Vol. 4 N.4 - Journal of Aerospace Technology and Management

Page 1

AND MA ANAGE N AG E M E N T Vol.4 N.4 Oct./Dec.2012 ISSN 1984-9648 ISSN 2175-9146 (online)

General Information JOU51A/ O) AE5OS3ACE TEC+1O/O*< A1D MA1A*EME1T (JATM) is a techno scienti¿c puElication seriali]ed, puElished Ey Departamento de Cirncia e Tecnologia Aeroespacial (DCTA) and aims to serYe the international aerospace community. ,t contains articles that haYe Eeen selected Ey an Editorial Committee composed of researchers and technologists from the scienti¿c community. The Mournal is Tuarterly puElished, and its main oEMectiYe is to proYide an archiYal form of presenting scienti¿c and technological research results related to the aerospace ¿eld, as Zell as promote an additional source of diffusion and interaction, proYiding puElic access to all of its contents, folloZing the principle of maNing free access to research and generate a greater gloEal e[change of NnoZledge. JATM is added/inde[ed in the folloZing dataEases SCO3US ElseYier CAS Chemical AEstracts SerYice DOAJ Directory of Open Access Journals J *ATE The e Mournal gateZay from gloEal literature /,V5E 3ortal to )ree Access Journals *OO*/E SC+O/A5 SUMÈ5,OS.O5* Summaries of %ra]ilian Journals EZ% Electronic Journals /iErary U/5,C+S:E% Ulrich s 3eriodicals Directory SOCO/#5 China Educational 3uElications /AT,1DE; 5egional CooperatiYe Online ,nformation System for Scholarly Journals from /atin America, the CariEEean, Spain and 3ortugal and 3E5,ÏD,COS CA3ES. ,n :E% QUA/,S System, JATM is classi¿ed as %4 in the *eosciences and Engineering ,,, areas. JATM is af¿liated to A%EC %ra]ilian Association of Scienti¿c Editors and all puElished articles contain DO, numEers attriEuted Ey C5OSS5E).

JATM is supported by:

Journal of Aerospace Technology and Management Vol. 4, n.4 (Oct./Dec. 2012) – São José dos Campos: Zeppelini Editorial, 2012 Quartely issued

1. Aerospace sciences 2. Technologies 3. Aerospace engineering

CDU: 629.73

Journal of Aerospace Technology and Management J. Aerosp. Technol. Manag. Vol.4, No 4, Oct.-Dec., 2012

EDITORIAL COMMITTEE EDITOR IN CHIEF Ana Cristina Avelar – IAE – São José dos Campos/SP – Brazil editor@jatm.com.br

EXECUTIVE EDITOR Ana Marlene F. Morais – IAE – São José dos Campos/SP – Brazil secretary@jatm.com.br

SCIENTIFIC COUNCIL Angelo Passaro – IEAv – São José dos Campos/SP– Brazil Antonio Pascoal Del'Arco Jr. – IAE – São José dos Campos/SP– Brazil Carlos Antônio M. Kasemodel – IAE – São José dos Campos/SP– Brazil Carlos de Moura Neto – ITA – São José dos Campos/SP– Brazil Eduardo Morgado Belo – EESC/USP – São Carlos/SP – Brazil Francisco Carlos M. Pantoja – DIRENG - Rio de Janeiro/RJ– Brazil Francisco Cristovão L. Melo – IAE – São José dos Campos/SP– Brazil João Marcos T. Romano – UNICAMP – Campinas/SP – Brazil Marco A. Sala Minucci – VALE Soluções em Energia – São José dos Campos/SP – Brazil Mischel Carmen N. Belderrain – ITA – São José dos Campos – Brazil Paulo Tadeu de Melo Lourenção – EMBRAER– São José dos Campos/SP– Brazil Rita de Cássia L. Dutra – IAE – São José dos Campos/SP– Brazil

ASSOCIATE EDITORS Acir Mércio Loredo Souza – UFRGS – Porto Alegre/RS – Brazil Adam S. Cumming – DSTL – Salisbury/Wiltshire–England Adiel Teixeira de Almeida – UFPE – Recife/PE – Brazil Alain Azoulay – SUPELEC– Gif–Sur–Yvette – France Alexandre Queiroz Bracarense – UFMG – Belo Horizonte/MG – Brazil Altamiro Susin – UFRGS – Porto Alegre/RS – Brazil Álvaro Damião – IEAv– São José dos Campos/SP– Brazil André Fenili – UFABC – Santo André/SP – Brazil Antonio F. Bertachini – INPE – São José dos Campos/SP–Brazil Antonio Henriques de Araújo Jr – UniFOA – Volta Redonda/RJ – Brazil Antonio Sergio Bezerra Sombra – UFC – Fortaleza/CE – Brazil Bert Pluymers – KU – Leuven – Belgium Carlos Henrique Marchi – UFPR – Curitiba/PR – Brazil Carlos Henrique Netto Lahoz – IAE – São José dos Campos/SP – Brazil Cosme Roberto Moreira da Silva – UnB – Brasília/DF – Brazil Cynthia Junqueira – IAE – São José dos Campos/SP– Brazil Daniel Alazard – ISAE – Toulouse – France David Murray–Smith – University of Glasgow – Glasgow – Scotland Edson Aparecido de A. Querido Oliveira – UNITAU – Taubaté/SP – Brazil

