. In : Sborník referátů z XLII. Mezinárodní konference kateder částí strojů a mechanismů, 4. - 5.9.2001, Ostrava, Česká republika. Ostrava: VŠB-TU Ostrava, 2001, s. 21 – 24, ISBN 80-7078-919-0. 2. HAĽKO, JozefKLIMO, Vladimír: Dvojstupňový viacvýstupový prevod. In: Sborník 45. mezinárodní konference Kateder částí a mechanismů strojů, 7. – 9.9.2004, Blansko, Česká republika, Brno: VUT v Brně, 2004, s. 110 – 115. 3. HAĽKO, Jozef - PAŠKO, Ján - PAVLENKO, Slavko: Epicyclic gear with friction gearing and cardan mechanism. In: Scientific Bulletin : Fascicle: Mechanics, Tribology, Machine Manufacturing Technology. vol. 20, serie c (2006), p. 129-134. ISSN 1224-3264 . 4. HAĽKO, Jozef - PAVLENKO, Slavko: Navrhovanie pohonov s ozubenými, remeňovými a reťazovými prevodmi. 1. vyd. Prešov : FVT TU, 2007, 246 s., ISBN 978-80-8073-976-8. 5. HOMIŠIN, J. a kol.: Základy strojného inžinierstva, 104

Košice: Vienala, 2001, ISBN 80- 7099-661-7. 6. KARDOŠ, František et al. : Investigation of gaseous medium state change in pneumatic element of flexible shaft coupling. In: Pneumatyka. vol. 62, no. 1 (2007), p. 34-36, ISSN 1426-6644. 7. KRAJŇÁK, Jozef et al. : Multi-user detection of nonlinearly distorted MC-CDMA symbols by microstatistic filtering. In: Wireless Personal Communications. vol. 47, no. 1 (2008), p. 149-160. Internet: <DOI 10.1007/s11277-007-9398-5> ISSN 0929-6212. 8. KUĽKA, Jozef - MANTIČ, Martin: Program Pro/Engineer Wildfire 2 : Základy modelovania. Košice : TU-SjF, 2005. 112 s. ISBN 80-8073-340-6. 9. KURMAZ, L.W. – KURMAZ, O.L.: Projektowanie wezlów i cześci maszin, Kielce: Wydawnictwo Politechniki Świetokrzyskiej, 2006, ISBN 83-88906-51-8. 10. ĽAHUČKÝ, Dušan: Vybrané problémy v utesňovaní vretien strojov. In: Sborník. mezinárodní XLVI konference kateder částí a mechanismů, strojů, Sedmihorky, 6. – 9.9.2005. Liberec: TU v Liberci 2005, s. 190 – 193, ISBN 80-7083-951-1. 11. TOMAGOVÁ, M. – VOJTKOVÁ, J. – MEDVECKÁ-BEŇOVÁ, S. – HARACHOVÁ, D. – MANTIČ, M.: Základy strojníctva. Učebné texty a praktiká. Košice: Strojnícka fakulta, TU v Košiciach, 2007, ISBN 978-80-8073-916-4.

APPLICATION OF PIV METHOD FOR DEFINITION OF TRAJECTORY AND MOVEMENT OF PARTICLES IN PNEUMATIC SEPARATOR Ignasiak K., Anweiler S. (Opole University of Technology, Poland) This article presents the PIV method used for definition of trajectory and movement of particles in two-component gas-solid flow arranged in horizontal pneumatic separator. This research was conducted for plastic spheres with different diameter for air velocity range from 5,95 to 9,92 m/s. Introduction The process of segregation has wide mechanical application in the field of heterogeneous grainy arrangements and means interaction between particles leading to changes in particles distribution so the property of particles arrangement is more uniform [1]. The essential question is the analysis of the undesirable segregation effects during the flow of heterogeneous grainy material in pneumatic transportation, which is part of many industrial processes. The phenomenon of particle segregation in pneumatic transportation installations is determined either by the presence of structural elements (elbows, connectors, distributors and others) either by the differences in properties of transported materials (differences in size, diameter, roughness and shape of particles) [2]. Other important factor which has influence on the process of particle segregation is the volume of the transported material stream and the velocity of air used for particles transportation [3]. The generally accepted element of pneumatic transportation arrangement are horizontal pipelines. The essential problem during transportation on larger distances is the sedimentation of solid particles in the lower part of the channel and the segregation during outflow of material from horizontal channel [4]. The horizontal pneumatic segregators (fig. 1.) are wide applied in industry and they operates on the principles of utilization of resultant forces differences which affect on solid particles during their movement in gas environment. In dependence of the size and the direction of action of these forces, the particles of solids move along different trajectories inside separative space. Particles which have smaller mass, smaller sizes or creating smaller resistances, flow through with gas and they are part of multifraction small product meanwhile particle with larger mass and sizes, they are fallout from stream of gas which is part of multifraction heavy product [5]. 105

Fig. 1. Classifier about gas horizontal flow The most commonly appearing improper side-effect of the particle segregation process is deterioration of operating conditions inside industrial installations, except the pipes erosion and solids pulsation [6,7]. The pneumatic transportation has wide practical application in power industry, for example in transfer of carbon milling products to the combustion chamber of the power boilers. The segregation of particles causes the unequal distribution of carbon dust to individual burners [8]. Segregation of solid particles has unfavorable influence on the efficiency of many production processes as well as on quality of the final products, which are dependent of the homogenization rate of the mixture, for example in the dehydration industry [9]. Experimental setup Investigations were conducted on experimental installation which consists of the observation zone placed after the horizontal channel which dimensions are 70 mm x 30 mm. The air is transported with the help of compressor and controlled with rotameter. In the initial part of the horizontal channel solid particles dozing setup is installed for the control of the inserted solid phase quantity (fig. 2.). In the lower part of the experimental setup there was reservoir divided on eight equal zones for the collection of separated particles. Measuring channel was illuminated with four halogen reflectors with power of 500 W each. The uniform lighting behind the measuring channel got through light dispersive screen placed between the flow channel and the lighting. Visual methodology of investigations was used, therefore the channel was made of transparent plexiglas. Measurements were realized with the use of high speed CMOS camera, and investigation data was recorded with frequency of 230 frames per second on 512 images in resolution of 1024 x 512 pixels. The camera was connected with the workstation computer, where images were stored as monochromatic bitmaps.

Fig. 2. Diagram of thetest stand 106

Methodology and results of research The conception of the investigations of segregation process connected with the outflow of gas-solid mixture from horizontal channel was based on two main foundations: ď&#x201A;§ qualification of the trajectory of solid particles movement with the help of the digital pictorial anemometry (DPIV); ď&#x201A;§ determination of the partial mass distribution of the solid material inside the individual receipt zones.

Fig. 3. Trajectories of the particles movement for the individual air velocity and mass fraction for the two-component mixture in individual zones. 107

For the qualification of solid particles movement trajectory was used digital pictorial anemometry with used the indicatory particles (Digital Particle Image Velocimetry - DPIV), which allow finding the vectors of velocity of solid particles with the correlation of the next image in the sequence method [10]. The investigations were conducted on plastic spheres with diameter of 6 mm differing with mass density (white balls 1150 kg/m3, black balls 1440 kg/m3). The range of the air velocity was 5,95 - 9,92 m/s. The movement trajectories of particles for individual air velocity and obtained mass fractions of the two-component mixture in the individual zones was shown on figure 3. Conclusions On the basis of conducted research it was found that digital pictorial anemometry is valuable research tool enabling qualification of the movement trajectories of the particles during pneumatic transportation and the process of particles segregation. Received result of the velocity field calculations together with complementary pictures of movement trajectories can be used for estimation of many essential parameters connected with flow of grainy material during pneumatic transportation and the process of particles segregation. On the basis of the PIV diagrams it was found that the velocity of air, flow channel shape and the properties of the solid particles have the essential influence on the movement direction of particles and on the process of segregation during outflow from horizontal channel. For the velocity of air flow 5,95 m/s there was no considerable disorders and changes of trajectories of particles, vectors of velocity oriented on first zones of the separator. With the growth of air velocity up to 7,94 m/s two-component material was concentrated in the central zones of the separator. The growth of velocity of air up to 9,92 m/s caused the enlargement of the velocity of plastic spheres which in result caused the grainy material to interact more intensively among oneself and the walls, the material accumulatesw in the end zones of the channel. The difference of mass density between the particles in two-component arrangement causes the segregation process. Material with larger density earlier falls down during flow in pneumatic separator than material with smaller density. References: 1. Dolgunin V. N., Ukolov A. A. Ivamov O. O.: Segregation Kintetics in the Radid Gravity Flow of Granular Materials. Theoretical Foundations of Chamical Engineering, 2005. 2. Wagner P.: Selecting Elbows for Pneumatic Conveying Systems, Chemical Engineering Progress, 2007. 3. Borsuk G., Olszowski T.: Rozkład pyłu w transporcie pneumatycznym mieszaniny dwufazowej w rurociągu poziomym, IX Międzynarodowa Konferencja Transport Pneumatyczny TP, 2005. 4. Hoaldey D., Gołąbek J.: Osiadanie się pyłu węglowego w rurociągach poziomych instalacji paleniskowej. Materiały VII Konferencji Kotłowej “ Aktualne problemy budowy i eksploatacji kotłów”, 1994. 5. Shapiro M., Galperin V.: Air classification of solid particles: a review. Cham. Eng. And Proces., 2005. 6. Li H., Tomita Y.: Particle velocity and concentration charactristics in a horizontal dilute swirling flow pneumatic conveying .Power Technology No. 107, 2000; 7. Piątkiewicz Z.: Transport Pneumatyczny.Wydawnictwo Politechniki Śląskiej, Gliwice, 1999. 8. Dobrowolski B., Borsuk G.: Badania segregacji cząstek pyłu węglowego w instalacji pyłowej kotła BP-1150. VIII Forum Energrtyków „Gospodarka Remontowa Energetyki 2002”,Międzynarodowa Konferencja Naukowo – Techniczna, Szczyrk 27-29.09.05-02, Zeszyty Naukowe Politechniki Opolskiej nr. 280/2002, seria Elektryka z. 51, Opole, 2002. 9.·Byung-Hwan Chu: Experimental investigation of particle segregation in Hopper discharge, 2008. 10. Suchecki W.: Wizualizacja przepływów z wykorzystaniem cyfrowej anemometrii obrazowej. Inżynieria I Aparatura Chemiczna, n. 39, 2000.

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CONTROL AUTOMATION BY THE MANAGEMENT OF ELECTRIC LOADS IN INDUSTRIAL PLANTS Isper G., Al-kaei F., Al-garbouh A. (Tishreen university, Al-baath university, Lattakia, Homs, Syria) A precise scientific methodology was applied to study the demand at the power in the operating systems of electric power networks , in industrial factories in order to reduce the loss in unregulated electric power consumption. We studied the Arab cement company in Aleppo as a typical example of a real and field electric study by knowing (recognizing /identifying) the electric equipment /motors in the various departments of the factory and their nominal powers, then we performed the load survey for each department and plot based on EXEL software the daily load curves for certain days of the year (2007-2008 ) before and after load displacement. We were able to deduce some scientific methods for diminishing the difference in peak load therefore reducing loss of power and improving the power factor of the whole factory based on the results of this study we automated the operation mechanism of this facility and controlling the existing electric loads by connecting and disconnecting some of these loads in certain specified times and to design control and monitoring factories for each part of the facility , connecting these factories with some PLC equipment which are in turn connected with electric loads in the facility under study to control their connection and disconnection policy during specific time periods , then to manage the entire system which uses an advanced software which is SCADA . [17], [18] The primary results and calculations showed that the application of this new scientific procedure will lead to reduction of the peak load by about (10.49% ) and improving of ( cos Ď&#x2022; ) of the facility to be within the required range . Introduction A precise scientific methodology was presented to study the demand for on power in the operating systems of electric power networks in order to reduce the both kinds of loss( household & industrial ) in unregulated electric power consumption from one hand and to reduce load on the main power supplying network from the other hand , in addition to postpone the construction of large power generating stations which require a huge amount of money . This methodology relies on control automation by the management of some electric loads and displacing (shifting) them from the time of peak load to other times during certain and well studied time periods by controlling their connection and disconnection using PLCs connected with these loads. The importance and objectives of this research the research aims to provide a scientific methodology which can be used to achieve optimized electric load management to reduce the demand for electric power during evening peak loads , therefore leveling the daily load curve and making the difference between maximum minimum loads as less as possible . The study of electric loads, automation and control management is one of the important issues in the fields of operating electric power supply systems and development , where the main objective of control automation of electric loads of certain plant (household â&#x20AC;&#x201C; industrial ) by changing the shape of daily load curve of this facility to serve the requirement of demand minimization of electric power during maximum load peaks ( by disconnecting them at certain time periods ) then shifting some loads to operate outside these times ( by connecting them at certain time periods ) 109

This will be positively reflected on the optimized operation & utilization of electric power sources and postponing the construction of large power generating stations which saves a huge amount of money for national economy . [6] [7] Therefore the importance of this research becomes clear which aims to make the difference between the peaks of the daily maximum and minimum loads as less as possible by optimized management of electric loads and controlling them which will be positively reflected on the optimized operation & utilization of electric power and limits the spending of huge amount of money for building new power generation plants to provide the progressively increasing demand for electric power . Research method We performed in this research a study of the Arab cement company in Aleppo ,as an industrial factory, where we studied the run of the technological processes in all departments of the factory by identifying the motors existing in each department and then we made a survey of electric loads of this factory and analyzed them we also plotted the diagrams of corresponding daily loads during the peak time and outside around the year by using the direct measurement of power analyzer, then we compared the resulting curves before and after shifting in time and we arrived to real differences in surplus achieved in electric power, then we designed a graphical interfaces which represent the run of the technological processes for each department in relevant to real situation existing in the factory for each department and then we designed a special control panel for each department which controls the connection and disconnection of some loads during certain times using PLC equipment and programming the system a whole using SCADA software [20]. This led to achieving real results for reduction and minimization of demand for electric power and economization through the management & modeling of these loads by a computer software called EXEL language 1-The run of the technological processes in the factory departments The geographical site of the factory and the production stages: The factory is located in Sheikh Sid area about 20 Km south east of Aleppo and it was founded in 1980 .It produces Portland cement under approved Syrian standard specification no. 1877 . It has 3 working shifts and the design daily production capacity is about 3500 tons /day the cement production passes through the following stages : 1quarry stage 2- breaking stage 3-storage stage 4-scale stage 5-raw material grinding 6-oven stage 7-clinker grinding stage ( cement ) 8-packaging stage . the factory is power supplied by main station and is supplied with fuel form the department of boilers and fuel 2- The electric equipment used in control and programming we used in this project the programmable logic controller (PLC) which is Siemens S7-200 and a CPU 226xm . The PLC is connected with the computer in order to use the software CITECT SCADA which takes the data from the graphic interface of the cement plant in order to enable us of controlling , monitoring and management of the operations performed , this project has many advantages for 2 reasons: 2-1-the existence of PLC which achieves several objectives such as : flexibility of control strategies and capability for development and upgrading very high reliability in industrial environments the ability of communication with computers and other PLC controllers to share the information 110

2-2-the existence of SCADA which achieves several objectives such as : providing local or central control using clear , brief , resizable and scrollable pages monitoring , controlling , log-in and display all alarm states and events with several formats monitoring the production quality by easy reading of statistical data for the running of production process 2- 3- Introduction to PLCs PLCs become the important building blocks of the automation systems because of the progressive increase of their ability and power and the constant decrease of their prices also they introduced themselves powerfully in the field of industry as an excellent solution for a wide range of control tasks the PLC is a digital electronic device that is build on the basis of microprocessor and it has a programmable memory in which a series of instructions are stored which enable the PLC to perform many efficient functions such as logic of relays , counting , timing , sequencing and other arithmetic and logic operations . 2- 4-Requirements of PLC programming 2- 4-a-Software : these are any data with certain format which make the PLC or computer systems operable by the operator .They contain the instructions , programs ( routines) which control the PLC here we are going to use micro/win32 specific for Siemens / S 7-200 / 2- 4-b- Hardware : they are all equipment such as PLC equipment , connection cable and programmer . We can use an industrial computer PG or normal PC however when we use a PC we should use special PPI/PC cable (point to point interface ) which allows the communication between the PLC and the PC by the serial port COM and on this cable there is DIP switches which specify the data transfer rate 2- 5- The supervisory control and data acquisition SCADA the SCADA system : is a system which collects the data from the sensors placed in the control system and sends them to the main PC for management . monitoring and control purposes itâ&#x20AC;&#x2122;s one of the applied software used for control operations in which data acquisition is performed in real time from remote sites to monitor the equipment and the ambient conditions and controlling them simultaneously SCADA system includes hardware and software components where the hardware are that equipment which collect data and transmit them to a computer which contain previously the special SCADA software [12]. then the computer will process these data, represent them and display them to the operator to read them and make a decision about them often the use of SCADA is coupled with PLC where this PLC represents the controller which organizes the data and transmits them to the SCADA system for executing the instructions and commands coming from the SCADA manager. 2- 6- Practical application at the Breaking stage In this page figure(2-6-a)clears the general chart to control whith factory departments , and figure (2-6-b) clears the control chart for the braking stage department.

111

Fig. 2-6-a

Fig. 2-6-b 3- Electric loads in factory departments -The next creek (3) clears the electrical loads in the factory departments : department Breaking stage Breaking stage The storage warehouse Scale stage raw material grinding raw material grinding The Ovens The Ovens

Voltage (KV) 6 0.4 0.4 0.4 6 0.4 6 0.4 112

Power (KW) 4200 1978.9 988.8 141.3 12840 1386 5190 1426.8

The packaging clinker grinding ( cement ) clinker grinding ( cement ) The boilers The water The water softening The fuel The groundwater wells Lighting Total

0.4 6 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 - 6 Creek (3)

1224.44 7360 1599.36 267.4 776 534 564.8 178 138.345 40794.181KW=40.794181MW

3-1-Analytical study for the load curve: 3-1-1-Breaking stage department Motors which may be displacement it: -The metallic conveyor before Breaker p=26kw The rubber belt conveyor under Breaker p=11.5kw-filter p=1.1 Ă&#x2014; 3=3.3kw Total load at voltage (0.4kv) p=1978.9kw

Pt=40.8kw

5464.92 30833.66 80634.5 112934.7 158696.3 160669.9 159885.8 160415.1 159888.8 159125 157640.6 156200.6 157971.5 113420.3 57365.49 46150.18 46118.17 45877.91 43570.71

Power before displaceme nt) w( 46264.92 71633.66 121434.5 153734.7 199496.3 201469.9 200685.9 201215.1 200688.8 199925 198440.6 197000.6 198771.5 154220.3 98165.49 86950.18 86918.17 86677.91 84370.71

12:16 12:18 12:20 12:22 12:24 12:26 12:28 12:30 12:32 12:34 12:36 12:38 12:40 12:42 12:44 12:46 12:48 12:50 12:52

2012864.24

2788064.77

Total

Power after displaceme nt) w(

Figure (3-1-1-a)

Figure(3-1-1-b)

Figure(3-1-1-c)

Fig. 3-1-1

Creek( 3-1-1)

113

Time

p=2788064.77-2012864.24=775.2kw Saved power 201469.9=0.797 pmin / pmax=160669.9/ Load factor k= 3- 2-Debating the results - We will calculate the save ratio of power from the total load to the factory at the voltage( 0.4kv -6kv):as at the Creek(3-2):

Displacement load (kw) 40.8 90.2 20.7 212.5 38.263 38.89 25.75 125 58 137.2 29 46.115 862.418 Displacement load (kw) 800 475 1600 2875

Voltage( 0.4kv) Total load (kw) Department 1978.9 988.8 141.3 1386 1426.8 1599.36 1224.44 267.4 776 534 564.8 178 138.345 11204.145 Voltage( 6kv) Total load (kw) 4200 12840 5190 7360 24400 Creek(3-2)

3-3-Debating: The save ratio of the power to the factory at (0.4kv):k=862.418 / 11204.145= 7.69 % 114

Breaking stage The storage warehouse Scale stage raw material grinding Oven clinker grinding (cement) Packaging Complementary Water water sweetening Fuel Wells Lighting Total Department Breaking stage The storage warehouse Scale stage raw material grinding Oven clinker grinding (cement) Packaging Complementary Water water sweetening Fuel Wells Lighting Total

The save ratio of the total power to the factory at (0.4kv-6kv):k=862.418 / 40794.181= 2.11 % The save ratio of the power to the factory at (6kv):k=2875 / 24400 =11. 78 % The save ratio of the total power to the factory at (0.4kv-6kv):k=2875 / 40794.181= 7 % The total save ratio of the power to the factory at (0.4kv-6kv):K = (862.418 +2875) /( 11204.145+24400) =10.49 % This ratio may be application in calculating the quantity of the electrical energy which may be saving it during the months of year or through the annual load to factory. 3-4-Analyzing the annual load: -The creek(3-4-a) and creek(3-4-b)clear the electrical loads through the year 2008: Oven (kwh)

clinker grinding (cement) (kwh)

48026000 50632000 53130000 55639000 58032000 60742000 62958000 65647000 68334000 69993000 72365000 74758000

60104000 63137000 66329000 69583000 72264000 75353000 78458000 81458000 84139000 87291000 89219000 93126000

Lighting transformer (kwh) 1442000 1532000 1620000 1710000 1790000 1876000 1956000 2038000 2123000 2200000 2278000 2364000

Lighting (kwh) 700000 743000 786000 828000 865000 902000 938000 974000 1009000 1044000 1081000 1124000

raw material (kwh) grinding(

Breaking stage (kwh)

Department

1373000 1624000 1889000 2129000 2331000 2545000 2740000 4908000 2287000 2434000 2640000 2842000

1/1/2008 2/1/2008 3/1/2008 4/1/2008 5/1/2008 6/6/2008 7/6/2008 8/6/2008 9/6/2008 10/6/2008 11/6/2008 12/6/2008

91825000 97178000 102273000 107209000 111661000 116482000 120675000 126007000 131348000 134717000 139011000 143575000 Creek(3-4-a)

Mechanical Complementary workroom (kwh) (kwh) 442000 1943000 495000 2039000 545000 2130000 586000 2229400 615000 2325000 639000 2429000 657000 2551000 671000 2633000 687000 2749000 708000 2855000 735000 2954000 778000 3064000 Creek(3-4-b) 115

Packaging Department (kwh) 2439000 2549000 2668000 2789000 2891000 3007000 3116000 3224000 3327000 3435000 3549000 3662000

1/1/2008 2/1/2008 3/1/2008 4/1/2008 5/1/2008 6/6/2008 7/6/2008 8/6/2008 9/6/2008 10/6/2008 11/6/2008 12/6/2008

3-5-Debating the pelf cost: The creek (3-5-a) clears the Cost of the electrical energy in 1/6/2008 for1kwh:Notis: (1Douler=50L.S) creek (3-5-a)

New price(L.s) 1.80 2.25 1.60 1.80

Old price(L.s) 0.80 1 0.70 0.80

Period Daytime Load peak evening Intermediate

The creek (3-5-b) clears the total Cost which we could saved it to the factory:Output the load peak P×1.8×10.49% 277376.58

During the load peak P×2.25 3305250

9771435

116437500

51750000

6235214.04

74299500

33022000

230926.86

27517550

1223000

5047536.24

60147000

26732000

211667.22

2522250

1121000

63443.52

756000

336000

80059.68

954000

424000

174092.04

2074500

922000

Complementary Mechanical workroom Lighting Lighting transformer

116999000

Total

22091751.18 L.S

263247750 L.S creek (3-5-b)

P ( kwh )

Department

1469000

Breaking stage raw material grinding clinker grinding (cement) Packaging Oven

3-6-End results: If the used up energy during year 2008 was: P =116999000kw =116999 Mwh Then the annual bill to the factory will be during load peak: F=263247750 L.S But when we use the load peak displacement method as Ratio 10.49%to output peak periods then the bill will be low to F=22091751,18 L.S This is good result for factory has total load 40.79MW Conclusions and recommendations 1the application of studied methodology for electric loads in general for all household and industrial factories which will reduce the load on the main supplying network and saves a quantities of power which can be used in other fields and other electric 116

applications and also will save a lot of money for building new and standby power generating plants . 2the replacement of conventional motors which now are operated in the company with high efficiency motors when the life of these motors ends or their performance is deteriorated where the use of high efficiency motors will save about 2-10% of the total consumed electric power 3the application of automatic control system in clinker grinders which insures the optimal grinding and increasing the production capacity along with the reduction of typical power consumption .The control system contains electric electronic and mechanical components which control , supervise and adjust the production in an efficient manner and this system can be implemented independently from the electrical automatic control system currently used in the company 4upgrading and developing the filtering system in the company where the air volatile cement can be used which is considered one of the best quality cement concerning its fineness and quality and will reduce the emission of gases and chemicals in air which adversely affect the human health . References: 1. Technical Statistical Report-1997-1998 Syrian Arab Republic-Ministry of Electricity-Damascus. 2. G.D.Rai-An Introduction to Power Plant Technology Second edition -1995-Delhi. 3. V.A.Venikov-Electric Power Systems – Moscow 1974. 4. A.Husain – Electrical Power Systems -3Ed Revised Edition -1990 Delhi. 5. A.S.Pabla- Electric Power Distribution Systems Ed . 1992 New York. 6. O.A.Hamandosh-Economics of Power SystemsAleppo University Publication –Ed.2003 Syrian. 7. Demand-Side Management Concepts and Methods Second Edition By :Clark W. Gelling John H.Chaberlin. 8. Guid to Energy Management –Barny L.Capehart –Wayne C.Turner –William J.Kennedy -1997 By the Fairmont Press,Inc. 9. Boiler Plant and Distribution System Optimization Manual By . Hary R.Taplin Jr. PE.C.E.M. 10. Standard Handbook for Mechanical EngineersTheodore Baumeister seven Edition Tokyo. 11. A.Daneels, W.Salter, “Technology Survey Summary of Study Report”, IT-CO/98-08-09, CERN, Geneva 26th Aug 1998.

BUBBLES RISING OBSERVATION AND MEASUREMENT Karaś M., Zając D. (Technical University of Opole, Opole, Poland) In this paper observation and measurements of single bubble ascent are described. Image sequences were recorded with use of high speed CMOS camera and macro lenses. Bubbles sizes, shapes, ascent trajectory, and quantity were observed. Such characteristics allowed for description of bubble behavior and show how complicated is two-phase flow phenomena. Introduction Two phase flow has become a field of many experimental studies. Even forming and rise of single bubble is very complex. In literature we can find numbers of theoretical models of this effect, but they are often based on not real assumptions [1] . In real flow there is a number complex factors influencing bubbles, like buoyancy, gravity, surface tension and liquid and gas properties. In Newtonian fluids bubble shapes are determined on the basis of inertial, lift, viscous and surface tension forces[5] . Most mathematical models are based on Newtonian liquid, but it gets more complicated if we want do describe bubble properties in complex liquid. In studies bubble rising behavior has been observed and determined [2] [3] 117

[4] . Although some studies have been conducted it is still needed to examine bubbles behavior in non-Newtonian fluids in order to understand their actions. Experimental apparatus. Main component of experimental apparatus was Plexiglas tank with 20×20×80cm size, equipped with draining valve and threaded slot, so it was possible to change nozzles during experiment. Two kinds of nozzles were used d 1 =1mm and d 2 =2mm. workstation main plexiglass tank

CMOS camera HCC-1000.

Bubbles flow

air inlet flowmeter

Fig. 1. Experimental apparatus Bubble flow was recorded using high speed CMOS camera HCC-1000. This camera allows to record images with 462Hz speed for resolution 1024×1024 pixels, and 1825Hz for 1024×256 pixels. Illumination was made by two halogen lamps flashing directly on white screen. Air flow was measured with use of flow meter. Bubbles flow and shapes. Bubble shape is basic phenomena affecting speed and path of bubble movement. With the growth of air flow bubble shape changes. For the lowest rates of air flow bubble shape is spherical with inside air circulation. Due this circulation bubble speed increase because of increased water speed gradient. Path of bubble movement changes from straight line into zigzag. Figure 2 shows single bubble trajectory.

Fig. 2. Trajectory of bubble ascent 118

During further growth of air volume bubble shape becomes ellipsoidal. In this case positive forces obtained from inside circulation are smaller than resistance forces created by bigger bubble shape. This makes bubble ascent speed decrease. Path of bubble movement become helical. Final bubble form during air volume increase is irregular form. His speed increase monotonously with the growth of air volume. Three basic shapes observed during our experiment are shown on figure 3.

spherical

elliptic

irregular

Fig. 3. Three basic bubble shapes Bubble shape is a resultant of inertial, gravity, pressure and surface tension forces. Apart from influence on speed and path of bubble ascent, bubble forms are important factor in describing mass and heat flow processes as well as coalescence and bubble disintegration. Bubble speed decides about time of bubble absence in system, and its shape can determine interface. Bubble creation observed during our examination is demonstrated in figure 4.

t=0 s

t=0,02816 s

t=0,04544 s

t=0,06488 s

t=0,06812 s

t=0,07136 s

Fig. 4. Successive stages of bubble creation Figures 5 and 6 shows that air flow rate change had bigger influence on bubbles sizes than nozzle diameter change.

119

10 dm3/h

20 dm3/h

40 dm3/h

20 dm3/h

50 dm3/h

70 dm3/h

Fig 5. Bubbles quantity and sizes with change of air flow rate

70dm3/h 1mm nozzle

70dm3/h 2mm nozzle

50dm3/h 1mm nozzle

70dm3/h 2mm nozzle

Fig 6. Bubbles quantity and sizes with change of nozzle diameter Bubbles dimensions and velocity were measured. Average results of 40 measurements are shown in table 1.

120

Table 1. Average measurements results Air flow [dm3/h] 20 50

Width [mm] 2,27 5,73

Height [mm] 3,01 8,85

Diameter [mm] 2,64 7,29

Velocity [m/s] 0,34 0,32

Conclusions. Research of two-phase flows, including flows with single bubbles, was conducted. Basic shapes described in references were observed. By using filming, bubbles sizes, and velocity were measured. Bubbles shapes, quantity and ascent trajectory were observed. Increase of gas flow influenced bubbles sizes significantly, but not the velocity. A change of the nozzle to a twice bigger one did not affect any parameters of bubbles. Bubbles shapes are non symmetric and changes during bubble flow because of factors influencing on them. Two phase flow is complicated phenomenon, and measuring techniques development is needed to describe it better. Work co-financed by European Social Fund References: 1. BRAUER H. Grundlagen der Einphasen â&#x20AC;&#x201C; und Mehrphasenstromungen. Aarau: Verlag Sauerlander 1971. 2. CHEN R.C., CHOU I.S., Wake structure of a single bubble rising in a two-dimensional column. Exp. Therm. Fluid Sci. 17, 165-178. 1998. 3. FUNFSCHILLING D. LI H., Z.: Flow of non-Newtonian fluids around the bubbles: PIV measurement and briefringence visualisation. Chem. Eng. Sci> 56, 1137-1141. 2001. 4. LIN T. J., LIN G. M.: An Experimental study of flow structures of a single bubble rising in a shear-thinning viscoelastic fluid with a new measuring technique. Int. J. of Multiphase Flow 31, 239-252, 2005. 5. RODRIGUE D.: A simple correlation for gas bubbles rising in power-law fluids. Can J. Chem. Eng. 80, 289-292, 2002.

CHOICE OF DESIGN DECISIONS DURING MODELLING TRANSFER OF QUALITY PARAMETERS OF MACHINE DETAILS Kheifetz M.1, Koukhta S.1, Prement G.1, Klimenko S.2 (Polotsk State University, Belarus1, Institute of Super Firm Materials it. V.N.Bakul National Academy of Sciences of Ukraine2) It is shown, that computer support of life cycle of products with use of CALStechnologies demands development of through mathematical models of inheritance of a complex of parameters of quality of products. At the automated designing intensive methods of processing of details of machines it is offered to use domination of properties of relations of technological decisions. On a basis synergetic the approach models of loss of serviceability of units of friction are considered. When in mathematical modelling, engineering and technological design, manufacturing and running of complex technical systems, the portability of decisions is based on principles of transfer of properties in life cycle of products. Application of synergistic concept makes it possible to generate a mathematical model of technological and operational inheritance of quality indexes, which describes various modes of behavior when in manufacturing and applying of technical systems. 121

Definition and estimation of changes in technological and operational processes of quality indexes of machines with a glance their mutual influence are complicated with multiply connected character of interactions of forming properties of products. To develop a mathematical apparatus of transfer of quality indexes at technological and operational inheritance it is necessary to decrease dimension of description problem of property transformation [1] in a correct way. Replacement of set of the objects, cooperating with a product, by one object − the technological or operational environment at identity of results of such a replacement − favours the correct decrease of dimension of description problem of property transformation. Definition of manifold characteristics allows, if disposing of cooperation results with a product, to find out rational level quality indexes and to carry out the directed formation of the technological and operational environment. These manifolds should favorable development of useful properties and suppression of development of the properties, which lower quality of products, by means of use of technological and operational barriers [2]. As a result, the method of processing is understood as a set of energy and information processes directed on change of a form, sizes, quality of a surface and physical and chemical properties of a constructional material [1, 2]. 1. Algorithm of choice of technological solutions For the purpose of formalization of conditions of the purposeful creation of new methods of treatment, each aggregate of homogeneous elements of the system is described as some set of technological solutions (TS). Such approach [2, 3] allows presenting any method of treatment as a cortege, each component of which is an element of the TS set. Let us suppose that any two elements of the treatment method possess even only one common property. Then there is a link between the two on the community of properties. The gives an opportunity to organize the choice of TS according to the equivalence and preference [3]. The equivalence permits to choose heterogeneous solutions, which, according to the aggregate of their properties, must correspond to each other. The preference allows to choose solutions but out of the number of the homogeneous ones that possess the best values of the essential properties. Such an approach makes it possible to formalize conditions of TS choice according to a certain level of the established selection criterion and enables to choose a solution according to several criteria corresponding to various TS properties. 1.1 The analysis of relation properties. Making TS in the systems of the automatized projecting is traditionally based on the analysis of the equivalence (x≡y) and the preference (non-strict х≤ у or strict x<y) of the solutions, which are inserted in the knowledge base. This presupposes the use of properties [4]: 1) reflexivity (х≡х, х≤х – true; х<x - false); 2) symmetry (x≡y⇒y≡x true; х≤у and у≤х⇒х=у - anti-symmetrical; х<y and y<x⇒ mutual exclusion - non- symmetrical); 3) transitivity (х≡у and у≡z⇒x≡z, x≤y and y≤z⇒ x≤z, x<y and y<z⇒x<z – true). In the result, using the property of transitivity, the most preferable of all the previous solutions is compared with a new offered or chosen out of the knowledge base on the basis of properties of quality indexes. However, in the general case different non-equivalent TS are the most preferable for different quality parameters from the whole complex of properties. In this it is necessary to use the dominating TS (x<<y), characterized by the following properties : 1) anti-reflexivity (x<<x - false); 2) non-symmetry (x<<y and y<<x ⇒ mutual exclusion); 3) non-transitivity (x<<z does not go out of x<<y). 122

1.2. Synergetic approach. To determine the parameter prevalence, when there is no transitivity or symmetry, it is rational to apply a synergetic concept that uses a mode of analog random quantity, which is such a parameter value, when the density of its distribution has a maximum [5]. Distributions of random variables on which background modes are shown, are described by laws [6]: 1) even ƒ(x) = 1 / (µ 1 −µ 0 ) at µ 0 ≤ x µ 1 ; 2) exponential ƒ(x) = (1 / µ) exp (−x / µ) at µ>0, x >0; 3) normal f(x) = (1 / (σ 2π ) ) exp(–(x – µ)2 / (2σ2)), at σ > 0, –∞ < µ < ∞ , –∞ < x < ∞ or other, where µ – mathematical expectation; µ 0 and µ 1 – imitations; σ2 – a dispersion of random variables х. To judge on the degree of correlation of statistical data to the law of distribution allows the ratio of Romanovsky: R = (λ2p − k ) / 2k , where λ2p – Pirson's criterion; k - number of degrees of freedom, i.e. quantity of groups in the investigated line, designed (µ, σ, etc.) and used at calculation of theoretical distribution of statistical characteristics. Statistical analysis of production characteristics in the frames of wide nomenclature of the technologies tools and equipment applied permits to limit the subsequent growth of the nomenclature of objects and processes. Choosing a quantity of imitations for objects and processes it is rational to consider interdependence of inconsistent requirements on reliability and flexibility of manufacturing system. As a result, the reliability- stability and flexibilityadaptability relations can serve as a criterion for accepting of TS about rational structure of manufacturing system. 1.3. Self-organizing systems. In self-organizing systems reliability and adaptability can be governed by changing the number of subsystems [7]. Each subsystem i has outlets: q 1 – strictly determined and q 2 – fluctuating with dissipated characteristics. Full outlet of a subsystem as a first approximation with a glance on additivity of material and information flows is q (i ) = q1(i ) + q2(i ) . Considering, that in conditions of manufacturing q(i) is an independent random n

variable, the full size of an output is the following: Q = ∑ q (i ) . i =1

The full output, according to the limiting central theorem, grows in proportion to the number of subsystems n while the size of dispersion grows only as n . These estimations are based on the analysis of linear dependence, in truth a feedback coupling, inherent in manufacturing systems, results in even more significant suppression of parameter dispersion [7]. Thus, in computer-aided design the acceptance of technological solutions on perfection of manufacturing systems are to be carried out on a basis of synergetic analysis of technological and operational processes and objects [8]. 2. Thermodynamic model of processes of processing According to the synergetic conception of the steady mode adjusted to the dominating unsteady mode and can be excluded. This leads to the abrupt reduction of the number of the 123

controlled parameters - degrees of freedom. The remaining unsteady mode can be the parameters of sequence, which define TS [7]. 2.1. The equations of unstable processes. The equations in the process of such reduction of parameters group up into several universal classes of the following type [7]: →  → → ∂ → → → U * = G  U *, ∇ U *  + D∇ 2 U *+ F (τ ) , ∂τ   →

→

where U * – controlled parameter; τ – current time; G - nonlinear function of U * and probably →

of a gradient U * ; D – a coefficient, describing diffusion when its value is valid, or describing →

distribution of waves, at imaginary value; F – fluctuating forces caused by interaction with an environment and by the dissipation within the system. The equations of such type are similar to the describing elements of phase transitions of the first and the second type, which are defined by the criteria of transfer. 2.2. Phase transitions. According to the synergetic conception phase transitions take place in the result of self-organization [7], the process of which is described by three degrees of freedom, which correspond to the parameter of sequence (S), the field conjugated to it (C), and governing parameter (G) [8]. It is possible to use the only degree of the freedom-parameter of sequence - for describing only the quasi-static phase transformation. In the systems considerably moved away from the state of thermodynamic balance, each of the pointed degrees of freedom obtains its own value [7]. Therefore, besides the process of relaxation to the balanced state during the time - τp - with the participation of two degrees of freedom, an auto-oscillatory condition can be realized. If three degrees of freedom participate, transition to the chaotic state is possible [8]. As a result, the overall state of the technologic system is characterized by several conditions; 1) relaxational - realized when the time of relaxation of the sequence parameter much surpasses the times of relaxation of other degrees of freedom (τ Sp >> τ Gp and

τ Sp >> τ Сp ) ; 2)

auto-oscillation - requires commensurability of the typical times of changing in > τ p or the sequence parameter and in the governing parameter, or in conjugated field (τ Sp < G

τ Sp <> τ Cp ) ; 3)

stochastic - characterized by a strange attractor and is possible through the commensurability of all the three degrees of freedom τ Gp <> τ Sp <> τ Сp ; 4) remembering - defined by the 'frozen' disorder at the transition point from the disorderly state and is realized when the relaxation time of the sequence parameter turns out

(

)

to be much less than other times (τ Sp << τ Gp and τ Sp << τ Сp ) . Thus, at modelling of technological and operational inheritance, the decrease of dimension of a description task of transfer of quality indexes up to three degrees of freedom of environment is possible during processing and wear process of a product. Modelling of transfer processes on a basis of synergetic approach allows to take into account stability of 124

formation of quality indexes and to consider mechanisms of management of stability of technological and operational processes using feedback [1]. 3. The analysis of processes of wear process of surfaces At the analysis wear process of machine details and their interfaces it is expedient to consider a vector [9]:

ϕ (X, t) = [ ξu (Х, t), …, ξu (Х, t), ..., 1

ξun (X, t)],

where ξu (Х, t) – speed of wear process of detail i (interface) at the moment of time t while loading influence X on a unit of a machine. Then it is accepted, that the wear process possesses a consequence, if the module and a direction of vector ϕ (X, t) at the moment of time t depends not only on the module and a direction of a vector X at present time, but also on the module and a direction of a vector X at the moment of time τ < t, and also on the size of deterioration U of rubbed surfaces for a period [0, t] (here U – a n-dimensional vector: U = (u 1 , …, u i , ..., u n ); at which u i - size of deterioration of detail i) [9]: i

ui ( t ) =∫ ξui ( τ ) d τ . 0

It is typical for wear process without consequence that the module and the direction of vector ϕ(X, t) at the moment of time t depend on the module and a direction of a vector X only at present. Depending on time τ р , when the loss of the serviceability, connected to background of operation of a product, is kept, there are two kinds of consequences: the first and second sort. The consequence of the first sort is characterized by the changes during loss of serviceability of the products caused by background of loading influence X, remains during all service life of product τ д , i.e. τ р ≥ τ д . If τ р < τ д , it is a process with «fading memory» or a consequence of the second sort. Dependences of intensity of wear process of units of friction of machines on operation time t differ from each other with a kind of connections between managing parameter – loading influence X and the wear process connected to it by intensity J. The choice of ordering parameter Н in each concrete case depends on research problems (definition of durability, comparison of wear resistance, an estimation of dynamic properties of system in view of wear process of its elements, etc.). It is possible, that for the same detail, but for various parameters, process of loss of serviceability can have or not have consequence at constant intensity of wear process J of rubbed surfaces. It is caused by a kind of connection (linear or nonlinear) between the ordering parameter Н on which the estimation of a resource of serviceability of a researched product and by saved up deterioration U [1]. Let's consider various connections between external influences and parameters of system fН , and also between characteristics of process of loss of serviceability g Н . 3.1. Model of loss of serviceability process of frictional units without consequence. In a case when connected to ordering parameter Н intensity of wear process J depends only on size of loading influence X:  J ( t ) = f Н ( X ( t ) ) ;   H ( t ) = g Н ( X ( t ) ,U ( t ) ,t ) .

125

If process of wear process is considered as continuous stochastic process [18] it is possible to receive a condition of wear process without consequence. Under constant conditions of friction the increment of deterioration U(∆t) = U(t + ∆t) – U(t) does not depend on time (process with independent increments), hence, speed of wear process ξu = dU/dτ is stationary during time τ [9]. Therefore such a wear process is described by a mode with storing: (τ pП << τ pУ и τ pП << τСp ) . However processes of loss of serviceability of details during the periods extra earnings and catastrophic destruction of superficial layers cannot be described with the help of the resulted equations as intensity of wear process J during these periods is not a constant, and depends on sizes of saved up deterioration U of rubbed surfaces. 3.2. Models of loss of serviceability processes of frictional units with the consequence of the first sort In cases when intensity of wear process J depends both on size of loading influence X and on size of saved up deterioration U, by the considered moment of time t:  J ( t ) = f H ( X ( t ) , U ( t ) , t ) ;   H ( t ) = g H ( X ( t ) , U ( t ) , t ) .

And at the account of a feedback of loading influence Х* with deterioration U:

(

)

 J ( t ) = f H X * ( t ) ,U ( t ) , t ;   * H (t ) = gH X (t ) , U (t ) , t ;  *  X ( t ) = qH ( X ( t ) ,U ( t ) ,t ) . 

(

)

Changes during time τ of intensity of wear process J of rubbed interfaces at constant loading influence on an input of technical system X can be caused by two groups of reasons [9]: - not taking into account a feedback of loading X with deterioration U, such as distinction of physic and mechanical properties of a material on depth of a superficial layer of the product, caused by manufacturing techniques; the ageing of lubricants resulting in their deterioration of frictional properties, to change of a thermal operating mode of interface, and in some cases and to change of kinds of wear process of rubbed surfaces; increase while in service concentration of abrasive particles, products of deterioration, etc.; - taking into account changes of dependence q н loading influence Х* on a detail of unit of friction as a result of deterioration of interface U which are connected to increase in backlashes in rubbed interfaces; with transformation of macrogeometry of surfaces of friction at wear process and короблении details; with change of contact rigidity of mobile joints, etc. Considered processes of loss of serviceability with последействием the first sort concern to processes with strong correlation which have certain connection between sizes of parameter about Н i (∆t) and H i+1 (∆t) even at rather big τ = t i+1 – t i . Here Н i (∆t) = H(t i + ∆t) – H(t i ); H i+1 (∆t) = Н(t i+1 +∆t) – Н(t i+1 ), t i < t i +1 . Thereof processes of loss of the serviceability, caused by the first and second groups of the reasons, are characterized self-oscillatory (τ pП <> τ pУ or τ pП <> τСp ) and stochastic ( τ pУ <> τ pП <> τСp ) by modes with two and three degrees of freedom of technical system. 3.3. The model of loss of serviceability process of frictional units with consequence of the second sort. Consequence of the second sort is shown at change of loading influence as special transitional in wear process of rubbed surfaces [9]. In a transition 126

period [t 0 , t 1 ] intensity of wear process J differs from those values which it accepted at the previous level of loading influence Х i-l , and from the value corresponding to new level Х i :  f H ( X i , X i −1 ,..., X i − n ,t ) , t0 ≤ t ≤ t1 ; J (t ) =   f H ( X i ,t ) , t > t1 .

Occurrence of transition periods speaks the several reasons [9]: an operational heredity of the materials deformable during friction of superficial layers of details; change diagram specific pressure in a zone of contact of details at transition from one level of loading influence on another and connected to it «secondary aging» rubbed surfaces; gradual restoration of conformity between size of loading influence and distribution of greasing and products of deterioration on rubbed surfaces. Proceeding from representations about the nature of the phenomena последействия the second sort it is possible to conclude, that from a position вероятностного the analysis processes of wear process in transition periods [t 0 , t 1 ] are characterized by strong correlation connection between increments of deterioration U i (∆t) and U i+1 (∆t) [9]. In this connection they should be considered as релаксационные (τ pП >> τ pУ and τ pП >> τСp ) with the characteristic period [t 0 , t 1 ]. Thus, downturn of dimension of a task of the description of transfer of properties of products in technological and operational processes is made by allocation of parameters of the order and definition of modes of a condition of system. After that on each of modes it is expedient to consider interrelations of the basic parameters of quality of a product with the determining parameter of the order and a condition of their steady formation. 3.4. Parameters of quality of surfaces of products. Parameters of quality of products of the mechanical engineering, being the basic, share on two categories [1]: what are characterized by the hereditary phenomena connected to properties of materials of products concern to the first; to the second - connected to geometrical parameters of their surfaces. Parameters of both categories in multicoherent technological and operational environments mutually influence against each other. Geometrical parameters of products, such as their configurations and the sizes can influence the voltage distributed in a material of a basis and superficial layers. And, on the contrary, the voltage formed during technological operations and stages of operation, can lead eventually to to changes of geometrical parameters of precision details. It testifies to mutual connection and conditionality of the phenomena accompanying technological and operational processes. Inheritance of the basic parameters of quality is the most full is opened by consideration of sequence of processes with synergetic of positions of joint action of technology factors at mutual influence of parameters. Initial parameters of quality of details of the machine at various scale levels change while in service [1]. Exception is made with residual voltage and structure of the basic material which can be kept before full destruction of rubbed surfaces of details. In most cases already during the period extra earnings the roughness and structure of a superficial relief essentially varies, the sinuosity and structure of superficial layers of a detail change at the established wear process, and the geometrical form of a surface of friction remains within the limits of the admitted values accepted at manufacturing, practically up to the end of service of unit of friction if the estimation of its serviceability is made on parameters of accuracy. Conclusion As a result of the analysis of processes of wear process of surfaces and loss of serviceability of units of friction, studying of features of management by processes of 127

processing the expediency of application synergetic the approach to technical systems is shown. On a basis synergetic the approach the mathematical model of technological and operational inheritance of parameters of quality in life cycle of products of the mechanical engineering, describing various modes of behaviour is generated by manufacture and application of technical systems. Mathematical modelling and algorithmization of decisionmaking, by definition of a kind of the equations have shown, that the system analysis at the automated designing methods of processing, besides equivalence and preference, should be based on domination of properties of relations of design decisions. References: 1. Technological Basis of Machine Quality Control / A.Vasilyev, A.Dalsckiy, S.Klimencko and others – Moscow: Mechanical Engineering, 2003. – 256 p. 2. A.Ryzhov, V.Averchenckov. Technological Process Optimization of Machine Working. – Kiyiv: Navukovaia dumka, 1989. – 192 p. 3. B.Golodenko, V.Smolencev. Object-Orientated Forming Organization of New Methods of Combined Processing // Mechanical Engineering Herald. – 1994. – № 4. – P. 25 – 28. 4. Yu.Korshunov. Mathematical Basis of Cybernetics – Moscow: Energoatomizdat, 1987. – 496 p. 5. V.Aberling. Pattern Formation at Irreversible Processes. – Moscow: Mir, 1979. – 279 p. 6. V.Sigorsckiy. Mathematical Apparatus of an Engineer. – Kiyiv: Technology, 1977. – 768 p. 7. G.Haken. Synergetics. – Moscow: Mir, 1980. – 404 p. 8. A.Olemsckiy, I.Koplyk. Theory of Spatio-temporal evolution of Nonequilibrium Thermodynamic System // Physical Sciences Progress. – 1995. – V. 165. – № 10. – P. 1105 – 1144. 9. Yu.Scorynin. Accelerated Wearing Tests of Machine’s Details and Equipment. – Minsk: Science and Technology, 1972. – 159 p.

