PV 1
EDUCATIONAL VIBRATION TEST UNIT
DIMENSIONS in meters Length: 0,5 Width: 0,5 Length: 0,7 Weight in Kilos (gross): 80
The Vibrations Test Unit model P.V.1 enables the students themselves to carry out tests on a phenomenon, apparently to simple, but in fact very complex and significant like vibrations, involving any field of engineering applications. A well-defined theory exists on this phenomenon, which can be expressed by means of a simple differential equation of second grade. But the study of such a theory may hardly ever make it possible to relate the theoretical knowledge to the widest variety of practical applications that vibration phenomenology may give rise. Therefore, on developing our vibration Test Unit model PV1 it has been viewed to make the learning of knowledge on vibration engineering easier to students.
I - 16153 P.D. da Bissone 36r. GENOA - ITALY - Tel.: +39 010 6501969 Fax: +39 010 6501969 e-mail: patrone@ giacomopatrone.com http://www.giacomopatrone.com
PV 1
DESCRIPTION OF THE UNIT The Educational Vibration Unit PV1 as shown in the attached photograph consists essentially of the following components: 1. Sturdy carrying structure from cast iron on which an elastically vibrating plate is supported through a spring and rubber pad suspension assembly 2. D.C. electric motor with speed range variable from 0 to 6.000 RPM. It provides motion to the vibrating plate through the action of an eccentric force exciter 3. Eccentric force exciter with eccentricity variable from 0 to 20.3 mm. by means of which the intensity of the exciting force can be varied 4. Electronic speed counter from 0 to 6.000 RPM speed range 5. Step less speed changer gear with inner down-gear to control exactly the proper frequency of the system 6. DC feeder with variable output. Further to the above equipment, also comprised are the basic accessories as shown below which are essential for the conduction of the required tests. ¾ Strips of different thickness and material qualities ¾ Two container of four Plexiglas cells ¾ Four rupture systems or four Plexiglas cells ¾ Four blocks of Plexiglas for filling the cells ¾ One bag containing steel balls, 300 g. in weight ¾ 4 pads to secure the vibration plate ¾ Tools set.
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dependence of vibratory state from excitation natural frequency of a dynamic system resonance and its macroscopic effects multi-grade liberty dynamic system relationship of natural frequency to vibrating mass relationship of natural flexural frequency to strip width relationship of natural flexural frequency to strip width relationship of natural flexural frequency to the strip thickness rigidity measurement of a strip and checkout through calculation two-grade liberty dynamic system on different planes relationship of existing magnitude to vibrating effect relationship of receptance to mass and rigidity torsional vibration of a dynamic system with one-grade of liberty relationship of natural torsional frequency to free end length of strip relationship of natural torsional frequency to strip width relationship of natural torsional frequency to strip thickness dynamic system with torsional frequency lower than flexural frequency research of flexural rotation frequency of mass around the axis "Y" composite flexural and torsional vibrating form vibration in 2nd harmonics free vibration efficient liquid mass continuous system discrete fundamental system
EXPERIMENTAL PERFORMANCE With this vibrating Test Unit equipped with basic accessories it is possible to obtain widely diversified simple or complicate structure further to reveal vibration phenomena that can be perceptible by macrometric inspection without a need of costly equipment which, among other things, would not allow the direct visualization of the vibratory phenomena. The instruction book shows about thirty different tests which however represent only a modest portion of what the teacher's fancy will be able to devise. These tests can be summarized as follows:
When complementary specializing courses are envisaged for increasing the technical level of the student's capacity, it has been foreseen, as optional, with the test stand additional instrumentation of professional type such as stroboscopes and electronic accelerometer with PC based data acquisition system with oscilloscopic function for the graphic detection of the frequency and amplitude of the generated vibration on the different structures under test.
I - 16153 P.D. da Bissone 36r. GENOA - ITALY - Tel.: +39 010 6501969 Fax: +39 010 6501969 e-mail: patrone@ giacomopatrone.com http://www.giacomopatrone.com
PV 1
VIBRATION TEST For an illustrative consideration we can describe briefly here below some significant tests which put into reciprocal relationship some fundamental parameters pursuant vibration phenomenology. -
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In the first test, for instance, we outline the dependence of the vibratory state from the excitation. The force exciter (variably working eccentric means with stepwise operation) moves the support plate using a vibratory frequency that can be varied through a suitable control. A container is mounted on a support plate, which vibrates with an amplitude that is proportional to the preset eccentricity this container simulates the simpler consisting of a mass attached to a spring. In the third test, the tensile bar supporting the mass in broken near the notch, owing to resonance effects. In the fourth test, instead, use is made of two containers that are attached to two strips situated on orthogonal planes. It is thus possible to observe how the I째 frequency of resonance is characterized by a knot and the II째 frequency by 2 knots. In the fifth test we see the relationship intercurring between the natural frequency and the mass which follows a law of type f2M = Cost. Conclusively, by the use of the educational Vibration Test Unit PV1 it is possible to execute experimentations on all the laws pursuant the vibration phenomenology and all relation-ship intercurring among the parameters that are occasionally used. This represents a valid help for the student to approach for the first time the world of vibrations as well as for the research too, who is therefore enabled to verify and make deeper his knowledge on applied theoretical laws.
I - 16153 P.D. da Bissone 36r. GENOA - ITALY - Tel.: +39 010 6501969 Fax: +39 010 6501969 e-mail: patrone@ giacomopatrone.com http://www.giacomopatrone.com