401

Edson Cocchieri Botelho – FEG/UNESP – Guaratinguetá/SP – Brazil Elizabeth da Costa Mattos – IAE – São José dos Campos/SP– Brazil Fabiano Fruett – UNICAMP – Campinas/SP – Brazil Fabrice Burel – INSA – Lion – France Flamínio Levy Neto – UnB – Brasília/DF – Brazil Francisco José de Souza – UFU – Uberlândia/MG – Brazil Gilberto Fisch – IAE – São José dos Campos/SP– Brazil Gilson da Silva – INPI – Rio de Janeiro/RJ – Brazil Hugo H. Figueroa – UNICAMP – Campinas/SP – Brazil João Luiz F. Azevedo – IAE – São José dos Campos/SP – Brazil José Alberto Cuminato – ICMC/USP – São Carlos/SP– Brazil José Atílio Fritz F. Rocco – ITA – São José dos Campos/SP – Brazil José Leandro Andrade Campos – UC – Coimbra – Portugal José Rubens G. Carneiro – PUC Minas – Belo Horizonte – Brazil José Márcio Machado – IBILCE/UNESP – São José do Rio Preto/SP – Brazil José Maria Fonte Ferreira – UA – Aveiro – Portugal José Pissolato Filho – UNICAMP – Campinas/SP – Brazil José Roberto de França Arruda – UNICAMP – Campinas/SP – Brazil Luís Carlos de Castro Santos – EMBRAER– São José dos Campos/SP– Brazil Luiz Claudio Pardini – IAE – São José dos Campos/SP– Brazil Marcello Faraco de Medeiros – EESC/USP – São Carlos/SP – Brazil Márcia B. H. Mantelli – UFSC– Florianópolis/SC – B Brazil Marc Lesturgie – ONERA– Palaiseau–France Marcos Pinotti Barbosa – UFMG– Belo Horizonte/MG – Brazil Michael Gaster – Queen Mary University of London – London – England Michele Leali Costa – FEG/UNESP – Guaratinguetá/SP – Brazil Mirabel Cerqueira Rezende – IAE – São José dos Campos/SP– Brazil Othon Cabo Winter – FEG/UNESP – Guaratinguetá/SP – Brazil Paulo Celso Greco – EESC/USP – São Carlos/SP – Brazil Paulo Sérgio Varoto – EESC/USP – São Carlos/SP – Brazil Raimundo Freire –UFCG– Campina Grande/PB–Brazil Renato Machado Cotta – UFRJ – Rio de Janeiro/RJ – Brasil Roberto Costa Lima – IPqM – Rio de Janeiro/RJ – Brazil Romis R. F. Attux – UNICAMP – Campinas/SP– Brasil Samuel Machado Leal da Silva – CTEx – Rio de Janeiro /RJ– Brazil Sandro Haddad – UnB– Brasília/DF–Brazil Selma Shin Shimizu Melnikoff – EP/USP – São Paulo/SP – Brazil Sérgio Frascino M. Almeida – ITA – São José dos Campos/SP – Brazil Ulrich Teipel – Georg Simon OHM – Nürnberg – Germany Valder Steffen Junior – UFU – Uberlândia/MG – Brazil 9DVVLOLV 7KHR¿OLV ± 830 ± 0DGULG± 6SDLQ Waldemar de Castro Leite Filho – IAE – São José dos Campos/SP – Brazil Willian Roberto Wolf – IAE– São José dos Campos/SP – Brazil Wim P. C. de Klerk – TNO – Rijswijk/SH – The Netherlands

EDITORIAL PRODUCTION Glauco da Silva – IAE – São José dos Campos/SP– Brazil Helena Prado A.Silva – IAE – São José dos Campos/SP– Brazil Janaina Pardi Moreira – IAE – São José dos Campos/SP– Brazil Lucia Helena de Oliveira – DCTA – São José dos Campos/SP– Brazil Mônica E. Rocha de Oliveira – INPE – São José dos Campos/SP–Brazil

402

ISSN 1948 - 9648 ISSN 2175 - 9146 (online)

Vol.04, N°4, Oct. – Dec. 2012

CONTENTS 405

EDITORIAL Access to Space in Brazil – Current and future scenarios Carlos Antônio Magalhães Kasemodel

407

REVIEW ARTICLE Hypergolic Systems - A Review in Patents Gilson da Silva, Koshun Iha

413

ORIGINAL PAPERS Generation of an Atomic Beam by Using Laser Ablation for Isotope Separation Purposes Juliana Barranco de Matos, Márcio de Lima Oliveira, Emmanuela Melo de Andrade Sternberg, Marcelo Geraldo Destro, Rudimar Riva, Nicolau André Silveira Rodrigues

4 1

Occurrence of Defects in Laser Beam Welded Al-Cu-Li SKeets witK T--oint Con¿guration André Luiz de Carvalho Higashi, Milton Sérgio Fernandes de Lima

431

Multidisciplinary Design Optimization of Sounding Rocket Fins Shape Using a Tool Called MDO-SONDA Alexandre Nogueira Barbosa, Lamartine Nogueira Frutuoso Guimarães

443

Studies on InÀuence of Testing Parameters on Dynamic and Transient Properties of Composite Solid Rocket Propellants Using Dynamic Mechanical Analyzer Vilas Wani, Mehilal, Sunil Jain, Praveen Prakash Singh, Bikash Bhattacharya

453

Kinematic Analysis of the Deployable Truss Structures for Space Applications Xu Yan, Guan Fu-ling, Zheng Yao, Zhao Mengliang

403

463

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying of the Wind Pattern at Centro de Lançamento de Alcântara Ana Cristina Avelar, Fabrício Lamosa Carneiro Brasileiro, Adolfo Gomes Marto, Edson R. Marciotto, Gilberto Fisch, Amanda Fellipe Faria

475

Propeller Induced Effects on the Aerodynamics of a Small Unmanned-Aerial-Vehicle Adnan Maqsood, Foong Herng Huei, Tiauw Hiong Go

481

Effect of Dielectric Barrier Discharge on the AirÀow Around a Cylinder Ashraf El Droubi, Dawson Tadeu Izola