FAIRE LES RECHERCHES DOCUMENTAIRES VIA L’INTERNET Kliaguine G. (Université nationale technique de Donetsk, Donetsk, Ukraine) Facile d'accès, immédiat, peu onéreux, l'Internet est un outil précieux pour qui veut faire des recherches bibliographiques. Encore faut-il avoir les bonnes adresses et la bonne méthode. Le présent article repose sur deux constats empiriques : • Alors que chacun, désormais, reconnaît que l'Internet constitue un formidable réservoir, un formidable gisement d'informations de tout genre dans de multiples domaines, certains profils d'utilisateurs potentiels résistent encore à sa consultation. À notre estime, cette affirmation semble davantage se vérifier chez les professeurs de français langue étrangère/seconde. Nous attribuerons cette tendance au fait que, plus que les professeurs de français langue étrangère/seconde se trouvent dans l'exercice de leur art "naturellement" confrontés à des technologies en constante évolution. Laboratoires de langues et informatiques, méthodes audiovisuelles et multimédia, didacticiels, vidéo, visioconférence, cédéroms, voire DVD sont autant d'instruments et d'outils auxquels ils ont dû s'initier. Sans doute peut-on voir également dans les résistances des "classiques" une part d'appréhension liée à l'utilisation de l'enseignement assisté par ordinateur. • Les professeurs de français ayant recours à Internet se limitent pour la plupart à la recherche de ressources en ligne directement exploitables sous forme de cours, de remédiation, d'activités de soutien,… Il suffit pour s'en convaincre de se référer aux différents articles publiés sous la rubrique multimédia dans la revue «Français dans le monde». Notre volonté sera ici de proposer aux enseignants déjà utilisateurs de l'Internet d'élargir leur champ d'investigation en se livrant à des activités de recherche bibliographique. 128

Ce faisant, nous espérons inciter les premiers nommés à s'essayer à la navigation sur le Web et à, eux-aussi, tirer profit des ressources offertes, notamment grâce aux sites permettant l'initiation à la navigation sur l'Internet à l'aide de tutoriels d'auto-apprentissages que nous présentons ci-après. S'initier à la recherche documentaire Les publications livres qui sont destinées aux novices présentent souvent les inconvénients liés à leur objectif "maximaliste" : définitions quelque peu avantageuses de certains sites quand elles ne constituent pas un leurre virtuel, connexions débouchant sur la fatidique "Error 404", sur les messages "la page demandée n'existe pas" ou "la page demandée est momentanément inaccessible", " le serveur vous refuse l'accès à cette page ", ... Signalons toutefois mais avec les précautions d'usage - touchant les limites relatives à l'accession au réseau, à la pertinence et à l'utilisation appropriée des moteurs de recherche, à la qualité intrinsèque des sites répertoriés… - que l'Internet offre des ressources internes au débutant. En effet, certains sites proposent des lexiques et des glossaires de termes spécialisés, des aides en ligne voire de véritables didacticiels pour l'utilisation de l'Internet, pour la recherche documentaire ou pour la recherche documentaire via l'Internet. L'internet professionnel : http://www.urec.cnrs.fr/cours/internet.pro/index.html Le guide d'initiation à la recherche dans l'Internet : http://www.bibl.ulaval.ca/vitrine/giri Un nouveau guide Internet : http://www.imaginet.fr/ime/toc.htm Un guide tutoriel pour apprendre l'Internet : http://www.learnthenet.com/french/index.html Un tutoriel pour débutants complets : http://www.france.diplomatie.fr/culture/france/ressources/guide/autofor/aide.htm Un tutoriel d'introduction à la navigation sur le Web à sur l'inforoute FPT : http://inforoutefpt.org/trousse/volet2/depart/htm Un guide de formation documentaire : http://www.aide-doc.qc.ca/voilier/index.html En outre, même si un énorme travail d'adéquation et de réflexion pédagogique reste selon nous à entreprendre, des cours et des tests en ligne (souvent gratuits mais parfois payants) sont accessibles à tout un chacun. Pour citer ceux auxquels de nombreux hyperliens donnent accès : http://www.dfsf.com http://www.cafe.umontreal.com http://www.fsj.ualberta.ca Notons que les sites ici présentés ont été identifiés au hasard de la navigation et non à partir d'une recherche ciblée. Celle-ci, systématique auprès des différents moteurs, tendrait sans doute à plus d'exhaustivité. Pratiquer à la recherche bibliographique via l'Internet Posons d'emblée qu'en matière de recherche à l'aide de l'Internet la plupart des bibliothèques universitaires permettent l'accès à leur catalogue en ligne, avec parfois la possibilité de consulter des publications ou d'en commander une copie papier. Souvent également, l'utilisation des moteurs de recherche proposés par ces sites universitaires permet de trouver des informations complémentaires ailleurs. Voir, par exemple, un lien vers les bibliothèques et les centres de documentation via l'adresse suivante : http://www.asi.fr/~ericbon/liens/biblioth.htm 129

Ceci étant acquis, nous souhaiterions susciter des démarches de recherche plus larges et novatrices par la consultation de banques de données spécialisées. Sans constituer la panacée et pour autant que l'on possède un esprit critique suffisamment aiguisé (mais n'est-ce pas là une qualité présupposée ?), l'Internet peut, au même titre que d'autres ressources, traditionnelles ou modernes, constituer un outil de recherche intéressant. Toutefois, pour ce qui est de nos domaines, l'utilisation désormais courante des moteurs est souvent synonyme de perte de temps. La masse des informations disponibles est tellement importante que l'utilisateur doit être suffisamment expérimenté pour poser aux moments clés de la procédure les filtres adéquats. Faute de quoi il se retrouve devant des résultats qui ne correspondent pas à ses intérêts. Il suffit de proposer aux différents moteurs francophones une recherche sur un mot ou un groupe de mots identique pour constater une grande diversité des résultats. Après avoir nous-même perdu du temps à des navigations stériles sur le Web, nous voudrions faire profiter nos collègues de nos recherches en présentant ci-après une liste nonexhaustive de sites entièrement ou partiellement relatifs au champ de la didactique du français langue maternelle ou du français langue étrangère et permettant de satisfaire des appétits aiguisés en matière de recherche bibliographique ; certains de ces sites (intérêt non négligeable) permettent même d'avoir accès à un résumé de la problématique définie au sein de l'article, voire à l'article lui-même. Deux adresses seront définies, la première permettant l'arrivée sur la page d'accueil du site, la seconde menant droit à une recherche simple (et parfois détaillée) des ressources disponibles, par mot-clé, par auteur, par titre, par domaine, ..., selon les cas. Nous clôturerons cette présentation par une définition de sites dévolus à la didactique du français langue maternelle et à la didactique du français langue étrangère. Des sites pour des recherches bibliographiques Site : « CIEP » Descriptif : " Office Français pour le Développement de l'Éducation dans le Monde ", Le CIEP a été créé il y a plus d'un demi-siècle pour développer la coopération internationale en éducation. Il a permis à des centaines de milliers d'enseignants et de responsables des systèmes éducatifs de se rencontrer, d'échanger, de confronter et de partager leurs expériences. Au CIEP, l'éducation n'a pas de frontière. Aujourd'hui, le CIEP agit dans trois secteurs : ingénierie de l'éducation, les échanges et l'enseignement international, la francophonie ". Adresse du site : http://www.ciep.fr/ Base documentaire : http://www..ciep.fr/doc/index.htm Site : « DAF » Descriptif : " Recherches en didactique et acquisition du français langue maternelle : DAF est une co-production de l'Université de Montréal (Québec) et de l'INRP (Paris, France) avec la collaboration du CEDOCEF (Namur, Belgique) et de l'IRDP (Neuchâtel, Suisse). " Adresse du site : http://daf.sdm.qc.ca Base documentaire : http://206.167.111.20/script/minisa.dll/144/DAF?DIRECTSEARCH Site : « EDUCASOURCES » Descriptif : Destiné à tous les enseignants, EDUCASOURCES (Ministère de l'Éducation Nationale, de la Recherche et de la Technologie) commente des ressources électroniques sélectionnées pour leur intérêt dans l'enseignement. " Adresse du site : http://www.educasource.education.fr Base documentaire : http://www.educasource.education.fr/educa/rechmot/indexni.htm 130

Site : « INIST » Descriptif : " Plate-forme applicatrice des services en ligne de l'Institut de l'Information Scientifique et Technique. Possibilité de consulter les catalogues avant de passer commande. Plus de cinq millions de notices bibliographiques référencées, de monographies, de rapports de congrès, ... avec mise à jour quotidienne " Adresse du site : http://antares.inist.fr Base documentaire : http://antares.inist.fr:80/public/fre/conslt.htm Site : « INRP » Descriptif : " L'institut National de Recherche Pédagogique est un établissement public national à caractère administratif, placé sous la houlette du ministre chargé de l'enseignement supérieur. Six missions lui ont été confiées : une mission de recherche, une mission de formation, une mission d'étude et d'expertise, une mission de veille scientifique, une mission de ressources, une mission patrimoniale. Adresse du site : http://www.inrp.fr/ Base documentaire : http://www.inrp.fr/Serveur.htm Site : « REPERES » Descriptif : " Recherche libre : pour trouver réponse à une question précise par sujet, auteur ou titre, etc. - Recherche thématique : pour faire le point sur un centre d'intérêt, un domaine de l'actualité - Périodiques dépouillés : des renseignements sur les revues où ont paru les articles indexés dans REPERES Adresse du site : http://206.167.111.20/scripts/minisa.dll Base documentaire : http://206.167.111.20/scripts/minisa.dll/144/repere?DIRECTSEARCH Didactique du français de langue maternelle Site : « LETTRES.NET » Descriptif : LETTRES.NET est un site entièrement consacré à l'étude et à l'enseignement du français et aux lettres. L'équipe qui anime ce site propose à ses visiteurs, lycéens ou enseignants en majorité, un ensemble de compléments utiles pour les cours, avec en particulier des conseils méthodologiques pour le Bac de français, des ressources sur les auteurs au programme ou encore un lexique des termes littéraires et des listes de diffusion ainsi qu'un portail d'accès aux sites éducatifs en français. En outre, une équipe de professeurs de français bénévoles répond aux demandes de correction personnalisées que peuvent envoyer les élèves par courrier électronique. Possibilité de s'abonner à EPISTO.Net, bulletin mensuel d'information consacré aux Technologies de l'Information et de la Communication dans l'Enseignement, aux sites en rapport avec l'éducation et en particulier ceux qui concernent l'étude et l'enseignement du français et le bac de français. Il est destiné aux enseignants de français, aux lycéens, mais aussi à toutes les personnes que le sujet intéresse. " Adresse : http://www.lettres.net Site : « RESTODE » Descriptif : "Le site du cours de français a été conçu pour constituer un espace d'échanges entre élèves et professeurs issus d'établissements différents. Il comprend deux espaces distincts à savoir le site des élèves et le site des professeurs de français du réseau d'enseignement organisé par la Communauté française de Belgique. Possibilité de s'inscrire à " Leaweb ", revue électronique consacrée à l'enseignement du français et aux nouvelles technologies." Adresse : http://www.restode.cfwb.be/francais 131

Didactique du français langue étrangère et seconde Site : « FLE.FR » Descriptif : " Site professionnel du français langue étrangère animé par l'Espace Universitaire Albert Camus (Montpellier). Possibilité de choisir un accès aux informations rédigées en quatre langues : deutsch, english, espanol, français. Comprend une description du Petit Guide FLE 2000 (présentation de 36 établissements, université ou centres linguistiques) et, dans les pages " ressources FLE " une sélection commentée des meilleurs sites Internet pour les professeurs et étudiants de FLE. Adresse : http://www.fle.fr

PROBLEM - BASED APPROACH AS A WAY TO IMPROVE THE QUALITY OF THE ENGINEERING EDUCATION Kovalev S. A., Barkalov A. A., Malcheva R. V. (DonNTU, Donetsk, Ukraine) At preparation of the engineers on computer and intellectual systems and networks on the chair “Computers” the methods of the problem- based approach are widely applied, as this approach is well entered in specificity of their future work. Practically, the tasks which are given out on all course projects, that or otherwise reflect real problems originating during activity of the system programmer, engineer - designer or adjuster of the computer equipment. The problem-oriented learning The idea of the problem-oriented learning is following [1]: the start point for learning should be used a problem, question or ripple which is desirable to be solved by the student, usually from the requirements of the professional field. Let us discuss briefly the problem-based learning, the approach which is applied with success and gaining in influence in professional schools. The key features of the problem-oriented learning approach which is the more and more in use in the laboratory works, course and undergraduate learning of the of future engineers are that: * Real life problems are used as the basis stimulus material. * Cross disciplinary views and methods are brought to bear on the problems under consideration. (The rationale is that this is more likely to lead to a holistic approach to solving a problem- a feature of some new courses in medicine and architecture). * Students are guided (but not told) how to approach the problems being studied. * It is resource based and requires ready access to a wide range of resource materials. * Students usually work in small groups or teams. * Guidance and exercises require an integration of the learning experience with existing knowledge and skill. * Using of computer-aided support for problem-based learning. The courses organization The problem-based courses use stimulus material to engage students in considering a problem which, as far as possible, is presented in the same context as they would of find it in the real life; this often means that it crosses traditional disciplinary boundaries. Information on how to tackle the problem is not given, although resources are available to assist students to clarify what the problem consists of and how they of may deal with it. Students work cooperatively in small groups or teams with access to a tutor who is 132

often not an expert in the field of the particular problem presented, but someone of who can facilitate the learning process. Needed areas of learning are identified through addressing the problem, and students study resources, some of which may have been provided, others which they of have located for themselves. They then reapply this learning to the original problem. Learning that has occurred from this process is summarized and integrated into students' existing knowledge and skills. Be taking six or more subjects simultaneously. Using of computer-aided learning. The development and using of the computer models and CAD-systems or special tools occur when computer displays or represents some form of real life system or where the student inputs information and the computer emulates the real response of the real life system. It is important in the training of the design procedure to teach students of the ability to choose and develop models by using of necessary tools. Experience of Computer Engineering Department of Donetsk National Technical University (DonNTU) shows that combination of simulation and expert systems (ES) gives a good effect for solution of the described educational problems. Such problems decision allows implement main aspects of computer-aided learning. Such aspects are: • Basic principles and analysis • Design of different systems and processes • Testing and diagnostics of technical systems In first case ES functions include assessment and explanation of the students’ answers, selection of the problems corresponding to the results of this assessment, displaying of the data from standard model of the technical system/process. Therefore two ways is possible for the task formation: traditional - from teachers or from computer system after analysis. Such media can be used both for testing and learning Such concepts are applicable to problems design. In this case the problem can be proposed to students and ES. If design process may be defined as procedure of the model creation, final result of this procedure is model too. ES is supposed to estimate quantity of the developed by student under given criteria using a standard model as a knowledge source. Active position of the student in the process of learning Let us discuss the problem of the active position of the student in the process of learning. It means that student must be involved in the task to be learned and he must execute some actions as the answer on the material obtained as the stimulus of learning. Mainly it is well achieved when they use some approaches from the multimedia to the working out of the learning systems. For example, in testing and diagnostics problems for technical systems ES makes independent expertise, and student works with the model, which was preliminary learned or developed. Such approach for using supports for active learning concept and ES can do some functions on student’s error analysis and auto formation of the problems taking into account the results of this analysis. In principle, training at DonNTU is built as described, but lecturers perform the function of multimedia computer program. Hence, changing of the demand to engineering education, appearance of the modern computer technologies, transition to market relations all these dictate the necessity of the creation of computer-aided testing or/and training intellectual systems formation of active student position. A course « Expert systems » CAL system is based on real expert system for prevention of the sudden outburst. It is really actual learning problem for coal mines of Ukraine because 133

The problem of improve of reliability of technical decisions acquire the specific gravity in conditions of growth of accident rate on coal mines of Donbass. One of the most difficult tasks in mining is the prevention of sudden outbursts of coal and gas. The whole complex of measures is directed to its solving. That measures include: determinations of category of outburst’s danger of stratum; the choosing of systems of development and technology of work, dangers reduce of occurrence of outbursts; the applications of measures on maintenance of safety working in case of sudden outburst. Learning process in that area had only theoretical character. In conditions of limitation of raw, power-generating and labour resources one of the ways of increase of reliability of technical decisions is the application of new information technologies, for example, of expert systems (ES), enabling to use as the accumulated knowledge, as current information. The opportunities of ES are completely suitable in solving of difficult tasks, when there is no standard theory, the accuracy and completeness of initial data is not provided, base theoretical regulations have basically the qualitative nature. The created hybrid expert system have used as intellectual CAL system successfully and allows to apply all features described above. “Historically” the system is expansion of the information system, enabling to solve the task of expert evaluation of gas-dynamic phenomena in mines and probably display them with the purpose of prevention of emergency from the one hand and real opportunity to conduct the mining work from other one. Such approach takes into account the interrelation of monitoring and archival data, which is important at impermanent situations in conditions of deficit of time. The monitoring data arrive from the information system and are used for formation of base of knowledge of system of processing of knowledge. The latter executes their analysis and uses archive data for evaluation of validity of hypothesises, as well as data, received from users in interactive mode. The account of instruction in decisive rules is based on correction of probability of hypothesis on secondary attributes with the use of Bayesian approach. The elements of system include module of the dynamic model of object. The model is used for reception of additional information, which enables to take into account the forecast of behaviour of an object at given current situation and gives the possibility for using it in CAL. The joint work of information system and expert environment imposes the definite rules on their interactions. The problems, which had to be solved in frameworks of organisation of this programme interface include the preliminary processing of nature data and system of buffering for co-ordination of sessions of exchange and examinations. The various types of data and specific characters of expert areas predetermined the structural features of the system of processing of knowledge. It is possible to allocate two settlement blocks, directed for evaluation of current information with the purpose of formation of recommendation at the choice of hypothesises and for solving the problem of data analyses on prehistory of work accumulated within the period of 30 years are attracted on the given site of mine. Thus, student’s learning use of the problems for real ES design and organization. A course « Object- oriented programming » The course "Object-oriented programming " is directed, first of all, on learning and mastering of skills of designing of real programs with the managing messages, generation and handle of the graphics output, use of various objects of a user interface. Within the framework of course the learning and practical fixing of skills of development of programs by tools of the Borland C++ compiler is provided, as it concerns to the class of hybrid object-oriented languages and allows: - To reach acceptable efficiency of resulting programs; - To ensure compatibility with the already written applications; 134

- To save huge experience of the operating programmers; -To ensure evolutionary transition to use of the concepts of object-oriented programming. Recently the object-oriented programming has become a synonym of good style in programming - from here tendency practically of all developers by that or different way to emphasize the advanced positions in this area. Practically any modern programming language allows define some structure of data and set of the means for manipulation by this structure, however, necessity to define a new data type insignificantly distinguished from already available, results in necessity of creation of the new program unit repeating a large part of functions source. The direction of development of tools of programming obtaining the incarnation in the object- oriented programming, is a creation of such tools, which would allow constructing program objects to the greatest degree suitable to the soluble task, and examining them as "bricks” for definition of algorithm for its solution. Thus the key idea of the object-oriented programming is the creation of language tools, which on the basis of the concept of abstract types of data allow to specify new classes of program objects forming the computing environment, oriented on concrete data domain. The natural way of simulation of data domain is a selection in it of classes of objects having from the point of view of the soluble task identical properties and behavior, installation between such classes of objects of the some relations. Similarly, at use of the object-oriented programming the programmer creates an application by definition (by program way) classes of objects, structure, the properties and which behavior correspond to a model of data domain. Thus the generality of their properties is reflected by creation of hierarchy of links. Thus, the object-oriented program can be considered as the special model of data domain. Summary In this paper the main singularities of the problem-oriented (or problem-based) approach to the organization of the teaching process are briefly discussed. Also some singularities of the teaching process's organization in the technical universities are pointed out, such as activation of the student as the participant of the process of the earning of the knowledge, the offset of the center of teaching from the tutor to the student, the singularities of the deep and surface teaching .In conclusion examples there are of the application of these approaches in the setting out of the educational courses for preparation of the engineers on the of computer and intelligent systems and networks. References: 1. Theobald, J., Classroom Testing; Principtes and Practice. Melbourne: Longman Cheshire (1979).2. Marton, F., Approaches to Learning. In Marton, F., Hounsell, D. And Entwistle, N. (Eds). The Experience of Learning, Edinburgh: Scottish Universities Press (1984).3. Entwistle, N.J., Styles of Learning and Teaching. Chichester: John Wilej (1983).

COKE GRADE FOR METALLURGY Kret J., Jursovoj S. (VŠB-Technická univerzita Ostrava, Ostrava, ČR) 1. Introduction The systematic research of the properties of metallurgical coke at the VŠB – Technical University Ostrava and the Technical University Košice brought a number of results, which have already been published [2]. The effect of alkaline compounds on the coke strength and 135

reactivity has clearly been proven, as well as the effect of these substances on the thermoplastic properties of coke ash. At the further stage, the effect of the graphitization degree on the coke strength and reactivity (CSR, CRI) was investigated. In the present paper, the first preliminary results are published. 2. Effect of alkalline compounds on the properties of blast-furnace coke The strength and reactivity of coke were verified after its penetration by alkaline compounds. Before soaking the samples in respective alkaline solutions, the samples were dried in a drier at 150Â°C for 2 hours. Then the samples were boiled in alkaline solutions for 5 min. These alkaline solutions were prepared by dissolving KOH and NaOH in water at the ratio 2:1. Then, after pouring out the solution and draining away the samples, they were weighed. After repeatedly drying the samples in the drier (150Â°C, 2 hours), they were weighed again (m 1 ). After this preparatory process, the samples were ready for the CRI â&#x20AC;&#x201C; CSR tests. For measuring, solutions containing 2, 5, 8, 10, 15, 30 and 45% alkalis were used. The graph shows that the coke reactivity, described by the CRI value, increases with the increasing alkali content. On the contrary, the CSR value, which expresses the coke strength after its reaction with CO 2 at high temperatures, significantly decreases. The coke reactivity and strength measuring results clearly demonstrate a negative effect of the increased alkali content on coke. Alkaline compounds have a catalytic effect on the course of the Boudouard reaction, increase the depth and the volume of pores and, as a result, increase the degradation of coke pieces during mechanical loading. With the increasing alkali content, coke loses its strength and increases its reactivity, which is reflected by a significant decrease in the coke piece size in the area below the cohesion zone, a decreased permeability of the charge column and a decreased productivity of the blast furnace.

Fig. 1. Dependence of the CRI, CSR values on the alkaline solution concentration 3. Effect of alkaline compounds on the thermoplastic properties of coke ash Since the degradation of blast-furnace coke at high temperatures can also be caused by changes in the coke ash softening and hemispherical temperatures as a result of an action of alkaline compounds, this effect was also reviewed in a laboratory. During measuring, temperatures at which characteristic shape changes occur are recorded, in particular: 136

a) Deformation temperature – DT is a temperature at which the point or the edges of the testing pyramid begin to round as a result of fusing, b) Softening temperature – ST is the temperature when the height of the testing pyramid is equal to its base, c) Hemispherical temperature – HT is the temperature at which the testing pyramid creates a hemisphere, i.e. its height is equal to a half of its base, d) Fluid temperature – FT is the temperature at which ash has spread to a fused mass on a substrate in a layer whose height is 1/5 of the width of the testing pyramid at the hemispherical temperature. Fig. 2 shows the course of the softening temperature depending on the concentration of alkaline compounds. The effect of alkalis on the courses of the deformation, hemispherical and fluid temperatures was similar.

Fig. 2. Dependence of the softening temperature on the concentration of alkaline solution 4. Degradation of blast-furnace coke due to graphitization At the first stage, the prepared coke samples underwent high-temperature graphitization in the Acheson electric resistance furnace at three various graphitization temperatures: 2000°C; 2500°C; 3000°C. The course of heating of the coke samples before graphitization involved a gradual increase of temperatures during five hours. After this increase period, the required graphitization temperature was reached. At this required graphitization temperature (for three samples – 2000°C; 2500°C; 3000°C), the samples were held for two hours. Then, four samples of graphitic mass were evaluated using the X-ray powder diffraction analysis, while the first analyzed sample was not thermally loaded and the remaining three samples were exposed to high-temperature graphitization at 2000°C, 2500°C and 3000°C for 2 hours. Despite a low number of input data, regression analyses were made for the abovementioned dependences, which confirmed a very good correlation relationship in the both cases. For the dependence of the specific electrical resistance on the graphitization temperature, the correlation coefficient was -0.977975. (T = 3432.93 -11.3977.Ω). For the 137

dependence of the graphitization degree on the graphitization temperature, the correlation coefficient was 0.973724 (G = 0.53591 + 0.0529064.T)[1]. From individual coke samples which underwent high-temperature graphitization at 2000°C; 2500°C; 3000°C, respectively, a part was taken, from which samples were taken with the coke weight of 200 g and the grain size from 19 to 22.4 mm, which reacted with CO 2 at 1100°C for 120 minutes. Then CSR and CRI parameters were evaluated. 80 70 60 CSR - CRI (%)

CRI (%)

50 CSR (%)

40 30 20 10 0 2000

2500

3000

Temperature (°C)

Fig. 3. Dependence of the CSR - CRI values on the graphitization temperature[1] 5. Conclusion The degradation of coke in the blast furnace is a very complex process and even partial pieces of knowledge of its course have a significant technological and economic importance. The degradation of coke by the gaseous phase is a typically surface reaction, but also structural changes inside the coke mass, e.g. in its ash, cause the formation of weakened points and the reduction of the coke quality. The catalytic effect of alkaline carbonates on the course of the Boudouard reaction was clearly proven during the CRI – CSR tests. Consequently, an increased content of alkalis in coke significantly increases the coke reactivity at high temperatures and decreases its strength (CSR). The effect of the graphitization degree on the change of the high-temperature properties of blast-furnace coke cannot be evaluated in a comprehensive way yet because of a few number of experiments made, but preliminary results indicate its significant effect on the coke reactivity at temperatures above 2000°C. References: 1. KRET, J. The Coke Quality for Ironproduction. In. Sborník : Iron and Steelmaking 2008, p. 74-77. 2. KRET, J. Škodliviny při výrobě surového železa. VŠB-TU Ostrava, 2003, p.38-58.ISBN 80-248-0552-9. 3. KRET, J. Vliv alkálií na vlastnosti vysokopecního koksu. Koksárenství a jeho alternativa sborník přednášek z 27. mezinárodní koksárenské konfederace, 10-12. listopadu 1998, Malenovice , Česká republika str. 126-132. The paper was prepared within the investigation of the Project MPO FI-IM5/119.

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NEW METHODS OF MANAGING THE INDUSTRIAL ENTERPRISE WITH THE SUPPORT PROCESSED LOGIC AS WELL AS THE CALCULATION OF COSTS WITH ACTIVITY BASED COSTING METHOD Krowiak A. (Central Mining Institute, Katowice, Poland) In the article was presented a new method of managing the industrial enterprise based on processed logic and counting costs with Activity Based Costing method. Processed logic is based on the division of the entire activity of the company into processes, in which the main process and auxiliary processes are standing out. The main process includes the cycle of action from importing material to the enterprise, through the manufacturing process for the selling of finished products to the outside customer. Auxiliary processes offer services for main process. It in method this introduces to interior of enterprise market logic across transactions of sale - purchases realized among processes. The method of ABC permits in enterprise on calculation the indirect costs, from attributing theirs to concrete articles. Introduction In sciences management, what of several years, they appear the proposals of new methods steered the economic activity of enterprises. This search such the working methods is, which permit from one side on enlargement the efficiency and the effectiveness of same process of management, and they from second have for task the reducing the costs of production, by conduct of high quality of articles. The presented in article model of management with support processed logic and it is the method of ABC of calculation of costs the alternative to the most often the stepping out hierarchic structure and the division of functional enterprise. Significance of hierarchic structure of management The hierarchic structure of management shaped at dawn of histories of mankind and she be applied still universal. She, on space of ages, underwent obviously continuous improvement and it for many managers seems to be sole unique and the most effective [6]. They are the most essential features of hierarchic structure:  hierarchy - lower rung be subject to higher, and the highest there is power over all;  division of operation according to definite organizational departments;  the specific flow of information - formalise, regulated (stiff), the business character (every informs his direct superior);  information circulates mainly vertically (from bottom to head), seldom horizontally (then informal circulation);  cooperation be limited to separated structures; task be spread on units to realization, it becomes integrate then; the individual members do not know about functioning and the aim of the whole (which reduces the justification ♣ informal leaders be seen reluctantly, because they can harm manager's formal authority; Logician of procesed organization of enterprise In contrast to hierarchic structure was admitted was, that in processed logic enterprise be functionally divided on processes which contain the whole activity of enterprise. Processes can run by different organizational departments. Main processes and auxiliary processes are distinguished. Main processes include the cycle of workings connected from production the market product directly. It usually includes the cycle from importing materials to the enterprise, through the process of producing, for the selling of finished articles to the customer. If the enterprise produces many different products, for each of them gives off independent from other basic process. 139

Auxiliary processes are all other processes necessary for functioning of the enterprise, providing services for the purposes of the basic process. Processes are being announced for sub processes, action and activities. In this way the whole of activity of enterprise was described. For each of processes (sub processes, actions and activities) they are defining [2]:  entry and exit that is qualification, what is on entry (material, half-finished product, service, information) and what has to be the product of process (half-finished product, service, information);  resources – that is employees, machines and devices, means of communication assigned at the process' disposal. For processes using the same resources one should precisely determine principles of the allocation of resources for the realization of concrete processes.  costs of process – all costs associated with performing the given bundle of the activity, i.e. operations resulting in the specific process include. The optimization of these costs is an object of permanent improving the process.  length of time of realization process – it is average execution time of all operations of the process. This information is attesting indirectly to the level of organising, applied procedures, used technologies or qualifications of employees. An answer to a question is an important component of this category for the structure of the activity on account of the participation in them of work effective, forming the value. Minimization of times of delays between individual activities and rational reducing the time of the performance of activities is an object of permanent improving the process;  elasticity of processes – this attribute defines the ability of the process to: of his total change, of improving, of moulding the order of the performance of activities, possibilities of performing sure activities parallel, of linking the operation. The elasticity of the process is also appointed by his susceptibility to transformations of applied resources, as well as the speed of the change in the reply to wishes of the customer. Building elastic processes as possibly as the most and creating alternative scenarios of action is an object of permanent improving the process;  signification for organization – it is measure determining the size of the value (for basic processes - the incomes) a process is generating which; determines the connection between the process and the customer (outside and internal). This is defines in process projecting processes once. He is subject to change at the restructuring of the system of processes in the enterprise.  measures of quality as well as the criteria of acceptance [4], i.e. the list of indicators measuring the efficiency of process, permitting on control of efficiency of the use of resources. Criteria of acceptance of the product of the process allow receiving on undertaking the proper decision. Very important novelty, in relation to other methods of management, implementing in enterprise of internal customer's notion is. This is transfer to interior of firm of market logic. Market customer buying some product at first estimates his usefulness, the functionality and the price, and only then he is effecting the transaction of the purchase. In this system processes, sub processes and acting are internal customers. The manager won't get back the given process, (conventionally „won't buy”) from other product or the service for him unnecessary, about the inappropriate quality or delivered untimely. They can he also not to agree on the cost of the performed service (it concerns especially auxiliary processes). In this way of principle of control quality and promptness of performing the work are being transferred from the senior staff in the hierarchical system, for 140

the mutual control on the level managers of processes or the employees involved in realization of the given process. It was summing up the above mentioned can accept considerations, that the most essential in notion of economic process in process conception is [3]:  Process is the chain the sequential actions, which are transforming measurable entries (materials, information, people, devices, methods) into measurable exits (products, services, information);  The process has measurable aim – most generally creating the value recognised and verified by the recipient, included in products, service, information or different possible to defining final effect;  The process has supplier and the recipient (of customer), that is his limits are set by some defined type of the transaction of the purchase and the sale of the product. It can be outside or internal customer (for example an other process or other organisational unit in the enterprise);  Process can to be repeated, which marks, that is possible his recording in form enabling to reading by executors his course; Passage on logic of processed management requires very large changes in management process. In processes management we have to deal with matrix system management i.e. employee (group of employees) two superiors have: in the hierarchical configuration and in the process configuration. It can generate a lot of problems concerning jurisdiction and dictated by ambition [8]. Managing processes is held in the following of competence structure [5]:  Owner (manager of the project). He is managing processes creating the economic system of the enterprise. He is responsible for the shape, course of individual processes, synchronization between them and coordination. For him also, substantially, owners (managers) of processes are reporting;  Owner (manager) of process. He is responsible for the shape, the course and outcomes of the process and achieving planned purposes, as well as too constant streamlining the process. Owners of sub processes are reporting to him;  Management team. Is dealing with problems of economic processes, however not entering details of their structure and principles of functioning. Members of the management of the enterprise, owners of processes and managers responsible for individual functions are a member of a team (supply, production, sale).  processes team is the most important advisory-coordinating group for owners of processes. They are team members: the owner of process and owners of subprocesses. Tasks of this team are similar for tasks of the management team, with the difference that they refer (as a rule) only to one economic process. It is possible to rank among his tasks: shaping the structure and the course of the supervised economic process, defining success factors and measures and values of purposes of economic processes and their elements, current streamlining processes, regular controlling benefits of the process to the thing of other processes, setting causes of deviations and picking anticipation measures up for correcting them, documenting processes.  Team to affairs improvements. Team this deals with problems and improvements relating the individual operations and acting and the entering in constitution of economic processes. They in the target model assume that the enterprise in the whole passes through on processed management. . Organizational divisions disappear and a division into functional depart aments are disappearing. All processes are being grouped into a few mega processes, at the head which managers of projects are being put. They are kind of an equivalent of directors 141

of divisions in the hierarchical structure. Only the enterprise is already then reorientation and his structure is rebuilt with respect to processed logic. In the new logic the management the worker they are assigned for the service of individual processes and grouped together in teams to matters of the realization of processes [7]. It requires then changes of their way of thinking from directing first of all on view of the whole of enterprise and his place in processes. Only doing its work isn't a purpose in order to satisfy the manager, but contributing to a gradual increase in number of the final product. For ambitious people it is impulse to expand its professional knowledge, promotion associated with it and a sense of togetherness in the workers' staff. "My work is not the only aim in oneself, the sense has only and the usefulness for different in chain of process” Counting costs with ABC method The Activity Based Costing [1] method is very good complementing of processed logic. She lets for counting indirect costs, i.e. costs which aren't directly associated with the manufacture of the product and they were carried in relation to needs of the entire company or the productive department. The general principle consists in the fact that all costs of auxiliary processes are being assigned for the basic process, according to the key of the number of services and their values, provided for this process. The special usefulness of this method is appearing when we produce in the enterprise a lot of different products that is we distinguish a lot of main sub processes in it. For individual sub processes we are assigning only these costs which result from supplied services for them and only in the real dimension. It lets for estimating actual costs the production of individual products in the enterprise. Summary Passing the enterprise to the full management in processed logic is a very difficult, labour absorbing and expensive undertaking. It requires previously a few years of the work on the reconstruction of the awareness of the senior staff and employees as well as making of maps of processes for whole enterprise. Therefore, to be perhaps, in the scale of the world economy, there are relatively few companies, which oneself for such an undertaking, in the full dimension, made up their mind. However it isn't deprecating this method. It is possible to lead in the enterprise, gradually, certain elements of this logic. Alone he is already implementing describing the activity of the company in processed logic and the definition of criteria of functioning of processes order in the management and an optimisation process of costs is facilitating productions. The already only description in the processed logic the activity of enterprise and the qualification of criteria of functioning the processes introduces the order in management and makes easier the process of optimization of costs production. Next the ABC method is suitable for implementing practically in every organizational and competence structure, for at least her one can see full effects only in the enterprise being at the advanced stage of implementing processed logic in the management. References: 1. Gołaj R. „ABC – metoda na poznanie rzeczywistego kosztu wytworzenia produktu. Serwis Finansowo-księgowy nr 40” Warszawa, 1996r. 2. Grajewski P. – „Organizacja procesowa”, PWE, Warszawa, 2007. 3. Grajewski P. – „Koncepcja struktury organizacji procesowej”, TNOiK, Toruń, 2003. 4. Gruchman G. – „Mierzyć, aby doskonalić”, „CXO Magazyn Kadry Zarządzającej, 2002, nr. 4. 5. Nowosielski S.(red.) – „Procesy i projekty logistyczne”, w druku. 6. Penc J. – „Strategie zarządzania – perspektywiczne myślenie, systemowe działanie”, Agencja Wydawnicza „Placet”, Warszawa 1994. 7. Rummler G., Brache A. – „Podnoszenie efektywności organizacji”, PWE, Warszawa, 2000. 8. Steinbuch P.A. – „Moderne Organization fur Praxis und Studium. Prozesorganization – Bisiness Reengineering Beispiel R/3”, Friedrich Kiehl Verlag GmBH, Ludwigshafen, 1997. 142

ESTIMATION OF INFLUENCE OF SOME PARAMETERS OF DOUBLE PNEUMATIC ELASTIC ELEMENTS ON A MOTION’S SMOOTHNESS OF THE BUS Lejda K., Akopjan R. (Rzeszow University of Technology, Transport Academy of Ukraine, Rzeszow, Kiev, Poland, Ukraine) Creation of the vehicle with pneumatic suspensions is facilitated the qualitative and quantitative data of complex researches of influence of design parameters of pneumatic suspensions and suspensions on steel elastic elements, and also various service conditions on a motion’s smoothness of the base vehicle It is determined, that decreasing of a suspension’s rigidity increases a motion’s smoothness almost during all test conditions of the loaded and non-loaded LAZ – 699A bus. For example, at its test in variant Н3 (see Table 1) on road with cobblestone road decreasing of a suspension’s rigidity decrease values zс in an front part on 20; 36 and 27 %, and in back - on 22; 36 and 16 % with speeds of movement 30; 50 and 70 km/h. If to decrease a suspension rate of the bus in variant H5 on road with a concrete covering the values zс in a front part are decreased insignificantly, and in back - by 22 %; on road with cobblestone road there is a decreasing on 27 and 25 % accordingly [1]. Table 1. Constructive (oscillatory) parameters of the researched buses Parameters Numerical Index value Static load on a The non-loaded bus 19500 Н suspension, N Loaded bus 31200 Г Force of resistance to Under a force of resistance (without shock A vertical oscillations Increased (with shock absorbers) 117/9,7 — (coefficient of Suspension rate, N/sm The non-loaded with the tank (lowered rigidity) 1280 — bus without the tank (increased 2270 Р Loaded bus with the tank (lowered rigidity) 1810 — without the tank (increased 3120 Р Tire rate, N/sm Non-loaded bus 0,3 MPa (lowered rigidity) 6850 3 with pressure in 0,4 MPa 8450 4 tires 0,5 MPa (increased rigidity) 9810 5 0,6 MPa 11300 6 Loaded bus with 0,3 MPa (lowered rigidity) 9140 3 pressure in tires 0,4 MPa 10000 4 0,5 MPa (increased rigidity) 11700 5 0,6 MPa — 6 Note. The legends of variants of the researched buses are marking by the indexes. So, the variant of the non-loaded bus supplied with shock absorbers, with additional tanks and buses with pressure 0,5 МPа can be in abbreviated form written by a combination Н5. During test of the loaded LAZ – 699A in a variant Г3 on road with a concrete covering with decreasing of a suspension rate the values zс decrease in a front part on 12; 15 and 18 %, and in back - on 7; 31 and 3 % according with speeds of movement 30; 50 and 70 km/h; on road with cobblestone road - 46 and 48 % in a front and on 45 and 50 % in a back part according to speeds of movement of 30 and 50 km/h. 143

The certain law of changing the values zс in function of speed of movement is traced. During increasing the suspension rate in many cases in a range of average speeds of movement the values zс increase, and with the further increasing the speed of movement decrease; at the lowered suspension rate the values zс or increase continuously with increasing the speed, or reach a minimum at average speed of movement. Last circumstance is typical of some variants of the loaded buses, moving on a concrete-surfaced road. Besides as a result of bench tests it is determined, that the least (by absolute values) vertical acceleration of sprung mass in a range of speed limits of movement observe at increased, and in a range of average speeds - at the lowered suspension rate. It is marked also, that decreasing of a suspension rate by installation of additional tanks of small volume (7…12 litres) practically does not influence almost on numerical values of maximal accelerations zс max of sprung mass, appreciably decrease the mean-square values zс of these accelerations. Some characteristics of free oscillations of systems «seat-man» of back and front parts of the LAZ – 695Г bus are given in Tab. 2, and values of the average frequencies of the oscillations, received by dumping the wheels of the bus, and frequencies of the oscillations obtained by the analysis of autocorrelation functions (are designated by asterisks), - in Tab. 3. Table 2. Values of accelerations of the system «seat-man» of the LAZ – 695Г bus, m/s2 Road Installation Mass of the sprung parts, which fall at one cylinder, kg covering site of an 760 1620 accelerogra Height of a cylinder under static loading, mm ph (seat) 160 200 240 160 200 240 Volume of the tank 12 litres Asphalt Front 1,6...2,7 1,7...2,7 2,3...3,5 0,4...0,8 0,55...1,1 0,8...1,1 Back 1,5...2,4 1,75...2,7 2,4...4,3 1,3...1,2 2,1...1,25 CobbleFront 2,3...4,5 2,1...4,1 2,7...5,5 1,0...1,2 1,05...1,7 1,3...2,5 stone Back 2,1...5,7 2,7...5,4 2,7...4,7 1,0...1,3 1,2...1,5 Volume of the tank 24 litres Asphalt Front 0,9...1,25 1,05…1,3 1,05...1,4 0,5...0,6 0,9...1,25 0,7…0,9 Back 0,55...0,75 0,8.1,0 0,75 0,8...0,8 0,8 CobbleFront 1,5...2,4 1,7...2,7 1,7...3,2 1,5...2,7 1,0...1,8 1,2...2,0 stone Back 1,3...4,0 1,4...2,4 1,2...1,7 1,2…1,4 Table 3. Values of oscillation’s frequencies of a system «seat-man» of the LAZ - 695Г bus, oscilations/minutes Height of a The non-loaded bus The loaded bus cylinder, Volume of the tank, litres mm 0 12 90 0 12 90 160 88 74 (78) 50 84 69 (70 *) 45 200 96 80 (75 *) 71 86 72 (73 *) 64 240 103 80 85 75 The data allow revealing the influence of some factors on convenience of driving. With increasing of a cylinder’s height up to 240 mm (initial height of 200 mm), acceleration of system «seat-man» are increased on the average on 40 %, and with decreasing this height up to 160 mm are decreased on 17 %. Theoretical researches of free oscillations of sprung mass with various cylinders’ height the similar results in qualitative and quantitative relations have shown. 144

The analysis of oscillation’s frequencies shows, that the increasing of a cylinder’s height at constant loading increase the frequency of own oscillations on 13 % (concerning initial height of a cylinder of 200 mm) and decreases frequency of oscillations on 8 % at decreasing of height up to 160 mm. With increasing the sprung mass twice at presence of the tank by volume of 12 litres frequency of oscillations is decreased on 10 %. According to Tab. 1 and 2, the increasing of the tank’s volume from 12 up to 24 litres positively influences on vertical acceleration and frequency of own oscillations of system «seat-man» of the LAZ – 695Г bus (the values of accelerations decrease on 50 %). The results of research of influence of radial tires rate on a motion’s smoothness of the bus show, that decreasing of tires rate, with the rare insignificant exceptions of, improves a motion’s smoothness in the non-loaded bus and worsens it in loaded buses. For example, during movement of the non-loaded bus on a concrete-surfaced road the decreasing of tires

The mean-square values accelerations, m/s2

rate results in insignificant decrease of zс in a front part and on 11; 10; 47 % in a back part according to speeds of movement 30; 50 and 70 km/h [2]. Other results are received during tests of the loaded bus on a road both with concretesurfaced, and with cobblestone road. In the loaded bus, as against non-loaded, the values zс essentially increasing with decreasing of tires rate in a range of considered speeds (30; 50 and 70 km/h): on concrete-surfaced road in a front part on 37; 22 and 6 %, in back - on 65; 33 and 0 %; on cobblestone road - in a front part on 0; 10 and 45 %. The partial conclusion is made also, that on cobblestone road at the increased suspension rate the decreasing of tires rate of the non-loaded and loaded buses (variants НР, ГР) have an adverse effect on a motion’s smoothness. In buses with the increased tires rate the values zс as a rule, ascend with increasing of speed of movement, and in the loaded buses the point of inflection of curve of values zс in function of speed of movement corresponds to 55 km/h (Fig. 1).