489

Electronic Simulator of the PLATO Satellite Imaging System Rafael Corsi Ferrão, Sergio Ribeiro Augusto, Tiago Sanches da Silva, Vanderlei Cunha Parro

495

THESIS ABSTRACTS A Comprehensive Investigation of Retrodirective Cross-Eye Jamming Warren Paul du Plessis

495

Ant Colony Optimization Applied to Laminated Composite Materials Rubem Matimoto Koide

496

Classifying Low Probability of Intercept Radar Using Fuzzy ARTMAP Pieter Frederick Potgieter

497

AD HOC REFEREES

499

INSTRUCTIONS TO AUTHORS

404

Editorial Access to Space in Brazil – Current and future scenarios Brig. Eng. Carlos AntĂ´nio M. Kasemodel* Director of Instituto de AeronĂĄutica e Espaço diretor@iae.cta.br

The search for autonomy to access to space has always been the objective of the Brazilian Space Program. At the end of the 1970s, the Complete Brazilian Space Mission – MECB established the goal to develop a national satellite to be launched, by a launch vehicle designed and manufactured in the country, from a launch site located in Brazil. In order to master the critical technologies to build this launch vehicle, sounding rockets of a family named SONDA were developed. With these, technologies were acquired to produce solid propellants, thermal protections, stage separation systems, motor structures made of highly resistant steel, structures of composite materials, attitude control systems, pyrotechnic devices, on-board electronics systems, as well as the associated ground support equipment. Even though MECB goal has not been completely achieved as initially planned, due to misalignments in the stage of development on its three segments (while the Launch Center was created in 1987, the satellite was concluded in 1992, the ÂżUVW WHVW RI WKH ODXQFK YHKLFOH 9/6 RQO\ RFFXUUHG LQ LWV HVWDEOLVKPHQW ZDV HVVHQWLDO IRU PDQ\ DGYDQFHV DQG IRU WKH consolidation of the development of space technology in the country. &RQFHUQLQJ WKH VXERUELWDO YHKLFOHV LQ UHSODFHPHQW RI WKH 621'$ IDPLO\ ZKLFK ZDV GHDFWLYDWHG WKH URFNHWV 96 96% DQG 96 ZHUH GHYHORSHG DQG QRZDGD\V WKH\ DUH LQWHUQDWLRQDOO\ DFNQRZOHGJHG IRU WKHLU SHUIRUPDQFH DQG UHOLDELOLW\ 96% LV ZLGHO\ XVHG LQ WKH (XURSHDQ 0LFURJUDYLW\ 3URJUDP DQG WKH 96 ZDV HPSOR\HG E\ WKH *HUPDQ 6SDFH $JHQF\ IRU WKH H[SHULPHQWDO Ă€LJKW 6+()(; &RQFHUQLQJ WKH RUELWDO ODXQFKHUV DIWHU WKH DFFLGHQW ZLWK WKH WKLUG SURWRW\SH RI 9/6 LQ WKH SURMHFW ZDV IXOO\ reviewed, resulting in the re-design of electrical and pyrotechnic networks, besides many minor changes in other systems, as well as the conducting of new ground tests. Nowadays, the construction of three other prototypes is predicted for the conclusion RI WKH SURMHFW WKH ÂżUVW RQH DLPV WKH TXDOLÂżFDWLRQ RI WKH ORZHU SDUW RI WKH YHKLFOH ÂżUVW DQG VHFRQG VWDJHV DQG WKH Ă€LJKW WHVW RI D national inertial navigation system; the second one concerns the complete test of the vehicle with a technological payload; and the third one aims to launch a national satellite into orbit. In 2005, in order to establish long term goals to develop launchers in the country, the Cruzeiro do Sul Program was proposed, FRQVLVWLQJ RI D IDPLO\ RI ÂżYH ODXQFKHUV ZLWK LQFUHDVLQJ VDWHOOLWH ODXQFKLQJ VNLOOV WKH ODVW YHKLFOH DEOH WR LQMHFW D IRXU WRQ VDWHOOLWH into geostationary transfer orbit. +RZHYHU FKDQJHV LQ WKH FXUUHQW VFHQDULR ZKLFK LQFOXGHV ORZHU ÂżQDQFLDO LQYHVWPHQWV ODFN RI VSHFLDOL]HG KXPDQ UHVRXUFHV low national demand for geostationary orbit satellites and the existence of a binational company, Alcântara Cyclone Space, with WKH 8NUDQLDQ URFNHW &\FORQH OHG WR D UHYLVLRQ RI WKH &UX]HLUR GR 6XO SURJUDP 7KH FXUUHQW SURSRVDO SODQV QRW RQO\ WKH FRQFOXVLRQ RI WKH 9/6 SURMHFW DV DIRUHPHQWLRQHG EXW DOVR WKH GHYHORSPHQW RI D PLFURVDWHOOLWH ODXQFK YHKLFOH Âą 9/0 DQG WKH GHYHORSPHQW RI WKH WZR ÂżUVW YHKLFOHV RI WKH Cruzeiro do Sul program, the 9/6 $OID DQG WKH 9/6 %HWD *UDGXDWHG LQ 0HFKDQLFDO DQG $HURQDXWLFDO (QJLQHHULQJ E\ WKH 7HFKQRORJLFDO ,QVWLWXWH RI $HURQDXWLFV Âą ,7$ 0DVWHU RI 6FLHQFH LQ Applied Physics by the Naval Postgraduate School, in the United States, in 1999. Master of Business Administration in Advanced Development of Executives – department of Institutional Strategic Management, by Universidade Federal Fluminense, in 2007, and postgraduation in Air $UP (QJLQHHULQJ Âą ,7$ $PRQJ WKH PDLQ SRVLWLRQV +H ZDV WKH LQVWUXFWRU RI WKH $LU $UP (QJLQHHULQJ FRXUVH +HDG RI WKH WHVWLQJ DQG LQWHJUDWLRQ GLYLVLRQ +HDG RI WKH VSDFH YHKLFOH PDQDJHPHQW +HDG RI WKH 9/6 SURMHFW 9LFH 'LUHFWRU RI 6SDFH +HDG RI WKH SURMHFW GLYLVLRQ LQ WKH WHFKQLFDO VXE GHSDUWPHQW RI '&7$ 9LFH 'LUHFWRU RI ,$( DQG +HDG RI WKH 6XE 'HSDUWPHQW RI $GPLQLVWUDWLRQ RI '&7$ +H LV FXUUHQWO\ WKH 'LUHFWRU RI WKH ,QVWLWXWH RI $HURQDXWLFV DQG 6SDFH ,$(

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 405-406, Oct.-Dec., 2012

405

7KH GHYHORSPHQW RI 9/0 VWDUWHG LQ DQG WKH ÂżUVW Ă€LJKW LV VFKHGXOHG IRU ,WV LQLWLDO YHUVLRQ ZLOO EH D WKUHH VWDJH vehicle, and all of them will use solid propellant and motor cases in composite material. 7KH $OID ODXQFKHU ZLOO FRQVLVW RI WKH ORZHU SDUW RI WKH 9/6 DV WKH ÂżUVW IRXU 6 ERRVWHUV DQG VHFRQG VWDJH RQH 6 DQG RI D OLTXLG URFNHW HQJLQH RI W RI WKUXVW / DV XSSHU VWDJH 7KH SHUIRUPDQFH RI WKH YHKLFOH KLJKHU WKDQ 9/6 ZLOO HQDEOH WKH LQMHFWLRQ RI NJ VDWHOOLWHV LQ NP HTXDWRULDO RUELWV NJ LQ NP HTXDWRULDO RUELWV RU NJ LQ SRODU RUELW 2Q WKH RWKHU KDQG WKH 9/6 %HWD VKRXOG EH DEOH WR DWWHQG WKH PLVVLRQV RI NJ WR DQ NP HTXDWRULDO RUELW 7KH %HWD YHKLFOH ZLOO XVH D W VROLG URFNHW PRWRU 3 DV ÂżUVW VWDJH D OLTXLG URFNHW HQJLQH RI W RI WKUXVW / DV VHFRQG VWDJH DQG D OLTXLG URFNHW HQJLQH RI W / DV WKLUG VWDJH Studies show that with the initiatives proposed in this review, 75% of the national needs concerning satellite launches will be met, and also the knowledge of critical technologies to access space will be ensured, including the development of larger vehicles, in case of future needs. As established by the National Program of Space Activities – PNAE and by the National Defense Strategy – END, considering that Brazil is a country of large dimensions, with extensive land and sea borders, it cannot give up the knowledge of space technology and the autonomous capability to access space. Also, according to the last document, “Whoever does not master critical technologies is neither independent for defense nor for developmentâ€?.

406

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 405-406, Oct.-Dec., 2012

doi: 10.5028/jatm.2012.04043812

Hypergolic Systems: A Review in Patents Gilson da Silva1*, Koshun Iha2 Instituto Nacional da Propriedade Industrial – Rio de Janeiro/RJ – Brazil Instituto Tecnológico de Aeronåutica – São JosÊ dos Campos/SP – Brazil

1 2

Abstract: Hypergolic reactions may be useful in civil and military applications. In the area of rocket propulsion, they constitute a potential Âżeld due to the reduced Zeight and comple[ity of fuel inMection systems, alloZing yet controlled use of the propulsors. This manuscript aimed at presenting different hypergolic systems and their particularities, comparing them Zith chemical propulsion systems, Zhich are most commonly employed in rocket motors, for e[ample. Keywords: Hypergolic, 3ropellant, 0onomethylhydra]ine, Hydro[yethylhydra]ine, /iTuid hydrogen, /iTuid o[ygen.

LIST OF SYMBOLS DETA EDA TNT HMX RDX DNAZ TMEDA TMPDA TMBDA AU LH LOX MON GLP MMH HGF HEH HEHN FTIR NTO

Diethylenetriamine Ethylenediamine 2, 4, 6-trinitrotoluene Octogen Hexogen 2-(N,N-dimethylamino)ethylazide N,N,N’,N’-tetramethyl-ethylene-diamine N,N,N’,N’-tetramethyl-1,3-diaminopropane N,N,N’,N’-tetramethyl-1,4-diaminobutane Astronomical unit (149,597,870,700 km) Liquid hydrogen Liquid oxygen Mixed oxides of nitrogen Gelled liquid propane Monomethylhydrazine Hypergolic green fuel Hydroxyethylhydrazine Hydroxyethylhydrazinium nitrate Fourier transform infrared spectroscopy Nitrogen tetroxide

INTRODUCTION The term ‘hypergolic’ includes igniting spontaneously upon contact with the complementary explosive or energetic substance. Then, hypergolicity is the propriety of self-ignition Received: 05/07/12