Speed, km/h

a b c d Fig. 1. Dependence of mean-square values accelerations of sprung mass of the LAZ – 699A bus from speed of movement. а - at various road coverings (I, II - accordingly concrete-surfaced and a cobblestone road); b а - at various road coverings (I, II - accordingly concrete-surfaced and a cobblestone road); b at various loading; c, d - at various design parameters (I, II - accordingly non-loaded and loaded buses); 1,2 - acceleration of sprung mass above the front left and right suspensions accordingly; 3, 4 - acceleration of sprung mass above back left and right suspensions accordingly; - I; - II. 145

During the quantitative analysis it is determined, that in the bus with tires of the increased rate the increasing of loading decreases the values zс on a concrete-surfaced road in a front part on 32; 26 and 20 % with speeds accordingly 30; 50 and 70 km/h, and in back - on 30 and 23 % with speeds of 30 and 50 km/h. On a cobblestone road a motion’s smoothness with increasing the loading also is improved, especially in a front part when values zс decrease on 32; 38 and 32 %, and in back - on 25; 7 and 1 % with speeds of movement 30; 50 and 70 km/h. In buses with pneumatic suspensions of the increased rate the decreasing of a spring track demands in most cases the installation of the stabilizer of cross stability which improves a motion’s smoothness a little or practically does not influence it. Qualitatively other situation of influence of cross rigidity on a motion’s smoothness is observed in buses with suspensions of the lowered rate. For example, in variant of bus H3 the increased cross rigidity worsens smoothness of a motion on a concrete-surfaced road: the values zс increase on 21; 42 and 16 % in a front part, on a cobblestone road - on 56; 44 and 31 % in a front and on 30; 10 and 20 % - in back parts accordingly with speeds of movement 30; 50 and 70 km/h. In the loaded bus (variant Г3) the increasing of resistance’s force to oscillations qualitatively and quantitatively has the same effect as and in non-loaded (variant Н3). On a concrete-surfaced road in a front part of the bus the values zс are increased, in back – decreased on 24; 6 and 5 % with speeds of movement 30; 50 and 70 km/h. On a cobblestone road the values zс in a front part also increased, and in back - are decreased on 45; 38 and 33 % with speeds of movement 30; 50 and 70 km/h. Overlapping of characteristics of free oscillations of system “seat-man” in front and back parts of the LAZ – 695Г bus, received by means of dumping the wheels, shows, that at presence of shock-absorbers the quantity of fading oscillations of the non-loaded bus decreases up to 2,5. In the loaded bus the number of oscillations of system «seat-man» is increased, that naturally and confirms necessity of application of shock absorbers with the characteristic regulated depending on loading. As a whole the average values of factor of aperiodicity ψ of the loaded LAZ – 695Г bus are 0,2…0,25 and provide effective damping of oscillations of system «seat-man»[3]. In passing we shall note, that the conclusion about positive influence of force of resistance to oscillations (shock-absorbers) on the bus smoothness of a motion in a range of operational speeds (see Fig. 1, d) partly coincides with a conclusion about influence of shockabsorbers on loading of the bus’s carrying system [2]. It is known, that loading of carrying system of the non-loaded bus with increasing the force of resistance to oscillations is increasing, and a motion’s smoothness also is increasing. In the loaded and non-loaded buses (variants Н3, H5, Г3, Г5) the values zс on concrete-surfaced road decrease (in comparison with cobblestone road) on 150…350 %, and the bottom limit corresponds to small speed of movement (see Fig. 1, a). References: 1. Akopjan R. Budowa pojazdow samochodowzch. Rzeszow, 1995 s.218. 2. Акопян Р.А. Пневматическое подрессоривание автотранспортных средств. Часть ІI. "Вища школа". Львов, 1984 - с.237. 3. Akopjan R., Lejda K. Theoretical and operational problems of buses and their prime movers. "Meta" Lviv. 2002 - s.450.

146

ARTIFICIAL INTELLIGENCE TECHNIQUES IN DESIGN MANUFACTURING SYSTEMS Lipski J. (Lublin University of Technology, Lublin, Poland) Enterprises are required constantly redesign their products and continuously reconfigure their manufacturing system. Traditional approaches to design manufacturing systems do not fully satisfy this new situation. This paper is a review of mechatronic methods, particularly artificial intelligence (AI), applied to design components of manufacturing systems. The paper first defines components of designed systems and show example applied in real conditions. 1. Introduction The growing of industrial manufacturing and the need for higher efficiency, better product quality and lower cost have change methods of design and control processes. Based on classical theory, engineers has devised several procedures which analyze or design systems. This procedures can be summarized as [ 6 ]:  control procedures such as series compensation, pole placement, optimal control, robust control etc. 

behavioral procedures of systems such as controllability, observability and

stability tests; 

modeling procedures which consist of differential equations, input-output

transfer functions and state-space formulations. The application of this procedures alone may not be sufficient to maximize the performance of a manufacturing organization, in today’s complex manufacturing systems. We can stated that when examining the nature of the different manufacturing processes, no single unifying mathematically- provable theory can cope with. We can observe the following problems:  incomplete or excessive data; 

unidentified processes;



inherent instability of the process;



mixture of continuous and batch operations;



changed processes;

Modern manufacturing technology is interdisciplinary in nature. In process design we must apply different knowledge from other scientific fields such as manufacturing, computer science, informatics, management, marketing and control systems. Advanced intelligent automatic system has been presented on fig1. We also need to look at all aspects of the process before manufacturing a product. In many cases we also need to predict how our system will perform under certain circumstances. Our aim is to model production and control processes as accurately as possible. This aim can be obtain when we apply mechatronic methods in design process of machinetools and products. This paper is a review of the use of AI (artificial intelligence) techniques in manufacturing and control systems. Described methods make a significant contribution to improving control and manufacturing systems. 147

Case of artificial intelligence

Artificial intelligence has provided several techniques with applications in manufacturing. The first attempt to be widely used to equip manufacturing systems with some degree of intelligent was the use of KBS (knowledge-based systems). It was seek to incorporate human knowledge about en application area, usually elicited from experts in the particular domain. The human knowledge is represented using the IF-THEN production systems or more structured formats such as frames and semantic nets. An intelligent control system can be organized as an on-line expert system and comprises [5]:  multi-control functions (executive functions), 

knowledge base,



inference mechanisms,



communication interfaces.

actuators

process

sensors

Multi-control functions

Knowledge base Tasks, schedules

Low lower control Documentation, prediction High lower control Qualitative optimization

Quantitative optimization Supervision fault detection

Qualitative design methods

Analytic design method Optimization coordination Parameter and state estimation

Qualitative estimation

managment

Qualitative process models Analytic process model

Communication interface

Inference mechanisms Decisions

Qualitative reasoning

External-internal communication Quantitative reasoning

Information management data-base

Interference strategies Man - machine interaction

Fig. 1. Advanced intelligent automatic system 2.1. On-line expert system The on-line control functions are usually organized in multi-levels. The knowledge base contains quantitative and qualitative knowledge. The quantitative part operates with analytic (mathematical) process models, parameter and state estimation methods, analytic design methods (e.g. for control and fault detection), and quantitative optimization methods. Similar modules hold for the qualitative knowledge, e.g. in form of rules (fuzzy and soft 148

computing). Further knowledge is the past history in the memory and the possibility to predict the behavior. Finally tasks or schedules must be known. The inference mechanism draws conclusions either by quantitative reasoning (e.g. Boolean methods) or by qualitative reasoning (e.g. possibilistic methods) and takes decisions for the executive functions. Finally communication between the different modules, an information management data base and the man-machine interaction, has to be organized. Based on these functions of an on-line expert system an intelligent system can be built up, with the ability "to model, reason and learn the process and its automatic functions within a given frame and to govern it towards a certain goal". Hence, intelligent mechatronic systems can be developed, ranging from "low-degree intelligent" [ 6 ], as intelligent actuators, to "fairly intelligent systems", as e.g. self-navigating automatic guided vehicles. An intelligent mechatronic system e.g. adapts the controller to the mostly nonlinear behavior (adaptation) and stores its controller parameters in dependence on the position and load (learning), supervises all relevant elements and performs a fault diagnosis (supervision) to request for maintenance or if a failure occurs to fail safe (decisions on actions). In the case of multiple components supervision may help to switch off the faulty component and to perform a reconfiguration of the controlled process. 2.2. Neural networks Neural networks (NN) have been applied with success in the identification and control of dynamic systems. The universal approximation capabilities of the multilayer perceptron make it a popular choice for modeling nonlinear systems and for implementing generalpurpose nonlinear controllers. Neural network can be applied as architectures: ď&#x192;&#x2DC; Model Predictive Control; ď&#x192;&#x2DC;

Feedback Linearization Control;

ď&#x192;&#x2DC;

Model Reference Control.

Design of control systems with Neural Network [1] can be make in two steps: system identification (fig.2) and control design. In the system identification stage, it is developed a neural network model of the plant that we want to control. In the control design stage, it is used the neural network plant model to design (or train) the controller. In each of the three control architectures, the system identification stage is identical. The control design stage, however, is different for each architecture. For model predictive control, the plant model is used to predict future behavior of the plant, and an optimization algorithm is used to select the control input that optimizes future performance. This controller uses a neural network model to predict future plant responses to potential control signals. An optimization algorithm then computes the control signals that optimize future plant performance. The neural network plant model is trained offline, in batch form, using backpropagation error algorithms. The controller, however, requires a significant amount of online computation, because an optimization algorithm is performed at each sample time to compute the optimal control input. For Feedback Linearization Control, the controller is simply a rearrangement of the neural network plant model, which is trained offline, in batch form. The only online computation is a forward pass through the neural network controller. The drawback of this method is that the plant must either be in companion form, or be capable of approximation by a companion form model. For model reference control, the controller is a neural network that is trained to control a plant so that it follows a reference model. The neural network plant model is used to assist in the controller training. the model reference architecture requires that a separate neural network controller be trained offline, in addition to the neural network plant model. The controller training is computationally expensive, because it requires the use of dynamic 149

backpropagation [1]. On the positive side, model reference control applies to a larger class of plant than does Feedback Linearization Control. yp Learning algorithm

Neural network model

Plant

Error

Fig. 2. System Identification 3.

Application examples

In Lublin University of Technology has been design the expert system for optimization of application of artificial intelligence â&#x20AC;&#x201C; diagnostic system of state production process. If production process is monitoring, impotent parameters can be acquired and may be treat as kind of picture represented current state of production process. For deferent states we can assign name and forecast results. If neural network has been learning bases on this information, we can examined it using to diagnostic on line. Ideas of so kind system has been shown on fig. 3. For implementation ideas expert system with applied neural network and genetic algorithm has been used informatics tools from high-level language and interactive environment MATLAB with SIMULINK. Production process Parameters of production process

Neural Network Base of state and related set of recommended algorithms Prediction of process state

Fig. 3. Ideas of diagnostic system To conclude, this review shows that the use of AI in design, planning, quality control, process control, can result in significant gains in these particular component areas of manufacturing. The continuing demands of the manufacturing industry will necessitate the development of AI to facilitate more integrated and holistic manufacturing systems. 150

References: 1. HAGAN, M.T., AND H.B. DEMUTH: Neural Networks for Control, Proceedings of the 1999 American Control Conference, San Diego, CA, 1999, pp. 1642-1656. 2. R. ISERMANN, On the design and control of mechatronic systems, IEEE Transactions on Industrial Electronics (special issue on Development in Mechatronics) (1995). 3. R. ISERMANN, On Fuzzy Logic Applications for Automatic Control, Supervision and Fault Diagnosis (EUFTT, Aachen, 1995). 4. LEWIS, ROBERT MICHAEL and VIRGINIA TORCZON: A Globally Convergent Augmented Lagrangian Pattern Search Algorithm for Optimization with General Constraints and Simple Bounds, SIAM Journal on Optimization, Volume 12, Number 4, 2002, 1075–1089. 5. E.H. MAMDANI AND S. ASSILIAN, An experiment in linguistic synthesis with a fuzzy logic controller, International Journal Man-Machine Studies 1 (1975) 1-13. 6. F. MEZIANE, S. VADERA, K. KOBBACY, N. PROUDLOVE: Intelligent systems in manufacturing: current developments and future prospects, Integrated Manufacturing Systems, 11/4, 2000.

RESEARCHES REGARDING THE INFLUENCE OF THE ECONOMICAL CRITERIA UPON THE MAINTENANCE ACTIVITIES POLICIES Lupescu O., Pruteanu O., Popa R., Popa I., Ulianov C. (TU “Gh.Asachi”, Iassy, Romania) The paper objective consists into a comparative analysis of the industrial maintenance activities that can be applied on different technological equipments, using economically criteria. Based on these, it is presented a calculus methodology for different maintenance policies costs, as well as, a case study in which is realized a comparative analysis for these policies. This study highlights the optimum maintenance variant which can be used, as well as, the cost of these. 1. Introduction The cost being a complexity notion, for his expression reported at the technological equipment maintenance activities it is necessary, after several authors [2], to take into account in most cases some simplified hypothesis, using a series of criteria’s as: mode of origin, mode of prominence time, destination, area of expansion etc. As any other cost, the maintenance activity cost has also a multitude of influence factors, which can evidence himself directly or indirectly. A classification [3] of these allows grouping them in: a) macro-economical influence factors, where are included factors acting over the whole company, as well as, over the maintenance department: legislative system, political climate, generally estate of the economy, governmental policy in the investment area, national infrastructure estate, economy and all world nation image; b) micro-economical influence factors, with a following structure: company structure and organizational form, mission, objectives and company strategies, technological degree of production, production type (unique, small series, big series), equipment, (installation, building) wear, technological degree of maintenance activities, methods, techniques and used management process, organizational culture, industrial branch. The maintenance activities are difficult to be estimated because the performance of the equipment working parameters are based on statistical dates, their variation being realized, in reality, in very large limits. As follows, one can considerate that the dimensioning main element of the maintenance activity will be the “cost” structured on maintenance or equipment types. 151

2. Method used The economical criteria which can stays on the dimensioning calculus base is the medium maintenance cost on time unit, having specified aspects function by the adopted maintenance system [1]: • total medium cost of corrective maintenance, on time unit ( C1 ): − total medium cost of curative maintenance, on time unit ( C11 ): p+P , [m.u . / h] MTBF

C11 =

(1)

in which: p – preventive intervention cost; P – additional cost, supported when the equipment suffer a failure; MTBF – Mean time between Failure (statistically determined). − total medium cost of palliative maintenance ( C12 ): p + P'

C12 =

MTBF '

, [m.u . / h]

(2)

where: P` - additional cost, (bigger than P); MTBF` - Mean Time Between Failure (much more smaller than initial MTBF). • total medium cost of preventive maintenance, on time unit ( C 2 ): − total medium cost of systematic preventive maintenance, on time unit ( C 21 ): C 21 =

p + P ⋅ F( t ) , [m.u . / h] m( t )

(3)

where: F(t)–failure probability of a critical element considered in the t service period. At the end of this period, will be necessary a corrective intervention, generally F(t)≠0; m(t)– medium time of the considered critically element utilization; in case of a systematic preventive replacement, at the end of the T period, he can be expressed as: x

m( t ) = ∫ [1 − F (t )] dt

(4)

The m(t) period is less than T systematic preventive period. If is expected average, one can attain to the corrective maintenance case, in which m( t ) = MTBF . − total medium cost of the conditional maintenance, on time unit ( C 22 ),(rel.5): C 22 =

p+g , [m.u . / h] Kc ⋅ MTBF

(5)

where: g- application cost of the conditional maintenance, expressed as a acquisition cost of the necessary sensors, K c -conditional intervention coefficient, that increase the MTBF; − total medium cost of the forecast maintenance, on time unit ( C 23 ), (rel. 6):

152

C 23 =

p+g , [m.u . / h] Kp â&#x2039;&#x2026; MTBF

(6)

where: K p â&#x20AC;&#x201C; forecast intervention coefficient, that will substantially increase the MTBF. As follow to the application policies in the maintenance area, the selection of the maintenance type function of cost will be done according to: replacement or preventive interventions cost (p), after failure intervention cost (P), mean time between failure (MTBF), conditional maintenance tools cost (g), normalized time of the fixed equipment used (T). From graphic analysis representation, (fig. 1), results some directions regarding the most convenient maintenance policy selection, as: the most economical maintenance policy is that of the forecast type ( C 23 ), in the condition that the utilisation time T of the fixed equipment must be sufficiently big, to allow the additional equipment amortisation; for the same T period, the most expensive policy is the curative one ( C11 ), leading to a powerful costs increasing in time; in case in which the normative working time is exceeded, the maintenance costs will

Fig. 1. Maintenance system costs become excessively high ( C12 ) having an accentuated trend to increase, in the continuous decreasing conditions of the MTBF; the systematically maintenance represents a first step to a cost amelioration; if it is wanted to use the equipment for a time period lower than MTBF then, the most advantageous alternative will be the curative maintenance because, theoretically, in these period a working breakdown must not appear; if it will be continued in the same manner, the maintenance costs will have an accentuated and in jumps increase, becoming hard to be supported by the company, as one has approach by the T period. 3. Results The case study was done in a production company of technological equipments, where the authors had the permission to effectuate their researches; their objective being to realise a comparative analysis for different policies costs that can be applied in case of CNC lathe maintenance. The technical dates necessary to the study, as well as, also those referring to the costs were provided by the product manager. After the maintenance activities monitoring resulted the following: a preventive intervention cost for such a lathe is 500 m.u., in case of a 153

failure, the equipment restore is done with a cost of 1.500 m.u., the normative working time is about 14.000h, and MTBF is 400h, if it is applied a systemic maintenance the failure probability, F(t), will be 0,5, adequate to a medium utilisation time m(t) of 500h, to realise the preventive maintenance for this equipment, one can use the SKF MX 500 microlog, that costs 25.000 m.u., on a working time of 10.000h, if it is applied a conditional maintenance, this will cost 180 m.u., leading to a K c coefficient by 1,5, the last type of SKF devices, to realise preventive maintenance, costs 35.000 m.u., but the working time of these is 20.000h, and has a K p coefficient by 1,9, at the same cost of the method application, because some equipments have a exceeded time, with all efforts, one can not obtain a MTBF smaller than 70h, the new machines are guaranteed for a working time by 1.200h. On these dates base, one can effectuate a comparative analysis of different maintenance policies that can be applied on the equipments. According to (rel.1), one can obtain a total medium cost of corrective maintenance, on time unit as: C11 =

500 + 1.500 = 5 , [m.u . / h] 400

If the equipments will be used over the normative working time, the medium cost of palliative maintenance, on time unit, will be: C12 =

500 + 1.500 = 28 ,57 , [m.u . / h] 70

If we use a systematic maintenance then, the total cost will become: C 21 =

500 + 1.500 × 0.5 = 2 ,5 , [m.u . / h] 500

In the case in which one adopt the acquisition of a measure and control device then, the application cost of the conditional maintenance g will become, according to (rel.5): g=

25.000 × 400 + 180 = 1.180 , [m.u .] 10.000

As follow, the total medium cost of conditional maintenance C 22 become: C 22 =

500 + 1.180 = 4 ,2 , [m.u . / h] 1.5 × 400

Application of the forecast maintenance will lead to g expenses, determined with: g=

35.000 × 400 + 180 = 880 , [m.u .] 20.000

The medium cost for the forecast maintenance, on time unit C 23 will become:

154

C 23 =

500 + 880 = 1,81 , [m.u . / h] 1.9 Ă&#x2014; 400

4. Conclusions The effectuated study highlights that the most economical maintenance policy is the forecast one (1,81 m.u./h), followed by the systematic maintenance and the most expensive is the corrective maintenance. In the case in which the CNC lathe is used only in the guaranty period, after that, it is replaced then, the most convenient alternative is the corrective maintenance and the medium cost, on time unit in this case is: ' C11 =

500 p = = 0 ,42 , [m.u . / h] MTBF 1.200

This case study highlights also, the fact that if one apply to the replacement of the lathe, at the MTBF moment, one can obtain the most convenient cost, according to (rel.7) but, in reality, it can not be realised because the investment will be immensely big. References: 1. Deac V., Managementul mentenantei industriale, Eficient, Bucuresti, 2000 ; ISBN: 973-9366-37-6; 2. Lupescu O., Gramescu T., Lupescu Ov. & Baciu C., Managementul mentenantei echipamentelor tehnologice, Junimea, Iasi, 2007, ISBN: 978-97337-1211-2; 3. Verzea I., Marc G., Richet D., Managementul Activitatii de Mentenanta, Editura POLIROM, Iasi, 1999, ISBN: 973-683-335-6.

ACTION OF THE CERAMIC TOOL ON BURNISHING PROCESS Manole I., Nagit G., Boca M. (Technical University â&#x20AC;&#x153;Gheorghe Asachiâ&#x20AC;? of Iasi, Iasi, Romania) Burnishing process is an important and a necessary action in machine manufacturing. Because of that, burnishing becomes a research subject. Burnishing of work pieces is realizes applying one of the methods of cold plastic superficial deformation. The aim of this paper is to analysis the rolling process which is burnishing process and a method of cold plastic deformation. Analysis of this burnishing process wants to highlight the action of the ceramic ball on the steel surfaces. This burnishing method leads to changes to the structure, the physical-mechanical properties and the geometrical condition of processed surfaces. All of these changes lead to high quality for the processed surfaces which means a better product. 1. Introduction Burnishing process is a post-machining operation based on plastic deformation. The special literature, define process of cold plastic superficial deformation of metals, as processing without splint removing from the parts. The process appears under the pressure and movement of one or more tools without cutting edges over part surface. Between tool and workpiece is a relative rotation or translation movement. In this process, the surface of the workpiece is compressed by the application of a highly polished and hardened ball. The effects of this process present interest for some researchers which concentrated their work on burnishing parameters such as burnishing speed [2], burnishing depth [2], burnishing feed rate [1,4], burnishing force [1], surface hardness [2], number of passes [1], or burnishing toll dimension [2], in relation on surfaces roughness. All of this researchers study the rolling 155

process only from parameter work side in relation with surfaces roughness and hardness. Surfaces roughness is influenced by the work parameters, by the tool, and by the burnishing device. This paper studies the tool influence on burnishing process. The influence of the tool is given by dimension, by material, by form or by number. We choose to see the action of one ceramic ball on external cylindrical steel surfaces in the rolling process. Using ceramic material for the rolling tool is an important step for introduce ceramic materials in burnishing process. Were analyses the experimental results which was obtain from ceramic ball action on surfaces in rolling process. The novelty element for this research is that were used instead of regular steel for tool, the ceramic material. The mechanical characteristics of the ceramic ball like high hardness, wear-resistant make the burnishing process on the steel workpiece, more efficient. The efficiency of the ceramic ball in burnishing process can be proved on a comparative analysis from two experimental researches. In first case were used one ceramic ball for rolling process, and for the second case were used one steel ball for the same action. 2. Experimental research The experiments were made on a cylindrical external surfaces from quality steel OLC 45 with chemical composition C 0, 45%; Mn 0, 53% obtained after a chemical analyze. The workpiece was mounted on a lathe, divided in 4 sections, each having 25 mm length seen on fig.1. Then was applied a turning regime using a RP3 finishing cutting tool with a radium edge r Îľ =0,4mm. The used turning work parameters were: the feed f=0,096 [mm/rot], rotation speed n=100[rot/min] and workpiece diameter D s =43[mm].

Fig. 1.View of the sections of the sample [5] These 4 sections were note in table 1 and prepare for experimental rolling determinations. Are specified the rolling parameters. The sample and the burnishing device were fixed on a lathe. The burnishing device (fig.2) uses one simple and inexpensive burnishing tool, with interchangeable adapter for ball. The ceramic ball has a diameter db=6, 35 mm (fig. 3).

Fig. 3. The ceramic ball

Fig. 2. Burnishing device 156

Using the same work parameters, the same burnishing device and one steel bar with the same dimensions, but changing the ceramic tool with one steel ball, realize the burnishing process for the second case. 3. Experimental results After applying the rolling process using a constant pressure force was analyses the processed surfaces (fig.4).

Fig. 4. Processed surfaces Than were measured the final roughness values and calculated the burnishing degree with relation 1, which express the rapport between initial roughness value and final roughness value. λ=Rai/Raf.

(1)

The objective of the rolling process is to obtain a better quality for processed surfaces. That superior quality is the results to a low value for the roughness. Values of initial roughness, final roughness and values of rolling parameters are specified on table 1 for first case and on table 2 for the second case. Table 1. Ceramic ball burnishing results Nr.

f [mm/rot]

n [rot/min]

Db [mm]

F [N]

Rai Raf [µm] [µm]

0,059

100

6,35

350

5,48

1,00

Burnishing degree λ 5,48

2. 3. 4.

0,075 0,106 0,132

100 100 100

6,35 6,35 6,35

350 350 350

5,78 5,67 5,29

0,87 0,62 1,22

6,64 9,14 4,33

Table 2. Steel ball burnishing results Nr

1. 2. 3. 4.

f [mm/rot] 0,059 0,075 0,106 0,132

n [rot/min] 100 100 100 100

Db [mm]

F [daN]

Rai [µm]

Raf [µm]

Burnishing degree

6.35 6.35 6.35 6.35

350 350 350 350

6,00 6,96 5,94 6,00

1,58 1,60 1,20 1,30

3,79 4,35 4,95 4,61

The experimental results show that values of roughness decreases. Can be observed that in case of the ceramic ball were obtain the best burnishing degree λ=9.14 and in case of steel ball were obtain the best burnishing degree λ=4.95, that for the same value for feed 157

f=0.106 mm/rot. So using ceramic ball was obtain a better burnishing degree front of case when was used steel ball. The difference between initial roughness (fig.5) and final roughness (fig.6) in first case is highlighting on graphics.

Fig. 5. Initial roughness curve R ai =5,67 µm

Fig. 6. Final roughness curve R af =0, 62 µm 4. Conclusions: Machined surfaces by conventional method may have inherent irregularities that cause energy dissipation (friction) and surface damage (wear) that affect element performance and reliability. For such surfaces, burnishing process is capable of improving the resistance to wear, corrosion and oxidation. These improvements can be extended to minimize friction and reduce adhesion. The experimental results show that ceramic materials can be a better alternative for steel materials regarding the deformed element, in cold plastic superficial deformation domain. The characteristics of the ceramic material that has major influence on cold plastic superficial deformation processes, is a future subject for research. 5. Acknowledgments: The authors thank to the “Burse Doctorale-O investitie in inteligenta (BRAIN)”ID6681 and Professor Nagit G. for the economical support and constructive suggestions. References: 1. Hassan AM., 1997 The effects of ball and roller burnishing on the surface roughness and hardness of some non-ferrous metals. JMaterProcessTechnol1997;72(3):385–91. 2. Hassan AM., 2000 The effects of initial burnishing parameters on non-ferrous components, JMaterProcessTechnol2000;102:115–21. 3. Hassan AM., Momani AMS., 2000 Further improvements in some properties of shot peened components using the burnishing process . IntJMachToolsManuf 2000;40(12):1775– 86. 4. Manole I., 2009 Mathematical model for determine roughness parameter Ra. Bulletin of the Politehnic Institute of Iasi., 5. M., Nemat and A.C. Lyons 2000 An Investigation of the Surface Topography of Ball Burnished Mild Steel and Aluminium. pp 469-473. 158

MODELING FLOW INTO THE BARREL - A METHOD OF SOLVING THE DIRECTLY PROBLEM OF THE INNER BALLISTICS Matache L. C., CherecheĹ&#x; T., Rotariu A., Sava A.-C. (Military Technical and Technologies Research Agency, Military Technical Academy) Calculation of gas flow during the projectile traveling in barrel is a complex issue because it is a unisotherm, turbulent and leads to permanently changes of the working domain. This paper will study the motion of a 76 mm projectile in barrel determining the characteristics of gas generated by combustion powder and projectile speed variation depending on time. The flow will be considered axial-symmetric, nonstationary, unisotherm, compressible and turbulent. In order to calculate and simulate the flow, the model was implemented in a commercial calculation software with finite volume, FLUENT. Introduction The barrel armament systems are complex thermodynamic systems that are designed to launch some types of ammunition: projectiles, rockets, etc. with controlled speeds and minimal deviations from a theoretical trajectory calculated so as to produce the desired results (destruction, neutralization) on a target located at a known distance. This goal must be achieved while maintaining the safety of personnel and equipment in the proximity of weapons and requires a better knowledge of how this phenomenonâ&#x20AC;&#x2122;s are taking place, since the powder initiation until the leaving of the barrel. Projectile motion in barrel is produced by combustion of a load powder in the loading chamber. Initiation powder involves the use of mechanical, electrical or other types of devices, designed to ensure full and effective start, since a partial taking may lead to unwanted fluctuations of gas pressure generated and the default speed of casting improper or even the pink drawing. Once produced the initiation is followed by the combustion, characterized by a rapid transformation in the powder mixture of gases or gas-solid particles with simultaneous evolution of pressure and heat. Increased pressure makes the projectile to move accelerated barrel. Top of movement depends on the strength of crimping (for crimping projectiles) and the strength of commitment to barrel. As the projectile moves in the barrel, the free behind is filled with a mixture of gas-solid (powder). The flow of the barrel determines the parameters barrel flow at the mouth of fire, so the interior ballistics being of particular importance in assessing the phenomena taking place later. Since combustion in the arms does not imply external fuel intake or oxygen, the flinging dust should contain both the structure elements. Fuels used in the classic weapons of barrel are solid and are made into pieces with a well defined geometry, such as, for example, spheres, cylinders, tubular elements, etc.. Mass flow rate during combustion and thus the pressure curve in terms of time depends on the speed of burning of the surface area and total instantaneous. 1. Aspects of gas dynamics phenomena inside of the barrel weapons systems Gas flow in the barrel, regarding interior ballistic is a rather complex phenomenon that includes turbulence, combustion gas-gas-particles or fragments of powder, etc. where pressure. For example Figure 1 shows some stages of the gas flow in barrel. Figure 1a shows the room with the loading system mounted to open in the rearward projectile and cartridge disposed in the tube with vp = 0. System start producing hot gases at high pressure with the solid particles are propelled towards incandescent load of powder casting producing its initiation.

159

Once the initiation took place, the variation of mass flow of gases and local pressure, together with macroscopic permeability of the powder load, determines the initial fuel loading room. Loading densities, the type and powder form, the layout of the powder cartridge in the tube plays an important role in the combustion load casting.

b. during combustion powder and projectile traveling in barrel Fig. 1. Schematic representation of gas flow in the arms with barrel

a. before initiation of flinging powder

Figure 1b shows the flow in the barrel at a later time initiation powder when vp â&#x2030; 0. It can be seen schematically mixture and the phases of evolution of combustion. 2. Description of the model proposed Movement of a projectile in the barrel is calculated according ballistics interior equations formulated in the case of the mouths studded fire, shot in a barrel movement rotation and translation. In the present study we consider a solid rigid projectile which is only moving in translation along the axis of symmetry of the barrel. The proposed model treats the translation movement and the energy consumed for the rotation. In order to more accurate simulation of this phenomenon will be considered firing projectile that is propelled by a compressible gas generated depending on the time variation in the same time as the powder gases which arise during firing whose characteristics were determined by firing in the ballistic bomb. Depending on the gas pressure exerted on the projectile, it starts moving in translation barrel, ranging in speed depending on the calculated pressure on the back of it. Since solving this problem requires a very large volume of simulation calculations was performed in 2D, an axially symmetric model. Figure 2 shows a physical model realized using software Gamba. Projectile barrel sizes and respects the values of 76 mm caliber weapons.

Fig. 2. Physical model simulated To solve the problem proposed to use the whole field of analysis a triangular queue, differentiated by the importance and magnitude of the phenomena produced. Thus for the Board of loading area, where the initiation of combustion and powder, powder movement elements and projectile, with pressure values of over 2000 bars to a preferred queue very fine (0.8 mm), but not unduly increase the time problem-solving. Area in front of the projectile used was a queue having a size of 4 mm. Figure 3 presents a detail of the loading chamber can see the layout of the initiation (a) and the powder (b). 160

The powder that can be seen in figure equivalent items are chosen so that the total mass of powder to be respected. Law of powder combustion, combustion temperature, the movement of elements in the powder barrel, the projectile displacement and gas properties used files are placed using UDF (user define function).

Fig. 3. Loading area room detail 3. Equations governing the phenomenon The problem to be solved consists of a compressible flow, and turbulent axially symmetric. Continuity equation is given by:

 → ∂ρ + ∇⋅ρ v  = S m   ∂t  

(1)

where: Sm - mass added to the continuous phase dispersed phase Related to the 2D axial symmetric model, the equation of continuity is written as:

( ) ( )

ρv ∂ρ ∂ ∂ ρv + ρv + r = 0 + x ∂r r r ∂t ∂x where: x - axial coordinate; r - radial coordinate; v x - axial velocity; v r - radial velocity. The equation of conservation of the moment is given by:  → → ∂  →  ρ v + ∇ ⋅  ρ v v  = −∇p +    ∂t      − − → →  ∇⋅ τ + ρ g + F       where: p - static pressure; 161

(2)

− −

τ - stress tensor; → ρ g - gravitational force; → F - external force; − −

 → →T   τ = µ  ∇ v + ∇ v 

   2 →   − ∇⋅ v I  3  

(3)

where: µ – molecular viscosity; I – unit tensor; For the model presented 2D axial symmetric, the equations of conservation of axial and radial moment are written as follows:

( )

(

)

(

)

1 ∂ 1 ∂ ∂ ρv + rρv v + rρv v = x r ∂x x x r ∂r r x ∂t ∂p 1 ∂   ∂v x 2  →   − + − ∇⋅ v + rµ 2   ∂x r ∂x   ∂x 3       +

(4)

1 ∂   ∂v x ∂v r   rµ +F + x ∂x  r ∂r   ∂r  

and

( )

(

)

(

)

∂ 1 ∂ 1 ∂ ρv + rρv v + rρv v = r x r r r ∂t r ∂x r ∂r ∂p 1 ∂   ∂vr ∂v x   rµ + − + + ∂r r ∂r   ∂x ∂r    1 ∂   ∂vr 2  →   rµ 2 − ∇⋅ v −   r ∂r   ∂r 3       v v2 2 µ  →  r 2µ + ∇⋅ v + ρ z + F r   2 3 r r r  

(5)

where: → ∂v ∂v v ∇⋅ v = x + r + r ∂x ∂r r 162

(6)

In FLUENT, the turbulent heat transport is modeled using the concept of analogies Reynold's turbulent transfer timing. Energy equation model "model" is thus given by:

]

[

∂ ∂ ( ρE ) + v (ρE + p ) + ∂t ∂x x 1 ∂ rv (ρE + p ) = r ∂r r  c µ  ∂  p t  ∂T k+ + u (τ )  ij eff Pr  ∂x ∂x  t  

[

]

 c µ 1 ∂   p t r k + + Pr r ∂x   t  

 +  

(7)

 ∂T   ∂x + ru (τ ij ) eff 

   

where E – total energy; - viscous heating; (τ ) ij eff Pr - Prandtl number, meaning 0,85; t The equation of state:

  v 2 + v 2    2 r p= E − M γ (γ − 1) k + x  (8)  2   M 2γ    

Turbulent kinetic energy, k and the change of dissipation, ε are obtained from the following transport equations:  ∂ (ρk ) + ∂ ( ρkui ) = ∂  µ + µ t ∂t ∂xi ∂x j  σk + Gk + Gb − ρε − YM + S k

 ∂k     ∂x j 

(9)

and  ∂ (ρε ) + ∂ ( ρεu i ) = ∂  µ + µ ε ∂t ∂xi ∂x j  σε + C1ε

ε k

(Gk + C3ε Gb ) − C 2ε ρ ε

  

(10)

+ Sε

Turbulent viscosity, µ T is calculated as follows:

µ t = ρC µ

ε 163

(11)

Model constants C 1ε , C 2ε , C μ , σ k şi σ ε have the following values: C1ε = 1,44 C 2ε = 1,92 C µ = 0.09

(12)

σk =1 σ ε = 1,3 4. Results obtained Viteza functie de timp

Presiune functie de timp

800

300000000

700

250000000

600 200000000

500

150000000

Presiune functie de timp

400

Viteza functie de timp

300

100000000

200 50000000

100

0.006894

0.006511

0.006129

0.005746

0.005363

0.004980

0.004597

0.004214

0.003831

0.003448

0.003065

0.002682

0.002299

0.001916

0.001533

0.001150

0.000767

0.000384

0.000001

0.006688

0.006336

0.005985

0.005633

0.005281

0.004929

0.004577

0.004225

0.003873

0.003521

0.003169

0.002817

0.002465

0.002113

0.001761

0.001409

0.001057

0.000705

0.000353

0.000001

Fig. 4. Results obtained by numerical simulation 5. Conclusions A numerical model for assessing the firing phenomenon with a system of 76 mm caliber weapons was implemented using a commercial software calculation with finite 164

volume, FLUENT. Also the proposed model contributes to solving the problem directly ballistics interior determining the characteristics of the powder gas generated by combustion and gas pressure variation and velocity projectile accord to time. Coefficients used were obtained by firing in experimental ballistic bomb or evaluated through the prism of the authors experience in the field. Paper to pave the way for new studies on intermediate ballistic mouths of fire and evaluation of shock waves generated during the drawings with the arms with barrel. References: 1. POWELL, E. G., Wilmot, G., HAAR, L., KLEIN, M. (1979). Equations of State and Thermodynamic for Interior Ballistics Calculations, Progress in Astronautics and Aeronautics, 139, (Interior Ballistics of Guns) AIAA, New York. 2. FLUENT, I. (September 2006). Fluent 6.3 User's Guide. 3. K. Jamsa dr., L. K. (2003). C si C++ Fundamental Manual Programming in C and C++, Bucharest, Teora Printing House, 973-601-911-X. МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ПРОЦЕССА ВОЛОЧЕНИЯ ПРОВОЛОКИ ИЗ СПЛАВА MgCa08 Milenin A., Kustra P. (AGH University of Science and Technology, Krakow, Poland) The magnesium alloy MgCa08, witch use in medical application, has a low technological plasticity during drawing. The process of MgCa08 wire drawing is considered. The mathematical model of drawing processes of MgCa08 alloy is proposed. With help of FEM model the depending between technological parameters of drawing is obtained. Optimization process of MgCa08 alloy wire drawing process is shown. As optimization parameters the fracture criterion is used. Введение Одним из новых направлений биомедицыны, основынных на применении сплавов магния, является создание нового поколения имплантантов, растворимых в организме человека после выполнения своих функций. Таким образом удается исключить болезненное хирургическое вмешательство, связанное с извлечением имплантанта. Сплав магния MgCa08 перспективен для использования в хирургии (новые типы имплантантов, материал для сшивания тканей) в связи с высокой биосовместимостью с организмом человека, оптимальной скоростью коррозии в организме и высокими механическими характеристиками в сравнении с применяемыми материалами [1-2]. Производство проволоки из MgCa08 затруднено его низкой технологической пластичностью при комнатной температуре. В связи с этим применяют различные способы подогрева заготовки, один из которых заключается в волочении через нагретую волоку [3-4]. Применение любых способов волочения сплава MgCa08 требует оптимизации процесса волочения с точки зрения возможного разрушения. Данная статья посвящена разработке математической модели процесса волочения проволоки из MgCa08 с учетом модели возможного разрушения и использования запаса пластичности. 1. Состояние вопроса В последних исследований деформируемости сплавов магния при волочении показано, что на их предельную деформацию существенное влияние оказывают геометрические параметры волочения. Так в работах [5-6] утверждается, что оптимальное распределение деформаций по проходам и оптимальный выбор угла 165

волочения позволяют повысить холодную деформацию сплава AZ31 при волочении проволоки до 60%. Сплав MgCa08, однако, значительно менее пластичен, чем AZ31 и для него желательным является, например, подогрев заготовки. В Университете в Гановере (Германия) предложено использовать волочение в подогреваемой волоке [3]. Экспериментальный [3] и теоретический [4] анализ этого процесса показал, что параметры процесса существенным образом зависят от скорости волочения. Этого вывода и существующего уровня теоретического моделирования волочения в подогреваемых волоках [4] недостаточно для проектирования режимов деформации и параметров инструмента. Для решения этих вопросов в математической модели волочения [7] необходимо учесть возможность разрушения. В этом случае критерием оптимизации процесса может быть величина ресурса пластичности [8-11]. 2. Описание математической модели процесса волочения Математическая модель процесса волочения подробно представлена в работе [7] и основана на использовании метода конечных элементов (МКЭ). Решение ищется на основе условия стационарности следующего функционала: ξi

J = ∫ ∫ σ S (ε i , ξ i , t )dV + ∫ σξ 0 dV − ∫ σ τ vτ dF , V 0

(1)

где: σ S – напряжение текучести сплава магния в зависимости от интенсивности деформации ε i , интенсивности скорости деформации ξ i и температуры t; V – объем металла; ξ 0 – скорость деформации объемного сжатия; F – площадь контакта металла с волокой; σ τ – напряжение трения; vτ – скорость скольжения металла по поверхности волоки. На основе анализа экспериментальных данных, описанных в работе [11], с помощью методов инверсного анализа получена следующая формула, описывающая напряжение текучести сплава MgCa08 при холодной деформации:

σ S = 230ε i0.08

(2)

Тепловая задача для рассматриваемого процесса является особенно важной, поскольку нагрев металла осуществляется посредством трех механизмов – деформационного разогрева, выделения тепла трения и передачи тепла от волоки. Решение тепловой задачи в металле основано на уравнении теплопроводности. Для получения решения с помощью МКЭ использована вариационная формулировка краевой задачи. Описанная в работе [7] модель в качестве результатов дает температуру и параметры напряженно-деформированного состояния металла в узлах сетки КЭ. Доработка данной модели выполнена в части прогнозирования разрушения материала на основе расчитанных параметров в узлах сетки КЭ. 3. Модель разрушения материала В качестве базовой модели разрушения материала при волочении принят подход, предложенный в работах [9, 11, 13]. Выполненные в настоящей работе модификации существующих подходов касались реализации численного алгоритма и особенностей деформации магниевых сплавов. В качестве основного параметра, характеризующего состояние металла выбран ресурс пластичности [8, 9, 13]. В этом случае условие деформации без разрушения записыватся следующим образом: 166

ψ =

εi

ε p (kσ , µσ )

< 1,

(3)

где ψ − ресурс пластичности; ε i − интенсивность деформации в данном узле сетки КЭ; ε p − критическая деформация, при которой наступает разрушение, являющаяся функцией параметра kσ =

σ и температуры; σ − среднее напряжение; σs

σ s − напряжение текучести. Для процесса многопроходного волочения уравнение (4) можно записать следующим образом: τ

ξi dτ < 1 , ε p (kσ (τ ), µσ (τ ) ) 0

ψ =∫

(4)

где: ξi − интенсивность скорости деформации; τ − время деформации. Для модификации программы Drawing2d [7], основанной на МКЭ, необходимо записать уравнение (6) в приращениях:

ψ =

ξ i( m )

m = mτ

∑ ε (k (τ )) ∆τ σ m =1

(m)

(5)

где ∆τ (m ) − текущее приращение времени, ξ i(m ) − интенсивность скорости деформации в данной точке металла, m – индекс номера шага по времени в процессе интегрирования по линиям тока. По результатам опытов на разрушение [11] получено следующее уравнение, описывающее критическую деформацию сплава MgCa08:

ε p = 0.306 exp(− k )

(6)

Уравнение (6) было учтено в модели (1)-(5) и имплементировано в конечноэлементную программу Drawing2d [7], после чего стало возможным выполнение расчетов и оптимизация волочения. 4. Условия выполнения расчетов Рассчеты выполнены для начальной температуры металла 20°C. Процесс волочения выполнялся с вытяжкой λ = 1,25 (d 0 =2,0 mm – d 1 =1,79 mm) и различными углами волоки 4°, 6° i 7°. Коэффициент трения принят f tr = 0,03. Коэффициент теплообмена между волокой и металлом принят α=8000Вт/м2K. 5. Анализ результатов Расчитанное распределение ресурса пластичности показано на рис. 1 для сплава MgCa08. Из полученных результатов следут, что при уголе волоки 6° возможно появление трещин на поверхности проволоки (величина ресурса пластичности превышает 1). Для угла волочения 4° в соответствии с полученными данными, процесс волочения должен протекать без разрушения. 167

б)

Рис. 1. Распределение ресурса пластичности: a) угол волоки 4°, б) угол волоки 6 Выводы Разработана математическая модель процесса волочения проволоки из сплава магния повышенной биосовместимости, основанная на МКЭ и теории разрушения. Выполненные экспериментальные исследования позволили определить эмпирические коэффициенты модедлей разрушения и напряжения текучести сплава MgCa08 в холодном состоянии. Определены величины угла волоки, обеспечивающие минимальный расчетный используемый ресурс пластичности. Список литературы: 1. Heublein B., Rohde R., Niemeyer M., Kaese V., Hartung W., Röcken C., Hausdorf G., Haverich A.; Degradation of Magnesium Alloys: A New Principle in Cardiovascular Implant Technology, Paper TCT-69, 11. Annual Symposium "Transcatheter Cardiovascular Therapeutics", The American Journal of Cardiology, Expcerpta Media Inc. New York, 1999. 2. Haferkamp H., Kaese V., Niemeyer M., Phillip K., Phan-Tan T., Heublein B., Rohde R.; Exploration of Magnesium Alloys as New Material for Implantation; Mat.-wiss. u. Werkstofftech, 32: Wiley-VCH Verlag GmbH, Weinheim, 2001, s.116÷120. 3. Головко А.Н. Разработка технологии производства капиллярных магниевых труб способами горячей деформации // в кн. Совершенствование процессов и оборудования обработки давлением в металлургии и машиностроении. – Краматорск, ДГМА, Украина, 2006. – С. 231-237. 4. Bach Fr.-W., Milenin A., Kucharski R., Bormann D., Kustra P.; Modelowanie za pomocą MES procesu ciągnienia drutów ze stopu magnezu wykorzystywanych w chirurgii, Hutnik, Nr1-2, (2007), s. 8-11. 5. Yoshida K.; Cold drawing of magnesium alloy wire and fabrication of microscrews. Steel Grips, 2 (2004), s.199÷202. 6. Yoshida K., Fueki T. Cold drawing of magnesium alloy wires and tubes // Proc. 45 th Annular Conf. of Metallurgists of CIM, Monreal, Canada,2006, P. 581-593. 7. Milenin A.; Program komputerowy Drawing2d – narzędzie do analizy procesów technologicznych ciągnienia wielostopniowego. Hutnik T.72 (2005) Nr 2, - s.100÷104. 8. Kolmogorov V.; Mechanika obrabotki metallow dawleniem – Moscow, Metallurgy, 1986. 9. Bogatow A.; Osobennosti reologiczeskogo povedenija i razruszenija metalla pri monotonnoj i 168

znakoperemennojdeformaciji. Plasticzeskaja deformacja stalej i spławów, Moscow (1996) s.90÷98. 10. Grosman F., Tkocz M.; Zastosowanie funkcji odkształcalności granicznej do prognozowania utraty spójności materiału. Mat. 11 Konf. Informatyka w Technologii Metali, Zakopane 2004, s.339÷346. 11. P.Kustra, A.Milenin, M.Schaper, O.Grydin MULTISCALE MODELING AND INTERPRETATION OF TENSILE TEST OF MAGNESIUM ALLOY IN MICROCHAMBER FOR THE SEM// Computer Methods in Materials Science, Vol. 9, 2009, No.2, p. 207-214. 12. Takuda H., Morishita T., Kinoshita T., Shirakawa N.; Modeling of Formula for Flow Stress for a Magnesium Alloy AZ31 Sheet At Elevated Temperatures. J. Mat. Proc. Techn., Nr. 164-165, 2005, s.1258÷1262. 13. Bogatov A.A., Mizirickij O.I., Smirnov S.V.; Resurs plastyczności metalów pri obrabotke davlenijem Moskwa, Metalurgia, 1984, 144 s. Acknowledgment Работа выполнена в рамках проекта 416/N-DFG-SFB/2009/0, финансируемого Министерством Науки и Высшего Образования Польши. ENGINEERING EDUCATION SUPPORTED BY ELECTRONIC SCRIPTS AND HANDBOOKS Monková K., Monka P., Hloch S. (FMT TU Košice, with the seat in Prešov, Slovakia) The article deals with the utilization of electronical documentation at the teaching of the subjects related to the 3D modelling. The generation of the electronical scripts in PDF format with virtual models enables to students not only the better visualisation of the created part in the choosing CAD system, but the possibility to obtain the geometrical data of the object without their descriptions in the scripts. The paper was written thanks to support provided by the project KEGA 3/5173/07. Introduction The electronic book is equivalent to the book in print version. This term correspondents to the special electronic equipment that can be used for the reading of books in digital (electronic) version or single file containing the text in electronic version. Its origination dates from the first personal computers generation which made possible to save and to process the text in electronic version. The impulse for its development was the idea to access the important writings to the whole world. Today are made the changes in the mode of study on the universities and it is connected with the mode of creation of new scripts and school-books. The ground for these changes is the increasing of the book and script price and schools are forced to publish a lot of study literature every year. The reasons for the growth of publish activities on universities lies in obsolescence present literature, but the big influence has the expansion human activity in scientific field and the high growth rate of information technique, too. Over the past decade, many people have found electronic portfolios as an effective way to more clearly present information not only through text, but also through visuals, audio, and video formats. Traditionally, portfolios have been stored in boxes and three-ring binders. Although this format works fine for paper and other print-based materials, it misses many other ways of communicating ideas. Documents can be stored on hard drives, Zip disks, or CD-ROM in many digital formats such as text documents, picture files, web pages, digital video, and presentation files. They can be stored on hard drives, Zip disks, websites, or CD-ROM. [3]

Electronic scripts with the virtual 3D models Electronic handbooks by their conception create the assumption for their utilization more frequently in school field. They don´t claim the printing and this form of distribution is 169

more available for student then the buying literature published in edition form. One of the disadvantages of electronic script is necessity of the computer hardware holding. Teachers who design meaningful learning experiences, facilitate the use of quality technology tools and information resources, and apply effective teaching strategies determine the effectiveness of technology. Technology is an important tool in today's schools; however it's not technology "itself" that facilitates learning. Technology can provide information and tools to help students identify problems, brainstorm ideas, discuss possibilities, test ideas, and draw conclusions. Technology can provide information and tools to help students identify problems, brainstorm ideas, discuss possibilities, test ideas, and draw conclusions. The computers become an important part of our life and about its benefits nobody doubts. The programmers get the strong tools into the development hands that use the potential of computer techniques for the creation of completely new applications, which alleviate the solution not only of common problems, but already the special defined, too. New technologies bring the change of mind. The classic way “imagine the solid figure, and then create the drawing to make the solid figure again by means of them” is often substituted by technology today that thanks to three dimensional graphic enables to solve the difficult phases of the body suggestion direct in its real version of full-value stereometric body. The creating of 3D object on the basis of drawing documentation is routine in today plants. The advantages of such processed object can be reduced to the following points:  The visualisation of the object enables the optimization of its structural solution before the production, its quick modification (the dimensions editing), eventually the quick suggestion of the similar objects inside the group technology.  The utilisation of the object in the assembly allows detecting the conflicts with other components not only in static, but in kinematics state, too, so in marginal constrains of the motion.  The defining of the couples, loadings, materials and other 3D model properties enables to execute the various types of analysis (structural, thermal, dynamic…) on the object and so predicts the object behaviour in real conditions.  It is possible to simulate the machining process by means of the created 3D models and so to find out the collisions between the tool and the piece.  One of the major advantages of 3D model is the possibility to generate CL data and with the utilization of postprocessor to make the NC program for the selected control system in very short time.  Very simple preparation of the negative shape of 3D geometry for the skillets manufacturing and other.  The drawings can be processed handle, but today often by means of computers. The software that used 3D techniques considerably makes easier the labour of constructers and designers. Today is 3D model created at the first time, then the analysis and the simulations of machining process are running, consequently the drawing and technological documentation are made after the eliminating the defaults. On the basis of this documentation is the part machined. It can be said that software used 3D techniques greatly save constructers and designers labour. On the other hand, it is necessary to prepare suitable schoolbooks and scripts at the teaching of the subjects associated with the 3D modelling in all kinds and stages of study. Today forms of electronic documentation enable to put in electronic scripts 3D models instead of classic pictures. It raises effectivity of education with the possibility to roll up the object to various views without the necessity to buy of expensive CAD software. One of such formats is PDF format that provides the wide scale of set up possibilities for result document 170

properties and so the transferred document always very exactly adapts to the using purpose. Software Acrobat 3D in version 8 provides the possibility of 3D sight, without the difference of CAD application in which software was created. Through the software Adobe Reader students and other users can rotate 3D objects to reach sufficient overview about model. They can check the model display, detect model dimensions, they can make cross section and execute other activities connected with 3D model. Acrobat 3D supports conversion to 3D PDF from over 40 formats, including those for Autodesk Inventor, Dassault Systemes CATIA, PTC Pro/ENGINEER, SolidWorks, and UGS NX and I-deas. The software also provides users the option of exporting precise manufacturing CAD data from PDF into neutral file formats such as STEP, IGES and Parasolid for downstream processes, including machining operations and tool and mould design. [2] Adobe provides an extensive list of engineering applications that it has tested, including ICEM Surf, Revit, Abaqus and Rhino. Of course, it’s also possible to include ‘standard’ 2D documents in the file, like spreadsheets, Word documents etc. It’s now possible to take Adobe-converted 3D data and insert that into Excel, Word and PowerPoint. With PowerPoint a whole presentation could be one 3D slide, or a number of PowerPoint slides, looking at various details or exploded elements of a design - less a presentation, more a live design review tool. Microsoft Office docs, which contain 3D could, in-turn, be also made into PDF files. As part of the conversion process, the 3D data is ‘thinned out’ so the files are significantly smaller than the originals. [2] The example of virtual 3D assembly created in CAD/CAM system Pro/Engineer and inputted into student electronic script is shown on Figure 1. [1]

Fig. 1. Virtual 3D assembly in electronic script Three-dimensional objects in many documents need measurements (height, width, and so on) to be displayed with the object. Measurements can be created between combinations of points or edges, by moving the pointer over the 3D model, or by highlighting specific points and edges. The 3D Measurement Tool supports four types of measurements: • Perpendicular distance between two straight edges • Linear distance between two points • Radius of circular edges • Angle between two edges (or three points)

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It can be associated 3D measurements with specific views. If the default view is active when a measurement is added, a new measurement view is created. This view is added to the view hierarchy in the Model Tree. The measurement is associated with that view only, and is displayed as a child of the view. The example of measured dimensions on one of assembly component is shown on the Figure 2.