Accepted: 30/07/12

*author for correspondence: gilsondasilva@uol.com.br Praça MauĂĄ, 7 – Centro CEP 20.081-240 Rio de Janeiro/RJ – Brazil

within milliseconds after fuel and oxidizer contact (Hawkins et al., 2011). This propriety is very important in propellant systems, because it can substitute the multistage rocket with the separate ignition system, resulting in high combustion HIÂżFLHQF\ DQG ORZ FRVWV 7R H[HPSOLI\ WKHVH V\VWHPV WKH hypergolic reactions can be used to improve ignition of nitroarene explosives, applied in unexploded ordnance, like bombs and mines, to neutralize these explosives, in agreement with the research of Koppes et al. (2010). Koppes et al. (2010) taught a method to chemically neutralize a nitroarene explosive composition comprising in RUGHU WR SURYLGH D QLWURDUHQH K\SHUJRO KDYLQJ ÄŽ ČŚ DPLQH and an accelerant by applying the nitroarene hypergolic to the H[SORVLYH FRPSRVLWLRQ WR LPSURYH LWV LJQLWLRQ 7KH ÄŽ ČŚ DPLQH of the nitroarene hypergolic may include linear polyamines with or without nitrogen or other heteroatom within the structure of the compound, such as diethylenetriamine (DETA), ethylenediamine (EDA), propanediamine, and so on. The accelerant of the nitroarene hypergol may include appropriate hydridoborate salts (M+BH4), hydrazine, alkylated derivatives of hydrazine, or combinations. The nitroarene hypergol provides a decrease in the delay to ignition of 90% or more, in agreement with Koppes et al. (2010), and an increase in heat generation. The nitroarene compounds that can be neutralized with the hypergolic system include nitrotoluenes, nitrobenzenes, nitronaphthalenes, nitrophenoxyalkyl nitrates, and their derivatives. The hypergols are added as pure liquids or as mixtures with other liquid or solid hypergols. In an unusual coupling with TNT, the amines with terminal amine groups (primary amines), i.e., ÄŽ ČŚ GLDPLQRDONDQHV UHDFWHG DW ERWK DPLQH IXQFWLRQDOLWLHV to provide a TNT-amine-TNT bridged product, with amines attaching at the ring carbons of the TNT bearing the methyl

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 407-412, Oct.-Dec., 2012

407

Silva, G., Iha, K.

group. DETA does this by leaving the central amine function unreacted. To the extent that this bridging could be maximized on the surface of TNT, there would be an energy release compressed into the smallest time scale, which is a condition favoring the evolution and conservation of heat, and thus a decrease in delayed ignition. CIVIL APPLICATION OF A HYPERGOLIC SYSTEM $Q LQĂ€DWDEOH UHVWUDLQW V\VWHP DLUEDJ XVLQJ D K\SHUJROLF reaction is taught by Blackburn (2006). In agreement with %ODFNEXUQ WKH JDV JHQHUDWLQJ V\VWHP RU LQĂ€DWRU XVHG LQ many occupant restraint ones tends to be the heaviest and most complex component of the restraint system. Then, Blackburn (2006) systems can simplify the design and manufacturing of DLUEDJ LQĂ€DWRUV The device comprises a cartridge formed from a container, two materials stored in the container; however, the second one LV VHSDUDWHG IURP WKH ÂżUVW PDWHULDO 7KH FRPELQDWLRQ RI WKH materials forms a hypergolic mixture upon contact with each other. Under exposure of the gas generating to an elevated WHPSHUDWXUH D SRUWLRQ RI WKH FRQWDLQHU VHSDUDWLQJ WKH ÂżUVW and second materials is breached, enabling the materials to combine to form the hypergolic mixture. A propellant charge may be used to generate gas, being the decomposition of the propellant initiated by the hypergolic reaction. The propellant can be a composition such as the ammonium nitrate. According to Blackburn (2006), the hypergolic reaction FDQ EH SURGXFHG E\ WKH FRQWDFW RI D ÂżUVW PDWHULDO LQ WKH OLTXLG form, like glycerol or any suitable alcohol such as polyvinyl alcohol, and a second material comprising potassium SHUPDQJDQDWH 7KH ÂżUVW PDWHULDO LQ OLTXLG IRUP LV LPSRUWDQW WR increase the surface interaction between the materials. MILITARY APPLICATION OF A HYPERGOLIC SYSTEM Hypergolic reactions can be used to defense systems according to Thuman et al. (2011). A projectile comprising a reactive charge is used to promote the destruction of an explosivecharged weapon, such as bombs, homemade explosive devices, and air, water or ground craft comprising explosives. An explosive can be made to detonate by the shock effect, which is generated by a splinter when it hits the explosive at high speed or by a pressure wave from an explosive charge (blasting). Then, the systems proposed by Thuman et al. (2011) FRQVLVW LQ D SURMHFWLOH FRQÂżJXUHG WR SHQHWUDWH WKH VXUIDFH RI WKH 408

shell upon impact so that a passage is opened into the explosive of the shell, through which passage the reactive charge is WUDQVIHUUHG WR WKH H[SORVLYH RI WKH VKHOO XQGHU WKH LQÀXHQFH RI the kinetic energy of the projectile. The projectile has a reactive charge disposed in at least one gas-and liquid-tight cavity to react and start a hypergolic reaction with the explosive. The projectile can have the gas- and/or liquid-tight container charged with zinc, zinc stearate, zirconium, magnesium perchlorate, bismuth trioxide, or a liquid, such as pyrrolidine. The gas- and liquid-tight container is constituted by the all-covering metal foil for preventing undesirable reactions with the surrounding atmosphere. When the reactive charge of the projectile is mixed with the weapon explosive, under effect from the kinetic energy of the projectile penetration, a reaction with the explosive occurs. Gas that is formed in the course of the burning generates an overpressure inside the weapon unit, which leads to splitting and destruction of the weapon unit. A suitable composition, being 99% by weight zinc and 1% by weight zinc stearate, is used, like a termed hypergolic composition, which, upon contact with the explosive weapon, spontaneously reacts. PROPELLANTS Useful propellant compositions were taught by Fawls et al. (2005), who described the effect of the oxygen in the metal passivation in the compositions of explosives and propellants. During the combustion process, the metal ingredients have an oxide shell formed in the surface that inhibits the oxidation of the metal, thereby reducing the overall available energy and forming a totally oxidized metal. 7R LPSURYH WKH HI¿FLHQF\ RI WKH FRPSRVLWLRQV )DZOV et al. (2005) taught how to increase the metal surface area, by means of the nanosized metallic particles, in combination with a halogenic oxidizer, to enhance the combustion of the metal by means of preventing the chemically-inhibiting FRDWLQJ IRUPDWLRQ LQ WKH PHWDO VXUIDFH 7KH ÀXRURFKHPLFDO species is pyrolytically or chemically degraded in the combustion or explosive zones, releasing halogens in the V\VWHP 7KH ÀXRURFKHPLFDO FRPSRXQGV DWRPV IRUP D PHWDOOLF ÀXRULGH LQ WKH VXUIDFH EXW WKH\ GR QRW LQKLELW WKH IXUWKHU R[LGDWLRQ WR WKH ¿QDO GHVLUHG SURGXFW PHWDOOLF R[LGH increasing the overall energy released. In general, the conventional metal nanoparticles can EH ERURQ DOXPLQXP RU FDUERQ LQ SURSHOODQWV DQG WKH ÀXRU FRPSRXQG FDQ EH D ÀXRURRUJDQR FKHPLFDO FRPSRXQG RU ÀXRURSRO\PHU OLNH PLFUREHDGV QDQRSDUWLFOHV SRZGHU RU