Fig. 2. The example of measured dimensions on virtual model Another advantage of modern electronic scripts can be shown at the utilization of variable video-sections (e.g. in *.avi formats). In the past, they had to be inserted in document as picture sequence (Fig. 3), but today short movies can be part of electronic text document.

Fig. 3. Picture sequence of mechanism motion Conclusions Multimedia electronic books play an important role now as the demand for creative education is becoming a major trend in all type schools. Although the textual scripting languages can describe powerful scenarios, users must be skilled with programming ability in order to create multimedia electronic books. For common users such as school teachers, it may not be an easy job for them to produce multimedia electronic books. Thus, innovative ways to create multimedia electronic books must be requested. Students and of course, engineering professionals, can now quickly share 3D CAD data with project team members, without the need for recipients to have CAD viewers or applications. With Acrobat 3D teachers, students, design engineers, technical publishers and creative professionals in manufacturing industries such as automotive, aerospace and 172

industrial machinery, as well as the architecture, engineering and construction market, can easily convert 3D models. It offers design engineers and technical publishers a complete and more secure way to collaborate with extended teams on 3D designs. For Technical Publications applications this is really fantastic. Acrobat 3D gives control capabilities to manipulate the original 3D CAD file to take ‘snap shots’ for technical docs, or technical docs can have a whole new twist and include live 3D models, with bill of materials and pre-defined animations. References: 1. HADVABOVÁ, L.: The utilization of 3D models in electric handbook for the assemblies and mechanism design, 2008, FMT TU with the seat in Prešov. 2. KREJČÍ, R.: „Adobe Acrobat 8 comes: what we can enjoy for?“; 2007, Available on internet: <http://www.grafika.cz/art/pdf/aa8.html>, Accessed: 2008-08-22. 3. ŠUŠOL, J.: Electronic information resources and book-information systems – actual problems and connectivity, 2006, Available on internet: <http://www.cvtisr.sk/itlib/itlib013/susol.htm>, Accessed: 200808-22.

THE UTILIZATION OF CAD/CAM SYSTEMS AT THE BASIC INTEGRAL MACHINE PART CHARACTERISTICS DEFINING Monková K. (FMT TU Košice, with the seat in Prešov, Slovakia) The article deals with the substance of the basic integral characteristics as are the volume, mass, centre of gravity and the moment of inertia. The article indicates on the problems, which originate at the determination of these characteristics for the parts with difficult shapes and on the possibilities of the CAD/CAM systems using as the tool that aids the solution these problems with the next applications to the process of machine parts and mechanism suggestion or dimensioning. Introduction Today the industry expansion is stimulated by contest and technical level increasing of new suggested products, therefore the utilization of computer techniques becomes necessary. There is effort for substantive advance workings time shortening (inside design, technological and project manufacturing preparation) and it does follow flexible producer reaction for the variable market conditions. The using of computers direct influences the part implementation time to the market and the product price that depends to the total costs. The most importance for today design and technological preparation stage and at the decision making about individual machine parts utilization in the manufacturing has the relationship “human-computer” with the direct iteration of the man in the process solution. The operator working in this system can communicate with computer by means of formalized language, he can change input information, analyze accounts; decide about variants of the solution atc. The level of iteration with the computers can be various. The operator covers only coding and the information input to the computer in the simpler systems, next actions are automated. These systems can be used for the technology suggestion at the design and technological simple parts, for the designing parts similar in type, atc. [3] The main role has a constructer in more advanced systems. Computers and other technical devices help at the work productivity increasing and guard higher stage of optimization for suggested solutions.

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The basic integral characteristics The term definition The dimensioning of parts and assembly components has important task at the machine and mechanism designing. The term “dimensioning” is in engineering practice marked as the dimension products definition to serve the purpose for which they was suggested. Important role within the part dimensioning and suggestion has the integral characteristics account. [1] The determination of these characteristics at parts with expressly defined shape and surface topography (block, cylinder, conic, … and their combination) can be realised by means of basic mathematical formulas. The problems originate if the part is complex shaped and its topography is not defined (for example at the prototype design). In this case is the integral characteristic calculation very laboured and time consuming also at the utilization such software equipments as is MathCAD, Matlab and Microsoft Office Excel) and in some cases even impossible (at the unknown dimensions of original body). The big role plays the computer design aiding within CAD systems and the possibility of solid presentation of the choices components. [2] The solid body represents set of points, which relative position at the arbitrary motion is always equal. It takes specific volume in space, therefore it is necessary to know not only its dimensions, but its shape, centre of gravity and weight distribution at the dynamics problems solution, too. The volume is the size of space that takes some body. Mathematically the volume is the measure describes part of space. Usually it is marked by the alphabet “V” from English Volume. The basic unit is cubic meter; the mark of unit is [m³]. The calculation of volume is one of the oldest geometry utilization in practise and today maybe most frequent. Volume of three dimensional spheres Ω it is possible expresses by triple integral

V = ∫∫∫ dxdydz

(1)

Ω

If the distribution of some quantity in space is known for example the density of mass ρ(x,y,z), than whole value of quantity, for example mass M in same space Ω, is given by triple integral

M = ∫∫∫ ρ ( x , y , z )dxdydz

(2)

Ω

It is often needed to know the centre of gravity position for individual machine and mechanism parts at the solving of problems in engineering tasks. In connection with this it is possible to say that the solid body consists from large number of matter elements of which relative position in body does not change. The gravitational forces that act on the separate elements are parallel to each other in every position of body. The resultant force is obtained by the addition of these individual parallel forces – it will be the whole gravitational body force acts in specific point of body that is called the centre of gravity. For the centre of gravity coordinates holds:

1 x.dm m V∫

1 y .dm m V∫

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1 z .dm m V∫

(3)

One of the values that characterize body mass distribution and that exist at the investigation of body rotary motion around the axis is the moment of inertia. It is marked by alphabet “I” (in older literature “J”), its unit is [kg.m2]. The bodies have the mass distributed continuously; therefore it is necessary to use integral accounts for the moments of inertia calculation. It holds the relation: I = ∫ r2 dm

(4)

during which time it is integrated through whole volume of body. The moment of inertia depends not only on the shape and mass of body, but on the axis of revolution, too. If it is needed to calculate the moment of inertia to the axis missing the centre of gravity, and the moment of inertia to the axis passes through the centre of gravity and parallel to the choosing axis is known, it is possible to use “Steiner sentence”, according to which it is valid: I = I T + md2

(5)

It can be said that the moment of inertia exists in the relations for rotary motion on these sites, where the mass exists in the relations for translate motion. The value of moment of inertia it is possible to use at the accounts of: • kinetic energy of rotary motion E k =1/2Iω2 (ω - is angular velocity of rotary motion), • moment of movement for the body doing the rotary motion Iω, • the size of moment according to the second impact sentence M = I .α (M is moment, α is angular acceleration of body) The computer aid of the moment of inertia determination The example for utilization of CAD/CAM software at the determination of integral characteristics can be shown on the camshaft. It is the shaft on which the cams are made. It is the basic part of cam mechanism used for transformation of rotary motion to the straight-line reciprocating motion. The shaft executes rotary motion; straight-line reciprocating motion is executed by cam scanned in arbitrary plane that passes the shaft axis. The camshaft is used for example at the overhead camshaft (OHC) of reciprocating internal combustion engine. The number of cams in this case depends on: • numbers of cylinders in one line of engine • numbers of valves per cylinder • OHC solution. The camshafts are usually made from cementation carbon steels or from alloyed steels. They are cemented to the depth 0,5 – 1,5 mm and hardened on 60 - 65 HRC. They can be made from cast iron or alloy cast iron, too. The shaft on Fig.1 was created in CAD/CAM system Pro/Engineer and the origin of coordinate system in regard of the model characteristics was determined, was positioned to the centre cylindrical shaft surface. The coordinate axis orientation is shown on the Fig.1a. As shaft material was selected the steel which density ρ is 7, 85 g/cm3.

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b) Fig. 1. The camshaft

It is visible from the picture that the part is symmetric to the plane pass through the axis individual cylindrical parts of shaft (xy plane), therefore the coordinate x that defines the centre gravity position must have zero value (x T =0). The model analysis was started after the defining input information; the results are shown on the Fig. 1b. Analysis takes time about several centesimal, the results was displayed almost immediately. The camshaft integral characteristics with the whole length 460 mm and with the diameter 45 mm are: • Volume V=1, 4609181. 106 mm3=1,4609181 dm3 • Weight m=1, 1343723. 10-2 t= 11,1343723 kg • The central gravity coordinates in regard to the coordinate system: x T =0, 00 mm, y T =0, 00062115409 mm, z T =215, 34613 mm The moment of inertia value depends on the axis of revolution. System calculates the moments of inertia not only to the axis pass the centre of gravity but to the axis x,y,z of the selected coordinate system. As the axis of revolution – axis z – is identical with the main axis I1, the values of the moment of inertia are identical, too. It holds: Izz = I1 = 1, 9994834 . 10 [ t.mm2] = 0, 01994834 [ kg.m2] Conclusion The creation of the shaft 3D model takes time that depends on the part complicacy and on the designer technique, respectively on his ability to have control of the software. This time is consequently equilibrated by the advantages that 3D model creating brings. By means of the virtual model it is possible to obtain not only integral characteristics, but it is possible:  to optimize the part (3D model) before the production, to modify (the dimensions editing), eventually to suggest new solutions,  to detect the conflicts with other components not only in static, but in kinematics state, too, so in limit constrains of the motion,  to define the couples, loadings, materials and other 3D model properties enables to execute the various types of analysis (structural, thermal, dynamic…) on the object and so predicts the object behaviour in real conditions,  it is possible to simulate the machining process by means of the created 3D models and so to find out the collisions between the tool and the piece, 176

 one of the major advantages of 3D model is the possibility to generate CL data and with the utilization of postprocessor to make the NC program for the selected control system in very short time, [4]  very simple preparation of the negative shape of 3D geometry for the skillets manufacturing and other. The computer aid is so effective tool for elimination of routine and uncreative activities. The computers become an important part of our life and about its benefits nobody doubts. The programmers get the strong tools into the development hands that use the potential of computer techniques for the creation of completely new applications, which alleviate the solution not only of common problems, but already the special defined, too. New technologies bring the change of mind. References: 1. MIŠÍK, Ladislav: Increasing of dynamic properties on maximal height of machined face after milling of carbonic steel C45. In: MATAR Praha 2008: Machine tools, automation and robotics in mechanical engineering: Proceedings of International Congress : Prague 16th - 17th September, Brno 2008. p. ISBN 978-80-904077-0-1. 2. MURČINKO, Jaromír: The application of XML language in CAM system Pro/Engineer Wildfire 3.0. In: Journal CA Systems in Production Planning. vol. 9, no. 1 (2008), p. 49-53. ISSN 1335-3799. 3. VALÍČEK, Jan - MULLEROVA, Jana - HLOCH, Sergej: Interpretation of the roughness measurement spectra of the surface profiles. In: Machines, technologies, materials: International virtual journal for science, technics and innovations for the industry. Vol. 2, no. 10-11 (2008), p. 22-24. 4. ZAJAC, Jozef: Adhesive properties after laser surface hardening. In: Zeszyty naukowe Politechniky Swietokrzyskiej : Kielce, 1995. Kielce : Politechnika, 1995. p. 283-288. ISSN 0239-4979 . ANALYSIS OF INTERMETALLIC PHASE PARTICLES IN IN CAST ALCU4NI2MG2 ALUMINIUM ALLOY IN T6 CONDITION Mrówka-Nowotnik G. (University of Technology, Zheshov, Poland) The main objective of this study was to analyze the morphology and composition of complex microstructure of intermetallic phases in cast AlCu4Ni2Mg2 aluminium alloy. In this study, several methods were used such as: optical light microscopy (LM), transmission (TEM) and scanning (SEM) electron microscopy in combination with X-ray analysis (EDS) using polished sample, and X-ray diffraction (XRD) to identify intermetallics in cast AlCu4Ni2Mg2 aluminum alloy. The results show that the microstructure of the examined aluminum alloy in T6 condition consisted a wide range of intermetallic phases. By using various instruments (LM, SEM, TEM, XRD) and techniques (imagine, EDS) following intermetallic phases in AlCu4Ni2Mg2 alloy were identified: θ’-Al 2 Cu, Al 6 Fe, Al 7 Cu 4 Ni, Al 12 Cu 23 Ni, Al 2 CuMg, AlCuFeNi. Introduction. Commercial aluminium alloys contains a number of second-phase particles, some of which are present because of deliberate alloying additions and others of which arise from common impurity elements and their interactions. Coarse intermetallic particles are formed during solidification - in the interdendric regions, or whilst the alloy is at a relatively high temperature in the solid state, for example, during homogenization, solution treatment or recrystallization [1-9]. They usually contain Fe and other alloying elements and/or impurities. In aluminium alloys besides the intentional additions, transition metals such as Fe, Mn and Cr are always present. Even not large amount of these impurities causes the formation of a new phase component. The exact composition of an alloy and the casting 177

condition will directly influence a selection and volume fraction of intermetallic phases [1-9]. The coarse particles can influence the recrystallization, fracture, surface, and corrosion behavior, while the dispersoids control grain size and provide stability to the metallurgical structure. The dispersoids can also affect the fracture performance and may limit strain localization during deformation. The formation of particles drains solute from the matrix and, consequently, changes the strength properties of the material. Thus, particle characterization is important not only to decide what sort of processing courses should be applied, but also for designing optimized chemical composition of a material. A variety of microscopic techniques are well appropriate to characterize intermetallics but only from a small section of an analyzed sample. From commercial point of view it is extremely advantageous to provide use quick, reliable and economical examination technique capable of providing data of particles from different locations of a full scale-sized ingot. One of these methods is dissolving the matrix of an aluminium alloy chemically or electrochemically [1-3]. Currently, there is no single method that can isolate all type of particles from different aluminium alloys. The aim of this paper is to check if chemical phenol extraction method is applicable to isolation of intermetallic particles from the casting alloy of AlCu4Ni2Mg2. Material and methodology. The investigation was carried out on the 2xxx group casting alumium alloy AlCu4Ni2Mg2. The chemical composition of the alloy is: 4.3% Cu, 2.1% Ni, 1.5% Ni, 0.3% Zn, 0.1% Fe, 0.1% Si, Al bal. The alloy was subjected to heat treatment T6: solution heat treated at 520°C for 5h followed by water cooling and artificially aging at 250°C for 5h followed by air cooling. The microstructure of examined alloy was observed using scanning and transmission electron microscopes. The intermetallic particles from investigated AlCu4Ni2Mg2 alloy were extracted chemically in phenol. and identified by using X-ray diffraction analysis. Results and discussion. The microstructure of investigated AlCu4Ni2Mg2 alloy in T6 consists different precipitates varied in shape, i.e.: fine spherulite and strip-like (I), complex rod-like (II) and ellipse-like (III) (Fig. 1) (Table 1). Table 1. The characteristic of the phases in AlCu4Ni2Mg2 alloy The phase number The characteristics I II Unetched

Fair gray

gray

Well shaped edges, the color changes into dark gray

The color changes into dark

Complex rod-like

Ellipse-like

Color Etched Shape

Distribution Type of phases Chemical composition of determined intermetallic phases (%wt) Volume fraction of the intermetallic phases in AlCu4Ni2Mg2 alloy V V

III

Spherulite and striplike Homogeneous in the matrix the α−Al alloy + poor in the boundary zone AlCu

In the interdendritic areas of the α-Al alloy

Al 46,59÷55,2 Cu 22,8÷29,5 Ni 19,8÷26,01

Al 65,48÷67,89 Cu 5,56÷7,93 Ni 13,39÷23,01 Fe 3,18÷5,95

2.3%

1.1%

178

AlCuNi

In the interdendritic areas of the αAl alloy AlCuFeNi

Fig. 1. a, b) Images from scanning electron microscope (SEM) of the AlCu4Ni2Mg2 alloy in the T6 condition; c, d) The corresponding EDS-spectra were acquired in positions indicated by the number 1 and 2 Microstructure of the examined alloy AlCu4Ni2Mg2 in T6 state consists primary precipitates of intermetallic phases combined with highly dispersed particles of hardening phases. TEM micrographs and electron diffraction patterns analysis proved that the dispersed precipitates showed in Fig. 1 are particles of intermetallic phases Al 2 CuMg and Al 6 Fe (Fig. 2) besides the precipitates of hardening phase Î¸â&#x20AC;˛-Al 2 Cu were present in AlCu4Ni2Mg alloy (Fig. 3).

Fig. 2. Microstructure of AlCu4Ni2Mg alloy in T6 condition (TEM): a) the precipitate of the Al 6 Fe phase, b) diffraction pattern, c) solution of diffraction pattern

179

The phenol extraction method was successfully applied to the examined alloy. The results of the analysis of the particles extracted from AlCu4Ni2Mg2 alloy by SEM [5-7] are consistent with the particles expected from the alloy, and this was further confirmed from Xray diffraction pattern. Since it is rather difficult to produce detailed identification of intermetallics using only one method therefore XRD technique was utilized to provide confidence in the results of phase classification based on metallographic study. X-ray diffraction pattern from the constituents extracted with boiling phenol form the solution Al alloy is shown in Fig. 3. The observed peaks confirmed optical and SEM results. The majority of the peaks were from AlCuNi, AlCuMg.

Fig. 3. The X-ray diffraction from the particles extracted from AlCu4Ni2Mg2 investigated alloy On the other hand, it is nearly impossible to make unambiguous identification of the all intermetallics present in an aluminium alloy which are rather complex, even applying all well-known measuring techniques. Diffraction analysis is one of the most powerful and appropriate technique giving the possibility to determine most of verified intermetallics based on their crystallographic parameters. Our analysis shows that the difficulties of having reliable results on the all possible existing phases in a microstructure of an alloy is related to preparation of phase isolation. The residue is separated by centrifuging and since some of the particles are very fine and available sieves are having too big outlet holes there is no chance prevents them from being flowing out from a solution. Conclusions. The electron energy-dispersive X -ray spectrometry (EDS) analysis technique evidenced that AlSi5Cu2Mg alloy microstructure is composed of only one type of the intermetallic phase, the α–AlFeMnSi phase. However, the as-cast alloy AlCu4Ni2Mg2 is mainly composed of intermetallics of AlCuNi type and as well as precipitates of Al 2 CuMg, AlCuFeNi phase. In both cases determination of all intermetallics occurred was based on two, it would appear incomparable technique, one yield chemical information while the XRD data yield crystallographic data. Basing on literature data the only technique allowing to verify the type of phases precipitates in the alloy is XRD. Only crystallographic data can strictly defined type of phases in the examined alloy. So far, there is no other technique existing for examination of isolate phases. All interested in phase’s isolation are supporting the chemical results with XRD analysis as a technique to characterization of crystalline phases of the residue. Thus, in present research this technique was used to confirm the results from microstructure observation. Since the EDS method is considered as a basic one, the thorough investigation by the use of the TEM method is carried on to confirm the results of XRD analysis. The results will be published soon. Nonetheless, even the preliminary analysis 180

showed in both cases, that the chemical composition, morphology, shape (rod-like or “Chinese script”) and distribution of the intermetallic phase depend on the condition of solidification process and applied heat treatment. Acknowledgements. This work was carried out with the financial support of the Ministry of Science and High Education under grant No. PBZ-MNiSW-3/3/2006 References: 1. P. Hodgson , B. A. Parker: The composition of insoluble intermetallic phases in aluminium alloy 6010, Journal of Materials Science 16 (1981) 1343-1348. 2. K. Sato, I. Izumi: Application of the techniques for the extraction of second-phase particles from aluminium alloys, Materials Characterization 37 (1985) 61-80. 3. A.K. Gupta, P.H. Marois, D.J. Lloyd: Review of the techniques for the extraction of second-phase particles from aluminium alloys, Materials Characterization 37 (1996). 4. M.Warmuzek, G.Mrówka, J.Sieniawski: Influence of the heat treatment on the precipitation of the intermetallic phases in comercial AlMn1FeSi alloy. Journ. of Materials Proc. Technology, 157-158(2004) 624-632.. 5. G.Mrówka-Nowotnik, J.Sieniawski: Proc. Int. Conf. „Achievements in Mechanical& Materials Engineering”, Gliwice-Wisła (2005) 447-450. 6. G.Mrówka-Nowotnik, J.Sieniawski, M.Wierzbińska: Intermetallic phase particles in 6082 aluminium alloy, Archives of Materials Science and Engineering, 28(2007)2 69-76. 7. G.Mrówka-Nowotnik, J.Sieniawski, M.Wierzbińska: Analysis of intermetallic particles in AlSi1MgMn aluminium alloys, Journal of Achievements in Materials and Manufacturing Engineering, 20(2007) 155158. 8. M.Wierzbińska, G.Mrówka-Nowotnik: Identification of phase composition of AlSi5Cu2Mg aluminium alloy in T6 condition, Archives of Materials Science and Engineering 30, 2 (2008) 85-88. 9. M. Warmuzek, J. Sieniawski, K. Wicher, G. MrówkaNowotnik, The study of distribution of the transition metals and Si during primary precipitation of the intermetallic phases in Al-Mn-Si alloys, Journal of Materials Processing Technology 175 1-3 (2006) 421-426.

TECHNICAL EDUCATION IN FACULTY OF CIVIL ENGINEERING, BRNO UNIVERSITY OF TECHNOLOGY, CZECH REPUBLIC Novotny M., Štěpánek L., Vlček M. (FCI BUT, Brno, Czech Republic) History of education in Technical Universities in the Czech Republic until 2004/2005. Transformation of the technical university education according to EU model at all universities in Czech Republic. New system of technical education used in CR since 2004/2005. The current, so-called structured study system in the Faculty of Civil Engineering of the Brno University of Technology. Technical education within the Czech Republic has a century tradition into history. One of the first technical based educational institutes in the state is the Brno University of Technology. It was founded on 17th of September 1899 to counter the already existing German technical university in Brno, which at the time already existed 50 years. The existence of the Czech Technical University was based on Austrian and German knowledge’s, which were due to the effect of historical connections, as in neighboring or hard times. The technical education came from German traditions and was different for technical high schools and universities. The technical education was therefore based on the Germanic tradition, which provided a different context of training for technical high schools and universities. According to this the secondary technical schools significantly contributed to the practice, their graduates had their working places defined, in the building industry, mechanical and electrical engineering. This type of training was usually a four year course and was completed 181

by graduation exams. The graduates were allowed to practice their profession, and had the possibility to continue their studies to obtain higher education with an engineer degree (Ing.). This tradition and hierarchy has been verified by centuries and thousands of educated professional. Many of them achieved significant successes, which we have and are seeing even today. This can be proved by the building industry which is one of the major engineering disciplines. In recent we are still surrounded by works which have been created in the past, and are still fulfilling the purpose why they have been built. Secodary education in the building industry prepared the students directly for all areas of practice, while the positions corresponded to the gained expertise. Graduates usually found their application in the following processes: building and structural design, preparation for their implementation and at the different levels of management. This also corresponded to the composition. The depth and content of teaching was prescribed for the high school training and was placed on the acquisition of practical knowledge that the graduates were able to apply in their future professions. The studies at the technical universities in the field of building construction have been allocated to deepen the expertise of the field, to deal with theory and training in the related technical and scientific disciplines. University graduates were intended to have different professional implementation within the design and management. Theyâ&#x20AC;&#x2122;ve had to spur the progress of technology by improving the existing or developing modern methods, science and further development of the knowledge and construction practice. This used and proven method of traditional secondary and university studies hierarchy in technical the fields was fully proven in the Czech Republic, the gradual modernization and improvement of educational methods to yield good results was fully compliant with the needs of practice. Since the second half of last century to universities provided the graduates with the possibility of further development by a three year post-graduate study. The aim was further enhancement of knowledge and skills by independent creative scientific work in the field. Graduates from these studies received the degrees of candidate of technical sciences - CSc., and their application was mostly in research institutes or as a teacher at universities. The structural scheme of the historical technical education in the Czech Republic is shown on fig. 1.

Fig. 1. Scheme of technical education in the Czech Republic before 2004/05 182

With the entrance of Czech Republic into the European Union and the subsequent integration of trends in the education systems were a concern of the 90 of the last century. The governments of EU member states adopted a Declaration in Sorbonne, in Bologne and in Lisboa according to which all member states are to take the given changes in the technical higher education. It was created according to the common Anglo-Saxon model of structured university hierarchy in three degrees - bachelor’s degree, master’s degree and doctoral studies, which are to be connected one to each other, but also to give the possibility to the graduates of each level to exercise their profession and training also in practice. The university studies of bachelor level are recommended with a design of 3-4 years, followed up by master‘s degree studies with a length of 2 years and doctoral studies with a duration of 3-4 years. According to this model the technical university education was gradually transformed at all universities in Czech Republic which also includes all of the faculties of Brno University of Technology after a long preparation since the mid-90s of the last century. The government of the Czech Republic determined this model of three degree education as compulsory for the studies from the academic year 2004/2005 at all universities, the ones which didn’t take this system of education till 1 9.2004 have lost their accreditation to be able to provide higher education. It was therefore necessary to make some significant and radical interventions into the historically certified system of university education which included the development of a new accreditation while submitting new plans of study for each grade, contents of courses included in the individual years of study including also the finishing of the studies by a final work made by the graduates up to its defense and state examinations. The composition of courses included in each year and semester was for the various stages of technical education in the new structure quantified in terms of volume and scope of subjects and objects in the following ranges: theoretical basis 20-25%, technical and vocational subjects 30-35 %, subjects with the orientation in technical field 20-25% and social science subjects 10-15%. As previously the teaching of subjects is carried out in three forms. Through lectures, where the students acquire the necessary information for a separate study of the issue, in the form of practices, where under the guidance of the teacher the students acquire expertise in application and solution of particular technical problems and in the form of individual studio instructions, which are essential for synthesis of theoretical and acquired expertise from all studied subjects in specific and comprehensive solutions based on technical tasks. The diagram of the current system so-called structured study system in the Faculty of Civil Engineering of the Brno University of Technology is shown on fig. 2.

183

Fig. 2. Scheme of technical education at the Faculty of Civil Engineering after 2004/05 In the initial phase of studies within the bachelor degree program the courses are primarily theory based to provide the necessary training to the students of scientific disciplines to master the professional subjects gradually while moving into the higher years of study. In the last year of the study each student finishes a drafting work which is usually known as Bachelor Degree Project, this project then has to be defended on the day of final state. The graduates of this degree obtain the title Bachelor of Science Bc., which entitles them to pursue the profession at an earlier stage of professional activity in practice, or they may continue their education in the follow-up courses for Master's degree. Specialization in the field during a the bachelor's degree study is quite limited. The follow-up Masterâ&#x20AC;&#x2122;s degree level is designed in a similar pattern, although the students get higher technical and theoretical knowledge. Also in its early stages are included the subjects with higher theoretical training after which the students are allowed to specialize to given fields. At the end of this level of study the students have to present their final projects, defend it and finally finish the state examination. The final project is known as Masterâ&#x20AC;&#x2122;s Thesis or Master Degree Project and is processed at a higher technical and theoretical level than the bachelor one. The Master's Degree graduates of technical education will receive the academic title engineer (Ing.) and are ready for self performed training, management and creative work in equivalent positions in practice. Master graduates who have proven their ability to work in the field of theory and further development of technical field may continue their studies at the university within the final level of the framework in doctoral study programs. This is the study of the individual. Under the guidance of professional trainers the students are engaged in addressing a specific technical problem and are educated to work separately in science. This professional theme is addressed at a given theoretical and experimental level, analyzes a technical problem in full context to obtain results for the further development of the field. At the end of their studies the students handle the dissertation thesis. Furthermore at the defense they must present their results within the field with their possible usage in practice in the future. Graduates of this 184

university level obtain the scientific degree Ph.D. and are ready to separately perform creatively and do scientific research in the technical field. This new system of education is applied in technical universities in Czech Republic for a relatively short time, due to this there can’t be drawn any conclusions with the preparation of the graduates to the practice. The faculty of civil engineering in the on-going academic year completed the second grade of bachelor's program graduates of the follow-up Master's programs will leave the buildings of the school for the first time in January 2010. Opinions about the success of this three grade system will be available according to the responses of the construction companies, institutions and agencies acting in the field of design. Only according to those will we be able to deliver results about the success of the new study programs in comparison to the old and traditional system of teaching. An essential aspect for the evaluation of the views of construction experience will be the comparison of knowledge in building practice between the graduates of Bachelor university courses and graduates of technical high school. The bachelor degree studies in the university education have the same length of study than the length of secondary technical education. But substantially greater emphasis is placed on theory. As to this the space to cover the necessary practical expertise is in comparison with the secondary technical schools considerably lower. The ratio of theoretical knowledge in relation to professional and practical knowledge is obviously higher for bachelor graduates than for graduates of technical high schools. In contrary the graduates of secondary technical schools have considerably much higher expertise and practical knowledge. In the end the building industry will be able to offer professions for both bachelor and technical high school graduates with the same requirements for expertise and professional level, although in the initial phase the graduates of secondary technical schools will be in the foreground according to the amount of expertise level, but the future will surely bring a serious advantageous response and the technical universities are likely to have a system of technical education to meet the requirements of practice. ASPEKTY DECYZYJNE W LOGISTYCE TRANSPORTU LEŚNEGO Pacana A. (Politechnika Rzeszowska, Rzeszów, Polska) Article presents method of estimate of quality in connection with analysis price – qualitative. It take advantage for improvement of process of taking a decision at shopping of tractor. Wstęp Postępujące w Polsce, ale również i na świecie, maszynowe pozyskanie drewna wymusza na przedsiębiorstwach sprawne i efektywne zarządzanie posiadanym transportem leśnym. Zarządzanie tym transportem wymaga działań w zakresie planowania rozwoju bazy transportowej, czyli działań w zakresie remontów, ale przede wszystkim racjonalnego zakupu ciągników.[3,4] Wspomniany proces planowania zakupów ściśle związany jest z podejmowaniem decyzji, które są zazwyczaj brzemienne w skutki. Dobre decyzje skutkujące zakupem odpowiedniej jakości środka transportu zapewniają sprawna realizację zadań. Złe decyzje utrudniają osiąganie celów, obniżają efektywność, komplikują zarządzanie. Tak, więc niezwykle ważnym, jest, aby decyzje o zakupie środka transportu były przemyślane, a najlepiej oparte o metody wspomagania decyzji. Jedną z takich dyscyplin wspomagających zarządzanie a w tym podejmowanie decyzji jest kwalitologia, czyli nauka o ocenianiu stopnia spełnialności wymagań (jakości).W artykule podjęto próbę wykorzystania jednej z metod oceny jakości w połączeniu z analizą cenowo – jakościową do wspomagania procesu 185

podejmowania decyzji o zakupie leśnego ciągnika do pozyskiwania drewna typu forwarder. Istotą artykułu jest prezentacja metodyki postępowania, a nie wykazanie najlepszego lub najgorszego ciągnika. Jakościowe elementy wspomagające podejmowanie decyzji zarządczych A) Ocena jakości metodą GSS ciągników typu forwarder Ocenę jakości wybranych ciągników forwarder dokonano na podstawie metody grupowej Wybrane do oceny jakości Tab. 1. ciągników kryteria [1] Selekcji Stanów – GSS [2]. Kryteria, do oceny KRYTERIUM jakości ciągników forwarder wybrano w oparciu o 1. Moc [kW] własną wiedzę i doświadczenie. W przypadku 2. Uciąg [kN] wykorzystywania zaprezentowanej metodyki, 3. Ładowność [kg] kupujący może wybrać inne kryteria. Wybrane na 4. Udźwig żurawia [kN] potrzeby artykułu kryteria zaprezentowano w tab. 1. 5. Wysięg żurawia [cm] Wartość jakości poszczególnych kryteriów 6. Pole poprzeczne chwytaka [m²] ustalono, podobnie jak przy wyborze kryteriów (z 7. Poziom bezpieczeństwa tych samych względów) w oparciu o własną wiedzę, 8. Serwis biorąc pod uwagę również opinię specjalistów. 9. Komfort 10. Ekologiczność Wybrane do analizy ciągniki forwarder zaprezentowano w tab. 3. W tab. 3. zaprezentowano również obliczone w oparciu o wzór (1) jakości poszczególnych ciągników. S n = 0,95U + 0,75W + 0,45X + 0,15Y

(1)

gdzie: Sn – to jakość [%], pozostałe symbole wyjaśniono w tab. 2. Oznaczenie grupy U W X Y Z

Tab. 2. Podział na grupy selekcyjne w GSS [2] Zakres spełnialności Określenie Rodzaj stanu Ponad 90% do 100% włącznie ponad 70% do 90% włącznie Ponad 50% do 70% wyłącznie ponad 30% do 50% włącznie od 0% do 30% włącznie

Zestawienie jakości ciagników Tab.31. typu forwarder obliczonej wg [1]

CIĄGNIK FORWARDER Lokomo 909P Timberjack 810 Timberjack 1010 Timberjack 1110 Timberjack 1410 Valmet 830 Valmet 840 Valmet 860 Ponsse Wisent Ponsse Elk

JAKOŚĆ [0,1] 0,54 0,66 0,69 0,79 0,81 0,66 0,75 0,79 0,79 0,79

najlepsza dobra pośrednia niedobra najgorsza

Bardzo korzystny Korzystny Pośredni Niekorzystny Bardzo niekorzystny

W celu lepszego zaprezentowania obliczonej metodą GSS jakości, wyniki przedstawiono na rys. 1. Z przedstawionego wykresu wynika, że najlepszym pod względem jakości jest ciągnik Timberjack 1410. Tuż za nim plasują się aż cztery ciągniki jednocześnie na jednym miejscu: Timberjack 1110, Valmet 860, Ponsse Wisent i Ponsse Elk. Najniżej został oceniony forwarder Lokomo 909P. B) Analiza cenowo – jakościowa ciągników forwarder Ustalono, że jakość wynosi tyle ile wyliczono w metodzie GSS po zaokrągleniu, a cenę średnią ustalono na podstawie dostępnych 186

ofert ciągników ok. 10 letnich, które prawdopodobnie najczęściej są kupowane w nadleśnictwach.

J a k o ś ć

1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 LokomoT J 810T J 1010T J 1110T J 1410V 830 V 840 V 860

P P Elk Wisent

Rys. 1. Jakość ciągników forwarder obliczona metodąGSS Ustalone dane zestawiono w tab. 4.

Tab. 4. Ustalenie wartości ceny i jakości ciągników forwarder [1] WSKAŹNIK LOKOMO TJ TJ TJ TJ VAL VAL VAL PONSSE PONSSE 909 P 810 1010 1110 1410 MET MET MET WISENT ELK 830 840 860 CENA 290 390 420 440 470 360 410 460 410 460 P [ tyś. zł] JAKOŚĆ 54 66 69 79 81 66 75 79 79 79 Q [%] Dla przeprowadzenia analizy cenowo-jakościowej, wykorzystano wzory dostępne w literaturze [2]: 1. Obliczenie wskaźnika cenowego jakości: cp =

[ ]

P zl Q 1%

(2)

gdzie: P - cena, Q - poziom jakości w [%] 2. Obliczenie ceny zrelatywizowanej

Pa − P Pa − Pi

(3)

gdzie: P - cena doraźna dla danego przypadku, Pa - cena największa dla danej ACJ, Pi - cena najmniejsza dla danej ACJ. 3. Obliczenie wskaźnika proporcjonalności cenowo-jakościowej e=

p q

(4)

187

gdzie: p - cena zrelatywizowana, q - poziom jakości wyrażony ułamkiem dziesiętnym. 4. Obliczenie wskaźnika funkcji decyzyjnej a) dla e = 0÷1 d = 0,5⋅e b) dla e > 1 d = 0,5 + 0,5⋅ (1 - 1/e)

(5) (6)

5. Obliczenie zrelatywizowanego wskaźnika cenowego

c pa − c p

(7)

c pa − c pi

gdzie: cpa - największy wskaźnik cenowy jakości w danej ACJ, cpi - najmniejszy wskaźnik cenowy jakości w danej ACJ, cp - wskaźnik cenowy jakości analizowanego wyrobu. 6. Obliczenie wskaźnika rozstrzygania dla preferencji technicznej rt = 0,167⋅(3⋅q + 2 d + c)

(8)

7. Obliczenie wskaźnika rozstrzygania dla preferencji ekonomicznej re = 0,167⋅(3⋅c + 2⋅d + q)

(9)

8.Obliczenie uśrednionego wskaźnika rozstrzygania decyzyjnego (Im wyższy wskaźnik r d , tym korzystniej dla wyrobu.)

rd = 0,5 ⋅ (rt + re )

(10)

Wyniki przedstawiono w tab. 5 i na rys. 2. Tab. 5. Zestawienie wyników obliczeń analizy cenowo – jakościowej [1] WSKAŹNIK LOKOMO 909P CENA 290 P [ tyś. zł] Jakość Q [%] Cp [zł / %] P E D C rt re rd Miejsce wg r d

TJ 810

TJ 1010

TJ 1110

TJ 1410

390

420

440

470

360

410

460

410

460

5370

5909

6086

5569

5802

5454

5466

5822

5189

5822

0,384 0,711 0,355 0,798 0,522 0,608 0,565

0,524 0,793 0,396 0,197 0,495 0,341 0,418

0,571 0,827 0,413 0 0,483 0,253 0,368

0,466 0,589 0,294 0,576 0,590 0,518 0,554

0,400 0,493 0,246 0,316 0,540 0,375 0,457

0,494 0,748 0,374 0,704 0,573 0,587 0,580

0,416 0,554 0,277 0,691 0,584 0,563 0,573

0,466 0,589 0,294 0,294 0,543 0,377 0,460

0,397 0,502 0,251 1 0,646 0,716 0,681

0,454 0,574 0,287 0,294 0,540 0,375 0,457

188

VALMET VALMET VALMET PONSSE PONSSE 830 840 860 WISENT ELK

0,7 0,6 0,5 0,4

rd 0,3 0,2 0,1 0 Lokomo

TJ 810 TJ 1010 TJ 1110 TJ 1410

V 830

V 840

V 860 P Wisent

P Elk

Rys. 2. Zestawienie wartości uśrednionego wskaźnika rozstrzygania decyzyjnego Średnia wartość wskaźnika rozstrzygania dla preferencji technicznej obliczona dla wybranych ciągników typu forwarder wyniosła 0,551. Najwyższą wartość osiągnął forwarder Ponsse Wisent – 0,646, najniższą natomiast Timberjack 1010 – 0,483. Posumowanie Przeprowadzona ACJ dla analizowanych ciągników zrywkowych wykazała, że: najbardziej opłacalnym zakupem spośród ciągników forwarder Ponsse Wisent, drugi w kolejności pod względem uśrednionego wskaźnika rozstrzygania decyzyjnego rd forwarderów Valmet 830 względem rd ustępował pierwszemu o 15%, biorąc pod uwagę wskaźnik rozstrzygania ekonomicznego re w grupie ciągników forwarder najlepszym okazał się ciągnik Ponsse Wisent, drugi w kolejności pod względem wskaźnika re w grupie forwarderów Lokomo względem wskaźnika re ustępował pierwszemu o 15%, wskaźnik rozstrzygania decyzyjnego uwzględniającego głównie aspekty techniczne rt jako najlepszy forwarder okazał się ponownie Ponsse Wisent, drugi w kolejności pod względem wskaźnika rt Timberjack 1110 ustępował pierwszemu o 9%. Wyciągnięte wnioski ukazują różnice cenowo – jakościowe w analizowanych, porównywalnych modelach ciągników. Różnice te pozwalają wskazać ciągnik najlepszy przy ustalonych założeniach. Możliwe jest również wskazanie najlepszego ciągnika z uwzględnieniem preferencji ekonomicznych i technicznych. Wyniki uzyskane w tej analizie potwierdzają poprawność metodyki postępowania, jako metodyki wspomagającej proces podejmowania decyzji zarządczych w zakresie zakupu. Formułując powyższe wnioski należy pamiętać, że w zasadzie jest to tylko prezentacja metody. Inny ekspert mógłby do oceny wybrać inne (interesujące jego) ciągniki, inne kryteria do oceny jakości jak też mógłby je ocenić. Oczywiście mógłby również wybrać inną metodę kwalitologiczną np. punktację sformalizowaną czy MAP. Ponieważ okazało się, że kryteria jakościowe odgrywają ważną rolę w podejmowaniu decyzji dlatego celowym wydaje się oparcie procesu decyzyjnego właśnie o kryteria jakościowe i cenowe,. Literatura: 1. Oliwko B., Pacana A., Jakościowe aspekty zarządzania transportem leśnym na przykładzie Lasów Państwowych, Materiały niepublikowane, Rzeszów 2008; 2. Pacana A., Sterowanie jakością, OWPRz, Rzeszów 2000; 3. Poradnik leśniczego, pod red. K. Rogalińskiego, Wydawnictwo Świat, Warszawa 2005.; 4. Użytkowanie maszyn leśnych, pod red. J. Walczyka, PAU, Kraków 2001. 189

THE MODEL OF BEARING REDUCER Paško J., Balara A. (FMT TU Košice, with the seat in Prešov, Slovakia) The paper describes the dynamic properties of the SPINEA TWINSPIN transmission (bearing reducer) as a linear three mass s ystem. The paper contains the movement equations, kinematics diagram and describes the simulated time responses of torque and speed on the output shaft of transmission. Described SPINEA TWINSPIN transmission has damped oscillations of output torque and very damped oscillations of output speed. The paper also contains the transient functions and frequency characteristics of this transmission. 1 Introduction The transmissions of SPINEA TWINSPIN type represent the new generation of transmission systems. Their manufacturing label is SDA (SPINEA Drive A series). They are based on the unique reduction mechanism that represents a new generation of a high precision transmissions. They integrate two functionalities: the reduction of revolutions and bearing [2]. The components of the SDA transmission are assembled in prestressed state in order to linearize the torsion characteristics of the transmission and elimination of its backlash. The prestress contributes to friction torque indicated on the input shaft of the transmission very slightly. Cylindrical bearing on the input shaft results in very low friction torque. The use of rolling kinematics coupling in the reduction mechanism results in the maximal possible effectiveness of the power transfer from input to output. Because of very low internal friction of the transmission, the gear wheels almost do not gall. That brings remarkably longer life cycle and reliability comparing to other available systems. Low internal friction allows the transmission to work with very high nominal revolutions. The properties of this kind of transmissions determine the range of use that are mainly: tool machines and tool machine centers, robots and assembling systems, manipulation and transport systems, indexing devices, manufacturing machines, production of aviation and arms industry, drive actuators and servosystems, navigation and measuring devices. The integration of the reducer and bearing allows the use of such transmission for example as: joint of a robot, rotating table of a tool machine, or as welding positioner. In such cases the external forces and torques are transferred by the radial-axial bearing installed inside the transmission. 2 The pricipal of the spinea twinspin transmission The basic parts of the transmission type SPINEA are pictured in the Fig. 1 [2]. The input shaft of the transmission is shaped in a way that there are two excenters on its body opposite to each other. The excenters transfer their movement onto SD wheels with cylindrical gearing by means of a roll guide. The above-mentioned SD wheels are then rolled by excenters so that they lean against cylindrical gearing of the main body of the transmission by their cylindrical gearing. Because of cylindrical gearing of the main body has more teeth than SD wheels, these, except rolling, also rotate by the angle speed given by the ratio of the number of teeth difference. The resulting reduced speed of the SD wheels is then transferred to the output shaft of the transmission by means of transformation parts that lean against SD wheels and output shaft by means of reduction cylinders. 3 Ilnear mathematical model of spinea transmission The components of the SDA transmission are assembled in prestressed state in order to linearize the torsion characteristics of the transmission and elimination of its backlash. Thus we assume it is linear system without backlash [1]. Then the SPINEA transmission appears to be a three mass system with elastic coupling (Fig. 2). 190

Linear differential equations describing the system according to Fig. 2 are as follows: J1

dω 1 = M 1 − M t1 − M 2 / i dt dω 2 J2 = M 2 − M t2 − M 3 dt

(1) (2)

dω 3 = M3 − M t 3 dt

(3)

M 2 = M 21 .i M 21 = k1 (φ1 − φ 2' ) + b1 (ω1 − ω 2' ) M 3 = k 2 (φ 2 − φ 3 ) + b2 (ω 2 − ω 3 )

(4) (5) (6)

J3 then

M 33 = M 3 − M t 3 ω 2′ = ω 2 .i φ2′ = φ 2 .i

(7) (8) (9)

where - torque of the servomotor, (input torque), M1 M 21 - torque of elastic coupling of the inertias, M2 - torque of elastic coupling of the inertias 1 and 2 (J 1 and J 2 ), M 33 - torque of elastic coupling of the inertias, - torque of elastic coupling of the inertias 2 and 3 (J 2 and J 3 ), M3 M t1 - torque of viscous friction of servomotor anchor and input shaft of the transmission, M t2 - torque of viscous friction of the mechanism inside the transmission, M t3 - torque of viscous friction of output flange of the transmission, i - gear ratio of the transmission, - servomotor anchor inertia, Jm J INP - input part of transmission inertia, J1 - inertia consisting of servomotor anchor inertia and input inertia, J2 - SD wheels with cylindrical gearing inertia, - output part of transmission inertia and inertia of load connected to output J3 flange of the transmission, φ1 - angle position of the input shaft, φ2 - angle position of the SD wheels with cylindrical gearing, φ‘ 2 - angle position of the SD wheels with cylindrical gearing adjusted to input, φ3 - angle position of the output shaft (flange), ω1 - angle speed of servomotor anchor and input shaft of the transmission, ω2 - angle speed of the SD wheels with cylindrical gearing, ω‘ 2 - angle speed of the SD wheels with cylindrical gearing adjusted to input, ω3 - angle speed of transmission output flange, - torsional spring constant of input, k1 k2 - torsional spring constant between SD wheels and transmission output flange, b1 - dissipative dumping constant of the transmission input, 191

b2 - dissipative dumping constant of the transmission output, p1 - viscous friction constant of transmission input, p2 - viscous friction constant of transmission internal parts, p3 - viscous friction constant of transmission output, s - Laplace operator. 4 Simulation of transmission properties The parameters of simulated transmission SPINEA SD 170 are as follows: J INP = 4,4.10-5 kgm2 J 1 = 0,711.10-4 kgm2 J 2 = 0,894.10-5 kgm2 J 3 = 0,13454 kgm2 i = 31 k 1 = 250 000 Nm/rad k 2 = 321 314 Nm/rad b 1 = 20 Nms/rad b 2 = 45 Nms/rad p 1 = 0,001 Nms/rad p 2 = p 3 = 0,05 Nms/rad The properties of transmission with the above parameters are starting point for solution of automatic control systems featuring SPINEA transmission. Simulated time responses of output angle speed and output torque of SPINEA transmission (SD 170 type) to step and time limited change of the input torque are pictured in the Fig. 3. Simulation was done to examine transmission model response to input torque of 0.6 Nm and its duration of 0,1 s. Fig. 3 shows „output torque“ response, or in the other words, it shows reaction of output flange of the SPINEA transmission to the defined input torque. Consolidation after dumping is shorter than 0,01 second. The curve „output speed“ displays angle speed of the output shaft of the transmission. Simulation was programmed in the MATLAB software package with SIMULINK module. With regards to torque responses the model of SPINEA transmission has properties of the oscillating system with a high stiffness and damping. This results in damped transient responses of the angle speed that approximate the characteristics of the proportional system. 5 Calculation of characteristics and determination of transfer function Frequency responses and the following parameters were acquired by using the abovementioned parameters of the transmission and differential equations, as well as by means of MATLAB software tools with SIMULING module: - the gain of transfer function K T = 1/ i = 1/97 = 0,01031 [K T ] dB = - 39,735 dB - damping (according to [5]) a = 0, 123 Fig. 4 confirms the values of the calculated gains and shows frequency responses of SPINEA SD 170 transmission that were simulated in MATLAB software package with SIMULINK module. The following values of the time constants and break frequencies of the image transfer F T (s) of SPINEA SD 170 transmission were read from the Fig. 4: T 0 = 7,69 . 10-4 s, T 1 = 10-4 s, T 2 = 3,33 . 10-6 s, T 3 = 3,636 . 10-11 s ω 0 =1,3.10 3 sec –1, ω1 =104 sec –1, ω 2 =3.105 sec –1 , ω 3 =2,75.1010sec -1 We determined the image transfer function of the examined transmission according to slope of the plots as follows:

192

FT ( s ) =

M o (s) KT (T1 s + 1) = 2 2 M i ( s ) (T0 s + 2aT0 s + 1)(T2 s + 1)(T3 s + 1)

(10)

After substitution of determined time constants and other parameters of SPINEA SD 170 transmission this general function becomes:

FT ( s ) =

M o (s) 0,01031.(0,0001s + 1) (11) = −7 2 M i ( s ) (5,91.10 s + 1,958.10 − 4 s + 1)(3,33.10 −6 s + 1)(3,636.10 −11 s + 1)

The properties of described transmission are the starting point for the solution of automatic control systems with SPINEA transmission. According to torque and frequency characteristics and image transfer function the SPINEA transmission appears to be a proportional-derivative system of the 4th-order. With regard to magnitude of the time constants we can neglect all of them except the biggest one. In that case the torque image transfer function of the transmission will be represented by an oscillating system transfer function:

FT ( s ) =

M o (s) KT = 2 2 M i ( s ) (T0 s + 2aT0 s + 1)

(12)

This simplified model is confirmed by the results of simulation. According to plot of the torque responses (Fig. 3) and frequency characteristics in complex coordinates (Fig. 4) the examined model of SPINEA transmission represents the oscillating system with a very high stiffness and rather high damping. The influence of the remaining smaller time constants was not observable. 6 Conclusion The SPINEA TWINSPIN transmission according to torque and frequency characteristics and image transfer function appears to be a proportional-derivative system of the 4th-order. With regard to magnitude of the time constants we can neglect all of them except the biggest one. In that case the torque image transfer function of the transmission will be represented by an oscillating system. In simulation of the transient responses the influence of the neglected smaller time constants was not observable. The nature of damped oscillating transient responses of angle speed approximates the proportional systems. Described SPINEA transmission and its model represent the oscillating system with a very high stiffness and damping. Consequently it leads to damped transient responses of angle speed that approximate the characteristics of proportional systems. In comparison to harmonic transmission the SPINEA TWINSPIN transmission appears to be a system with higher stiffness and higher damping. Except the function of a high precision reducer it functions also as a bearing, which is its significant advantage. References: 1. Balara, M., Balara, D., Balara, A., Gots, I., 1998: The Three Mass Model of Harmonic Transmission. International Journal Automation Austria, Heft 1,2, Jg.6, (1998), Wienna, Austria, pp. 27 - 36. 2. SPINEA DRIVE SDA SERIES, 1998, New High Precison Reduction Gear, Obchodno technický buletin firmy SPINEA Ltd., Košice. 3.·Balara, M., Balara, A.: Nonlinear Model of Harmonic Drive. ROBTEP ´95, Automation Robotics in Theory and Practice, Prešov, 2. Celoštátna konferencia s medzinárodnou účasťou, 27. - 28. 9. 1995, Str. 82 – 85. 4. Balara, M.: Matematický model dynamických vlastností ložiskového reduktora Twinspin. Automa, roč. 8, č. 5 – 2002, ISSN 1210 – 9592. FCC Public 193

s. r. o. Praha, Česká republika. Str. 49 – 51. 5. Dorf, C.R.: Modern Control Systems. AddisonWesley Publ. Company. Menlo Park, Ca., 1980, ISBN 0- 201-01258-8, pp. 109 – 145.

Fig. 1. The transmission (bearing reducer) SPINEA - TWINSPIN

Fig. 2. Kinematics diagram of the The transmission SPINEA - TWINSPIN

194

Output torque

Output speed

Input torque

Fig. 3. The time responses of the transmission SPINEA SD 170 after the time limited impulse form of the input torque change

Fig.4. Frequency (Bode) characteristics in logarithmic axes of the SPINEA SD 170 transmission

195

RESEARCHES REGARDING THE DETERMINATION OF SPARE PARTS ACQUISITION COST USED IN TECHNOLOGICAL EQUIPMENT CORRECTIVE MAINTENANCE Popa R., Pruteanu O., Lupescu O., Popa I., Baciu C. (TU “Gh.Asachi”, Iassy, Roumania) The purpose of this paper is to establish the acquisition cost of spare parts, which are necessary in the corrective maintenance activities, depending to the quantity that is bayed. Defining a well established methodology, the authors realize even a case study regarding the necessary spare parts quantity determination, as well as, the minimum acquisition cost of these, if the producer company offer discount in order to the required quantity. 1. Introduction The establishment of stokes administration policy is connected to the knowledge of those elements which characterize the stoking process and who determine the forming level of stocks as [1]: • consume demand - base element that determine the necessary issue and entrance level, rhythm and volume, and also the stock level; • costs - representing the expenses that must be effectuated for the provisionstoking process deployment (respectively those related to order, contraction, transport, storage, materials stocking, etc.). To calculate stocks one consider: stoking costs; penury costs or breakage stock costs; cost due to the rhythm vibrations of the production; acquisition cost or direct costs of production. • reprovision quantity - representing the necessary provision that can be established depending by the necessary spare parts to consume the entire administrated period; • lot – representing the quantity with which one makes the provision, at some intervals, in the established administration time (trimester, semester, years) and which is depending by the demand character; • temporal parameters – specifically to the stocking process dynamics, the most important being: administration period that usually is considerate to be one year; time interval between two consecutive provisions; reprovision time; calendar moment at which the reprovision orders are issued. • processing degree of products. In all models of the spare parts stock administration (determinist or stochastically) the acquisition cost for a time unit, C a , is constantly [3]. Also exists some in which is gived a deduction by “p” percents at the acquisition cost, for some biggest quantity of products achieved. For example, if we have an initial acquisition cost, c a but, we buy at least a1 90 products and one give a deduction by 10%, the new acquisition cost become: ⋅ Ca . 100 Also, even the stocking cost, on a product unit can be expressed as a α percent from the acquisition cost. Thus, depending by the bayed quantity; we can have more acquisition costs and more stocking costs. 2. Method used Using a stocking determinist model with a delivery time provision for spare parts, when the absence in stock may not be accepted, the work hypotheses can be: • τ days for the delivery time; • the absence in stock may be not accepted (s≠0); 196

• launching costs cl is constant, known and independently from the delivered products number; • the demand ( r ) is constant an known; • stocking cost ( c s ) is constant and known; • c a (acquisition cost of a product unit) can be replaced in the delivery time provision case with (rel.1):

c1 c  ca =  2  ... c m

a0 ≤ Q < a1 ,( a0 = 0 )

a1 ≤ Q < a 2

am ≤ Q

(1)

Supposing that initially, in stock are Q spare parts after a T time interval (the demand being constant), the stock becomes 0. In this moment a new command is remitted, for the stock restoration and the stock will have again Q spare parts. Because the absence in stock is not accepted, the order is launching with τ days before the stock will be finished. The orders number that must be launched can be determined through θ / T rapport, or by N / Q , and can be calculated with (rel.2): θ N = T Q

(2)

Considering the case in which the acquisition cost for a product, per year, is: c s = α ⋅ ca

(3)

then, for each acquisition cost ci , that depends by the bayed quantity (rel.1) dependung by the total stocking cost, the total orders launching cost and also the total acquisition cost for those N products, realise the total cost f(Q), which is a function with a single variable Q (fig.1)[2]: fi ( Q ) =

α ⋅ ci c ⋅N ⋅Q + l + N ⋅ ci 2 Q

Fig. 1. Cost function graphic [2] 197

(4)

in which:

α ⋅ ci ⋅ Q = c s - stocking cost = F2 ( Q ) 2 cl ⋅ N = cl - launching cost = F1 ( Q ) Q N ⋅c i = c a - acquisition cost

Because in (rel.4), the acquisition cost does not depends by the quantity Q then, one can use the Wilson formula that allows the economical order quantity determination (rel.5):

Qi* =

2 ⋅ cl ⋅ N ,i = 1, m α ⋅ c2 ⋅ θ

(5)

Replacing (rel.5) in (rel.4) and (rel.2), the minimum cost will be determined with (rel.6):

f i ( Q* ) = f min = 2 ⋅ N ⋅ cl ⋅ α ⋅ ci ⋅ θ + N ⋅ ci

(6)

To determine the quantity that needs to be bayed and his cost and also, to obtain a minimum cost, one calculates for each acquisition cost ci the economical ordered quantity Qi∗ , with (rel.5). So, one can appear the following cases: - Q1* ∈ [ ai − 1 ; ai ] - on these interval, the total minimum cost can be determined through (rel.6), or (rel.4);

- Qi* < ai − 1 , where Qi∗ ∈ [ai − 1 ; ai ) - on these interval, the total minimum cost for Qi = ai − 1 , can be obtained with (rel.4);

Qi* > ai , where Qi∗ ∈ [ai + 1 ; ∞ ) - on these interval, the total minimum cost for Qi = ai + 1 , can be obtained with (rel.4). 3. Results Monitoring the corrective maintenance activities of a company, technical equipments producer, we observe that for an entire year are necessary 4.000 spare parts. The launching cost of a provision order is 200 m.u. The stocking cost for spare parts per year is 10 m.u., and the acquisition cost for a piece is 100 m.u. The company from where the acquisition is done gives discounts, depending by the ordered spare parts quantity Q, as: 2% deduction, if 800 ≤ Q ≤ 1.599 ; 5% deduction, if 1.600 ≤ Q ≤ 1.999 6% deduction, if 2.000 ≤ Q . The policy that has to be adopted by the company maintenance manager is to follow permanently which is the quantity that must be ordered and his cost, the minimum acquisition cost, the time between orders and how many orders will be done on a year. In this way, for the discounts that will be gived result the following acquisition costs:

- c1 = 100

198

98 ⋅ c a ⇒ c 2 = 0 ,98 ⋅ 100 ⇒ c 2 = 98 100 95 - c3 = ⋅ c a ⇒ c3 = 0 ,95 ⋅ 100 ⇒ c 2 = 95 100 94 - c4 = ⋅ c a ⇒ c4 = 0 ,94 ⋅ 50 ⇒ c4 = 94 100 - c2 =

Replacing (rel.3) in (rel.5) allowed the economical quantity determination for the first acquisition cost, as:

2 ⋅ 200 ⋅ 4.000 = 400 , having 0 ≤ 400 ≤ 799 , the minimum cost will be gived 10 by the following relation: Q1∗ =

f 1 = 2 ⋅ 4.000 ⋅ 200 ⋅ 10 + 4.000 ⋅ 100 = 404.000u .m.

Knowing that: Q2∗ = Q1∗ = 400 , on [800 ;1.599 ) , Q2∗ < 800 then, the minimum cost on these interval can be obtained from (rel.4), so Q = 800 . 10 200 ⋅ 4.000 f 2 (800 ) = 800 + + 4.000 ⋅ 98 = 397.000 2 800 Q3∗ = Q2∗ = Q1∗ = 400 , on [1.600 ;1.999 ) interval, so Q = 1.600 200 ⋅ 4.000 10 f 3 (1.600 ) = 1.600 + + 4.000 ⋅ 96 = 392.000 1.600 2

Q4∗ = Q3∗ = Q2∗ = Q1∗ = 200 , on [2.000 ; ∞ ) interval, so Q = 2.000 200 ⋅ 4.000 10 2.000 + f 4 (2.000 ) = + 4.000 ⋅ 94 = 386.400 2.000 2 4. Conclusions Analysing the obtained results we can appreciate the following: • because the minimum cost is by 386.400 m.u result that will be bayed 2.000 spare parts at an acquisition cost 94 m.u., for a piece; • the acquisitioned orders number will be 4.000 / 2000 = 2 , and the time between orders will be 365 / 2 = 182 ,5 days . References: 1. Rusu, E., Decizii optime in management, prin metode ale cercetarii operationale. (2001). Economica, Bucuresti, ISBN: 973-590-513-2. 2. Lupescu, O., Gramescu, Tr., Popa, I., Popa, R. (2008). Using stocking strategy in technological equipment life cycle management, Academic Journal of Manufacturing Engineering, Vol. 6, pp.87-92, ISSN: 1583-7904, Timisoara. 3. Lupescu, Ov., Leonte, P., Popa, I., Murarasu, M.(2008) Researches regarding the analisys methodology of spare parts stocks necessary in maintenance activities, Buletinul Institutului Politehnic din Iasi, Tom LIV(LVIII), pp.301308, ISSN: 1011-2855, Iasi. 199

RESEARCES REGARDING THE LIFE CYCLE COST ESTABLISHMENT OF THE TEHNOLOGICAL EQUIPMENTS Popa I., Pruteanu O., Lupescu O., Popa R., Baciu M. (TU “Gh.Asachi”, Iassy, Roumania) This paper objective consists into establish the principal elements that constitute the component of the technological equipments life cycle cost. The life cycle cost analysis is very important to know the real costs that the user may support on the operating cycle time of the acquired equipment, this thing attaining to the optimal variants from economically point of view. The paper presents also a case study realized on a CNC lathe, in which is presented a methodology to calculate the life cycle cost through the similar cost method, based on historical dates. Introduction LCC analysis has a long tradition in USA Department of Defense [6], and has been applied to each new weapon system proposed, on under development. In industry the LCC is used to determine which product will cost less, in his life time. The LCC analysis helps after [2] the specialty personnel to justify the selection mode of equipment or process on the total costs base and not only using their initial acquisition costs, because the using, maintenance and the cassation costs exceed, several times, the other costs. After [7], the advantages of the costs analysis on the whole equipment life cycle are: • the evaluation of the equipments realization and utilization possibilities; • LCC requires a multiple information’s regarding: equipment acquisition, damages device, haw maintenance is realized, etc; • the LCC results are useful to compare and to limited the budget. In the System Analysis and Studies (SAS) of NATO, it was established a unitary frame to define the specifically terminology, so, in [3] are presented the specific elements for identification: LCC (life cycle cost) = direct costs + indirect variable costs

(1)

TCO(total awner cost) = LCC + dependent indirect fixed costs

(2)

WLC (whole life cycle cost) = TCO + independent indirect fixed costs

(3)

Method used Pursuant to [1] the life cycle cost of a system represents all the costs that have to be supported by the holder of that system, to buy, to use and to eliminate him. In this way the cycle cost of an equipment can be calculated according to (rel. 4) in this way: LCC = acquisition cost + maintenance cost + lost production cost + + input energy cost - residual value

(4)

After [4] to estimate costs one can use one of the following methods: the technological cost method, the similarly cost method, the parametrical cost method. For the first method the costs are directly estimated, examining the product element with element or, part with part. If it is used the similarly cost method, the costs estimations are 200

based on historical information’s updated, method easily applied to the product elements if some experience on actual dates exists. The last method use parameters and variables to develop the estimated cost relation, under equations form. The method choose by the paper authors, used to establish the measure of a technological equipment life cycle cost was that of the “similarly cost” using in this purpose the historical dates (T.E. datasheets founded in the maintenance department). The method follows the LCC component elements determination, as: • C a – the acquisition cost, being the cost used to buy the equipment ; • C m – the maintenance cost, determined by the spare parts and necessary interventions time cost, and also by the inspection and periodical control hours costs; • Cp P – the lost production cost, determined by the equipment down-time cost for different reasons as: accidental failure, adjustments, raw material absences, etc.; • C e – energy costs representing the equipment input cost on his entire working time, being: electric current, compressed air, petrol, diesel oil, carbon, etc.; • V r – representing the residual value, that is the value in money recovered after the equipment is scrapped. According to these things, (rel.4) becomes:

LCC = C a + C m + Cp p + C e - Vr

(5)

The total maintenance cost can be determinate as follow: C m = nt m ⋅ c m/h + cp s

(6)

in which : nt m - total number of hour that are necessary to these activity; c m/h – medium cost on hour of these activity ; cp s – spare parts costs. The last production cost will be determined as:

Clp = nt nef ⋅ c nef/h

(7)

in which: nt nef - total number of hours in which the lathe has been stopped; c nef/h – medium cost of a no operation hour. Results The case study has been realized on a CNC lathe from a company in which the research has been effectuated. The life time of the lathe according to his technical specifications was about 15 years, and his acquisition cost has increased at 50.000 euro. In the mechanical processing section, this equipment worked 20 years, after that, because of multiple failures and of an inadequate processing precision, the lathe has been scrapped and delivered on a REMAT centre. The lathe having a weight by 3.700 kg, his residual value was 650 euro. To calculate the LCC, from the maintenance department one gather dates for his whole working period, these being centralized in table 1: On a centralization base from table 1 one determined with (rel.6) the maintenance total cost with: C m = nt m ⋅ c m/h + cp s = 2.450 ⋅ 8,1 + 9.090 = 2.8935 euro

201

(8)

Table 1. Maintenance summarizer PURSUANC NO. OF NAME AND COST OF ONE LATHE E TIME IN HOURS THE REPLACED HOUR NONWORKING PIECES OF PRODUCTIONECESSAR TIME (DUE TO MAINTE THE N Y [CP S ] TO THE NANCE FAILURES,ACC IDENTAL MAINTEN AND ANCE REPAIR STOPPAGES, ACTIVITIE COST ADJUSTMENTS, S [C M/H ] ETC.) [NT NEF ] [NT M ] 1989-1990 100 hours 1. Emulsion (20 Є) 6 euro 318 hours 1990-1991 100 hours 1. Emulsion (20 Є) 6 euro 322 hours 2.Hidraulic oil (80 Є) 1991-1992 100 hours 1.Emulsion (20 Є) 2.Door prot. glass (160 Є) 7 euro 320 hours 1992-1993 100 hours 1. Emulsion (20 Є) 7 euro 330 hours 1993-1994 1. Emulsion (20 Є) 100 hours 2. Hydraulic oil (80 Є) 7 euro 330 hours 3. Driving belt for universal chuck (70 Є) 1994-1995 110hours 1. Emulsion (20 Є) 2. Specially bearing for 7,5 euro 345 hours universal chuck (3000 Є) 1995-1996 110 hours 1. Emulsion (20 Є) 7,5 euro 352 hours 1996-1997 110 hours 1. Emulsion (20 Є) 7,5 euro 348 hours 2. Cheeks (40 Є) 1997-1998 115 hours 1. Emulsion (20 Є) 7,5 euro 362 hours 2. Driving belt for universal chuck (70 Є) 1998-1999 115 hours 1. Emulsion (20 Є) 8 euro 366 hours 2. Hydraulic oil (80 Є) 1999-2000 1. Emulsion (20 Є) 115 hours 2. Door protective glass 8 euro 364 hours (160 Є) 2000-2001 115hours 1. Emulsion (20 Є) 8 euro 374 hours 2. Contactor (120 Є) 2001-2002 1. Emulsion (20 Є) 115 hours 2. Cheeks (40 Є) 8 euro 372 hours 3. Conveying belt (60 Є) 2002-2003 1. Emulsion (20 Є) 125 hours 2. Hydraulic oil (80 Є) 9 euro 386 hours 3. Radial unit (250 Є) 2003-2004 1. Emulsion (20 Є) 125 hours 2. Axial unit (270 Є) 9 euro 384 hours 3. Cheeks (40 Є) 2004-2005 1. Emulsion (20 Є) 140 hours 2. Engine conveying 9 euro 388 hours belt (350 Є) 2005-2006 1. Emulsion (20 Є) 140 hours 2. Hydraulic oil (80 Є) 9,5 euro 403 hours 3. Engine bearing (30 Є) 2006-2007 1. Emulsion (20 Є)

202

NON INPUT WORKI COST OF NG THE HOUR LATHE COST PER [C NEF/H ] YEAR [C E ]

25 Є 25 Є

5737,5 Є 5736,32 Є

27 Є 27 Є

5733,9 Є 5715,8 Є

27 Є

5715,8 Є

28,5 Є

5705,63 Є

28,5 Є 28,5 Є

5697,38 Є 5702,1 Є

28,5 Є

5685,58 Є

30 Є

5680,86 Є

30 Є

5683,22 Є

30 Є

5671,42 Є

30 Є

5673,78 Є

32 Є

5657,26 Є

32 Є

5659,62 Є

32 Є

5654,9 Є

33 Є

5637,2 Є

2. Universal bearings 150 hours (3000 Є) 9,5 euro 411 hours 3. Chain link conveying belt (75 Є) 2007-2008 1. Emulsion (20 Є) 2. Conveying belt 165 hours driving (60 Є) 10,5 euro 431 hours 3. Conveying belt bearings(15 Є) 2008-2009 1. Emulsion (20 Є) 2. Driving belt for universal chuck (70 Є) 10,5 euro 446 hours 200 hours 3. Contactor (120 Є) 4. Radial unit (250 Є) 5. Cheeks (40 Є) TOTAL 2450 hours 9090 Є 8,1 euro 7352 hours

The last production cost calculated with (rel.7) becomes: Clp = nt nef ⋅ c nef/h = 7.352 ⋅ 29,85 = 219.457,2 euro

33 Є

5627,76 Є

35 Є

5604,16 Є

35 Є

5586,46 Є

29,85Є 113566,7 Є

(9)

Using the (rel.5) subsequently has been determined the life cycle cost for the CNC lathe: LCC = C a + C m + Cp p + C e - Vr = 50.000 + 28.935 + 219.457 ,2 + euro (10) + 113.566 ,65 − 650 = 411.308 ,85 Conclusions The effectuated study highlights the followed aspects and conclusions: • the exploitation and maintenance cost of the CNC lathe exceed approximately eightfold his acquisition cost, this thing highlighting the necessity to know the life cycle cost at the equipment spare parts or product acquisition, for choosing the best economically variant; • so as results from the effectuated analysis, a high life cycle cost in big measure is owed to the losing time due to the non-working CNC lathe, from different reasons such as: failures, accidental stoppages, adjustments, etc.; • a significant percent in LCC represent also his input energy costs; therefore, very important for any equipment is to be dimensioned through the input/productivity rapport versus technological demands of the process; • futures researches will be turned to decrease the life cycle cost through reducing the non-working time, by increasing the equipment reliability and also, through the maintenance activities improvement reducing the accidental failures. References: 1. Barringer P., Why You Practical Details To Define Life Cycle Costs For Your Products and Competitors Products and Competitors Products , Barringer and Associates, Inc., 2000. 2. C e r n a t M., Costul pe ciclul de viata al echipamentelor militare, Agentia de Cercetare pentru Tehnica si Tehnologii Militare, Bucuresti, 2000. 3. P o p a M., Model de calcul al costului pe ciclul de viata necesar la achizitia de aeronave, Agentia de Cercetare pentru Tehnica si Tehnologii Militare, Bucuresti, 1999. 4. x x x , Life Cycle Cost Analysis, American Concrete Pipe Association, Design Data 25, May 2007. 5. x x x, Life Cycle Cost Estimate, Cost Estimating Guide, U.S. Department of Energy, U.S. 1997. 6. x x x , Cost Structure and Life Cycle Costs for Military Systems, AC/323(SAS - 028) TP/37,RTO TECHNICAL REPORT TR – 058, 1998. 7. x x x, Stainless Steel – Life Cycle Costing, Atlas Specialty Metals, Australia, 2007. 203

ASPECTS REGARDING THE SIX SIGMA CONCEPT IMPLEMENTATION UPON THE BEARINGS MANUFACTURING PROCESS Popa S1., Paraschiv D1., Popa V2., Popa I1, Popa R1. ( TU â&#x20AC;&#x153;Gh.Asachiâ&#x20AC;?, Iassy, Romania; 2 S.C. Rulmenti S.A. Barlad, Romania) 1

In this paper is presented an optimization model that will assist management to choose process improvement opportunities. This model consider a multi-stage, asynchronous manufacturing process with the opportunity to improve quality (scrap and rework rates) at each of the stages. This model is to maximizing the sigma qulity level of a process under cost constrain. 1. Introduction In any organization the customer satisfaction is the number one priority. Customer satisfaction also means profitability. The success of any company depends on the ability to ensure the highest quality at the lowest cost. Today the competitive market leaves no space for error. It is now necessary to implement the concepts of Lean Six Sigma. Six Sigma philosophies are related to statistical process control, stochastic control (relating to probability), and engineering process control [3]. In addition, it requires process and data analysis, optimization methods, lean manufacturing, design of experiment, analysis of variance, statistical methods, mistake-proofing, on-time and or on-schedule shipping, waste reduction, and consistency assurance. II. Method used The implementation cost for successful Six Sigma initiatives can be considerably high for many companies, especially to those companies with small profit margin and limited resources. To improve the quality of a process often requires signifiant capital investment in new, emerging process alternatives. In this paper is presented a mathematical programing model that can be used as a management tool to solve the problem of optimizing the sigma level of a process subject to a budget constrain. The mathematical model is constructed by assuming that units are processed through an n stage sequential process. For each stage, there are q i process alternatives that can be implemented to improve the process Sigma level. Moreover, each of these stage improvement alternatives has a known improvement rate and an associated implementation cost. Then, the problem is to find the alternatives that will maximize process quality improvement without exceeding the allocated budget. The scheme of the process under consideration is presented in Fig. 1.

Fig. 1. n-Stage processes For the model under consideration, quality improvement is defined as a reduction in both rework and scrape. Thus, a relationship between the Sigma level and the stage quality 204

improvement needs to be defined. In general, the Sigma level or Sigma quality level can be understood as the Z value of the standard normal distribution under the assumption that there is no shift in the process mean. Several polynomian approximations [1] are available to calculate the value of Z. Similarly, when the assumption of no shift in the process mean does not hold and when the shift is likely to be as much as Λσ, The following mathematical relationship [2] can be used to approximate the value of Z:  C 0 + C 1Q + C 2 Q 2 Z = Λ + Q −  1 + d 1Q + d 2 Q 2 + d 3 Q 3 

   

(1)

Where C0 = 2.515517 , C1 = 0.802853 , C 2 = 0.010328 , d 1 = 1.432788 , d 2 = 0.189269 , d 3 = 0.001308 , and −2  Y   Q = ln  1 −   100    

(2)

The process yield, defined by Y in (2), can be obtained with the following formula: Y=

(3)

Number of opportunities - Number of defects x100% Number of opportunities

It is important to notice that Y is a measurement of process performance and thus, the mathematical model presented uses Y as a surrogate measure to maximaze the sigma quality level. n  qi  Max Y = ∏  ∑ δ ik (1 − f i1 + ri1k ) i = 1 k = 1 

(4)

Subject to: qi

∑ δ ik = 1∀i

(5)

∑ ∑ δ ik Qik ≤ B

(6)

I1 ≤ S I i ≤ K i ∀i I n + 1 = D where, (I n + 1 = On )  qi  I i + 1 = I i  ∑ δ ik (1 − f i1 + ri1k )∀i  k =1 

(7) (8) (9)

k =1 n qi

i =1 k =1

δ 1k = Bin(0 ,1) and I i ∈ Z +

205

(10) (11)

Table 1 Nomenclature i ith stage of process, i = 1............n Y Process yield j jth defect type for each stage, j = 1,2. (1 = srap, 2 = rework) k kth Six Sigma implementation alternative, k = 1, ........., qi f ij Rate of defect type j at state i r ijk Rate or defect type j for alternative k in state i δ ij Decision variable related to the kth process alternative for the ith stage Ii Number of units that are processed at the ith stage m ci Marginal production cost of an item at the ith stage Q ik Implementation cost for the kth process alternative for the ith stage S Raw material available at the first stage D Process demand B Budget available for Six Sigma Alternatives Ki Production capacity for the ith production stage Ri Amount of rework resulting from the ith stage ciR Rework cost at the ith stage Z+ Set of positive integers The improvement of the process is driven by the binary decision variables, δ ik in the objective function of model. That is, for each stage i, these variables dictate by how much the current scrap rate, defined by f i1 , can be reduced by selecting the kth alternative, defined by r i1k . The initial constraint in model specifies that among the q i possible improvement alternatives for stage i, only one can be selected. It is important to mention that among the alternatives for each stage, the current process should be included with the appropiate associated parameters. That is, the model should consider the possibility that it may not be economically viable to implement a Sigma stage improvement alternative. Given that most companies do not have unlimited funds to implement process improvement alternatives, there is generally a predetermined budget for the decision. Thus, the second constraint guarantees that this upper limit is not exceeded. The next three constraints of the model are related to the units processed at each stage. Under the model rationale, the third constraint presumes that there is a limit on the availability of raw material coming into the first production stage. Equivalently, each stage capacitated as described by the fourth constraint. The fifth constraint guarantees not to build up any unnecessary inventory at the final stage of the process. The sixth constraint acknowledges that the input of each stage is a function of the input of the previous stage and the reduction in the scrap rate obtained from the implementation of a improvement alternative. The last constraint defines the decision variables δ ik as binary and the stage inputs to be restricted to nonnegative integers. Model defines a non-linear mixed integer-programming model in which the decision variables δ ik define the stage improvement alternatives that may by chosen to replace the existing process and, maximize its sigma quality level based on the yield as a surrogate measure. It must be noted that, the reduction in the occurrence of either rework or scrap 206

cannot exceed its corresponding existing value. For each stage, the alternatives cannot degrade its current Sigma level. Although the objective function of model is non-linear, an equivalent linear objective function can be used to transform this model into Mixed Linear Integer Program (MLIP). In [4] as noted that „An „equivalent objective function” is one that has the same optimal solution, although the objective function value is not equal. These types of functions allow the creation of a new problem, easier to solve and yields the optimal solution to the original problem”. The function in this model can be replaced by the following equivalent functions: n  q1  ∑ ln ∑ δ ik (1 − f i1 + ri1k ) i =1  k =1  n  qi  ∑  ∑ δ ik γ i1k ; γ i1k = − ln(1 − f i1 + ri1k ) i =1  k =1 

(12) (13)

The second equivalent function can be used because the first constraint of model dictates that only one of the q i alternatives for stage i can be chosen. Thus, based on this last equation, model can be transformed into an MILP. III. Experimental results The purpose of this example is to illustrate that the selection of process improvement alternatives play a crucial role in the successful implementation and improvement in the Six Sigma level of the process. This example illustrate that the Six Sigma implementation team should first carryout an analysis regarding the benefits of the different alternatives before engaging in a particular Six Sigma alternative. The process depicted in Fig. 2. is a five-stage process.

Fig. 2. Five-stage process For this process, current yield can be improved by selecting among three different stage improvement alternatives for each stage. The current scrap and rework rates at each stage are show in Table 2.

Stage 0a 1 2 3 4 5

Table 2. Current process rates, costs and capacities f i1 f i2 ciR cim 1 0.05 0.06 1 2 0.09 0.012 1.5 3 0.09 0.08 2 4 0.15 0.05 2.5 5 0.06 0.08 3 6

ki 245000 220000 210000 180000 170000

Table 3 illustrates the potential reduction in scrap and rework rates of implementing the stage improvement alternatives along with its associated implementation cost. 207

For this example, the model presented in this paper have been solved using LINDO (Linear Interactive Discrete Optimizer). The optimal solution for model, maximizing the process yield subject to a budget constraint provides a value of Y = 94.1% (assuming only scrap rate). The Sigma stage improvement alternatives resulting in the optimal defect reduction are presented in Table 4. Table 3. Reduction in scrap and rework rates and associated cost for each stage improvement alternative Stage r i10 0 0 0 0 0

1 2 3 4 5

0 r i20 0 0 0 0 0

Q i0 0 0 0 0 0

r i11 0.02 0.03 0.02 0.14 0.01

1 r i21 Q i1 0.03 40 0.01 30 0.04 30 0.03 20 0.02 50

Alternativea 2 r i12 r i22 Q i2 0.01 0.02 60 0.08 0.01 40 0.04 0.01 35 0.05 0.01 25 0.04 0.02 45

r i13 0.03 0.04 0.05 0.04 0.05

3 r i23 Q i3 0.02 65 0.01 42 0.01 37 0.01 26 0.07 46

4 r i24 Q i4 0.06 55 0.01 45 0.07 40 0.04 30 0.07 40

r i14 0.04 0.05 0.07 0.1 0.03

Table 4. Optimal values for δ ik Stage 1 2 3 4 5

0 0 0 0 0 0

1 0 0 0 1 0

Alternativea 2 0 1 0 0 0

3 0 0 0 0 1

4 1 0 1 0 0

This table, illustrates that alternatives one, two, one and no action are chosen to improve stages one, two, three, four and five, respectively. This model introduces a mathematical model consistent with a common management approach of trying to maximize the overall yield when making Six Sigma decision. IV. Conclusions and future research Six Sigma continues to be predominate target to try and obtain a competitive advantage. However, not all companies are successful in implenting many of these quality improve stategies. Although many companies attribute their succes to following a quality improvement program such as TQM and Six Sigma, there are significant number of companies that fail to gain any measurable benefit after implementing these quality strategies. The objective of this paper is to develop mathematical model that can be used to select the process improvement techniques in a optimal way. The mathematical programming model have been developed in this paper, find to optimal sigma quality level using yield as a surrogate revenue measure. Illustrative example is used to show how the mathematical model developed in the paper can be used in practice. Additional research is required to developed model that fully capture the economic advantages of Six Sigma, most notably increased market share, apart from reduction in wastage cost. Once the relationship between benefit due to improved quality of a manufacturing process and higher sigma level is established, one can modify the optimization model presented in this paper. References: 1. Abramowitz, M., Stegun, I.A., Handbook of Mathematical Functions. Dover, New York, 1972. 2. Kumar, U.D., Crocker, J., Chitra, T., Saranga, H., Reliability and Six Sigma. Springer, Berlin, 2006. 3. Kwak, Y.H., Anbari, F.T., Benefits, obstacles and future of Six Sigma’’. Technovation: The International Journal of Technological Innovation, Entrepreneurship and Technology Management 26 (5-6), 708–715, 2006. 4. RamirezMarquez, J.E., Coit, D., Konak, A., Reliability optimization of series-parallel systems using a Max–Min approach. IIE Transactions 36 (9), 891–898, 2004. 208

FOUNDRY SLAG WASTES AND POSSIBILITIES OF THEIR UTILIZATION Pribulová A., Gengeľ P., Demeter P., Baricová D. (Technical University of Kosice, Kosice, Slovakia) Slag waste often has a complex chemical composition and contains a variety of contaminants from the scrap metals. It may constitute about 25 % of solid waste stream from a foundry. Common slag components include metal oxides, melted refractories, sand, and coke ash. Slag should be reused and reuse options may, depending on slag characteristics, include block making, road – base construction, and as coarse aggregate. This contribution describes different types of slag in dependence of melted aggregates, their chemical composition and next reuse. The main amount of foundry slag in Slovakia represents slag from cupola furnace. Utilization of cupola furnace by concrete production is described in this contribution. Introduction Pollution prevention, also termed waste minimization, is the reduction to the extent feasible, of waste that is generated or subsequently treated, stored or disposed of. The highest priorities to pollution prevention are assigned to source reduction and recycling in that order. Environmental concerns of foundries are air emissions, solid wastes and in the case of foundries using wet scrubbers, having electroplating facilities or in some cases using water for direct cooling or annealing, wastewater discharges. Sources of particulate air emission in sand casting foundries are molding and core making, melting, casting shake-outs and cleaning of castings. Foundries employing chemical no – bake binders also emit gaseous emissions. Generation of waste is directly related to the type of material melted and depends on the type of molds and cores used, as well as the technology employed. The bulk of wastes generated by foundries is from melting operations, metal pouring and disposal of spent molding materials. Waste generated as a result of metal casting processes are. Molding and Core making – spent system sand, sweepings, core buttes, dust an sludge. Melting – dust and fumes, slag. Casting – investment casting, shell and waxes. Cleaning – spent shot, grinding, wheels, dust. Melting aggregates in foundry The foundry or metal casting process begins with melting of the metal to be poured into foundry molds. During melting, the metal may be alloyed by the addition of other metals, refined when undesirable impurities are present or inoculated to improve their final solidification structure. Cupola, electric arc, induction, hearth, and crucible furnaces are all used to melt metals. The cupola furnace is the oldest type of furnace used in the metal casting industry and is still used for producing cast iron. It is a fixed –bed, cylindrical, vertical shaft furnace, in which alternate leyers of metal scrap and ferroalloys, together with foundry coke and limestone or dolomite, are changed at the top. High-quality foundry grade coke is used as a fuel source. The amount of coke in the charge usually falls within a range of 8 to 16 percent of the metal charge. Coke burning is intensified by blowing oxygen anriched air through nozzle. The metal is melted by direct contact with a counter-current flow of hot gases from coke combustion. Molten metal collects in the well, where it is discharged by intermittent tapping or by continuous flow. Electric arc furnaces (EAF) are used primarily by large steel foundries and steel mils. Heat is supplied by an electrical arc established from three carbon or graphite electrodes. The furnace is lined with refractories that deteriorate during the melting process, thereby generating slag. Protective slag layers are formed in the furnace by intentional addition of 209

silica and lime. Fluxes such as calcium fluoride may be added to make the slag more fluid and easier to remove from the melt. The slag protects the molten metal from the air and extracts certain impurities. The slag removed from the melt may be hazardous depending on the alloys being melted. Electric induction furnaces (EIF)are either cylindrical or cup shaped refractory lined vessels that are surrounded by electrical coils which, when energizer with high frequency alternating current, produce a fluctuating electromagnetic field to heat the metal charge. For safety reasons, the scrap metal added to the furnace charge is cleaned and heated before being introduced into a furnace. Only oil or moisture on the scrap could cause an explosion in the furnace. Induction furnace are kept closed except when charging, skimming, and taping. The molten metal is tapped by tilting and pouring through a hole in the side of vessels. Induction furnaces also may be used for metal refining in conjunction with melting in other furnaces and for holding and superheating the molten metal before pouring [1]. Ferrous foundry slag and their utilization Slag from melting furnaces arises from: 1. Extraneous materials in or the charge constituents such as rust, oxide, dirt, coating etc. 2.Oxidation of elements in the metal mix, typically Si, Mn, Mg and Al. 3. Residues from fuels, in particular ash from coke in conventional cupola furnaces.4. Fluxes used in the process, including limestone, dolomite and fluorspar in cupola operations, and slag coagulants in induction furnace practice. 5. Refractory erosion [2]. The main types of ferrous slag are created in foundries: cupola furnace slag, slag from EIF and from EAF Slag from EAF and EIF In table 1 the electric arc furnace (EAF) slag composition and electric induction furnace slag composition are referred Tab.1 Chemical composition of electric induction and electric arc furnace slag [3] Composition EIF [%] EAF [%] SiO 2 40 – 70 28,6 – 41,8 CaO 0–3 7,2 – 17,7 MgO 0–3 18,3 – 27,0 Al 2 O 3 2 – 15 7,4 – 9,4 FeO 10 – 30 0,5 – 1,0 MnO 2 – 15 4,0 – 29,6 TiO 2 0,39 – 2,7 Na 2 O 0,11 – 0,57 K2O 0,1 – 0,23 EIF generated almost 10 – 20 kg slag per 1 ton of metal charge. In Slovakia it is around 500 tones per year. The generated slag amount depends on charge materials quality. By steel production in EAF around 50 – 60 kg slag per 1 ton of steel is generated. In Slovakia it is around 500 tones per year. Considering that in EIF a smaller amount of slag is generated, that slag is exported on dump yard these days. The next treatment of EIF slag is dismissing yet. EAF slag are treated by two basic methods in presence. The first way is based on a separation of individual slag components and their using in building industry or eventually in other industries. Using of this slag is suitable e.g. for way building, as slag gravel, gravel into the asphalt surface, for biological filtration and many other applications. The second method is used for an immediate slag addition (after demetallisation) into the blast furnace, sinter or steel charge or can 210

substitute a part of charged lime (recommended substitution ratio is 2:1 slag/lime). But a condition of utilization of these slag is their retreatment on metallurgical valuable raw materials, which are suitable with their composition and granularity for returning to the metallurgical process. Cupola furnace slag Cupola furnace slag may be divided into two categories – acid and basic. The former type has always been by far the most common and today usually acid cupola operations remain. The appearance of cupola slag, both acidic and basic, varies widely depending upon the operation of the furnace and the slag collection process. Cupola slag tends to be dense, solid, vitrified material that varies in color from cream to black, but the predominant coloration would be green to brown. Lighter colored slag is sometimes associated with high basicity materials and darker slag with more oxidizing conditions in the furnace. If the iron oxide content is too high and the lime level too low, the slag could have an “Aero – Chocolate” appearance instead of being solid. Some slag will exhibit lighter colored grains in it´s make up which are usually refractory particles eroded from the furnace lining [2]. Cupola furnace slag is very often compared with blast furnace slag. There is a comparison of chemical composition of both of slag in tab.2 [3]. Tab.2 Comparison of cupola furnace and blast furnace slag chemical composition Cupola furnace slag Blast furnace slag Composition [%] Composition [%] SiO 2 45 - 55 SiO 2 27-38 CaO 25 – 40 Al 2 O 3 7-15 Al 2 O 3 8 – 20 CaO 32-43 MgO 1–3 MgO 3-18 MnO 1–4 FeO 0,2-1,6 FeO 1–6 MnO 0,2-1,1 Sulphides <1 TiO 2 0,4-2,1 TiO 2 <1 S (as CaS) 0,8-1,9 ZnO <1 A utilization of blast furnace slag by concrete production is famous. Quantity of cupola furnace slag in Slovakia is around 1928 tone per year. The slag (Fig.1) is not treated and it is put on a landscape. There are experiences with using of blast furnace slag by this production at the Department of Iron Metallurgy and Foundry. There were experiments realized by that the blast furnace slag was replaced by cupola furnace slag. By experiments cupola furnace slag with next chemical composition was used: Fe – 1,68%, FeO – 1,15%, SiO 2 – 55,19%, CaO – 33,68%, MgO – 0,349%, Al 2 O 3 – 7,26%, MnO – 1,30%, TiO 2 – 0,498%, ZnO – 0,078%. Blast furnace slag chemical composition was : CaO – 40%, SiO 2 – 38%, Al 2 O 3 – 7%, MgO – 9% and FeO – 1,1%. During experiments the cupola slag was grinded and milled. It was tested concrete making from 100% of cupola slag with 3 different fractions: 0 – 4 mm, 4 – 8 mm and more then 8 mm. In next experiment the cupola slag with fraction 0 – 4 mm was replaced by cupola slag in amount 10%, 20% and 30%.