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 407-412, Oct.-Dec., 2012

Hypergolic Systems: A Review in Patents

RWKHU ODUJHU VL]HG ÀXRURDGGLWLYH VXFK DV 7HÀRQŽ, VitonŽ, or VRPH RWKHU KDORJHQDWHG ÀXRURSRO\PHU DGGLWLYH $GGLWLRQDOO\ energetic ingredients may be added to the fuel or hybrid grain to improve the energy output of these propellants, such as HMX, RDX, or other energetic ingredients. Liquid rocket propellant systems produce thrust by means of expulsion of high velocity exhaust gases made by the reaction between a fuel and an oxidizer. Non hypergolic systems are useful, but they need complex ignition systems with igniters and/ or catalyst beds, which are expensive, introduce extra weight to the thrust, and increase the risk of failure (Natan et al., 2011). HYPERGOLIC PROPELLANTS The conventional hypergolic system is composed of hydrazine as the fuel component, being very toxic. Hawkins et al. (2011) taught a bipropellant fuel based upon salts containing the dicyanamide anion, employing nitrogen-containing, heterocyclic-based cations such as the imidazolium cation. While salt molecules contain highly energetic (formation of enthalpy), high nitrogen anions, the dicyanamide-based molecule solely displays fast ignition. The fuel proposed by Hawkins et al. (2011) is stored in a propulsion system fuel tank and the oxidizer in a separate one. The ignition happens just after the contact of the fuel and oxidizer sprayed into a chamber in a rocket. The ionic liquid fuel can provide greater than 40% improvement in density over hydrazine fuels. Watkins (2004) suggested a hypergolic fuel system comprising hydrogen peroxide, silane, and liquid fuel. In agreement with Watkins, in order that hydrogen peroxide is used as a propellant in rocket engines, a decomposition catalyst is required, which accelerates the decomposition of the hydrogen peroxide, however this technology is expensive. Therefore, a system where the hydrogen peroxide (H2O2) and silane (SiH4) are contacted to improve the decomposition of the peroxide, forming a gas that is contacted with a liquid fuel, igniting the liquid fuel (such as kerosene), was proposed. To thrust a rocket engine, the hydrogen peroxide is contacted with the silane in the combustion zone, at room temperature, to provide effective ignition. Upon ignition, a liquid fuel is fed to the combustion zone and combusted therein to provide thrust, since exhaust gases exit combustion zone of the rocket chamber through the exhaust outlet port. A hypergolic fuel propulsion system containing a fuel composition (azide compound) and an oxidizer composition (hydrogen peroxide) is showed by Hallit and Bauerle (2004).

The azide compound in the fuel has at least one tertiary nitrogen and one azide functional group in combination with a catalyst, which has at least one transition metal compound (preferably, cobalt and manganese). An azide functional group is represented by -N3. Upon oxidation after contact with the oxidizer composition, the azide compound loses nitrogen and reacts to produce the energy needed to provide thrust. The catalyst is added to the azide compound to produce a transition metal level in the fuel composition of about 0.2% or greater. The fuel composition and the oxidizer composition are brought into contact in stoichiometric ratios, which lead to the desired ignition. In general, with hypergolic fuels in rocket motor or missile engines, the oxidizer to fuel ratio may vary over a relatively wide range, depending on the performance desired, propellant tank pressures, and other operating parameters. In such bipropellant mixtures, the fuel and oxidizer are unstable when mixed together, and they are generally stored separately. Bipropellant rocket motor propulsion systems consist of oxidizer and fuel propellant tanks, pressurizing system, plumbing, valves, and engine. Currently known hypergolic, bipropellant rocket propulsion systems have a number of drawbacks. For example, one system consists of monomethylhydrazine (MMH) and red fuming nitric acid. Stevenson et al. (2011) proposed a fuel mixture to use as hypergolic liquid or gel fuel in bipropellant propulsion systems, with the chemical compounds preferably having similar ignition characteristics as monomethyl hydrazine, and not EHLQJ WR[LF RU FODVVL¿HG DV D VXVSHFWHG KXPDQ FDUFLQRJHQ )XHO combinations consist of one or more of a family of hypergolic DPLQH D]LGHV RU K\SHUJROLF LPLGLF DPLGH FRPSRXQGV ¿UVW compound), mixed with one or more hypergolic tertiary diamine compounds (second compound). The hypergolic amine azides have the general structure (R1)(R2)(R3)N, in which R1, R2, an R3 can be an hydrogen and an aliphatic alkene, alkyne, or cycloalkyl group, without hetero-atoms or heterocyclic atoms, but where at least one of the R groups have an azide. Examples of hypergolic amine azides are the 2-(N, N-dimethylamino) ethylazide (DNAZ), 2-(N-cyclo-propylamino)ethylazide, bis(2-azidoethyl)methylamine, and so on. The tertiary diamines have the general formula R4R5N-R6NR7R8, where R4, R5, R7 e R8 are aliphatic groups and R6 may be aliphatic, alkene, or alkyne groups. Examples of hypergolic diamines include the N,N,N’,N’-tetramethyl-ethylene-diamine (TMEDA), N,N,N’,N’-tetramethyl-1,3-diaminopropane (TMPDA), N,N,N’,N’-tetramethyl-1,4-diaminobutane (TMBDA), etc.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 407-412, Oct.-Dec., 2012

409

Silva, G., Iha, K.

)RU RSWLPDO PRWRU VSHFLÂżF DQG GHQVLW\ VSHFLÂżF LPSXOVH values, it is generally desirable to incorporate into the fuel the maximum percentage of amine azide compound, which will still allow an acceptably low ignition delay of about 3 milliseconds to about 15 milliseconds. For example, a fuel containing about 33.3% DMAZ and about 66.7% TMEDA has an ignition delay of about 9.0 milliseconds. DiSalvo (2012) described problems to prepare a low-storage temperature bipropellant for missions far from the sun greater than 3 AU, because the portion of the power budged consumed by heaters to prevent propellant freezing increases VLJQLÂżFDQWO\ 7KHQ IXHOV DQG R[LGL]HUV KDYLQJ ORZ IUHH]LQJ points such as liquid hydrogen (LH) and liquid oxygen (LOX) are not suitable for using on planetary probes, because they require cryogenic storage vessels capable of containing them within several AU of the sun. In agreement with such author, propane is a potential low-temperature propellant, because LW LV UHDGLO\ OLTXHÂżHG E\ FRPSUHVVLRQ DQG FRROLQJ PHOWV DW -189.9 ÂşC, and boils at -42.2 ÂşC. However, mixed oxides of nitrogen (MON) have freezing points not low enough to be ideal on deep space missions. Then, DiSalvo (2012) taught a method for preparing a bipropellant system comprising gelled liquid propane (GLP) fuel, which is well-suited for outer planet missions with additives, such as powders of boron, carbon, lithium and/or aluminum added to the fuel to improve its performance and enhance hypergolicity. The gelling agent can be silicon dioxide, clay, carbon, organic or inorganic polymers. The oxidizer for the low-temperature propellant combination is MON-30 (70%N2O4+30%NO), produced by an exothermic reaction (6000 kcal/kg) between nitric oxide and dinitrogen tetroxide/nitrogen dioxide. The reaction should be done in vacuum system with the tank into the ice water bath to maintain the temperature of the reactants at 0 ÂşC. The MON-30 can be gelled at around -25 ÂşC with 3% of fumed silica by weight, using a plate churn mixer and its freezing point is of -81 ÂşC. Propane can be gelled using a plate churn mixer placed LQVLGH DQ LQVXODWHG SRO\HWK\OHQH GUXP ÂżOOHG ZLWK D ZDWHU ethylene glycol mixture cooled at -55 ÂşC. A total of 20g of fumed silica is introduced into the mixing vessel, which is attached to a vacuum pump and cooled in dry ice. 500 grams of liquid propane is introduced into the mixing vessel. For the churning phase, the system is submerged in a 70/30-ethylene glycol/water bath and cooled to -55 ÂşC. The gelled propane has a freezing point of -189.9 ÂşC.

410

GREEN PROPELLANTS Natan et al. (2011) showed a composition comprising a gelled fuel in which catalyst or reactive particles are suspended. The particles can ignite hypergolically with an oxidizer. The fuel and the oxidizer can be chosen from a wide spectrum of materials that are environmentally friendly (green propellants), without the need of carrying a complex ignition system. The catalyst or reactive particles can react spontaneously with an oxidizer or can be as catalysts to promote the ignition reaction. The rheological properties of the gelled fuel, e.g., the yield stress and the high viscosity while at rest, assure that no particle sedimentation takes place even at high acceleration levels of the vehicle. The hypergolic composition taught by them comprises at least one fuel in the form of a gel, at least one particulate ignition agent suspended in the fuel, and one oxidizer. The ignition agent is selected from the group consisting of hydrazine, its derivatives and a metal hydride (selected from the group consisting of sodium borohydride, lithium borohydride and potassium borohydride), it can comprise a hypergolic catalyst too, like an alkyl-substituted amine and metal salt (selected from the group consisting of an alkylsubstituted diamine and triamine and metal salt of an aliphatic carboxylic acid – such as acetate, propionate, and butyrate). The fuel is chosen from the group consisting of hydrocarbons, alcohols, amines, amides, metal-organic liquid compounds, alkaloids, and liquid hydrogen, with a gelling agent (nano-silica fumed powder, aluminum stearate and gelling polymers), and an oxidizer (hydrogen peroxide, liquid oxygen, nitrous oxide, nitrous acid, nitric acid, perchloric acid, FHULXP FRPSRXQGV FKORULWHV EURPLWHV ÀXRULWHV FKORUDWHV EURPDWHV ÀXRUDWHV DQG K\SHUFKORULWHV The method for preparing a hypergolic composition for rocket propellant comprises adding a gelling agent to the liquid fuel and suspending a particulate ignition agent in this fuel, upon contact with an oxidizer, the ignition agent initiates the reaction between the fuel and the oxidizer. MMH is a widely employed fuel in hypergolic and bipropellant systems. It has desirable propellant properties, but it is highly toxic, carcinogenic, and corrosive. A rocket fuel composition comprising one or more tertiary amine azides is taught by Sengupta (2008). The fuel is hypergolic when combined with a strong oxidizer, such as red fuming nitric acid, hydrogen peroxide, nitrogen tetroxide, or hydroxyl ammonium nitrate.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 407-412, Oct.-Dec., 2012