211

Fig. 1. Cupola furnace slag used by experiments Fig. 2 shows the way of concrete production from cupola furnace and blast furnace slag.

a – batch materials b – concrete production c – cone test d – concrete samples prepared for testing

Fig. 2. Concrete production with using of cupola furnace slag In dependence on technique which can be used for treatment of molten slag next types of products are produced : granulate, gravel, expanded (ultra-lightweight) slag, pumice and slag cotton. The possibilities of treated foundry slag use are as a road building material, railway embankment, concrete filler, material on concrete production, fertilizer on soil improvement, utilization in civil engineering and as a material for tiled stove. Conclusions Foundry slag constitute about 25% of the solid waste from a foundry. In Slovakia it is around 2900 tones every year. All foundry slag are dumped, they are not treated or reused. Slag should be reused and reused options may, depending on slag characteristic, include block making, road – base construction, and as coarse aggregate. Results of experiments with use of cupola furnace slag by concrete production showed the possibility for use of cupola furnace slag by making of that product. 212

Acknowledgements This work has been done within the APVV-0180-07 project “Study of Foundry Wastes Properties and Possibilities of their Utilization” of the Agency for the support of the science and research. References: 1. Emission factors for iron foundries – criteria and toxic pollutants, prepared for: Hemilton County Chattanooga, Tenessee – research report, Research Triangel Park NC 27711. 2. Powell J.: Detailed Description of Foundry Slag – Appendix V. 3. Integrated Pollution Prevention and Control, Reference Document on Best Available Techniques in the Smitheries and Foundries Industry, July 2004.

ALTSCHULLER ALGORITHM APPLICATION TO DESIGN A DEVICE Rădeanu A., Uliuliuc D., Lupu V., Purcariu R. (TU “Gheorghe Asachi”, SG “Mihail Sturdza’’, Iaşi, Romania) In the paper, a device for the clamping the electrode holder of the electro-spark equipment with fixing on the tool holder of the universal lathe is presented. The design of this device is interesting in the context of the hardening or filling operations of the cylindrical or conical workpieces. To optimize the design process, the Altschuller’s algorithm was selected. Applying this type of design is based on the fact that the device must meet a series of functions and premises for the optimum development of electrospark processing. 1. Introduction As support for a creative activity, many methods have been proposed along the time. All these methods used in the process of design are based on applying certain logic methods to generate new ideas. One of the methods aiming to stimulate the creativity in the technical field, considered as being more specific and applied by different researchers in the last period is the Altschuller’s algorithm [4]. The name of the algorithm is in connection with the name of the researcher who founded it in 1956. The author's name is Saulovici Altschuller Henry; he was a Russian engineer who published an interesting article on creative solving the various problems, in the journal „Problems of Philosophy”. The paper was considered as the base for the theory of creative problems solving; this concept was abbreviated in the Russian language by TRIZ (Teoria Reshenia Izobretatelskih Zadaci). The Altschuller's algorithm is characterized by the creative possibilities able to allow the analyzing and solving the technical problems, being based on the identifying oft his so-called contradictions and sometimes offering unexpected solutions [1, 2]. A definition that explains the term device is that it represents an assembly of several elements, such as mechanical, electrical or hydraulic, which can catch and fix the workpiece, during the machining process. The electro-spark processing is one of the manufacturing procedures which uses non conventional processing sources and some effects of the electrical discharges, such as erosion, thermal and physic-chemically phenomena [3]. The electro-spark processing for hardening certain areas and for the diffusion or deposition of the material is applied by using an electrode tool; the initiation of the discharge is possible by breaking the contact between the electrode and workpiece, thus ensuring the transfer of items within a material transfer from the electrode tool to the workpiece surface. At the hardening process by the electro-spark, the 213

electrode tool is connected to the anode and the workpiece to the cathode; the process develops in principle in the air. Yuan Feng considered that the association of the TRIZ method with the functional analysis could ensure an increased efficiency of the innovative process, due to the fact that the above mentioned methods are complementary [5]. C. C. Tsai succeeded to modify the shape and the material specific to a valve necessary to achieve the obturating of a tube by using the Altschullerâ&#x20AC;&#x2122;s algorithm. Because the valve works at high pressures and temperatures, within the decision process at the passing to other level of the Altschullerâ&#x20AC;&#x2122;s algorithm, the ANSYS software was used [6]; this software can emphasize the critical values of the stresses in imposed situations. 2. Applying the Altschullerâ&#x20AC;&#x2122;s algorithm Part I. Problem analysis Aim: Ii is necessary to design the device for clamping the electrode-holder of the electrospark processing electrode and placing it on the tool holder of the universal lathe, to achieve the hardening operation both of the cylindrical and conical workpieces. In developing the constructive solution, the designer must fulfill some specific conditions to obtain the desired result. Essentially, the device must fulfill the requirements specific to the electrospark deposition or allowing in optimal Fig. 1. Conditions of the processing conditions. In the electro-spark hardening process of the cylindrical surfaces, a movement of alternative translation of the electrode tool in the horizontal direction and along the rotation axis of the workpiece could be considered. This condition must be fulfilled to obtain a surface characterized by a small and uniform surface roughness. Step 1.1. Mini problem: the system is composed of the lathe on which the tool holder can be placed, the device of electrode holder, the equipment of electro-spark processing. CT-1. Processing step by step, by repositioning the electrode tool along the workpiece axis could lead to overlapping, which is able to generate areas with different properties and unwanted and high productivity. CT-2. A rectilinear and uniform movement of the electrode tool on the entire length of the workpiece reduces the risk of overlapping zones, which could be characterized by different properties and a low productivity of the process. Minimal changes in the system must ensure the quality of the processed surface. Step 1.2. The conflict pair includes the workpiece and adjusting of the device in a time as short is possible and at the necessary accuracy. Step 1.3. Conflict representation: applying the idea of changing the elements that give the movement of alternative translation of the electrode tool subsystem, to increase or decrease the distance of the work, depending on the size of the area to be processed. Step 1.4. Election conflict schedule: because the processing is required to uniformly cover the surface, one chooses the contradiction CT-2, even the process productivity is lower. Step 1.5. Conflict amplification: in its limit form, one may consider the possibility to process the workpiece area of certain size. Step 1.6. Problem reformulation: Compromises pair includes the workpiece and the subsystem of the device which ensures the motion of the electrode holder. The subsystem which generates the motion of the electrode holder must have a fast control both of the motion distance and of motion speed. 214

Part II. Analysis of the problem model Aim: Emphasizing the resource of space, time and substance Step 2.1. Operational area is represented by the subsystem of generating the rectilinear and alternative movement of the electrode holder. Step 2.2. Operational time: time during the conflict which is the time required to change the subsystem, to play back rectilinear and alternative movement of the electrode holder, in order to achieve the movement on a size greater or lesser degree. Step 2.3. The resources of substance and field are presented in table 1.

Resources Interiors Subsystem movement tool Workpieces Exterior Electrode tool General resources Supra system Loss Cheap resources

Table 1 Type of substance Resources Material: steel Material: steel

Field

Mechanical work

Material: metallic carbide Air

Motion, hardening Electric field

Air

Part III. Determination of the final solution and of the physical contradiction Aim: Ideal final design solution, which solves the problem and makes the perception to prevent the physical contradiction and accepting this solution. Step 3.1. The final ideal solution SFI-1: the element X should not change the subsystem which induces alternative rectilinear movement to not generate adverse effects; it should not lead to an uneven surface processing, while maintaining high productivity. Step 3.2. Amplification of the applications for identifying the ideal final solution: since the most probable direction of designing the sub-assemble to achieve the rectilinear and alternative movement, X only element, that can be changed in this subsystem, is the crank gear, which converts the rotational movement of the axis of the electric motor, powered by alternative translation. Step 3.3. Reformulation of the contradiction at the macro level: positioning crank gear will be done to change the workpieces to be worked in a very short time, and ensuring the surface precise processing length, and the uniformity of its appearance can avoid the necessary auxiliary time only by processing batches to avoid the more frequent change of the crank position. Step 3.4. Reformulation contradiction at the micro level: Changing the crank gear position is required to be made as rarely is possible, to avoid the occurrence of auxiliary actions able to generate the decreasing of the productivity. Step 3.5. Final ideal solution SFI-2: The crank should be applied to different distances, to ensure the possibility to control the reciprocating rod length, in order to obtain the alternative rectilinear motion on different distances. 3. Obtained result The devices finally designed by applying the Allschullerâ&#x20AC;&#x2122;s algorithm can be considered as a viable solution (fig. 2). 215

Fig. 2. Scheme of principle of the identified device 1-clamping dies; 2-cylindrical workpieces; 3-tool holder; 4-foot plate; 5-vertical guide; 6vertical guard rail; 7-disc; 8-collar for clamping the engine; 9-engine; 10-crank gear; 11-biel; 12-articulation; 13-draw bar; 14-horizontal guide; 15-slide; 16-electrode-holder; 17-circular scale 4. Conclusion In the present state of development of a device able to allow the processing of the semi-cylindrical or conical surfaces in laboratory conditions, the result obtained by the use of TRIZ proves to be positive, both in construction and the simplicity of use. To solve this problem of design the device, the TRIZ method is well adapted if the problem is well defined. TRIZ is a method that allows to the researchers to work in a systematic and rational manner. In the particular case examined within this paper, the total time spent to explain the mechanics of the method was of about 30 minutes. References: 1. Y. Salamatov – TRIZ: The Right Solution at the Right Time. A Guide to Innovative Problem Solving Insytec BV, 1999, ISBN 90-804680-1-0 2. Zlotin B., Zusman A., Altshuller G., Philatov V.: 1999, Tools of classical TRIZ. Ideation International Inc. 2, ISBN 1928747027 3. R.N. Johnson, Electrospark deposition: principles and applications. Society of Vacuum Coaters, 45th Annual Technical Conference Proceedings, 2002, 87. 4. G. Bertoluci, M. Le Coq – Intégration du TRIZ au sein du cycle de conception de produit. 3e Conférence internationale sur la conception et la fabrication intégrée en mécanique IDMME’2000, Montréal, 2000. 5. Yuan Feng, Wang Tai-Yong , Nie Hui-juan, Function and principle innovative design of mechanical products based on TRIZ/FA, Higher Education Press and Springer-Verlag, 350−355 p, 2006. 6. C.C. Tsai, C.Y. Chang and C.H. Tseng, Optimal design of metal seated ball valve mechanism, Industrial applications and design case study, 249–255 p, 2004.

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USING THE UTILITIES THEORY FOR CHOOSING THE TYPE DEVICE FOR EXTERIOR CYLINDRICAL SURFACES ROTOROLLING Sava O. , Pruteanu O. , Lupescu O., Popa R., Popa I., Murarasu E. (T.U „Gh.Asachi”, Iassy, Roumania) The paper objectiv consist to elaborate a methodology and a decisional algorithm which allow the establishment of the optimal technological decision in choosing the rolling or rotorolling type device, necessary to process metallical external cylindrical surfaces pieces, using superficial cold plastic deformation (SCPD). In this purpose the authors started using the utility concept, the constructiv solution price and respectively, the total device rigidity. To adopt the final decision, one take also into account the uncertainties which can appear during their design, execution and explotation. 1. Introduction The constructiv solutions diversity which can be used to the devices design to apply the SCPD process throught rolling or rotorolling is relatively high.[1]. This impose, at one moment, to take some decisions in view of using any type of device or other, to process the distinguished piece surfaces. In this meaning the paper authors appealed to the ”utility”concept defined, for the first time, by Newmann and Morgenstern in 1947 and representing the conventional rate-setted value gived by a governer to some variable, taking into account a certain estimation criterion. 2. Method used To elaborate the decision algorithm, the authors began considering like as a variable – the device constructiv solution - the possible variants technically taked into account being: D 1 – unbalanced device for hardening long external cylindrical surfaces; D 2 - unbalanced device for hardening long external cylindrical surfaces and for the interface connector radius; D 3 balaced device for hardening flat cylindrical surfaces, short and long; D 4 - device for rotorolling with rigid contact, unbalanced, to long external cylindrical surfaces hardening (l s / d > 10). The used criteria to estimate this variants were established like being: the constructiv solution price x 1 (determining any production process) and respectively total device rigidity x 2 (justified choise by his conection and dominant influence upon the processing precision and also upon the obtained performances in the case of this tehnological process application). In (tab.1) are gruped the known elements for these four analysed variants.

VARIANTS D1 D2 D3 D4

Table 1.Estimated variants D i , after the x j criteria CONSEQUENCES Criterion x 1 (cost - lei) Criterion x 2 (rigidity – daN / mm) 5500 1220 3000 1960 9400 3500 3700 3350

The general objective of these analysis consist in the SCPD device constructive solution establishment, over the external cylindrical surface, that may be obtained with minimal execution costs, in maximum rigidity assurance conditions during the working process. The each constructive variants estimations reported to the considerate criteria were noted with x ij = consequences, subscript parameters significance being as follow: the first one represents the solution estimation – i, and the second one, the criterion estimation – j. Rate217

setting into 1 and 0 limits the u ij utilities, those can be rendered as subjective probability using the proposed variants for the SCPD device. The values deduction of those utilities involves, first of all, the extreme adjustment for: u 12 = 1 (maximum utility) for the lowest cost and respectively u 31 = 0 (minimum utility) for the highest cost. For the other consequences, the utilities are granted proportionally with the respectively consequence, through linear interpolation, between the maximum and minimum utilities, using (rel.1) and (rel.2) [3]: uij =

uij =

xij − x minj x maxj − x minj x maxj − xij

x maxj − x minj

(1)

(2)

The first relation can be applied for the utilities deduction, in case in which these varies directly proportional with the consequences values and the second relation can be used for those utilities granted inverse proportional with the consequences. 3. Results In the case of x 1 criterion, using those presented before and the (rel.2) one obtain for D 1 and respectively D 2 devices: u11 =

x max1 − x11 9400 − 5500 = = 0 ,6 x max1 − x min1 9400 − 3000

(3)

u 41 =

x max1 − x41 9400 − 3700 = = 0 ,89 x max1 − x min1 9400 − 3000

(4)

Calculating the utilities also for x 2 criterion, but using the (rel.1) one obtain in (tab.2): Table 2. Calculating utilities for D i variants and x j criterion VARIANTS CONSEQUANCES Criterion x 1 Criterion x 2 D1 0,6 0 D2 1 0,3 D3 0 1 D4 0,8 0,9 If for each estimated criterion is granted a significance k j coefficient one can determined sum utility for the D i variant, using (rel. 5): m

u (Di ) = ∑ k j ⋅ u ij j =1

(5) where: "m” is the number of established criterion utilities and k j are significance coefficients for the j criteria. This coeficients can be choosed in the way to verify (rel. 6): 218

∑ kj =1

j =1

(6)

In the mechanical cutting processing case the speciality literature [2] recomands that k 1 > k 2 , the cost determinating, with priority, the choise of the technological variant, the processing precision being not so much related to costs, as especially, by the cutting regim parameters and other factors. At SCPD the work device rigidity becomes the primary criterion (implied k 2 > k 1 ), this essentially determinining the performances obtained at the process application more then the contact force (specific pressure between tool and piece) became one of the work regim parameters. In this conditions, the importance coefficients weighting, statically determinated, being: k 1 = 0,42 and k 2 = 0,58 (the difference between them being smaller than in the case of cutting processing because, in the rotorolling case, the device costs are bigger,fact that approach the cost importance between those of the device rigidity), obtained the sum utilities using the sistem:

u (D1 ) = 0 ,42 ⋅ 0 ,6 + 0 ,58 ⋅ 0 = 0 ,25 u (D ) = 0 ,42 ⋅ 1 + 0 ,58 ⋅ 0 ,3 = 0 ,60  2  u (D3 ) = 0 ,42 ⋅ 0 + 0.58 ⋅ 1 = 0 ,58 u (D4 ) = 0 ,42 ⋅ 0 ,8 + 0 ,58 ⋅ 0 ,9 = 0 ,86

(7)

One impose as an optimal decision the variant to which corresponds the maximum sum utility, this being in this case the constructiv solution D 4 . In the productivity activity some consequences can appear with a value or another one, in some probability limits. Those can take more values depending by the concrete conditions in which the production process is deployed. So, in the previously presented in (tab.1) one can purpose that is possible to exist two estates as: S 1 – the most favorable estate, caused by the possibility realization of cheaper constructiv solutions (estate influenced by the optimal, cheaper and delivered on time semiproducts, reduced tools consumption and energy) or a bigger rigidity; S 2 – the least favorable estate, caused by the unexpected and unfavourable situations. Uncertainty knowing which of the two situations will be produced, in the decision analysis process must be taken into consideration both of the variants. In this sence, one can consider that the estimation of the device constructiv variants solutions for the SCPD process application, through x 1 , x 2 criteria and S 1 , S 2 situations are those from (tab.3). Calculating the utilities for each criterion, one obtain the values from (tab.4). Table 3. Established situation: S 1 the most favorable estate and S 2 : the least favorable estate CRITERIA VARIANTS Situation S 1 Situation S 2 x1 x2 x1 x2 D1 5500 1220 4100 970 D2 3000 1960 4300 2850 D3 9400 3500 7200 3200 D4 3700 3350 4800 3300 219

Table 4. Variants utilities D i calculated for the x j criteria in those two situations S 1 and S 2 CRITERIA VARIANTS Situation S 1 Situation S 2 x1 x2 x1 x2 D1 0,61 0,00 1,00 0,00 D2 1,00 0,32 0,94 0,81 D3 0,00 1,00 0,00 0,96 D4 0,89 0,93 0,77 1,00 With the known values of the adequate importance coefficients (k 1 = 0,42, k 2 = 0,58), the sum utilities are calculated for the D 1 , D 2 , D 3 , D 4 variants, at the S 1 and S 2 estates, presented in (tab.5).

VARIANT D1 D2 D3 D4

Table 5. The sum utilities values Situation S 1 0,26 0,61 0,58 0,91

Situation S 2 0,42 0,86 0,56 0,90

4. Conclusions From the devices D 1 , D 2 , D 3 , D 4 constructiv solutions analaysis regarding the establishment of the optimal variants that can be used to applly the SCPD process, results: • the contact type between tool and piece is necessary to be established through the device constructiv solution and influence both the rigidity and the costs measure of these; • the tools number from the device component (1, 2, 3 or more), through which one transmitt the contact force of the processed piece, depends and is invers proportional with his rigidity; • the constructiv solutions variety that can be used to realize the SCPD devices depending by a high number of factors (tools geometry, processed surface geometry, rolling operation nature that depends on the followed purpose, etc.), engage to the optimal variant chooses based on some decision, in accordance with some technological performance criteria, that can justify quantitative and qualitative the final adopted decision. Referinces: 1.Bragaru A., Stăncescu C. Bazele optimizării proceselor tehnologice. Îndrumar de laborator, Institutul Politehnic Bucureşti, 1977; 2. Lupescu O.,(1999) Netezirea suprafeţelor prin deformare plastică,Editura Tehnică info Chişinău (1999) Iaşi. 3.Lupescu O., (2005) Ingineria calităţii în procesele de deformaţie plastică superficială la rece. Editura Politehnium Iaşi.

220

EVALUATION OF THE MACHINABILITY BY FACE TURNING Slătineanu L., Coteaţă M., Uliuliuc D., Rădeanu Al., Rotman I. (Technical University “Gh. Asachi” of Iaşi, Iaşi, Romania) The machinability of a certain material is the technological property which characterizes the possibility to machine the material in the most convenient conditions for the producer (with high machining speed, with minimum mechanical and energetic solicitation, with obtaining of the small surface roughness, of the easy-to-remove chips etc. There are different methods for the evaluation of the materials machinability, one of them being the method of face turning. As machinability index, the diameter at which the tool wear is of 0.2 mm in the direction of the test piece axis is used. To increase the number of the tests performed by the same tool lathe, a tool having a zone with an equilateral triangle cross section was used. The experimental researches allowed establishing some empirical relations to emphasize the influence exerted by the rotation speed of the test piece and by the work feed on the machinability index. 1. Introduction The machinability of a certain material can be defined as that technological property which offers an image concerning the possibility to machine the material in the best conditions for the producer: with high machining speed, but at minimum wear of the tool, with the minimum mechanical solicitation and with the minimum energetic consumption, with obtaining of the minimum surface roughness, of the most convenient shapes of the chips etc. One can notice that to characterize the machinability of a material, it is not enough to use a single evaluation criterion or when there is a statement concerning the material machinability, it is necessary to specify the criterion used for its evaluation. There are different methods which can be applied to evaluate the machinability [2, 3, 4]: a) Direct methods, when proper machining techniques are used to obtain information concerning the tool wear, the forces generated by machining, the surface roughness etc.; b) Indirect methods, when the evaluation of the material machinability takes into consideration aspects which are not directly correlated with a certain machining process. On the other hand, there are long duration methods, applied in proper machining conditions and short duration methods, when the results of the machinability evaluation must be offered in a short time. The face turning method is considered as a short duration direct method used for the evaluation of the metallic material machinability. The method seems to be proposed long time ago by Brandsma [5]. A variant of the face turning method was proposed and developed by the French researcher P. Mathon [2, 3]; because the researches were made in connection with the Renault enterprises group, this variant was called the Renault-Mathon method. Within the Technical University “Gheorghe Asachi” of Iaşi, the face turning method was applied by taking into consideration firstly the Renault-Mathon method, but, because the change of the tool was necessary after each test, we tried to find a tool able to allow many tests before substituting it by a new tool. The researches led to the using of a tool whose active zone has a cross section of equilateral triangle; obviously, after the using of a corner, the tool can be rotated with 120 ° and the possibility to use a new tool corner is thus ensured (fig. 1). O course, as a face turning method, the test implies the transversal turning of a cylindrical test sample, clamped in the universal chuck, from the axial hole to the exterior of the test piece, by using a certain speed rotation of the test sample and a certain work feed of the lathe tool. Due to the continuous increasing of the cutting speed, the tool is affected by the accelerated wear and there is a moment when the dept of cut becomes better than the initial 221

Fig. 1. Machining schema valid in the case of the face turning

size (1 mm) or just the tool does still not cut. As machinability index, P. Mathon proposed to use the diameter D 0.20 of the machined surface when the dept of cut decreases with 0.20 mm. This diameter can be measured (fig. 2) by means of a dial gauge (to identify the zone where the dept of cut decreased with 0.2 mm) and of a slide gauge (to measure the diameter D 0.20 ). 2. Machinability evaluation by face turning As above mentioned, the researches concerning the machinability by cutting developed within the Technical University “Gheorghe Asachi” of Iaşi were devoted to establish some empirical mathematical models able to emphasize the influence exerted by the rotation speed (the number n of revolutions per minute) and the transversal feed f on the

diameter D 0.20 . The experimental results were processed by means of a specialized software [1], based on the using of the method of the smallest squares. The software allows selecting the most adequate functions among some such available functions; the selection is made by taking into consideration the so called Gauss’s sum. As one can see (table 1), a factorial experiment with two variables at two levels was proposed and applied. The rotation speeds of the test sample were n max =630 rev/min and n min = 400 rev/min; the feed had the sizes f min =0.032 mm/rev and f max =0.088 mm/rev. The dept of cut was a p =1 mm. The sizes of the rotation speeds and of the feeds were introduced in a codified manner in the table 1 (using the symbol “-1” for the minimum size and the symbol “+1” for the maximum size). In the fourth column of the table 1, there were inscribed symbols corresponding to the multiplication of the algebraic sizes attributed to the independent variables (-1 and +1). Table 1. Experimental results in the case of the steel containing 0.45 % carbon Test Rotation Feed f, (vf) D 0.20 Average size of no. speed, mm/rev D0.20 n, rev/min 1 2 3 4 5 6 7 8 1 +1 -1 -1 69.0 62.7 63.5 65.06 2 -1 -1 +1 45.0 41.0 43.2 43.06 3 -1 +1 -1 36.6 36.0 38.4 37.00 4 +1 +1 +1 24.4 23.0 22.5 23.30 In the column no. 5-7 of the table 1, the sizes of the diameter D 0.20 were inscribed; these sizes were determined by three distinct experimental tests, in the same work conditions. The column 8 contains the average size of the diameter D 0.20 . In such conditions, if only the independent variables n and f are considered, the most adequate function is: 222

D0.20 = 179.5176 ⋅ 0.9980 n ⋅ (6.3778 ⋅ 10 −5 ) f ,

(1)

the Gauss’s sum being S G =0.4134435. Because the power type function is frequently considered as offering more direct information concerning the influence exerted by different factors on the diameter D 0.20 , such a function was also established: D0.20 = 3645n −0.9635 f −0.4769 ,

(2)

the Gauss’s sum being S G =0.4150658.

Fig. 2. Measuring of the diameter corresponding to a tool axial wear of 0.2 mm If the last empirical relation is analysed, one can notice that the most important influence on the size of the diameter D 0.20 is exerted by the speed rotation n, because the absolute size of the exponent attached to the variable n is bigger than the absolute size of the exponent corresponding to the variable f (0.9635>0.4769). Similar empirical relations were also established for other steels: D0.20 = 1756n −0.862 f −0.446

(3)

for steel containing 0.41 % carbon, 0.25 % molybdenum and 1.1 % chromium and D0.20 = 43n −0.869 f −0.532 ,

(4)

for steel containing 0.4 % carbon and 13 % chromium etc. By taking into consideration the empirical relations (2), (3) and (4), the figure 3 was elaborated; the figure shows the influence exerted by the feed f on the machinability index D 0.20 . Some actual mathematical knowledge allows nowadays evaluating if some interactions among the considered independent variables could exist. To analyse this aspect in 223

the above mentioned case, the information included in the table 1 was considered. Thus, if the information included in the fourth column of the table 1 is taken into consideration and the product (nf) is considered as an independent variable, the following empirical relation can be established: 11283 0.1876 320.5245 (5) + + D0.20 = −2.7084 + n f nf The Gauss’s sum corresponding to the function described by the relation (5) is S G =1.909939·10-10. For the same initial considerations (taking into consideration the product (nf) as an independent variable), the following empirical power type relation was determined:

Machinability index, mm

D0.20 = 3639.69n1.3429 f 1.8292 (nf ) −2.3062

140 120 100 80 60 40 20 0

(6)

Steel 1 Steel 2 Steel 3

0,02 0,04 0,06 0,08 0,1 0,12 f, mm/rev

Fig. 3. Influence exerted by the feed on the machinability index D 0.20 (n=250 rev/min; steel 1 – steel containing 0.45 % C, steel 2 – steel containing 0.25 % Mo, 1.1 % Cr, steel 3 – steel containing 0.40 % C and 13 % Cr) The relation (6) emphasizes that the interaction (nf) could be considered as important, the exponent of the product (nf) having a significant absolute value and even bigger than the exponents corresponding to the independent variable n and f. 4. Conclusions The information concerning the metallic materials machinability could be used to optimize the values of the operation parameters at the cutting. The evaluation of the machinability is performed by direct and indirect methods; on the other hand, there are long and short duration methods. The face turning is taken into consideration when some information concerning the material machinability must be established in short time. Within the Technical University “Gheorghe Asachi” of Iaşi - Romania, a special tool was designed and used to decrease the time for the experimental tests, when many such tests are required. As machinability index which can be determined by face turning, the diameter D 0.20 (corresponding to the diameter where the tool wear is of 0.2 mm, if it is measured along the rotation axis of the test piece) was considered. Some experimental researches were developed to establish the empirical mathematical models able to emphasize the influence exerted by some operating parameters (the speed rotation n and the feed f) on the size of the diameter D 0.20 . 224

References: 1. Creţu, G. Fundamentals of the experimental research. Handbook for the laboratory activities (in Romanian), Polytechnic Institut of Iaşi, Romania, 1992. 2. Mathon, P. Essais de coupe accélerés. Mécanique, Matériaux, Electricité, No. 322, 1976. 3. Mathon, P. Usinabilité et lois générales de l’usinage des aciers et des fontes. Mécanique, Matériaux, Electricité, 246-247, 1970, 23-34. 4. Salak, A., Vasilko, K., Selecka, M., Danninger, H. New short time face turning method for testing the machinability of PM steels. Journal of Materials Processing Technology, 176, 2006, 62–69. 5. Slătineanu, L. Contributions to the study of the machinability of some Romanian steels (in Romanian). Doctoral thesis. Polytechnic Institute of Iaşi, Romania, 1980. EXPERIMENTAL STUDIES REGARDING THE INFLUENCE OF THE CUTTING CONDITIONS ON THE SHAPE ACCURACY OF THREADS PROCESSED BY LATHE CUTTING Stanciu A., Pruteanu O. V., Cărăuşu C. (TU „Gh. Asachi”, Iassy, Roumania) The parameters of the cutting conditions influence the deviations of the thread shape half-angle, ∆α/2, in the variation range analysed in the study. Increasing the cutting speed determines an increase in the deviation values in the case of OL52 steel, and a decrease in the deviation values when processing 34MoCr11 alloy steel. Increasing the cutting depth determines an increase in the deviation values with both types of steel. The simultaneous increase of both cutting speed and cutting depth causes a substantial increase in the deviations of the thread shape half-angle with both types of steel. 1. Introduction The technological process of lathe cutting is a complex one, with numerous interactions among the factors involved in it, so that an evaluation of these factors’ influence on the performance parameters of the process is necessary. From a technological point of view, it is important to ascertain the influence of the cutting conditions in turning threads with threading tools on the deviations of the thread flanks half-angle. In order to determine such dependencies and the mathematical models capable to describe them, respectively, as regression functions, it was necessary to set the other parameters of the process at certain values, which limit, however, the validity range of the resulted models. 2. Generals conditions for the experiments The processing in the experiments carried out in the field of threading has been performed with a SNA 400 x 1000 universal lathe that is part of the equipment of the Faculty of Machine Manufacturing in Iaşi. In determining the methodology and the general conditions for carrying out the research on the processing accuracy of threads with screw cutting tools we have started from the following facts:  in order to be able to compare the results of the experimental research, the diameter of the workpiece has been set at a d = 22 mm value;  the longitudinal advance S l is equal to the step of the thread and cannot be considered an influence factor: p = 2.5 mm;  the rake angle has been set at γ s = 0°, in order to allow for an easy sharpening of the tools on the front face and the relief angle at α s = 8, respectively;  OL52 steel threads have been processed with rapid steel tools and 34MoCr11 alloy steel threads have been processed with tools that had cemented-carbide tips, respectively; 225

 the cutting speed has been determined by varying the spindle speed of the lathe, while the value of the penetration feed, t, has been modified by mechanical command;  the total tooling allowance is equal to the height of the thread: h = 1.353 mm. 3. Experimental results 3.1 The influence of the cutting speed, v p In order to determine the influence of the cutting speed, v p , on the deviations of the thread flanks half-angle, experimental trials and measurements have been carried out in five experimental points for both types of steel. The experimental points are presented in Tables 1 and 2. Table 1. Experimental points used to determine the influence of the cutting speed and the values of the ∆α/2 parameter for OL52 workpieces No 1. 2. 3. 4. 5.

Tool material, M

αs [°]

rapid steel Rp3

vp [m/min] 4,354 6,911 11,058 17,278 27,646

np [rot/min] 63 100 160 250 400

t [mm] 0,1691 (i=8)

∆α/2 [′] 3 4 5 7 9

Table 2. Experimental points used to determine the influence of the cutting speed and the values of the ∆α/2 parameter for 34MoCr11 workpieces No Tool material, M αs, vp np t ∆α/2 [m/min] [rot/min] [mm] [°] [′] 1. 6,911 100 8 cemented8 0,0966 2. 11,058 160 7 carbide tips (i=14) 3. 17,278 250 6 4. 27,646 400 5 5. 34,557 500 3 Table 3 presents the mathematical forms of the regression functions obtained with the help of the DataFit programme, which gives the best approximation of the dependency models of the ∆α/2 parameter values for the previously presented strings of data, as well as the corresponding values of the multiple regression coefficients R2. Following the mathematical models presented in table 3, fig. 1 and 2 are the graphic representations of the experimental points and the response curves for each ∆ α = ∆ α (v p ) 2

model, together with the errors of the models in the points that have been considered.

226

Deviation of the thread flanks half-angle [‘]

Model ∆α/2 = ∆α/2 (v p ), OL52

Cutting speed, vp [m/min]

Fig. 1. Experimental points and response curve for the ∆α/2=∆α/2 (v p ) model for the OL52 steel Table 3. The mathematical forms of the ∆α/2=∆α/2 (v p ) dependencies Material Regression function R2 -4 3 -3 α · ·v p 2 + 2,54 ·10- 1 · v p + ∆ = – 2,11 ·10 · v p + 5,95 ·10 2 OL52 0,9979 1,86 -4 3 -2 2 -1 α ∆ = – 5,16 ·10 · v p + 3,07 ·10 · ·v p – 6,93 ·10 · v p + 2 34MoCr11 0,9991 11,52

Deviation of the thread flanks half-angle [‘]

Model ∆α/2=∆α/2 (vp), 34MoCr11

Cutting speed, vp [m/min]

Fig. 2. Experimental points and response curve for the ∆α/2=∆α/2 (v p ) model for the 34MoCr11 steel

227

3.2 The influence of the cutting depth, t In order to determine the influence of the cutting depth, t, on the parameters analysed in this study, experimental tests and measurements have been carried out for the two types of steel. The results are presented in tables 4 and 5. Following the mathematical models presented in table 6, figures 3 and 4 are the graphic representations of the experimental points and the response curves for each ∆

α = α (t) model, together with the errors of the models in the points that have been ∆ 2

considered. Table 4. Experimental points used to determine the influence of the cutting depth and the values of the ∆α/2 parameter for the OL52 workpieces np ∆α/ αs vp t No Tool material, M [rot/min i 2 [mm] [°] [m/min] ] [′] 1. 0,33825 4 18 2.

0,2255

0,16912

0,1353

0,11275 12

0,09664 14

rapid steel Rp3

17,278

250

Table 5. Experimental points used to determine the influence of the cutting depth and the values of the ∆α/2 parameter for the 34MoCr11 workpieces No Tool material, M α s [°] v p [m/min] n p [rot/min] t [mm] i ∆α/2 [′] 1. 0,33825 4 20 2. 0,2255 6 15 cemented8 27,646 400 3. 0,16912 8 7 carbide tips 4. 0,1353 10 5 5. 0,11275 12 4 6. 0,09664 14 3 Table 6. presents the mathematical forms of the regression functions obtained with the help of the DataFit programme, as well as the corresponding values of the multiple regression coefficients R2 Table 6. The mathematical forms of the ∆α/2=∆α/2 (t) dependencies Material Regression function R2 3 2 α ∆ = – 58,61 · t + 16,21 · t + + 59,71 · t – 1,77 OL52 0,9956 2

34MoCr11

∆

= exp (–1,33 +27,69 · t –44,02.r2)

228

0,9915

Deviation of the thread flanks half-angle [‘]

Model ∆α/2 = ∆α/2 (t), OL52

Cutting depth [mm]

Deviation of the thread flanks half-angle [‘]

Fig. 3. Experimental points and response curve/ for the ∆α/2=∆α/2 (t) model for OL52 steel Model ∆α/2 = ∆α/2 (t), 34MoCr11

Cutting depth [mm]

Fig.4. Experimental points and response curve/ for the ∆α/2=∆α/2 (t) model for 34MoCr11 steel 3.3 The two-dimensional dependency of the deviations of the thread shape, dependent on the v p and t parameters Although the analysed parameters, v p and t, respectively, are independent of each other, it was considered convenient that, in addition to studying their individual influences, their two-dimensional dependencies on the performance parameters of the analysed process also be determined (table 7). Table 7. Experimental plan for determining the two-dimensional dependencies of the lathe cutting process results and the values of the ∆α/2 parameter dependent on v p and t No 1. 2. 3. 4. 5. 6.

αs [°]

vp np t [m/min] [rot/min] [mm] 17,278 250 0,16912 17,278 250 0,1353 17,278 250 0,11275 17,278 250 0,09664 27,646 400 0,16912 27,646 400 0,1353

229

i 8 10 12 14 8 10

∆α/2, [′] OL52 34MoCr 11 7 8 5 7 4 6 3 5 10 7 8 6

7. 8.

27,646 27,646

400 400

0,11275 0,09664

12 14

7 5

5 4

Table 8. The mathematical forms of the ∆α/2=∆α/2 (v p ,t) dependencies Material Regression function R2 2 -1 2 α ∆ =3,42 ·10 +2,65 ·10 ·v p +4,88 ·10 · log t 2 OL52 0,9898 +2,34 · 102 · log t2 + 37,87 · log t3 -2 α ∆ = 9,73 – 9,64 ·10 · v p – 6,08 · log t – 34MoCr11 2 1,0 – 5,72 ·log t 2 – 1 ,87 · log t3 – 3,33 ·10-1 · log t4 The mathematical formulae of the regression functions obtained with the help of the DataFit programme, as well as the corresponding values of the multiple regression coefficients R2 are presented in table 8. Following the mathematical models presented in table 8, figures 5 and 6 are the graphic representations of the experimental points and the response curves for each ∆

α = α (v ,t) model, together with the errors of the models in the points that have been p ∆ 2

Deviation of the thread flanks half-angle [‘]

considered. 4. Conclusions The analysis of the response curves and surface presented in this study leads to the following conclusions:  the influence of the cutting speed, v p , in the variation range analysed in this study, on the deviations of the thread shape half-angle, ∆α/2, is manifested differently according to the processed material, in that the increase the cutting speed determines an increase in the deviation values in the case of OL52 steel, and a decrease in the deviation values when processing 34MoCr11 alloy steel;  the increase of the cutting depth, t, has shown an increase in the deviation values of the thread shape half-angle in the processing of both types of steel;

Fig. 6. Experimental points and response surface/area for the ∆ α = ∆ α (vp ,t) model for OL52 2

steel

230

Deviation of the thread flanks half-angle [‘]

Fig.7. Experimental points and response surface/area for/of the ∆ α = ∆ α (v p ,t) model for 2

34MoCr11 steel  the simultaneous increase of the cutting speed and of the cutting depth has led to a substantial increase of the deviations of the thread shape half-angle in the processing of both types of steel;  the mathematical models are described by complex, polynomial and polynomial-logarithmical functions. References: 1. Ciocârdia, C. ş.a. Bazele cercetării experimentale în tehnologia construcţiei de maşini, EDP, Bucureşti, 1979. 2. Muscă, G. ş.a. Experimentarea, modelarea şi optimizarea produselor şi proceselor, ET, Chişinău, 1988. 3. Duşa Petru, Pruteanu O.V., Popa V. Concepţia fabricaţie, Ed. Tehnica Info, Chişinău, Republica Moldova, 2000. 4. Gh.Creţu. Contribuţii teoretice şi practice în domeniul prelucrării melcilor folosind principiul filetării în vârtej, UTIaşi, 1997. 5. V. Merticaru jr.,O.V.Pruteanu. Matrix modeling for the influences of some process parameters upon the power consumptios at whirling thread-cutting – Act Mechanica Slovaca, nr.3/1999, ISSN 1335-2393, p.159-162. НОВЫЕ РАЗРАБОТКИ ТЕХНОЛОГИИ И ОБОРУДОВАНИЯ ТЕРМОДИФФУЗИОНОГО ЦИНКОВАНИЯ Stikan I., Almen J., Шнуренко А. В., Андрющенко В. А. (Distek, ЦТЦ, Донецк, Israel, Украина) The Company DiSTeK Israel has developed new ecologically clean technology for thermal diffusion zinc coating, which is extremely protective against corrosion and able to vary thickness of coating from 20 up to 100 microns depending on requirements of a customer. Company DiSTeK established tens plants all over the world equipped for thermal diffusion zinc coating of metal items from fasteners up to profiles and pipes 12m length. Для защиты металлических изделий от коррозии широкое применение находят разного рода цинковые покрытия поверхности металла. В основном применяются способы горячего цинкования, опусканием в расплав цинка, электролитического осаждением цинка из раствора электролита и термодиффузионного - нагреванием изделий в среде цинкового порошка. 231

Открытый более ста лет назад процесс термодиффузионного цинкования названный по имени автора шерардазингом, предусматривающий нагрев изделий в смеси цинкового порошка с балластной (в основном песочной средой) за последние годы получил достаточно широкое распространение, несмотря на известные недостатки - высокую энергоемкость из-за нагрева большого объема балласта, запыленность, трудности регулировки толщины покрытия. В настоящее время в мировой практике получения защитных цинковых покрытий все большую известность получает новая экологически чистая технология термодиффузионного цинкования фирмы DISTEK [1] (торговые марки Дистек тм, DiAV 93, Victocor), не требующая песочного балласта и отличающая малым расходом (1,0-3,0% от массы цинкуемых изделий) специальной насыщающей смеси [2, 3]. Технология Дистек позволяет осуществить надежную защиты от коррозии различных изделий, как малых и средних размеров, в том числе резьбовых, из стали и чугуна, так и длинномерных до 12м, труб и фасонных профилей, работающих на открытом воздухе, в промышленной и морской атмосфере и требующих толщин покрытия свыше 20 мкм. Разработанная технология термодиффузионного цинкования имеет ряд существенных преимуществ, основными характеристиками которых являются: - высокая антикоррозионная стойкость - покрытие в точности воспроизводит профиль поверхности изделия в целом и отдельных деталей на ней (резьбу, маркировку, другой тонкий рельеф поверхности). - покрытие имеет более высокую твердость, чем другие цинковые покрытия и обладает хорошим сопротивлением абразивному износу. - шероховатость покрытия зависит от режима процесса цинкования и последующей финишной обработки, и позволяет удовлетворить разнообразные требования к поверхностям деталей подлежащих последующей окраске, гуммированию и.т.п. - температура насыщения невелика, поэтому покрытие может быть нанесено на пружинные и другие предварительно термообработанные детали. - процесс может быть использован для нанесения покрытий на изделия полученные по порошковой технологии, на пористые изделия, а также на предварительно собранные узлы. - детали, подвергаемые насыщению, требуют минимальных затрат на подготовку поверхности к покрытию. Допускается наличие на деталях пятен коррозии, остатков смазки и СОЖ. - в процессе исключено образование жидких и твердых отходов, нуждающихся в нейтрализации или захоронении. -покрытие, получаемое по новой технологии, полностью соответствует требованиям ASTM B633, ASTM B695, Британского стандарта BS 4921:1988 и стандарта Российской федерации ГОСТР 51163-98 - по требованию заказчика толщина покрытия может варьироваться в пределах от 20 до 100 мкм и более Структура покрытия представляет собой интерметаллид железо-цинк переменного состава, в основном FeZn7(1-фаза). Плотность 7,2 см3, микротвердость ~4500 МПа.

232

Получаемое покрытие однородно по толщине, имеет матовый темно-серый цвет. По данным Британской Ассоциации Железа и Стали, Государственного стандарта Российской Федерации (ГОСТР 51163-98), коррозионная стойкость такого покрытия превосходит по своим защитным свойствам другие цинковые покрытия, что видно в приведенном ниже графике сравнительной стойкости в соляном тумане разного типа покрытий.

Качество покрытия протестировано: Брюссельской Металлургической Лабораторией; Шведским Национальным Институтом Тестирования; Израильским Институтом Стандартов;  Рос с ийс к Машиностроительной лабораторией; Институтом коррозии, Дрезден, Германия ; Национальным центром промышленного развития ЮАР. В предлагаемой технологии существует, кроме того, возможность получения цветных и блестящих покрытий, а также покрытий с коррозионной стойкостью свыше 1500 часов при испытаниях в камере соляного тумана. Технологический процесс 233

награждён золотой медалью всемирной технологической Выставки «Eureka 96». Процесс отличается низкими потребностями в производственных площадях, электроэнергии и рабочей силе. Цинкование осуществляется в термических печах барабанного типа в интервале температур 360-4200С с использованием специальной насыщающей смеси в количестве 1-3% от веса цинкуемых изделий. Фирмой "Дистек" разработан комплекс оборудования и технологических линий термодиффузионного цинкования различной степени механизации и автоматизации на производительность от 50 до 1000 кг/час. Все линии включают не только термические печи с вращателями контейнеров для проведения процесса цинкования, но и комплекс оборудования для загрузки и выгрузки изделий, обеспыливания, вибрационной очистки, пассивации и мойки поверхности изделий после цинкования. В качестве примера ниже показан участок цинкования с печами малой (50 – 70 кг/час) производительности. [5] Участок цинкования производительностью 150 кг/час на базе трех печей MDS -125, вибрационного пассиватора VM- 100 и проходной сушильной камеры Ящик готовых изделий

MDS-125

Сушильная камера

Корзина

4000 Кантователь

2000

VM-100

2200 8000

1200

Впервые в мировой практике созданы полунепрерывные линии [4] высокой производительности, отличающиеся полной механизацией и автоматизацией процесса термодиффузионного цинкования. Эти линии предназначены в основном для покрытия однотипных изделий (метизов, гвоздей и.т.п). Для работы на линии производительностью до 1000кг в час достаточно двух рабочих.

234

235

INDUSTRIAL SAFETY FROM THE POINT OF VIEW OF EUROPEAN LEGISLATURE Štroch L. (VVUÚ, Ostrava, Czech Republic) Main laws and technical regulations that are related to the industrial safety in the sense of technology protection against occurrence and propagation of explosions are defined here, in order to provide fundamental information about ČR and EU legislative. We are showing order of these regulations and their short descriptions. Development of industrial production is a constant process of mutually related activities, which leads to increased production, optimization of production processes, implementing of new technologies and products, in order to achieve efficient results, while holding market positions and reaching satisfactory economic results. Present development of industries also posts new questions, like for example ecologic views, human resources, personnel health, social environment and last, but not least, safety. With increasing standard of living in society and modernization of production technologies the view of work safety and approach to safety changes, especially in industrial production. As far as this lecture is concerned, the industrial safety is understood as a systematic approach to searching and description of risks in industrial production, and their elimination to a tolerable limit by technical and organizational measures. Approach to the industrial safety in ČR and EU is performed by many legislative regulations and undergoes constant development to increase the industrial production safety to the highest level possible, in order to minimize amount of work injuries, technology damages, work stoppages, affecting of environment etc. Legislative framework, used to achieve the high level of safety in the industry, follows customs and standards of a given society. As it is customary in ČR, industrial safety is grounded in its constitution, laws, directives, technical standards and operation regulations. The industrial safety can be understood very widely, from the safety of machinery, work procedures, personal protective aids, documentation, liquidation of accidents, all the way to emergency procedures. Some of very risky activities in industry are activities performed in areas with fire and explosion dangers. Fires and explosions are undesirable phenomena in industrial production and often are the reason of large technology and personnel health damages. Safety in industrial production starts with individual provisions of the Work Code, which is the main regulation concerning rules for industrial workers. This is followed by other lawful regulations, including the government directive no. 406/2004 Coll. in ČR, or 1999/92/EC in EU. This accepted European parliament and council guideline, which has been consequently implemented in national legislatives of the member countries, contains exactly defined conditions for adherence to safety, and is already defined by its name “About minimum requirements for improvement of safety and protection of workers exposed to explosion danger environment“. Together with this government directive the government directive no. 405/2004 Coll. is valid that defines areas, where these explosive atmospheres can be found. The law about fire protection no. 133/85 Coll., including the notice no. 246/2001 Coll., is related to the above mentioned law. Analysis of individual regulations: 236

1. The Law no. 262/2006 Coll. – The Work Code stipulates employer obligations for conditions of safe, harmless and health not endangering work activities that are defined by formulation in individual sections (102 and 103). 2. The Law no 133/1985 Coll., About fire protection, as amended In this law, which is valid in ČR, performed activities are divided, according to fire danger, into individual categories: a) Without increased fire danger b) With increased fire danger c) With high fire danger The increased fire danger is for example represented, among other things, by combustible gases in tanks or vessels with volume larger than 100 l, or occurrence of combustible dust in air, or in equipment in such amount that origination of explosive concentration cannot be excluded, or where the combustible dusts settles in a continuous layer at least 1 mm thick. In these cases it is not possible to eliminate origination and development of explosion. urther this law regulation defines obligations of legal and physical entities, among which also are settings of fire and technical characteristics of materials (FTCH). 3. The notice about fire prevention no. 246/2001 Coll. Among other things this regulation stipulates fire safety conditions, defines authorized types of fire equipment, technical and safety parameters, fire and technical characteristics etc., which are necessary materials for determination of industrial safety in technology lines in areas with explosion danger. 4. The Law no. 59/2006 Coll., About prevention of serious accidents caused by selected dangerous substances. 5. The government directive no. 406/2004 Coll., About detailed requirements to provide safety and protection of health during work in explosion danger environment (ATEX 137). This is the implementation of the European parliament and council directive 1999/92/EC, About minimum requirements to improve safety and protection of workers exposed to explosion danger environment. This regulation defines the way of classification of areas to secure safety and protection during work in explosion danger environment, including requirements for selection of equipment and protection systems. 6. The government directive no. 405/2004 Coll., which determines the appearance and placement of safety signs and implementation of signals (picture of the sign “danger – explosive environment”). 7. The government directive no. 23/2003 Coll. (94/9/EC), which stipulates technical requirements for equipment and protection systems intended for use in explosion danger environment (ATEX 100). This is implementation of the European parliament and council directive 94/9/EC, about harmonizing of legal regulations of the member states about equipment and protection systems intended for use in explosion danger environment. 8. ČSN EN 1127-1 Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts and methodology 9. ČSN EN 13 463-1 to 8 Non-electrical equipment for explosive danger environment

237

10. ČSN EN 61 241-10 Electrical equipment for explosive dust atmosphere - Part 10: Determination of dangerous areas 11. ČSN 33 2000-3 Electro technical regulations. Electrical equipment – Part 3: Determination of basic characteristics 12. ČSN EN 13 237 – Potentially explosive atmospheres - Terms and definitions for equipment and protective systems intended for use in potentially explosive atmospheres. 13. ČSN EN 14 460 Explosion resistant designs 14. ČSN EN 14 373 – Explosion suppression systems 15. ČSN EN 15 089 Explosion separation protection systems 16. ČSN EN 14 994 17. ČSN EN 14 491 18. ČSN EN 14 797 Explosion venting devices 19. ČSN EN ISO 12 100-1 Safety of machinery – Part 1: Basic terminology and methodology 20. 12 100-2 Safety of machinery – Part 2: Technical fundamentals 21. 14 121-1 Safety of machinery – Evaluation of risks - Part 1: Fundamentals Activities preceding creation of documentation of protection against explosion (DOPAE), according to GD no. 406/2004 Coll., are – determination of basic risks, FTCH definitions, technology descriptions etc. In order to fulfill requirements of the existing ČR and EU legislature, the evaluation of industrial technology and creation of specific addressable DOPAE, which contains at minimum the following chapters, are necessary: 1. Technical measures 2. Organizational measures 3. Coordination measures 4. Education 5. Documents 6. DOPAE validity, usefulness and update conditions Findings and conclusions coming out of DOPAE must be entered into operational documentation, production technological processes, and work procedures during stopping and starting of technology, maintenance, repairs, inspection activities etc. In case of designing of new technologies, it is suitable to prepare safety studies in the pre-project stage, dealing with questions of explosion dangers and consequently very carefully deal with the project anti-explosion prevention for particular production lines, in order to secure high level of industrial safety for areas with explosion dangers. Updating of such documentation is needed also during changes of materials or parts of technological equipment. A complex approach and constant system activities, during maintenance of DOPAE, guarantee that risks concerning origination and propagation of explosions in these technologies will be minimized. By adherence to law regulations we will achieve safety for technologies, where explosion danger environment exists, and reach smooth production without emergencies. This way we will provide work safety for personnel at these production lines and constant economic development of companies without production stoppages and risks of market position losses. 238

DESIGN REQUIREMENTS FOR TECHNOLOGICAL EQUIPMENT IN EXPLOSION DANGER ENVIRONMENT Štůrala J. (RSBP spol. s r. o., Ostrava-Radvanice, Czech Republic) Explosions can occur during processing, transport and storage of industrial combustible dusts that are, at the first sight, harmless – destruction effects of these processes thus represent heavy economic damages on industrial equipment, and human health and life can be easily endangered. Here we have to name especially coal dust, dust occurring during processing of flour, sugar, cellulose, and other dusts, which are produced during production processes in wood, feed, pharmaceutical, food and other industries. Some metal dusts are especially dangerous, for example, magnesium and aluminum ones. Explosion danger represented by a given process must be determined by evaluation of technological equipment, in which explosion or potentially explosive atmosphere occurs. This analysis leads to definition of endangered technology sections, which have to be handled as separate and individual parts from the point of view of prevention and protection against explosion. These endangered sections can include more than one vessel and interconnecting pipes; their borders often are rotary valves and screw conveyors. Any possible explosion event must be completely dealt with within such endangered section. It is a normal practice that during application of an explosion suppression system all HRD extinguishing units in the endangered section are activated. However, HRD extinguishing units that are installed in any other section are not activated, unless there is explosion initiation in that section. Types of Explosion Prevention A philosophy of explosion protection results basically from the knowledge of an initiation and a process of an explosion itself. For this reason it can have two types: – the preventive protection, which protects against initiation of explosion as such - called the active prevention – design preventive measures, which do not protect against the explosion initiation, but limit or lessen dangerous explosion effects - called the passive prevention. Passive Prevention For application of the passive prevention we need to solve a complex design of explosion protection with regard to valid standards, regulations and the state-of-the-art equipment. A wide range of protective elements helps us to do this. The passive protection against explosion deals with alleviation of dangerous explosion effects inside of technological equipment. Use of design anti-explosion protection does not exclude occurrence of explosion. Therefore the equipment, in which the explosion danger environment occurs, must be designed for the expected inside explosion pressure. Beyond this, transfer of explosion to another connected device must be prevented. Software simulation is applied to verify vessel pressure resistance; this identifies locations, where plastic deformation can take place.

Fig. 1. Filter software simulation 239

Explosion Relief Anti-explosion safety devices with a membrane are used to reduce explosive pressure of dust, gas or vapor dispersion mixtures with air, or hybrid ones that evolve inside of a protected space (e.g. in storage tanks, filters, mills, crushers, separators, classifiers, homogenizers dryers etc.). They protect machines, technological equipment, storage spaces etc., with low to medium pressure resistance, from rupture and destruction in case of nonpermissible over or under pressure. They are installed in outside areas, where they do not endanger life, health and activities of personnel. The installed membranes must be certified according to the directive 94/9/EC (ATEX 100).

Graph. 1 â&#x20AC;&#x201C; Explosion relief The membranes open in the initial stage of an explosion, combustion material is released and the pressure inside of a vessel is reduced.

Fig. 2. Closed membrane

Fig. 3. Opened membrane

Reaction forces occur during explosion relief due to flow of material from a membrane. There is an imbalance of forces acting on the vessel due to opening. This imbalance must be accounted for during a static calculation. 240

Installation of exhaust pipe onto the membranes increases demands on pressure resistance of the vessel. Exhaust speed can reach up to 350 m.s-1, according to the type of explosive mixture, while the flame front can reach 15 to 20 m. Explosion Suppression If protected devices are located inside buildings, we need to protect them with the HRD (High Rate Discharge) system, which is characterized by extremely quick discharge of an extinguishing agent into such protected device, in which suppression of explosion in its incipient stage takes place. This process takes only milliseconds.

Fig. 4. Progress of explosion suppression

Graph. 2. Explosion suppression

241

In the first phase a sensor detects increase in pressure within 2 msec. In this period it performs two more verifications of pressure increase. A pressure detector is used in enclosed vessels, an optical detector in open systems. To extinguish powder mixtures, the explosion suppression is performed by NH 4 H 2 PO 4 , or in case of food powder by NaHCO 3 . Nitrogen under approximately 90 bars of pressure is used as the carrying medium. In order for the explosion not to be transferred by connecting pipes to following technologies, anti-explosion barriers are installed in the pipes. During explosion tests a very strong influence of localization of explosion inside of a vessel was demonstrated. During initiation next to the back wall of the vessel one or possibly two shock waves follow that are related to combustion of a mixture. If the initiation happened at the pipe entrance into the vessel, then there may be up to 5 shock waves (there is effect of the shock wave reflection from a vessel back wall). The anti-explosion barrier must fulfill conditions of optimum extinguishing, which means that it may not be extremely fast in order to extinguish all the shock waves. At the same time it may not be too slow, which means that the flame front may not get through the anti-explosion barrier.

Fig. 5. Explosion in pipe without HRD barier Fig. 6. Explosion in pipe with HRD barier Pressure resistance of the technology equipment thus protected must be approx. 50 kPa. HRD systems are applied in the energy industry in coal mill circuits, in filters at coal hoppers, in the food industry in milk dryers, starch production lines etc. Protection against explosion of combustible dusts inside of industrial equipment must prevent destruction of the equipment and consequent damage to health or death of persons that move around such equipment. The protection then generally lies in minimization of explosion pressure effects on the equipment and elimination of the explosion transfer from the original location to other technology parts.

THEORETICAL AND EXPERIMENTAL CONSIDERATIONS ON WORKING TIME TO GRINDING MACHNE Timofte G., Chirugu M., Paraschiv Dr., Borcila R. (Tehnical University of Iassy, Iassy, Romania) The main objective of this paper is to highlight the work time lost to machine grinding teeth. First are presented the key concepts underlying the research and then presents an experimental study and interpretation of results. 242

1. Introduction The production includes all activities and natural processes that occur in connection with organized transformation of work objects, directed and produced by people with the means of work in order to obtain material things necessary to meet the needs. The production has two sides: the work activity which is the operator in the production of material things or the fulfillment of functions and the technological process is the direct quantitative and qualitative scope of work. To ensure high labor productivity, it is necessary to correct a labor organization and a sensible organization of the workplace.[2] Organization of work includes: timely supply of materials, semi-tools, devices-SDV, judicious division of work, servability of equipment and workplace; endowment by means of suitable lifting and transport; operators training before beginning work and supervision continue during labor, the first piece performed, and control during production to prevent scraps. Workplace organization entails: a rational arrangement of the workplace including the seat for storage of materials, semi, parts and waste of time to prepare materials and semi; provision of auxiliary means necessary in maintaining a state of functioning equipment, maintain cleanliness and order at work.[5] 2. General information Work norming consists in determining the amount of work required for execution of works in certain organizational and technical conditions specified. Standard time(Fig.1) is the time the executor of a qualified professional to perform a unit of work in organizational and technical conditions specified for the workplace concerned.

Fig.1.Time standard The ussing machine time (Fig.2.) available for the entire period of exchange for use of machine. It consists of: the use of operating machine, the unnecessary operation of machine and during the downtime of machine. Knowing how it is used during the operation affected machines, along with how knowledge is used during the work of the operator, allowing detailed study and knowledge of how the development of the production process.[6] The ussing time machine is expressed in unit of time machine. I whole structure is represented in the following schedule : 243

Ussing time machine

useful for operation

time driving task

for the unnecessary operation

idle time

interruptions during the time corresponding to rest and physiological needs of the operator

for downtime

interruptions for liquidatedes

conditioned for interruptions of technology and the organization of employment

interruptions for non - liquidatedes

interruptions for independent equipment

interruptions for dependent equipment

Fig.2. Ussing time machine 3. Experimental research 3.1.Object and methodology of research This study are following the time working and wants to highlight the time lost. Researches were conducted in the workshop of teeth grinding. Grinding is a method of processing by using a cutting tool geometry manytools unconventional tools are abrasive granules.[4] Grinding gears (Fig.3.) Maag process creates a very high accuracy while using the grinding stones of an abrasive in the form of snail, Reisshuer process presents a high productivity but also some difficulties related to wear and profiling stone.[3]

Fig.3. Grinding gears In grinding workshop can be found two types of machines for grinding teeth presented in fig 4 and grinding parameters are the following: peripheral speed of the grinding disc, 244

peripheral speed / number of rotations of the song, the tangential speed and radial value trap.[1]

Fig.4.Grinding machine To start the research were chosen two items, namely S1- major defects and S2 -minor defects which were analyzed in the period 1 January -30 April 2009. The results obtained have led to the conclusion that S1 and S2 are not relevant and that are lost and other times and for this have been chosen since nine items: S3-maintenance car , S4-preparation SDV, S6documentation error, S8-lack of load, S9-meeting, E-lunch break , I-item unknown. 3.2.Results The results obtained are represented by the following graphs In Figure 5 we can observe Oy-axis the number of hours lost and ox-months. In January it had lost 3.71 hours for major defects and 43.56 hours for defects minore.In February 308 for major defects and 23.5 hours for minore defects.In March 0 for major defects respectively 0.62 for minor defects. In April there was not any defect .Analyzed these 245

data to observe long time lost on defects. With all that is lost with defects not leaving the total number of lost time.

Fig. 5. Lost time S1 and S2 In Figure 6 observe Oy-axis the number of hours lost and ox-brand operator, which means that are followed lost time by each operator.It is interesting that the operator 658 has lost 30 hours for the supply of tools, which means that the tool is not arranged properly. This follows from the fact that there was no proper organization of the workplace.

Fig. 6.Lost Time S1-S9 In Figure 7 notice that the more time lost in 2006 - April 2009 were in January 2009.

246

Fig. 7. Lost time 2006-april 2009 4.Conclusions After centralizing the data obtained there I reached the following conclusions: -It is long time lost on defects -It has lost time for the supply of tools -In grinding workshop was no proper organization of the workplace. 5.Directions for future research In the future we want to watch and other items and to identify effective methods of decreasing the time lost. Acknowledgements I wish to thank for its support in making this work to Doctoral training Brain – “Investment in Intelligence”,to the dean faculty of Machine Manufacturing and Industrial Management professor Gheorghe Nagîţ and last but not least the scientific coordinator professor Dragoş Paraschiv. References: 1. Base of date Industrial Gears Watteeuw Romania Intranet, accessed : 05.01.2009-01.06.2009. 2. Burloiu P., Ergonomia şi organizarea muncii. Ed. Didactică,Bucureşti, 1971, pag. 120-125. 3. Paraschiv Dr. - Tehnologii de procesare a suprafetelor metalice, Ed.. Junimea, Iasi, 2005, pag.98-102. 4. Pruteanu V. ,Tehnologia Constructiei de Masini. vol.I-II,Ed. Junimea,Iasi 2005,pag.40-52. 5. Ranga Gh., Ergonomia locului de muncă. Lit. Acad. Şt. Gheorghiu, 1980,pag.189-200. 6. Rosca C.,Dictionar de ergonomie.Ed.Certi, Craiova, 1997, pag.326.

FORMATION OF QUALITY INDEXES OF MACHINE DETAILS ON THE BASIS OF TECHNOLOGICAL INHERITANCE Vasiliev A., Kheifetz M., Koukhta S., Prement G. (Moscow State Technical University it N.Bauman, Polotsk State University, Polotsk, Moscow, Belarus1, Russia2) From positions of technological inheritance of operational parameters actions on quality management of products of mechanical engineering are offered. The mathematical model of inheritance of quality indexes in life cycle of the product, describing various modes of behavior is developed by manufacture and application of technical systems. Use of mathematical model at computer designing gives ample opportunities for reduction of expenses at manufacturing and operation of constructive - complex products of mechanical engineering. 247

The use of a principle of superposition is a distinctive feature of existing approaches in definition and forecasting of quality indexes of machine-building production. According to this principle, each of technology contributors operates irrespective of others, and the result of joint action is defined as their partial sum represented in this or that form [1, 2]. Technological systems are multiply connected, objects of manufacture are characterized by nonlinearity, irreversibility and non-equilibriallity. However application of a principle of superposition reduces the multiply connected interactions which are carried out in technological systems, to one-coherent, ignoring mutual influence of technology contributors [3]. Growth of requirements to quality of manufacturing of machine elements make the methods of definition and forecasting the qualities based on a principle of superposition, practically useless as the effect of mutual influence of factors is commensurable with the results of their direct influence. Process of property change of products should be considered as a set of cooperating processes, changes and preservations of properties [4, 5]. Plurality of product properties, each of which is characterized by corresponding set of quality indexes, is also display of multicoupling of technology factors in the process of formation of product quality. Product properties are interdependently formed in the process of manufacturing. However in work practice of mechanical engineering this fact is insufficiently taken into account. Such isolated consideration of process of formation of the allocated quality indexes can lead to serious mistakes at designing and realization of technological processes [1, 2]. The technical difficulties connected to the description of multiply connected interactions, at formation of set of quality indexes at product manufacturing can be got over on the basis of application of modern information technologies and methodology of acceptance of technological solutions [4, 5]. 1. The conceptual approach The mathematical device of methodology is based on substantive provisions [3]: quality of a detail is formed during all its technological background and the set of quality indexes is a result of backgrounds; each technological or connected to it influence lead to changes of all quality indexes of material blank; change of any quality index results in change of all other quality indexes of material blank. Characteristics of technological mediums and laws of their change have permitted to generate the primary goal of the directed formation quality indexes of a product: at knowing initial and final properties of a manufacture subject to define the optimal technological medium from the point of view of property transformation. The major feature of the approach is formation for each technological repartition of through process of manufacturing of a product of the optimum technological medium providing the most rational distribution of levels of quality indexes on repartitions and giving to process of formation of product quality a necessary orientation. While changing medium or its characteristics, it is possible to operate forming product properties. 1.1. Model of multiply connected interactions of a medium. Necessary adjusting influences on structure change, structure and conditions of interaction of technological medium elements and of the element with a manufacture subject can be determined on the basis of comparison of characteristics of medium of a technological process and desirable processes. On the basis of the conceptual approach it is offered to define the following factors [3]: operative change quality index і while using technological method j − (mi j ; changes of quality index і of the product connected to conditions of realization of technological method j − (ui) j ; changes of quality index і in interaction with medium of an operation level, realizing a technological method j− (Si j . Operatively forming component (Ki) jon values of parameter K i is: 248

(K i ) j on = (m i ) j (K i ) j-1 + (u i ) j (K i ) j-1 , where (K i ) j – a set of levels of product quality indexes after performance of operation of its manufacturing in view of laws of a technological heredity; (K i ) j-1 – a set of levels of the quality indexes describing a product condition after performance of the previous operation. If the method is not realized (mi ) j = 1, (ui ) j = 0, otherwise 0 <(mi ) j ≤ 1. Change of a sign and value of a quality index occurs as a result of cumulative change of factors (mi ) j and (ui ) j . For each technological method the regular conditions of realization determining values (mi ) j are found. The factor (mi ) j takes into account regular conditions of realization of a method (in particular, the regular economically justified conditions of processing), and (ui ) j - distinguished from regular, and also other conditions in addition describing the medium (basing and fastening of preparation, elastic characteristics of elements of technological system, etc.). Analytical definition of factors (mi) j , (u i ) j , (S i ) j is impossible, therefore they are defined by statistical processing of an experimental material. For a concrete method with an index of realization r composed (u i ) j (K i ) j-1 it is allocated in a regular component (С): [(Ki) оп j ] r = (m i ) j [(K i ) оп j-1 ] r +C. 1.2 Techniques of definition of factors of transfer. At definition of values of factors of operative change of quality indexes (m i ) j techniques of the maximal crossing of set of entrance and target values of quality indexes, and also averaging of borders of ranges (fig.) are used.

Fig. Comparison of factors of operative change of accuracy of the size (m ІТ ) for methods of processing of external cylindrical surfaces: 1, 2, 3, 4 - accordingly точение draft, получистовое, fair, thin; 5, 6, 7 - accordingly grinding preliminary, final, thin; І, ІІІ - a technique of the maximal crossing of sets; ІІ - a technique of averaging of borders At known (m i ) j values (u i ) j are defined according to

[(ui ) j ]γ = [(Ki )onj ]γ [(Ki )onj−1]γ − (mi ) j . At knowing (m i ) j , (u i ) j

(Si ) j =

(Ki )опj (Ki )опj −1

Tables of the average values of factors of operative change of properties (mi) j for the basic technological methods of processing of external and internal cylindrical surfaces, and also planes are used. 249

It is established, that the optimum error of definition of factors of operative change of quality indexes of processable material blanks for methods of abrasive machining on the average is in 3 times higher, than for edge cutting machining, that testifies to the greater sensitivity of corresponding technological mediums to condition change of realization and a condition of objects forming them. Average value of a relative error of definition of size m ІТ factor of operative change of accuracy of the sizes for group of methods of detail sharpening and grindings from constructional carbonaceous steels has made 2,5 %, and roughnesses m Ra - 11,0 %. Dependences of characteristics of technological medium of an operation level on a condition of objects forming them are adequately represented with the help of linear regression models or are piecewise -linear approximated at the relative error which are not exceeding 10 % It is established, that preservation and mutual influence of properties are especially shown while flat-topped diamond-abrasive machining, polishing and super finishing when the removed allowance is within the limits of initial height of rough edges asperity. 1.3. Definition of factors of preservation and interference. Multicoupling of technological mediums, distinction of the physical processes accompanying interaction of mediums with a subject of work, is a principal cause of absence of the uniform methodical approach to definition of elements of factors of preservation and mutual influence of formed properties k ij matrixes [k ij]. Factors are defined at realization of through technological process of product manufacturing at continuous research of quality condition of a subject of manufacture. Primary value k ij for an initial phase of process: kij ≈

(Ki )1 − Sij (Ki )0 , (Ki )0

where (K i ) 1 - value of parameter K i after operation performance; (K i ) 0 - value of parameter K i prior to the beginning of operation performance; S ij - factor of change of a quality index at interaction of a subject of manufacture with the technological medium of an operation level. In contrast to m i , u i , factors k ij have physical dimension. The offered device of the description of transformation of quality indexes in view of their interaction and mutual influence in multiply connected technological mediums is adequate to real processes of property formation of mechanical engineering products and can be used for forecasting technological decisions. Application of the offered approach allows from 2 up to 5 times to reduce a relative error of preliminary definition of level of quality index in comparison with the value received on the basis of known laws of mechanical engineering technology [3]. 2. Calculating and analytical method Consideration of mutual influence of technology factors at interaction of technological mediums with a subject of manufacture allows to bring in corresponding specifications to a settlement - analytical method of definition of a total error of machining. Preparations of an error arising at processing are interconnected and influence against each other and a total error of processing. Making errors are formed as a result of interaction of preparation with the technological medium of a level of operation, and with the technological medium of a level of process. 2.1. Definition of an error of processing. In result the mathematical device of definition of values of components and a total error of processing is developed. For the first it is fair that 250

 ∆Y  ε  ∆H   ∆u  ∆ T

      

 1  a  ε , ∆Y =  a ∆H , ∆Y   a ∆u , ∆Y a  ∆T , ∆Y

a ∆Y ,ε

a ∆Y , ∆H

a ∆Y , ∆u

a ε , ∆H

a ε , ∆u

a ∆H ,ε

a ∆H , ∆u

a ∆u ,ε

a ∆u , ∆H

a ∆T ,ε

a ∆T , ∆H

a ∆T , ∆u

a ∆Y , ∆T   a ε , ∆T  a ∆H , ∆T   a ∆u , ∆T  1 

 ∆Y  ε  ∆H   ∆u  ∆ T

      

дj

where (∆Y, ε, ∆H, ∆u, ∆T)Т j – a vector - column of values of making errors (an error caused by elastic deformations; an error of installation; an error of adjustment; an error caused by dimensional deterioration; an error caused by thermal deformations), determined in view of mutual influence; a- factors of transformation of the errors, taking into account mutual influence of errors; (∆Y, ε, ∆H, ∆u, ∆T)Т дj – a vector - column of the determined values, the making errors determined on the basis of a traditional settlement - analytical method. The square of final value of total error ∆ is defined in the form ∆2 = [λ i P i ]T[P i ], where λ i – the factors determining the form of a curve of distribution of the making error P i ; Т – symbol of transposing. The account of multiconnectivity of technological mediums at definition of a total error of processing allows more than in 2 times to raise accuracy of existing methods of calculation. 2.2. Model of formation of quality indexes. The developed device of the description of transformation of properties of products allows to distribute in the desirable image levels of properties of a product on stages of technological process of its manufacturing. For any part of through technological process of manufacturing of a product and for any of properties of the last on the basis of the developed technique can be determined and the desirable level of values of corresponding quality indexes is if necessary optimized. So, for example, after end of procuring repartition the achieved levels of quasi-stable K с з and changing K v з quality indexes are defined as following:  K cз =Scз ⋅ K M + kcз ,М K M ;  з M з ,М M з  K v =Sv ⋅ K + kv K ,

where Sс з, Sv з – factors of property change of a subject of manufacture as a result of its interaction with the technological medium of a level of procuring repartition; KМ – levels of quality indexes of an initial material; kcЗ ,М , kvЗ ,М – factors of preservation and mutual influence of properties of the initial material, shown at a procuring stage of through process of manufacturing of a product. Similar parities can be determined for repartitions of manufacturing of details and assembly of a product. These parities can be considered as model of formation of properties of a product in through technological process of his manufacturing. Practically for any stage N of group of operations parities of a kind can be received: K N = H N ⋅KM, 251

where K N â&#x20AC;&#x201C; value of the quality index generated after stage N; H N â&#x20AC;&#x201C; factor of transformation of properties of a product in relation to initial (KM). Introduction of set of criteria of optimization it is possible to proceed to the decision of problems of optimization of values of quality indexes for each stage (operation) of technological process. As not all quality indexes are equivalent from a position of technological maintenance of their values expediently to define desirable levels not for everything, and only for hard-to-achieve quality indexes, considering thus "by default", that other indexes will be provided. Use of "passport" of a subject of the manufacture including, for example, for a detail the data about most hard-to achieve levels of quality indexes and the general number of its surfaces, allows to lower dimension of technological problems solved in a correct way. 3. Technological algorithm Distribution of levels of properties in a combination to definition of quantitative characteristics of possible property transformation allows to change essentially existing approaches to construction of technological processes [6]. For successful performance of the set of functions the technological medium should be provided with necessary reserves. A reserve of the technological medium sets of its characteristics and values form the last which are not used at performance by the medium of set functions and conditions of their realization. The estimation of medium on each of its parameters can be carried out on the basis of the offered quantitative characteristics. The medium of any level should possess necessarily a reserve on parameters (opportunities) which size should correspond optimum to set of carried out functions and a range of possible changes of conditions of their realization. The choice of technological mediums and any of the technological objects possessing rational reserves, can effectively be carried out on the basis of the suggested device of an estimation of quality of corresponding technological decisions. Formation of a reserve of medium can be carried out on each of its separately taken parameters and should take into account both stochastic character of the last, and their interaction. In view of influence of all cycle of manufacturing of a detail on its operational properties the algorithm according to which on required operational properties values of parameters of a condition of a superficial layer of a ready detail are recommended is developed and the technological process of its manufacturing providing the specified parameters is formed, modes of cutting, the characteristic of the tool and the equipment, mark lubricant-cooling agent (the lubricant-cooling technological medium), providing necessary parameters of a condition of a superficial layer of preparation and a semifinished item at each stage of processing are appointed. The technological algorithm includes the following stages: - Proceeding from operational properties and conditions of operation of elementary surfaces of detail requirements to condition of a surface of a detail are established; - On the basis of mathematical models or in a database on a required condition of a superficial layer modes of processing, the tool, the equipment, lubricant-cooling agent, necessary for realization of final processing the set of details are defined; - On parameters of a condition of a superficial layer modes of processing, the tool, the equipment, lubricant-cooling agent, necessary for realization of the previous operation (transition) of processing are defined. Designing of technological processes of product manufacturing in view of mutual influence of formed quality indexes is ineffective outside of his automation on the basis of modern computer facilities. Designing of individual routing technological processes (RTP) of 252

detail manufacturing is desirable for carrying out in a mode of the automated synthesis at the minimal dialogue of the user with system [7, 8]. Strategy of the sanction of a problem of automated synthesis of RTP in view of laws of change, preservation and mutual influence of formed quality indexes, provides: performance of synthesis of RTP in the automated mode on a basis general technological principles and reception of the basic characteristics of a route; forecasting change of quality indexes in view of laws of property transformation on the basis of structure generated by RTP; performance of necessary updating RTP in case a desirable level of values of quality indexes does not achieve. Conclusion The automated generation of technological mediums of the set level concerning the allocated object is possible on the basis of their functional models created with application of CALS-technologies. Functional models of multiply connected technological mediums allow to carry out depending on statement of a decided problem decrease in its dimension by allocation of set of essential communications and suppression insignificant at preservation of a correctness and adequacy. Reduction in sensitivity of technological and operational mediums to change of conditions of realization of modes of manufacture and application of products allows to carry out with the least expenses the directed formation of quality indexes in life cycle of products of mechanical engineering. References: 1. Technological Basis of Machine Quality Control / K.Kolesnickov, G.Balandin, A.Dalsckiy and others. – Moscow: Mechanical Engineering, 1990. – 256 p. 2. N.Kuznetzov, V.Tzeitlin, V.Volkov. Technological Methods of Machine’s Details Reliability Growth. – Moscow: Mechanical Engineering, 1993. – 304 p. 3. Technological Basis of Machine Quality Control / A.Vasilyev, A.Dalsckiy, S.Klimencko and others – Moscow: Mechanical Engineering, 2003. – 256 p. 4. Analysis of Property Relations of Technological Solutions at Designing of Combined Methods of Materials Processing / P.Yaschericyn, V.Averchenckov, M.Kheifetz, S.Koukhta // Report of National Academy of Sciences of Belarus. – 2001. – V. 45, № 4. – P. 106 – 109. 5. Property Control of Technological Medium at Electrophysical Processing / P.Vityaz, L.Kozhuro, I.Filonov, M.Kheifetz // Heavy Engineering Construction. – 2004. – № 7. – P. 18 – 23. 6. Intelligent Production: State and Future Prospects/ Under red. of M.Kheifetz and B.Chemisov. – Novopolotsk: PSU 2002. – 268 p. 7. A.Ryzhov, V.Averchenckov. Technological Process Optimization of Machine Working. – Kiyiv: Navukovaia dumka, 1989. – 192 p. 8. Automatization of Technological Processes and Equipment Aids Designing / Under red. of A.Rakovich. – Minsk: ITC of National Academy of Sciences of Belarus, 1997. – 276 p.

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FORMULATION OF VIBRATIONS PROBLEM OF THE CLAMPED BEAM SUPPORTED BY AN ELASTIC CONSTRAINT IN ROTATIONAL TRANSPORTATION Żółkiewski S. (Silesian University of Technology, Gliwice, Poland) Abstract: presented work applies to problem of the vibrating beam in transportation. There is considered the beam clamped at one end and supported by elastic constraint at second end. The beam is fixed on the rotational disk. The disk is being rotated round one axis of the global reference frame. Considered system can be put to use for modelling of blades of high speed pumps and turbines gas, steam or water ones for example. 1. Introduction Problem of vibrating elastic systems in one dominant dimension is a very well-known problem. There are many systems that apart from stationary vibrations with one-dimensional direction of displacement vibrate in terms of rotational motion. This article consider type of vibrations of the beam placed on the rotational disk. Main difference from known models [6, 7] is taking into consideration the transportation effect. In this case transportation effect points is that Coriolis forces and centrifugal forces were took into consideration. There are some publications considering the problem of rotating beam and rod systems [1-5, 7]. Mainly in literature [1-5] rotation of the system is considered as transportation motion. In this thesis also this rule was applied. Applied transportation was limited to plane motion but of course it can be changed to spherical motion or general motion in different working terms. 2. The model of vibrating clamped-supported beam The model of vibrating beam is considered in this section. The beam is clamped at one end and supported at other end. This support is provided by an elastic constraint. The beam is placed on rotational disk that rotates round the Y axis of global reference frame. Cross section of the beam A is constant on the whole its length l (fig. 1). System was made from material with Young’s modulus E and mass density ρ. This prismatic system was treated as homogeneous beam with constant material characteristics and with straight axis line. The beam was loaded by harmonic transverse force. The model was determined in global independent reference system in terms of plane motion (XY). In figure 1 the analyzed model of the beam was presented where: ρ – mass-density, A – cross-section, l – length of beam, x – location of analyzed cross-section, n – modes of vibrations, M – mass of beam, ω – angular velocity, Ω – frequency, Q – rotation matrix, S – position vector, F – harmonic force, E – Young modulus, I Z – geometric moment of inertia, w – vector of displacement.

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Fig. 1. The model of analyzed beam, clamped at one end on the rotational disk and supported by an elastic constrain at other end 3. Equations of motion Center line of the beam overlaps with axis “x” of the local reference frame so all transverse forces have compatible senses with the sense of axis y of the local reference frame and they produce positive moments. Forces with reverse senses produce negative moments [5] and the Hooke’s law is performed. After calculations, we can obtain equations of motion in matrix form: cos ϕ M ⋅  sin ϕ  0

− sin ϕ cos ϕ 0

 0  0  2  cos ϕ ∂ w  0  ⋅  2  − M ⋅  sin ϕ  ∂t   0 1     0 

− sin ϕ cos ϕ 0

 ∂w  ω⋅ cos ϕ − sin ϕ 0   ∂t  cos ϕ      −2 ⋅ M ⋅  sin ϕ cos ϕ 0  ⋅  0  + M ⋅  sin ϕ  0  0 0 1   0       0  cos ϕ − sin ϕ 0   ∂F ⋅ s  =  sin ϕ cos ϕ 0  ⋅  − g  .  ∂x  0 1     0  0 

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0  ω 2 ⋅ s    0  ⋅ ω 2 ⋅ w + 1   0 

− sin ϕ cos ϕ 0

0   −ω ⋅ w 0  ⋅  ω ⋅ s  = 1   0 

(1)

where: = Fg

∂ ∂q j

 ∂2w   E ⋅ I Z ⋅ 2  . ∂q j  

(2)

After assuming constant angular velocity and after introducing (2) to (1) we can now write equations of motion as follow:

− sin ϕ 0  02  cos ϕ − sin ϕ 0  ω 2 ⋅ s  ∂ w   cos ϕ 0 ⋅  2  −  sin ϕ cos ϕ 0 ⋅ ω 2 ⋅ w +    ∂t 0 1  0   0 0 1  0   ∂w  cos ϕ − sin ϕ 0  04  cos ϕ − sin ϕ 0 ω ⋅ ∂t  ∂ w ⋅ E I Z  ⋅  sin ϕ cos ϕ 0 ⋅  4 ; − 2 ⋅  sin ϕ cos ϕ 0 ⋅  0  = −   ρ⋅A ∂x  0  0 0 1  0  0 1  0    cos ϕ  sin ϕ   0

(3)

Because of introducing equations of motion (3) by individual projections we can obtain the projection onto the X axis of global reference frame:

−

∂2w E ⋅ IZ ∂4w ∂w ⋅ sin ϕ − ⋅ 4 ⋅ sin ϕ = ω 2 ⋅ (s ⋅ cos ϕ − w ⋅ sin ϕ ) + 2 ⋅ ω ⋅ ⋅ cos ϕ 2 ∂t ρ ⋅ A ∂x ∂t

(4)

and onto the Z axis of the global reference frame:

∂2w E ⋅ IZ ∂4w ∂w ⋅ cos ϕ + ⋅ 4 ⋅ cos ϕ = ω 2 ⋅ ( s ⋅ sin ϕ + w ⋅ cos ϕ ) + 2 ⋅ ω ⋅ ⋅ sin ϕ . 2 ∂t ∂t ρ ⋅ A ∂x

(5)

4. Boundary conditions In the system at the end acting the harmonic force and the one end is clamped and second end is supported by an elastic constraint. So the boundary conditions are as follow:

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 w ( 0, t ) = 0,   E ⋅ I ⋅ ∂w ( 0, t ) = 0, Z  ∂x  ∂2w (l, t )  ⋅ ⋅ = E I 0, Z  ∂x 2  l ∂2w (l, t )  ∂  2 ⋅ ⋅ = − ⋅ E I F0 ⋅ δ ( x − l ) ⋅ sin ( Ωt )dx,  Z  ∂x  ∂x 2  ν ( l ) ∫0  

(6)

where ν ( l ) is a deflection of an elastic constraint produced by the force with unitary amplitude. 5. Conclusions Formulation of the problem of vibrating beam on rotational disk was presented in this thesis. Considered systems are basis of further dynamical analysis. The equations of motion (proper vibrations with a harmonic force in sense of dynamical flexibility) of the clampedelastic constraint beam were presented. Acting of assumed harmonic force was expressed in boundary conditions for beam with taking into consideration a deflection of the elastic support. Analyzed in this work systems can be put to use in different type pumps, compressors and turbines where the rotor assembly is treated as a rotational disk or shaft that moves with attached blades. Future works will be connected with damped systems, systems with changeable cross-sections both linear and non-linear in a geometrical sense. Acknowledgements: This work has been conducted as a part of research project N N501 222035 supported by the Ministry of Science and Higher Education in 2008-2011. References: 1. Buchacz A., Żółkiewski S.: Dynamic analysis of the mechanical systems vibrating transversally in transportation. Journal of Achievements in Materials and Manufacturing Engineering vol. 20, issues 1-2, 2007, p. 331-334. 2. Buchacz A., Żółkiewski S.: Mechanical systems vibrating longitudinally with the transportation effect. Journal of Achievements in Materials and Manufacturing Engineering vol. 21, issue 1, 2007, p. 63-66. 3. Buchacz A., Żółkiewski S.: Formalization of the longitudinally vibrating rod in spatial transportation. International Conference of Machine-Building and Technosphere of the XXI Century. Sevastopol 2007 vol. 4 , p. 279-283. 4. Buchacz A., Żółkiewski S.: Dynamical flexibility of the free rod with longitudinal vibrations in transportation. XLV Symposium PTMTS „Modelling in Mechanics”, Publishing house of Department of Applied Mechanics, Wisła 2006, p. 27-28. 5. Buchacz A., Żółkiewski S.: Longitudinal three-dimensional vibrations of the round rod with taking into consideration the transportation effect. International Conference of Machine-Building and Technosphere of the XXI Century. Sevastopol 2005 vol. 5, p. 17-20. 6. Craig J. J.: Introduction to robotics. Mechanics and Control. WNT, Warszawa 1995 (Polish edition). 7. Genta G.: Dynamics of Rotating Systems. Springer, New York 2005.

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ABOUT METHODOLOGIES OF FAULT DETECTIONAND ISOLATION IN INDUSTRIAL SYSTEMS - A COMPARITIVE STUDY Jawish I. ( Damascus University , Damascus , Syria) Abstract : For the improvement of reliability, safety and efficiency advanced methods of supervision, fault detection and fault diagnosis become increasingly important for many Dynamic processes. The early detection of faults can help avoid system shutdown, breakdown and even catastrophes involving human fatalities and material damage. There is an abundance of literature on process fault detection and diagnosis (FDI) ranging from analytical methods to artificial intelligence and statistical approaches. In recent years, growing interest in the development of diagnostic methods based upon soft computing (SC) methods as well as their application in industry can be observed. The use of SC methods is considered an important extension to the quantitative model-based approach for residual generation in FDI, especially when the system is complex and uncertain and the data are ambiguous i.e. not information rich. In this paper we provide the basic concepts of FDI Systems, and a review of various techniques that have been proposed to solve the problem of fault detection and diagnosis in Dynamic Systems, theirs advantages and limitations. The comparative study reveals the relative strengths and weaknesses of the different approaches. Integrating these complementary features is one way to develop hybrid systems that could overcome the limitations of individual solution strategies. An application study of electro-pneumatic valve actuator, as one of the most important components in the evaporation unit of sugar factory is presented. The key issues of finding a suitable structure for detecting and isolating ten realistic actuator faults are outlined using soft computing approach. Keywords: fault detection, fault diagnosis, supervision, Quantitative and Qualitative Model based approaches, Soft computing, neural networks, fuzzy models, neuro-fuzzy FDI systems. 1. INTRODUCTION During the last two decades increasing interest among researchers to apply different process monitoring and fault diagnosis systems has been recorded .The methods of process fault detection and diagnosis FDI ranging from analytical methods to artificial intelligence and statistical approaches. Many investigations have been made using analytical approaches, based on quantitative models. The idea is to generate signals that reflect inconsistencies between nominal and faulty system operation. Such signals, termed residuals, are usually generated using analytical approaches, such as observers (Patton et al 2000, Chen & Patton, 1999), parameter estimation (Isermann, 1994) or parity equations (Gertler, 1998) based on analytical (or functional) redundancy. V.Venkatasubramanian et,al. (2003) have published a review of FDI methods. They classified the methods according to the form of process knowledge used. One category of the methods are those based on process models. These include both qualitative causal models and quantitative methods. The other category is based on process history. This group includes both qualitative (e.g. rule-based) and quantitative methods (neural networks and multivariate statistical methods). The review showed that no single method was able to meet all the prerequisites for a good diagnostic system. Yoon and MacGregor (2000) classified the different methods into three categories: methods based on (i) causal models, (ii) qualitative knowledge and (iii) correlation models, such as neural networks 258

and multivariate statistical methods. They compared statistical methods and causal modelbased approaches. They concluded that, while the causal methods can usually only be applied to problems with a small number of variables, the statistical methods are strong in fault detection. However, their ability to identify the causes might be inadequate. Therefore, they suggest that statistical methods should be augmented with some causal information or prior fault knowledge. Isermann and BallĂŠ (1997) and Patton et al. (2002), both reviews indicate that there is a growing tendency to substitute the use of quantitative model based methods by neural networks and fuzzy logic. Some of authors (Patton et al., 1999; Calado and Sa da Costa, 1999) try to integrate neural networks and fuzzy logic in order to benefit of the advantages of both techniques for fault diagnosis applications. Process modelling has limitations, especially when the system is complex and uncertain and the data are ambiguous i.e. not information rich. Soft Computing methods (SC) (Neural Networks (NN), Fuzzy Logic (FL), Evolutionary Algorithms (EA) are known to overcome some of the above mentioned problems. Using hybrid methods of integrating quantitative and qualitative model information, based upon SC methods has shown to be promising. Generally, in an industrial control system a fault may occur in the process components, in the control loop (controller and actuators) and in the measurement sensors for the input and output variables. In this paper we discuss the basic concepts of FDI systems and give a review of the various techniques that have been proposed to solve the problem of fault detection and diagnosis in Dynamical Systems. As an illustrative example, an application study of an electro-pneumatic valve actuator in evaporation unit of sugar factory is presented. The key issues of finding a suitable structure for detecting and isolating ten realistic actuator faults are outlined using FDI Neuro-Fuzzy approaches.

2 - Faults Definition and Modeling A fault is defined as an unpermitted deviation of at least one characteristic property of a variable from an acceptable behavior. Therefore, the fault is a state that may lead to a malfunction or failure of the system. The time dependency of faults can be distinguished, as show in Figure 1, abrupt fault (stepwise), incipient fault (drift like), intermittent fault. With regard to the process models, the faults can be further classified. According to Figure 2 additive faults influence a variable Y by an addition of the fault f, and multiplicative faults by the product of another variable U with f. Additive faults appear, e.g., as offsets of sensors, whereas multiplicative faults are parameter changes within a process ,Isermann,2004).

Fig. 1 Time-dependency of faults: (a) abrupt; faults; (b) incipient; (c) intermittent

Fig. 2 Basic models of faults: (a) additive (b) multiplicative faults

In general, one has to deal with three classes of failures or malfunctions as in V.V,(2003,Part1): 259

A) Gross parameter changes in a model An example of such a malfunction is a change in the concentration of the reactant from its normal or steady state value in a reactor feed. Another example is the change in the heat transfer coefficient due to fouling in a heat exchanger. B) Structural changes Structural changes refer to changes in the process itself. An example of a structural failure would be failure of a controller. Other examples include a stuck valve, a broken or leaking pipe and so on. C) Malfunctioning sensors and actuators Gross errors usually occur with actuators and sensors. These could be due to a fixed failure, a constant bias (positive or negative) or an outof range failure. Unstructured uncertainties are mainly faults that are not modeled a priori. Process noise refers to the mismatch between the actual process and the predictions from model equations, whereas, measurement noise refers to high frequency additive component in the sensor measurements. 3. Fault Diagnosis System A system which includes the capacity of detecting, isolating, identifying or classifying faults is called a fault diagnosis system. The task of fault diagnosis consists of the determination of the type of fault with as many details as possible such as the fault size, location and time of detection. The conceptual diagram for a fault diagnosis system is depicted in Figure 3.

Fig. 3. The general structure of a diagnosis system The diagnosis consists of two sequential steps: residual generation and residual evaluation. In the first step a number of residual signals are generated in order to determine the state of the process. The diagnostic procedure is based on the observed analytical and heuristic symptoms and the heuristic knowledge of the process. The symptoms may be presented just as binary values [0,1] or as, e.g., fuzzy sets to take gradual sizes into account (Fig.4).

Fig.4 Model based Fuzzy FDI System Scheme 3-1 Classification methods If no further knowledge is available for the relations between features and faults classification or pattern recognition methods can be used, Table 1 , Isermann,(2004)). Here, reference 260

vectors Sn are determined for the normal behaviour. Then the corresponding input vectors S of the features are determined experimentally for certain faults Fj. The relationship between F und S is therefore learned (or trained) experimentally and stored, forming an explicit knowledge base. By comparison of the observed S with the normal reference Sn, faults F can be concluded. 3-2 Inference methods For some technical processes, the basic relationships between faults and symptoms are at least partially known. Then this a-priori-knowledge can be represented in causal relations: fault 6 events 6 symptoms. Table 1shows a simple causal network, with the nodes as states and edges as relations. The establishment of these causalities follows the fault-tree analysis (FTA), proceeding from faults through intermediate events to symptoms (the physical causalities) or the event-tree analysis (ETA), proceeding from the symptoms to the faults (the diagnostic forward-chaining causalities). To perform a diagnosis, this qualitative knowledge can now be expressed in form of rules: IF <condition> THEN<conclusion>. The condition part (premise) contains facts in the form of symptoms Si as inputs, and the conclusion part includes events Ek and faults Fj as a logical cause of the facts. If several symptoms indicate an event or fault, the facts are associated by AND and OR connectives, leading to rules in the form IF < S1 AND S2 > THEN < E1 > IF < E1 OR E2 > THEN < F1 >. Table 1 Methods of fault diagnosis

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3-3 Desirable Characteristics of a fault diagnostic system In order to compare various diagnostic approaches, it is useful to identify a set of desirable characteristics that a diagnostic system should possess These address important issues, both theoretical and practical, such as how quickly the system detects a fault, can it diagnose the fault with minimum misclassification, its robustness to noise and uncertainties, adaptability, explanation facility modelling effort, computational requirements and the like .

4. MODEL-BASED FAULT-DETECTION METHODS There are two general methods for fault Detection and isolation(FDI): Quantitative Model based approach and Qualitative Model –based approach .Quantitative Model based approach consists of Differential equations,state- space model,S-and/or Transfer function Qualitative Model –based approach consists of neural networks , fuzzy , neuro-fuzzy, Expert Systems ,Ghahroodi,(2002). Recent advances to FDI for dynamical systems using hybrid methods for building Quantitative and Qualitative Model has shown to be promising.

4-1 Quantitative model-based approaches The process model is usually developed based on some fundamental understanding of the physics of the process. In quantitative models this understanding is expressed in terms of mathematical functional relationships between the inputs and outputs of the system. The aim of a quantitative model-based fault diagnosis is to generate information about the location and timing of a fault, using the measurements available in that system, as well as the precise mathematical relationships that relate them. More information on the process can usually be obtained with dynamic process models. Table 2 shows the basic input/output models in form of a differential equation or a state -space model as vector differential equation. However, there are a wide variety of quantitative model types that have been considered in fault diagnosis such as first-principles models, frequency response models. Similar representations hold for non-linear processes and for multi-input multi-output processes, also in discrete time, V.V,(2003,Part1). Different approaches for fault detection using mathematical models have been developed in the last two decades, see, e.g., (Isermann, 1994; Gertler, 1998; Chen and Patton, 1999; Patton et al. 2000). The task consists of the detection of faults in the processes, actuators and sensors by using the dependencies between different measurable signals. These dependencies are expressed by mathematical process models using analytical redundancy techniques to generate residuals for isolating process failures.. Figure 5 depicts the basic structure of model-based fault detection and indicates the different sources of failures in it. Based on measured input signals U and output signals Y, the detection methods generate residuals r, parameter estimates Θ or state estimates ˆx , which are called features. By comparison with the normal features, changes of features are detected, leading to analytical symptoms s, Isermann,(2004) ).

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Table 2 Linear dynamic process models and fault fault detection and diagnosis

Fig.5 General scheme of process model-based modelling

4-2. Qualitative model-based approaches The qualitative models thes relationships between the inputs and outputs of the system are expressed in terms of qualitative functions centered around different units in a process. The qualitative models can be developed either as qualitative causal models or abstraction hierarchies. Though qualitative models have a number of advantages the major disadvantage is the generation of spurious solutions. Considerable amount of work has been done in the reduction of the number of spurious solutions while reasoning with qualitative models,V.V,(2003,Part2). 4-3 Process history based methods In contrast to the model-based approaches where a priori knowledge (either quantitative or qualitative) about the process is needed, in process history based methods, only the availability of large amount of historical process data is needed. There are different ways in which this data can be transformed and presented as a priori knowledge to a diagnostic system. This is known as feature extraction. This extraction process can be either qualitative or quantitative in nature. Two of the major methods that extract qualitative history information are the expert systems and trend modelling methods. Methods that extract quantitative information can be broadly classified as non-statisticalor statistical methods. Neural networks are an important class of non-statistical classifiers. Principal component analysis (PCA)/partial least squares (PLS) and statistical pattern classifiers form a major component of statistical feature extraction methods. There are different ways in which knowledge can be extracted from process history, V.V,(2003,Part3). From industrial application viewpoint, the maximum number of fault diagnostic applications in process industries are based on process history based approaches. This is due to the fact that process history based approaches are easy to implement, requiring very little modelling effort and a priori knowledge. Further, even for processes for which models are available, the models are usually steady-state models. It would require considerable effort to develop dynamic models specialized towards fault diagnosis applications. 263

5. A comparison of various FDI methods In terms of the desirable characteristics of diagnostic systems, Table 3 gives a comparison of various methods. In the table only some representative methods in each of the three approaches (quantitative model-based, qualitative model-based, process history based) are chosen for comparison. A check mark would indicate that the particular method (column) satisfies the corresponding desirable property (row). A cross would indicate that the property is not satisfied and a question mark would indicate that the satisfiability of the property is case dependent(V.V,2003,Part3).

Table 3 comparison of various diagnostic methods This comparative study reveals the relative strengths and weaknesses of the different approaches. One realizes that no single method has all the desirable features one would like a diagnostic system to possess. It is our view that some of these methods can complement one another resulting in better diagnostic systems. Integrating these complementary features is one way to develop hybrid systems that could overcome the limitations of individual solution strategies. 6. HYBRID FDI METHODS USING SOFT COMPUTING TECHNIQUES Process modeling has limitations, especially when the system is complex and uncertain and the data are ambiguous i.e. not information rich. Recent advances to FDI for dynamical systems using hybrid methods for building Quantitative and Qualitative Models through a neuro-fuzzy system has shown to be promising . Neural networks are very good modelling tools for highly non-linear processes. However, the neural network does not easily provide insight into model behavior; the model is explicit rather than implicit in form. This main difficulty can be overcome using qualitative modelling or rule-based inference methods. For example, fuzzy logic can be used together with state space models or neural networks to enhance FDI diagnostic reasoning capabilities. The aim is to combine the neural network learning ability with the explicit knowledge representation of fuzzy-logic in order to benefit of the advantages of both techniques for fault diagnosis applications. Some other tools like evolutionary algorithms, genetic algorithms or probabilistic reasoning can also be combined with the above techniques, to enhance the parameter tuning or to deal with the uncertainty in order to establish the desired Intelligent System,Patton,(2002).

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7. FDI Neuro-Fuzzy Networks In the area of neuro-fuzzy systems there are two principal types of neuro-fuzzy networks preferred by most of the authors in the field of neuro-fuzzy integration., for residual generation and for fault classification. The most common neuro-fuzzy network is used to develop or adjust a fuzzy model in Mamdani form given by the below relation , using input – output data. The network is a five layers network as shown in Figure 6 . A Mamdani fuzzy model consists of a set of fuzzy if-then rules in the following form, V.Palade,et,al,2002: If x1 is X1i1 and x2 is X2i2 and ….. xn is Xnin then y is Yj where: x1, x2, …, xn are the system inputs, y is the output, Xki k with k=1,2, …, n and ik=1,2, …, lk are the linguistic values of the linguistic variable xk, and Yj j=1,2, …. ly are the linguistic values of the output. Another major class of neuro-fuzzy networks are the neuro-fuzzy networks used to develop and adjust a Sugeno-type fuzzy(TSK) model. The structure of such a neuro-fuzzy network is shown in figure 7. The first 3 layers are the same with those in a neuro-fuzzy network for Mamdani models. In the rule layer, it can be used the traditional fuzzy min operator, but many authors prefer to use a product operator as fuzzy intersection operator. Usually, all weights of this layer are set to 1. If some prior knowledge on process functioning is available, it can be established the number of nodes in layer 3 (the number of rules or fuzzy partition regions) and the corresponding links between layer 2 and 3.

Fig. 6. The general structure of a neuro-fuzzy Fig.7. Neuro-Fuzzy network for TSK fuzzy model network for Mamdani model Implementation 8. Neuro –fuzzy FDI Applications in Sugar Industry The sugar production contains a number of unit operations in series , mainly: Beet/Cane preperation , Diffusion, \dried pulp , Purification ; Evaporation ; Crystallization and Centrifugation .The sucrose juice extracted by diffusion , this juice is concentrated in a 265

multiple effect evaporator to produce a syrup.The syrup is directed to the crystallization process.The sugar crystals and syrup are separated in centrifugues ,and then cooled and dried prior to shipment, Jawish,(2007). In the evaporation station ,the purified juice is a sugar solution containing approximately 14% sugar and 1% non-sugars. It is now necessary to concentrate this solution. This is done by boiling off water from the solution in large vessels known as evaporators. On entering the evaporators, the solution contains approximately 14% sugar. On leaving the evaporators it contains approximately 60%.. A typical Functional Diagram of 3-effect Evaporation Station is shown in Fig. 8, the layout of SCADA supervision ,monitoring and measuring equipments as well,

Fig. 8 Functional diagram of Evaporation Station in Sugar Industry 9. FDI System for Electro-Pneumatic Valve Actuator (An illustrative example ) Electro-Pneumatic Valve Actuator is one of the most important components in the evaporation station, which is a part of the technological installation for sugar manufacturing, where the densification of thin sugar beet juice takes place. The main faults which may be occurred in the evaporation unit are : evaporator carcass internal, leakage or fouling, tubes , sensors of temperature, pressure, flow rate , juice level.. actuators, e.g., electro-pneumatic valve , incorrect process states, and the like .The set of considered faults are defined based on installation description, expert knowledge and industrial practice. The valve considered for FDI is an electro-pneumatic flow controller in the evaporisation stage of a sugar factory. A non-linear mathematical model of the evaporation unit valve is constructed using SIMULINK and MATLAB , J Uppal ,(2002). The model is then used to generate faulty/ fault-free data to evaluate the Neuro-fuzzy based fault isolation schemes presented in the previous sections. The Block diagram of Electro-Pneumatic Valve control system is shown in Fig. 9. 266

Fig.9 Block diagram of Electro-Pneumatic Valve control system

The whole valve assembly consists of 3 main parts: The PI controller controls the Positioner & Actuator output to regulate the flow through the valve Positioner and Actuator: Pneumatic pressure is applied to the servomotor diaphragm to control the stem position that changes the flow. The Positioner adjusts this pressure input to the servomotor to obtain the correct stem position of the actuator. The Valve is the final element in the assembly that alters the flow according to the stem position, see Fig.10. The following list of faults are considered in the valve actuator assembly: f1 - External PI proportional gain fault f2 - External PI integral gain fault f3 - Increased friction of the servomotor f4 - Decreased elasticity of servomotor f5 - Decrease of pneumatic pressure f6 - Internal PI controller fault f7- Internal position sensor fault , f8 - Valve clogging f9 - Valve leakage f10 - Choked flow

Fig.10 Actuator fault detection scheme Two neuro-fuzzy models are used here with transparent structure.. A TSK structure with linear dynamic models as consequents is used to approximate the internal PI controller, the Positioner and servomotor. The systemâ&#x20AC;&#x2122;s non-linearity is mainly in the dynamics and a transparent TSK model is ideal for this case. These changes are the residuals that can be used for fault isolation. A Linguistic/Mamdani NF model is identified to approximate the valve. The model input is the stem position x and the output is volumetric flow rate f. From input set-point flow and measured flow, integrating and using RLSE, the control input u can be predicted. GK-clustering algorithm ,(1979) is used to partition the input space (Fig.11), where 267

clusters are projected onto the I/O space to find MFâ&#x20AC;&#x2122;s. Gradient-based optimisation method is used to fine-tune theMFs.

Fig.11 Valve data clustered in three groups.

Table 4: Fault Isolation

The predicted values u, x, f and the measured values are used to generate the residuals ru , rx , rf. The fault isolation table given in table-4 shows that some faults could only be detected during the time when the valve is being opened and closed. Moreover, choked flow could only be detected at high values of flow. The results of this illustrative example have shown that Neuro-fuzzy systems not only have powerful approximation abilities for modellingunknown dynamic non-linear systems, but a high level language description of the system can also be obtained. Uppal, Faisel J & Ron J Patton, (2002). 10.Conclusions In this paper we have discussed the basic concepts of FDI systems and a review of the various I techniques that have been proposed to solve the problem of fault detection and diagnosis in Dynamical Systems. As an illustrative example, an application study of electro-pneumatic valve actuator in the evaporation unit of a sugar factory was presented. The key issues of finding a suitable structure for detecting and isolating ten realistic actuator faults are outlined. AI approaches to fault diagnosis seem to be very 268

effective in enhancing the powerful detection and isolation capabilities of quantitative modelbased methods. One realizes that no single method has all the desirable features one would like a diagnostic system to possess. It is our view that some of these methods can complement one another resulting in better diagnostic systems. Integrating these complementary features is one way to develop hybrid systems that could overcome the limitations of individual solution strategies.

REFERENCES Bergman S., M. Sourander, S-L. Jämsä-Jounela, (2002) ,Monitoring of an Industrial Dearomatisation Process , Copyright © 2002 IFAC 15th Triennial World Congress, Barcelona, Spain. Ghahroodi,Ali Hossini (2002),Intelligent Condition Monitoring And Fault SupervisionIn Dynamic Systems, (2002)Shiraz University, Shiraz, Iran. Gustafson ,D. E. and W. C. Kessel (1979). Fuzzy clustering with a fuzzy covariance matrix, in Proc. IEEE Conf. Decision Contr., San Diego, pp761-766 Isermann, Rolf,(2004),Model-based Fault Detection and Diagnosis - Status and Applications, copyright © 2004 IFAC Jabbari A., R. Jedermann, and W. Lang, (2007), Application of Computational Intelligence for Sensor Fault Detection and Isolation, PROCEEDINGS OF WORLD ACADEMY OF SCIENCE, ENGINEERING AND TECHNOLOGY VOLUME 22 JULY 2007 ISSN 13076884 Jawish,I ,(2007), Modeling and Fuzzy Control of a Multiple- Effect Evaporator In Sugar Industry, Al Bassel Scientific Engineering Journal , 2007 , July , N. 23,Ministry of Higher Education-Syria Patton, R J, F J Uppal & C J Lopez-Toribio, (2002), Soft Computing Approaches to Fault Diagnosis for Dynamic Systems: a survey, The University of Hull, United Kingdom. Patton, R J. Chen,f and S. B. Nielsen&Dagger;(1995) Model-based methods for fault, diagnosis: some guide-lines, Transactions of the Institute of Measurement and Control 1995;17;73. Palade,V. et,al,(2002),FAULT DIAGNOSIS OF AN INDUSTRIAL GAS TURBINE USING NEURO-FUZZY METHODS, Copyright © 2002 IFAC. Syfert,M. P. Rzepiejewski, P. Wnuk, J.M. Kościelny, (2005) ,Current Diagnostics of the Evaporation Station, Copyright © 2002 IFA ,15th Triennial World Congress, Barcelona, Spain. Uppal, Faisel J & Ron J Patton, (2002) Fault Diagnosis of an Electro-pneumatic Valve Actuator Using Neural Networks With Fuzzy Capabilities, ESANN'2002 proceedings European Symposium on Artificial Neural Networks.. Venkatasubramanian V. et al. (2003),A review of process fault detection and diagnosis Part I, (2003) , Quantitative model-based methods ,2003,Computers and Chemical Engineering 27 (2003) 293_/311. Venkatasubramanian et al, (2003),A review of process fault detection and diagnosis Part II: (2003) Qualitative models and search strategies Computers and Chemical Engineering 27 (2003) 313_/326. Venkatasubramanian et al. (2003),A review of process fault detection and diagnosis Part III, (2003),Process history based methods,Computers and Chemical Engineering 27 (2003) 327_/346. 269

MANAGEMENT OF TECHNICAL DATA FOR PRODUCT DESIGN Gavril Muscă1, Elena Muscă2 & Vasile V. Merticaru1 (1Technical University “Gheorghe Asachi” of Iasi - Romania, Department of Machine Manufacturing Technology, 2Institute of Computer Science of Iasi – Romania) Abstract: The paper proposes the development of some standard software procedures for the management of technical data for mechanical projects development, within some multi-agent collaborative networks. Connecting some CAD software solutions with systems of technical data management needs formation and training of the work teams members. The present research targets gathering the competencies of several work teams for establishing the product structure and generating a multitude of product variants using the PDM/PLM concepts. 1. INTRODUCTION Many important PLM software companies are acting today on the profile market. Among them we can nominate: Siemens, SAP, Arena Solutions, Dassault Systemes, PTC and Oracle. Of course, as a result of the research and business activities of these companies, many PLM systems, including Arena, Agile, eMatrix, Enovia, I-man, Metaphase, SAP PLM, Sherpa, SmarTeam, Teamcenter and Windchill have been released and implemented within a lot of organizations. Most of the PLM applications focus on data management in different stages of the product development, in engineering design or in the development of the manufacturing technologies. 2. MANAGEMENT OF TECHNICAL DATA IN PDM/PLM SYSTEMS Technical data must be organized in special databases able to allow searching, retrieving, changing and current use of data, because they have a set of characteristics that impose this aspect, respectively: they are large and need an important memory resource; they have a complex structure (different formats resulted from: general design data, data referring to component parts of the product, CAD model, technological data, CAM model, data regarding the testing and simulation of the product’s behavior etc.); they have a dynamic structure (they are used in several products, assemblies, subassemblies); they are frequently modified at least for two reasons, respectively: changes imposed by the optimization of the manufacturing and of the functioning conditions; changes imposed by the beneficiaries’ requests (shape, color, dimensions etc.). Data are heterogeneous because for a product we meet original components, re-used components or modified components, and for each component part we meet the technological model (CAM), the model for testing, simulation, behavior, adjacent data (tasks, messages, calculus sheets, reports etc.). In conclusion, there exist different databases for different stages of product development, with the following disadvantages: a) This databases have different data structures; b) Difficulties occur in data analysis and processing; c) Communication between these databases is difficult. That is why it is targeted the realization of some databases able to assure the data management along the entire product lifecycle (PDM, PLM). PLM databases have an efficient structure and they are organized on other principles than the purpose and the stage they address to. The effectiveness of data processing targets the realization of some formats independent of the targeted aim, the normalization and formalization of data. 270

For an efficient management of the technical data, there must be considered the stages in the product lifecycle. The efficiency comes from: easiness of data searching and retrieving, in all the stages (design, manufacturing, selling, use etc.). The method is named data management for the entire product lifecycle and has two main stages: - management of the technical data and of the documentation (PDM); - entire data management for the entire product lifecycle (PLM). 3. DEVELOPMENT OF PRODUCT VARIANTS USING PLM More and more concern is noticed for the development of on-line collaboration platforms in the field of mechanical computer aided-design. Interest in CAD designing based on solid entities occurs both for students and designers from many companies specialized in design and manufacturing. Success in the activity of implementation of mechanical projects developed in CAD environments is also determined by knowing the procedures for the management of CAD files, of revisions and of their modification. The large number of CAD files and of other appendix documents of a project and their development in local or collaborative networks require familiarity of the product developers with the procedures of technical data management. The experience of some teams for the implementation of some PLM systems shows that formation and training of specialists in PDM/PLM is a current necessity. Collaborative development of mechanical projects indicates that more and more participants in the projects development, specialized in design, manufacturing, marketing, presentation, sales and maintenance of products perceive the product development as a social activity, of collaboration between different specialists. There are necessary skills for integrating with communication channels, for accelerating data exchange, for on-line development of product components and assemblies. A case study on collaborative design developed at MIT shows interest in team project development, consulting experts and using variants of the project, taking elements from libraries and project archives. The results of this study define the ideal on-line system as a common area of work, having attached a database for the project in continuous development; an area to solve problems, and an open communication and social interaction area. The paper presents the efforts of a team from The CAD/CAM/PLM Laboratory from TUI for collaborative development of some industrial projects. TeamCenter environment has been used for product data management and the projects development uses SolidEdge. Previous concerns included the development of projects of stamping devices within some work teams. Integration of the PLM environment was realized within a VPN network providing the collaborative development conditions. Optimization of the structure of the approached products used both the facilities of SolidEdge and of the TeamCenter environment, fig.1. For a type project of stamping device, 18 project variants have been developed. Each variant has different dimensions and components, being available for further development, fig.2. The completion of a certain project is done by analyzing the workability of the parts processed by stamping, the design of the scheme for placing the parts on the sheet metal strip, the establishment of the processing phases. Accordingly to these elements, one of the previously designed variants is used, which by configuration and dimensions frames the working scheme developed for a stipulated part. The active elements and the punches are designed and function of those, the active plate and the port-punch plate are adapted. The elements for material guidance, the fixing-retaining during processing and the evacuation of the stamped elements are further on developed. Using the data management systems, project variants are 271

developed, characterized by codification of assemblies, sub-assemblies and components. These variants are available in final or achieved variant.

\ Fig. 1. Accessing of CAD software and data management using TeamCenter 4. CONCLUSION The work proposes a collaborative methodology for developing some type projects, specific to the machine manufacturing industry. The realization of the projects for some stamping devices, using computer aided design software, uses the experience and the specialty knowledge of the economic agents, partners in the project and the abilities of the teams from the universities in knowing the latest CAD software at international level. Development of the design knowledge at the level of the network of the partners in the project is assured by integrating the CAD, CAM and CAE modules into an integrated solution, into an open developing environment, leading to a greater efficiency of integrating information in the designed products and processes. Including in the partnership a university specialized in design allows a collaborative conceiving activity which leads to the introduction of some aesthetical aspects, favorable to the development of competitive products. These approaches are stipulated in the phase of product conception but also in this of presentation and realizing some visualization elements, product promotion and presentation catalogues, using specialized software and compatible to the software used in computer aided design. The work proposes to use product lifecycle management software for small and medium companies, which ensure collaboration oriented to product and based on web platform to develop new products, quickly and with reduced costs. One of the moment requests is to develop projects using technical data management for the phases of the products lifecycle. The phases of the developing cycle are: â&#x20AC;˘ Realization of some alternative variants of project, characterized by different dimensions; â&#x20AC;˘ Different solutions for solving conception problems or manufacturing technology; â&#x20AC;˘ Typifying and normalization of some families of parts or assemblies; 272

â&#x20AC;˘ Creation and generation of some specialized databases containing components and assemblies specific to the activities of the economic agents; â&#x20AC;˘ Finishing an efficient solution for the management of the information and of the technical data developed in previous phases, at the level of the partnership network. For accomplishing this aim there is proposed the development of a methodology for implementing the technical data management at the level of some SME-s, with minimal costs. The ability of technical data management must facilitate synchronization of knowledge about product with ERP systems, allowing economic agents to maximize the profitability starting from design phase, as opposed to actual tackling which is based on production costs control.

Fig. 2. Example of design optimization using product variants For providing access to the members of the participant teams at the process of collaborative data development in The CAD/CAM/PLM Laboratory from TUI, a VPN network have been developed, allowing accessing of CAD and PLM software. The teleworking system is operative, is preferred by a part of the users, but it requests a detailed scheduling of the activities in product development stages. There are necessary procedures for improving the communication between the network members (e-mail, attached documents, their including in the database specific to the developed product) which represent the next stage in our approach. We appreciate as of great interest the future development for the collaborative product design, the involvement and training of students in knowing the CAD, PDM and PLM procedures. REFERENCES Grieves, Michael (2006), Product Lifecycle Management, McGraw-Hill, USA Sawhney, Nitin, Collaborative Design and Learning in Studio Courses. Phase 1: Summary of Online Survey Conducted at MIT.

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ИННОВАЦИОННЫЕ ТЕХНИКА И ТЕХНОЛОГИИ ОСНОВА УСПЕШНОГО СТАНОВЛЕНИЯ СТАНКОСТРОИТЕЛЬНОЙ ПОДОТРАСЛИ РЕСПУБЛИКИ УЗБЕКИСТАН Ан В.Ф. (ПО «НМЗ» ГП НГМК, г.Навои, Республика Узбекистан) Когда речь идёт об инновационной технике и инновационных технологиях, то это, безусловно, и верно относится находящемуся на этапе поступательного развития станкостроения Узбекистана. С первых изделий - широкоуниверсальных токарно-винторезных станков НТ200, 16Н28 и начался, провыв в области приводной техники и СЧПУ. Это были первые попытки создать станок с микропроцессорной техникой и упрощённой диалоговой системой в программном обеспечении. Эта идеология была усовершенствована и расширена на следующем изделии с маркой НТ-250И.

Рис.1 Станок НТ-250И Этот станок с интерполятором и цифровой индикацией стал прекрасным образцом сотрудничества механиков, электроспециалистов, металлообработчиков, приводчиков, и системщиков. Станки, в кратчайшие сроки, вошли как лучшие образцы металлообрабатывающей техники в жизнь мастерских, заводов, цехов, фирм имеющих дело с резанием металлов. Эта модель со временем не стала удовлетворять станкостроителей. Практически с первых лет эксплуатации витал вопрос об усовершенствовании системы управления в плане расширения его технических возможностей и, в частности, увеличении технологических «Кадров». Долгие поиски вывели нас на контакт с ЗАО «МШАК». Эта фирма, созданная на не большой части научно-производственной базы известного в Советское время проектно-технологического авиационного института г.Ереван. По нашему техническому заданию был создан привод и система управления «МШАК». С этой фирмой мы расширили область сотрудничества, т.е. Ереван поставляет нам не только приводную часть и СУ, но и органично объединённую с ними силовую часть станка электроавтоматику, все кабели связи с кабелеукладчиками, т.е. разработано и поставляется комплектное устройство управления (КУУ). Таким образом результатом совместного двухлетнего труда с фирмой «МШАК» г.Ереван стал станок НТ-250М, имеющий

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Рис.2 Станок НТ-250М не только мощные технические возможности, но и современный привлекательный дизайн, жидкокристаллический дисплей и широкие программные возможности. С этим КУУ расширена технологическая возможность привода и СУ до 99 рабочих «Кадров», т.е. можно программировать и изготавливать сложнейшие многооперационные детали с множеством переходов и проходов. СУ перешла с аппаратной логики на программную, что придало большую гибкость в управлении эл. автоматики и позволило корректировать многие ранее жёстко заданные параметры (отключение шпинделя через определённое время, электронные упоры, задание времени смазки направляющих и т.д.). Появился жидкокристаллический экран, отображающий как программирование, так и исполнение. Панель управления, жостик и штурвалы имеют современные формы и дизайн. Одной из основополагающих задач при создании станков с новой идеологией управления была - сделать труд токаря на станках этого типоразмера физически лёгкой - для использования труда женщин и интересной, с целью привлечения молодёжи в металлообработку. Вместе с совершенствованием «мозгов» станка совершенствовалась как механическая структура, так, и его внешний вид. Мы считаем достоинством нашего НТ-250 простоту управления (не требуется инженерное сопровождение), самообучаемость, лёгкость работы на нём (возможность использования женского труда) привлекательные исполнения и дизайн, пробуждающий интерес молодёжи к работе на этих станках (фото или видео станочников-женщин и парней). Стремление к совершенствованию аппаратной части, подтолкнули нас искать партнёров по разработке приводов и СУ по нашим ТЗ и по нашей идеологии. Поиски привели нас к сотрудничеству с ООО «Техсервис» г. Самара, Россия и ООО «Модмашсофт» Н. Новгород, Россия. В содружестве с ООО «Техсервис», г.Самара, Россия разработано комплектное устройство управления, состоящее из привода, и СУ, электроавтоматики и кабелей связи на основе комплектующих передовых японских товаропроизводителей. Программная же часть разработана по нашему техническому заданию и представляет продукт, вобравший в себя многолетний наш опыт и сложившееся на это время представление об управлении процессом металлообработки с наибольшей 275

эффективностью в сочетании с простотой и привлекательностью. Это КУУ условно названо «Джин».

Рис.3 Дисплей КУУ «Джин» Это самообучающаяся диалоговая система, которая может освоить любой выпускник(ца) колледжа в кратчайшие сроки и выполнять операции по обработке металла (тел вращения) максимальной сложности. Для сравнения: работая на традиционном «железном» станке типа 1К62, 16К20, 1М63 и т.д. не всегда и не каждый токарь, имеющий квалификацию 7 разряда и стаж более десяти лет, сможет выполнить то, что может сделать токарь 4-го разряда на НТ-250М. В самом названии «Джин» уже заложен намёк, что он как волшебник… может почти всё и претензия на то, что на сегодня аналогов ему нет. Руководство станкостроительного производства при создании новых образцов станкопродукции руководствовалось идеей создания таких изделий, которые одновременно бы вобрали в себя и простоту управления, и широчайшие функциональные возможности с современным дизайном. Станки рассчитывались на молодёжь, выпускников колледжей и школ, а так же на девушек, входящих в последнее время в промышленное производство и, в частности в металлообработку. Это уже было реализовано в НТ-250М. В 2008-2009гг. наша работа направлена на решение вопросов психологической совместимости станка и человека, на повышение его партнёрских качеств. Станочники при виде своего станка, ещё на подступах к нему должен испытывать чувство волнения и восторга, видеть в нём не просто машину, не просто орудие, а партнёра по труду, единомышленника и собрата, который должен помочь заработать столько, сколько нужно для достойной жизни современного человека. Они должны любить и лелеять станок, а по окончании рабочей смены с чувством величайшего сожаления расставаться с ним. Но и станок должен отвечать тем же. Он должен быть привлекателен и эргономичен, его цвета должны воодушевлять человека на труд, как бы приглашать станочника к производственному общению. Частично это направление реализовано в комплектном устройстве управления (КУУ) под названием «Джин». Прикосновение человека к пусковой кнопке приводит к тому, что включается жидкокристаллический дисплей и станок приветствует рабочего - «О, мой Повелитель! Приветствую тебя! … Слушаю и повинуюсь!»

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Рис.4 Приветствие на дисплее КУУ «Джин» В дальнейшем машина будет это делать приятным мужским или женским голосом. Так же задумано, чтобы станок предостерегал рабочего от неправильных действий и от ошибочных решений, помимо этого, станок будет обучать сложным технологическим приёмам, т.е. показывать на примере, как выполнять те или иные операции. Этим осуществится полноценный диалог станка и человека, и, конечно же, в таких условиях станочник будет чувствовать себя более комфортно, и, с чувством самоуважения и личной значимости станет выполнять порученную ему работу. В 1995году был изготовлен первый широкоуниверсальный фрезерно-расточной станок НФ-630.

Рис.5 Станок НФ630 А летом 2009г. на заводе прошли заводские приёмно-сдаточные испытания нового образца фрезерно-расточного станка НФ-630МФ4. 277

Рис.6 Станок НФ630МФ4 Примечательно, то, что теперь этот станок обзавёлся инструментальным магазином на 20 единиц. Это не единственное и не главное изменение. Очень важен тот момент, что каждый модернизированный станок становится Умнее и привлекательнее. На фоне завод, между делами, освоил производство обдирочно-заточного станка 3Н340,

Рис.7 Станок 3Н340 278

настольно-сверлильного 21Н16

Рис.8 Станок 21Н16 и деревообрабатывающего СДУ-1 и СДУ-1П.

Станок СДУ-1 На базе современных аппаратных комплектующих и радиокомпонентов освоена модернизация станков 16А20Ф3 и 16К20Ф3. 279

Рис.9 Станок 16А20Ф3 Мы вдохнули в груды металла вторую жизнь, вернув в строй дорогостоящее металлорежущее оборудовании. На фоне разработки и изготовления инновационной металлорежущей техники, не очень заметно было освоено с Рязанским станкостроительным заводом совместное производство таких всемирно известных станков, как 1М63 и 16К40.

Рис.10 Станок 1М63Н Приоритет нашего токарного и фрезерного станков, создание подтверждено патентами. Особое направление в деятельности станкостроительного производства занимает создание специальных станков, каждый из которых является примером инновационной техники, вобравшей в себя массу инновационных технологий. И так: 1. Инновационные проекты станкостроения: Спроектированы и изготовлены: 1.1. Специальный расточной станок НС-2М, предназначенный для расточки траков и пластин питателя, что позволяет увеличить производительность труда и высвободить горизонтально-расточные станки. 280

Рис.11 Станок НС-2М 1.2. Спец. станок для обработки роторов электромоторов до ф700мм и длиной до 2,5м. 1.3. Специальный станок 19Н1000 с электроприводами и программной системой управления для расточки труб роликоопор Ф194х5, L до 720 мм и торцевания осей роликоопор, центровки и проточки осей Ф60 мм, L до 820 мм.

Рис.12 Станок 19Н1000 1.4. В начале 2008 года СКБС разработало сложнейший проект на спец. металлорежущее оборудование для обработки опорных роликов. Размеры которых составляют (L= до 1350 мм, Ф=2200 мм, вес до 15 тн.) и бандажей (Ф=8350 мм, H= 1200 мм, вес - около 100тн) установленных на цементных печах ОАО «Кызылкумцемент». 1.5.Разрабатывается станок специальный для обработки труб роликоопор длиной до 2300мм и соответственно осей к ним. Особое место в работе станкостроения занимает разработка приводов и СУ для металлорежущих станков производства ПО НМЗ. 2. Совместные инновационные проекты: Закончено совместное проектирование: 2.1 приводов и СУ с интерактивным дисплеем нового поколения к металлорежущим станкам (токарным и фрезерным) с ООО «Техсервис» г.Самара, Россия. 281

2.2. Приводы и СУ с упрощенной схемой ввода данных и команд оператора с сенсорным дисплеем с ООО «Модмашсофт» г.Нижний Новгород, Россия. 2.3. В стадии разработки Узбекский вариант привода и СУ к широкоуниверсальному токарно-винторезному станку с ОАО «Алгоритм» концерн «Узэлтехсаноат» г.Ташкент, РУз. Успешное выполнение этого раздела позволит нашему объединению оставаться на передовых позициях по производству современных станков. ПО НМЗ участвует в выставках как в отраслевых и республиканских, так и в международных. Тому подтверждение многочисленные дипломы. Участие в конкурсах «Лучшее изделие Узбекистана» позволило нам стать её дипломантами. Наши станки дважды признаны лучшей продукцией Республики Узбекистан

Рис.13 Диплом «Лучшая продукция Узбекистана» и дважды нам вручены хрустальные кубки за высокое качество станкопродукции.

282

Рис.14 Кубок за «Лучшую продукцию Узбекистана» Станкостроительное производство сертифицировано и отвечает требованиям международной системы ISO 9001:2000. И в завершении своего выступления хочу проинформировать, что наш ПО НМЗ с 2008 года является членом международного союза машиностроителей.

Рис.15 Сертификат коллективного члена Международного союза машиностроителей Производство металлорежущих станков подтверждение - высокого технического уровня нашего объединения, высокой квалификации, его инженерного состава и рабочего класса и значительного потенциала машиностроительной отрасли независимого Узбекистана.

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СОДЕРЖАНИЕ Adamczyk J., Kaliński W. BELASTUNGSANALYSE DER GABEL EINES GABELSTAPLERS…………………..…3 Antonyuk S., Dosta M., Heinrich S. INFLUENCE OF LIQUID LAYER ON ENERGY LOSS AT GRANULE IMPACT............7 Bakšiová Z. SOME METHODS OF PRINCIPAL STRESS SEPARATION IN PHOTOSTRESS MEASUREMENTS…………………………………………………………………………..12 Barkalov A. A., Kovalyov S. A., Krasichkov A. A., Miroshkin A. N. LOGICAL CONDITION REPLACEMENT IN COMPOSITIONAL MICROPROGRAM CONTROL UNIT WITH CODE SHARING………………………………………….……..16 Barkalov A. A., Zelenyova I. Y., Kovalev S. A., Lavrik A. S. OPTIMIZATION OF COMPOSITIONAL MICROPROGRAM CONTROL UNITS WITH CPLD…………………………………………………………………………………………21 Bernat Р. КОМПЬЮТЕРНАЯ ПОДДЕРЖКА ПРОЕКТНЫХ РАБОТ……………………………....26 Besliu V., Topala P., Ojegov A. PREDICTING THE THICKNESS OF THE SURFACE LAYER SUBJECTED TO THERMO-CHEMICAL TREATMENT APPLYING EDI USING MODELING THROUGH THE METHOD OF NEURONAL MODEL…………………………………..……………..30 Boca M., Nagîţ, G., Manole I. THEORETICAL ASPECTS CONCERNING THE ELASTIC BEHAVIOR ON A BEAM UNDER THE ACTION OF THE CUTIING FORCE IN THE TURNING PROCESS……..34 Buchacz A., Galeziowski D. INTRODUCTION TO SYTHESIS AND TRANSFORMATIONS OF MECHATRONICS SYSTEMES……………………………………………………………………………..……38 Buchacz A., Płaczek M. EQUATIONS OF MOTION OF THE VIBRATING MECHATRONIC SYSTEM WITH THE GLUE LAYER……………………………………………………………………..…...42 Bunga G., Pikurs G. REPLACEMENT OF PROCESSING METHODS FOR ADVANCED OPERATIONS..….46 Burek J., Ostrowski R., Szular A. CUTTER ROTATIONAL SPEED OPTIMIZATION IN HIGH PERFORMANCE CUTTING OF ALUMINUM ALLOYS………………………………………………………………….49 Burek J., Ostrowski R., Szular A. HIGH PERFORMANCE CUTTING OF ALUMINUM ALLOYS………………….………54 284

Chirugu M., Timofte G., Paraschiv Dr., Rotaru M. NEW ON SYNOPTICAL REALIGNMENT CARS FROM THE ECONOMIC – FINANCIAL…………………………………………………………………………….……59 Dziczkowska M. APPLICATION OF THE EDDY CURRENT METHOD FOR MEASUREMENTS OF GEOMETRICAL DIMENSIONS IN TWO-LAYER STRUCTURES………………………62 Dziczkowski L. ERRORS IN CONDUCTANCE MEASUREMENTS OF MATERIALS THAT ARE USED FOR CONSTRUCTION OF THICK PLATES…………………………………………...….66 Dziczkowski L. A MATHEMATIC MODEL TO DETERMINE OPTIMUM CONDITIONS FOR MEASUREMENTS OF MATERIAL CONDUCTANCE BY MEANS OF THE EDDY CURRENT METHOD APPLICABLE TO LARGE STRUCTURES………….……………69 Dziczkowski L. EXAMINATION OF EDDY CURRENT PROPERTIES SUITABLE FOR APPLICATION IN CONDUCTOMETRIC TECHNOLOGY……………………………………………..…..73 Fröhlich L., Martončíková J. CINETICS OF DRYING OF HIGH ALUMINIUM REFRACTORY CONCRETE MATRICS CONTAINING MICROSILICA..............................................................................................78 Frőhlichová, M., Bálintová, Kucková, A. EMISSIONS FROM COKE PRODUCTION...........................................................................83 Daschievici L., Ghelase D. TECHNICAL-ECONOMICAL COMPETITIVENESS OF THE MANUFACTURING SYSTEMS................................................................................................................................87 Ghelase D., Daschievici L. METHODS FOR IMPROVEMENT OF QUALITY………………………………..……….91 Guziałowska J., Ulbrich R. CHARACTERISTIC’S OF TWO-PHASE GAS-LIQUID FLOW IN HEAT EXCHANGER WITH SEGMENTAL BAFFLES…………………………………………………………….95 Hajduk M., Baláž V. PALLETIZATION WITH ROBOT OTC DAIHEN..............................................................99 Haľko J., Paško J. COAXIAL OTH SIDE MORE - OUTPUT GEARS………………………………………..102 Ignasiak K., Anweiler S. APPLICATION OF PIV METHOD FOR DEFINITION OF TRAJECTORY AND MOVEMENT OF PARTICLES IN PNEUMATIC SEPARATOR……………………..….105 285

Isper G., Al-kaei F., Al-garbouh A. CONTROL AUTOMATION BY THE MANAGEMENT OF ELECTRIC LOADS IN INDUSTRIAL PLANTS……………………………………………………………….……109 Karaś M., Zając D. BUBBLES RISING OBSERVATION AND MEASUREMENT……………………..……117 Kheifetz M., Koukhta S., Prement G., Klimenko S. CHOICE OF DESIGN DECISIONS DURING MODELLING TRANSFER OF QUALITY PARAMETERS OF MACHINE DETAILS................................................................................................................................121 Kliaguine G. FAIRE LES RECHERCHES DOCUMENTAIRES VIA L’INTERNET…………………..128 Kovalev S. A., Barkalov A. A., Malcheva R. V. PROBLEM - BASED APPROACH AS A WAY TO IMPROVE THE QUALITY OF THE ENGINEERING EDUCATION…………………………………………………………….132 Kret J., Jursovoj S. COKE GRADE FOR METALLURGY………………………………………………….…135 Krowiak A. NEW METHODS OF MANAGING THE INDUSTRIAL ENTERPRISE WITH THE SUPPORT PROCESSED LOGIC AS WELL AS THE CALCULATION OF COSTS WITH ACTIVITY BASED COSTING METHOD.........................................................................139 Lejda K., Akopjan R. ESTIMATION OF INFLUENCE OF SOME PARAMETERS OF DOUBLE PNEUMATIC ELASTIC ELEMENTS ON A MOTION’S SMOOTHNESS OF THE BUS………….…..143 Lipski J. ARTIFICIAL INTELLIGENCE TECHNIQUES IN DESIGN MANUFACTURING SYSTEMS………………………………………………………………………………...…147 Lupescu O., Pruteanu O., Popa R., Popa I., Ulianov C. RESEARCHES REGARDING THE INFLUENCE OF THE ECONOMICAL CRITERIA UPON THE MAINTENANCE ACTIVITIES POLICIES………………………...………..151 Manole I., Nagit G., Boca M. ACTION OF THE CERAMIC TOOL ON BURNISHING PROCESS…………….………155 Matache L. C., Cherecheş T., Rotariu A., Sava A.-C. MODELING FLOW INTO THE BARREL - A METHOD OF SOLVING THE DIRECTLY PROBLEM OF THE INNER BALLISTICS………………………………………………..159 Milenin A., Kustra P. МАТЕМАТИЧЕСКАЯ МОДЕЛЬ ПРОЦЕССА ВОЛОЧЕНИЯ ПРОВОЛОКИ ИЗ СПЛАВА MgCa08…………………………………………………………………….……165 286

Monková K., Monka P., Hloch S. ENGINEERING EDUCATION SUPPORTED BY ELECTRONIC SCRIPTS AND HANDBOOKS.....................................................................................................................169 Monková K. THE UTILIZATION OF CAD/CAM SYSTEMS AT THE BASIC INTEGRAL MACHINE PART CHARACTERISTICS DEFINING...........................................................................173 Mrówka-Nowotnik G. ANALYSIS OF INTERMETALLIC PHASE PARTICLES IN IN CAST ALCU4NI2MG2 ALUMINIUM ALLOY IN T6 CONDITION……………………………………………....177 Novotny M., Štěpánek L., Vlček M. TECHNICAL EDUCATION IN FACULTY OF CIVIL ENGINEERING, BRNO UNIVERSITY OF TECHNOLOGY, CZECH REPUBLIC……………………………..….181 Pacana A. ASPEKTY DECYZYJNE W LOGISTYCE TRANSPORTU LEŚNEGO...............185 Paško J., Balara A. THE MODEL OF BEARING REDUCER……………………………………………...…..190 Popa R., Pruteanu O., Lupescu O., Popa I., Baciu C. RESEARCHES REGARDING THE DETERMINATION OF SPARE PARTS ACQUISITION COST USED IN TECHNOLOGICAL EQUIPMENT CORRECTIVE MAINTENANCE..................................................................................................................196 Popa I., Pruteanu O., Lupescu O., Popa R., Baciu M. RESEARCES REGARDING THE LIFE CYCLE COST ESTABLISHMENT OF THE TEHNOLOGICAL EQUIPMENTS………………………………………………….……..200 Popa S., Paraschiv D., Popa V., Popa I., Popa R. ASPECTS REGARDING THE SIX SIGMA CONCEPT IMPLEMENTATION UPON THE BEARINGS MANUFACTURING PROCESS....................................................................204 Pribulová A., Gengeľ P., Demeter P., Baricová D. FOUNDRY SLAG WASTES AND POSSIBILITIES OF THEIR UTILIZATION……..…209 Rădeanu A., Uliuliuc D., Lupu V., Purcariu R. ALTSCHULLER ALGORITHM APPLICATION TO DESIGN A DEVICE……………..213 Sava O. , Pruteanu O. , Lupescu O., Popa R., Popa I., Murarasu E. USING THE UTILITIES THEORY FOR CHOOSING THE TYPE DEVICE FOR EXTERIOR CYLINDRICAL SURFACES ROTOROLLING……………………………..217 Slătineanu L., Coteaţă M., Uliuliuc D., Rădeanu Al., Rotman I. EVALUATION OF THE MACHINABILITY BY FACE TURNING..................................221

287

Stanciu A., Pruteanu O. V., Cărăuşu C. EXPERIMENTAL STUDIES REGARDING THE INFLUENCE OF THE CUTTING CONDITIONS ON THE SHAPE ACCURACY OF THREADS PROCESSED BY LATHE CUTTING...............................................................................................................................225 Stikan I., Almen J., Шнуренко А. В., Андрющенко В. А. НОВЫЕ РАЗРАБОТКИ ТЕХНОЛОГИИ И ОБОРУДОВАНИЯ ТЕРМОДИФФУЗИОНОГО ЦИНКОВАНИЯ……………………………………...…….231 Štroch L. INDUSTRIAL SAFETY FROM THE POINT OF VIEW OF EUROPEAN LEGISLATURE……………………………………………………………………………..236 Štůrala J. DESIGN REQUIREMENTS FOR TECHNOLOGICAL EQUIPMENT IN EXPLOSION DANGER ENVIRONMENT………………………………………………………………..239 Timofte G., Chirugu M., Paraschiv Dr., Borcila R. THEORETICAL AND EXPERIMENTAL CONSIDERATIONS ON WORKING TIME TO GRINDING MACHNE……………………………………………………………………..242 Vasiliev A., Kheifetz M., Koukhta S., Prement G. FORMATION OF QUALITY INDEXES OF MACHINE DETAILS ON THE BASIS OF TECHNOLOGICAL INHERITANCE……………………………………………..……….247 Żółkiewski S. FORMULATION OF VIBRATIONS PROBLEM OF THE CLAMPED BEAM SUPPORTED BY AN ELASTIC CONSTRAINT IN ROTATIONAL TRANSPORTATION……………………………………………………………………….254 Jawish I. ABOUT METHODOLOGIES OF FAULT DETECTIONAND ISOLATION IN INDUSTRIAL SYSTEMS - A COMPARITIVE STUDY………………………………..258 Gavril Muscă, Elena Muscă & Vasile V. Merticaru MANAGEMENT OF TECHNICAL DATA FOR PRODUCT DESIGN………………….270 Ан В.Ф. ИННОВАЦИОННЫЕ ТЕХНИКА И ТЕХНОЛОГИИ ОСНОВА УСПЕШНОГО СТАНОВЛЕНИЯ СТАНКОСТРОИТЕЛЬНОЙ ПОДОТРАСЛИ РЕСПУБЛИКИ УЗБЕКИСТАН………………………………………..274

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ИМЕННОЙ УКАЗАТЕЛЬ A Adamczyk J., 3 Akopjan R., 143 Al-garbouh A., 109 Al-kaei F., 109 Almen J., 231 Antonyuk S., 7 Anweiler S., 105 B Baciu C., 196 Baciu M., 200 Bakšiová Z., 12 Balara A., 190 Baláž V., 99 Bálintová, 83 Baricová D., 209 Barkalov A. A., 16, 21, 132 Bernat Р., 26 Besliu V., 30 Boca M., 34, 155 Borcila R., 242 Buchacz A., 38, 42 Bunga G., 46 Burek J., 49, 54 C Cărăuşu C., 225 Cherecheş T., 159 Chirugu M., 59, 242 Coteaţă M., 221 D Daschievici L., 87, 91 Demeter P., 209 Dosta M., 7 Dziczkowska M., 62 Dziczkowski L., 66, 69, 73 F Fröhlich L., 78 Frőhlichová, M., 83 G Galeziowski D., 38 Gengeľ P., 209 Ghelase D., 87, 91 Guziałowska J., 95 H Hajduk M., 99 Haľko J., 102

Heinrich S., 7 Hloch S., 169 I Ignasiak K., 105 Isper G., 109 J Jursovoj S., 135 K Kaliński W., 3 Karaś M., 117 Kheifetz M., 121, 247 Kliaguine G., 128 Klimenko S., 121 Koukhta S., 121, 247 Kovalev S. A., 21, 132 Kovalyov S. A., 16 Krasichkov A. A., 16 Kret J., 135 Krowiak A., 139 Kucková, A., 83 Kustra P., 165 L Lavrik A. S., 21 Lejda K., 143 Lipski J., 147 Lupescu O., 151, 196, 200, 217 Lupu V., 213 M Malcheva R. V., 132 Manole I., 34, 155 Martončíková J., 78 Matache L. C., 159 Milenin A., 165 Miroshkin A. N., 16 Monka P., 169 Monková K., 169, 173 Mrówka-Nowotnik G., 177 Murarasu E., 217 N Nagîţ, G., 34 Novotny M., 181 O Ojegov A., 30 Ostrowski R., 49, 54 P Pacana A., 185 283

ИМЕННОЙ УКАЗАТЕЛЬ Paraschiv Dr., 59, 204, 242 Paško J., 102, 190 Pikurs G., 46 Płaczek M., 42 Popa I., 151, 196, 200, 204, 217 Popa R., 151, 196, 200, 204, 217 Popa S., 151, 204 Popa V., 204 Prement G., 121, 247 Pribulová A., 209 Pruteanu O., 151, 196, 200, 217, 225 Purcariu R., 213 R Rădeanu A., 213, 221 Rotariu A., 159 Rotaru M., 59 Rotman I., 221 S Sava A.-C., 159 Sava O., 217 Slătineanu L., 221 Stanciu A., 225 Štěpánek L., 181 Stikan I., 231 Štroch L., 236 Štůrala J., 239 Szular A., 49, 54 T Timofte G., 59, 242 Topala P., 30 U Ulbrich R., 95 Ulianov C., 151 Uliuliuc D., 213, 221 V Vasiliev A., 247 Vlček M., 181 Z Zając D., 117 Zelenyova I. Y., 21 Żółkiewski S., 254

А Ан В.Ф., 270 Андрющенко В. А., 231 Ш Шнуренко А. В., 231 J Jawish I., 258 M Muscă Gavril, 267 Muscă Elena, 267 Merticaru Vasile V., 267

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XVI международная научно-техническая конференция «МАШИНОСТРОЕНИЕ И ТЕХНОСФЕРА ХХІ ВЕКА» Сборник трудов Том 4

ISBN 966-7907-25-2

Компьютерная верстка сборника – асс. Сидорова Е.В.

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