Hypergolic Systems: A Review in Patents

In agreement with Smith et al. (2010), hypergolic green fuel (HGF) can be produced from 2-hydroxyethylhydrazine (HEH) by means of its nitration, resulting in hydroxyethylhydrazinium nitrate-acetone. At the beginning, the precursor HEH is pumped into a reactor under nitrogen atmosphere, set at 0.5 ºC, and deionized water is slowly added to the reactor under agitation. At 1 ºC and under agitation, nitric acid (HNO3) is slowly added, in order to prevent the temperature increasing above 10 ºC. The pH of the mixture is about 8 to 9 at the beginning and the nitric acid should be slowly added until pH is in the range of 4.8 to 5.0. The produced hydroxyethylhydrazinium nitrate (HEHN) is light yellow and should be transferred into a rotary evaporator, where the water is removed and neutralized until reaches 10% of water. The remaining water is removed by means of sparging the HEHN with nitrogen, then from the rotary evaporator and put into a storage vessel under nitrogen. To produce a hypergolic green fuel, HEHN produced must be mixed with the solvent acetone. Smith et al. (2010) showed a one-step synthesis process to prepare a HGF propellant from HEH. In agreement with them, the process included: providing a solution of acetone in 2-hydroxyethylhydrazine, wherein the solution is about 15 to 50% by volume acetone in HEH; and adding nitric acid containing less than 5% water to the acetone-HEH solution to form the HGF propellant, wherein the molar ratio of nitric acid to HEH is less than about 0.05:1 to 1.4:1. The process HI¿FLHQF\ RI 6PLWK et al. (2010) can be evaluated by means of a comparison between the sample and the reference Fourier transform infrared (FT-IR) spectrum. INJECTORS Bipropellant injection elements are useful in a typical liquid propellant rocket engine to facilitate the injection, distribution, mixing, and combustion of the elements in a combustion chamber. The injector may be composed by a system assembly, spark, to ignite the propellants by creating D VWDQGLQJ ÀDPH RU WRUFK ZKRVH FRPSRVLWLRQ LV GLIIHUHQW from the propellant one. The size and mass are undesirable characteristics to this kind of system assembly, when used in small rocket engines (Fisher, 2009). There are also known spark ignition systems for providing ignition sparks within a reaction zone in the combustion FKDPEHU +RZHYHU VXFK V\VWHPV SUHVHQW GLI¿FXOWLHV LQ fabricating system components and pose problems with component degradation during use. For instance, special

LQMHFWLRQ RULÂżFHV DQG PDQLIROGV DUH UHTXLUHG WR GLUHFW IXHO DQG oxidizer and to create an easily ignited mixture of propellants at the exposed electrodes. Direct spark ignition systems through an injector faceplate can also add weight, increase design complexity, and typically operate at off-optimum mixture ratios (usually at fuel-rich rations) to preclude thermal damage to the electrodes, but which lower overall combustion performance. Brown et al. (2010) taught a fuel manifold for the injector of a hypergolic rocket engine. According to them, hypergolic rocket engines that use the MON-25/MMH ((25% mixed oxides of nitrogen and 75% nitrogen tetroxide)/ (Monomethylhydrazine)) propellant combination may be relatively sensitive to pulsing frequencies imparted form the propellant system. Thus, compact vehicles that provide relatively small packaging envelopes may only further complicate this sensitivity. The rocket engine proposed by Brown et al. (2010) LQFOXGHV D IXHO PDQLIROG GHÂżQHG ZLWKLQ DQ LQMHFWRU ERG\ LW comprises a main fuel chamber that is generally frustroconical LQ VKDSH DQG GHÂżQHG DERXW DQ D[LV $Q R[LGL]HU PDQLIROG LV formed within the injector body, generally along the axis such WKDW WKH PDLQ IXHO FKDPEHU LV GHÂżQHG DURXQG DW OHDVW D VHFWLRQ of oxidizer manifold. The rocket engine includes yet a combustion chamber having an acoustic resonance frequency and a fuel manifold having a resonance frequency, which is at least an order of magnitude lower than the acoustic resonance frequency. An engine generally includes a thrust chamber assembly powered by a propellant system having a fuel and an oxidizer system. The fuel and oxidizer systems provide a fuel and an oxidizer into the thrust chamber assembly. The propellant combination self-ignites within the thrust chamber assembly to provide reliable performance and thrust. MON-25 is highly reactive with MMH and has a tendency to drive unstable combustion processes. It should be understood that other oxidizers, such as nitrogen tetroxide (NTO) and other fuels, may alternatively or additionally be utilized. The combustion chamber is retained adjacent to an injector body through a chamber retention ring. A valve system selectively communicates the propellant combination into the injector body. The oxidizer manifold may be at least partially GHÂżQHG DORQJ WKH WKUXVW D[LV DQG WKH IXHO PDQLIROG PD\ EH DW OHDVW SDUWLDOO\ GHÂżQHG WKHUH DURXQG LQ DQ DQQXODU UHODWLRQVKLS The fuel manifold may be utilized for any bipropellant rocket engine that operates at several thrust levels from, for example, relatively small thrust attitude control thrusters, medium thrust divert engines, or large axial engine rocket engines.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 407-412, Oct.-Dec., 2012

411

Silva, G., Iha, K.

FINAL CONSIDERATIONS The useful common propulsion systems need a complex ignition system, which are expensive and introduce extra weight to the thrust. Solid rocket systems do not allow a controlled actuation of the propulsion and show increased risk of the failure in the ignition step. The liquid propulsion brings security (LH/LOX) and/or healthy (MMH) problems. Then, a hypergolic propellant system seems to be the most secure and controlled system to be developed. On the other hand, considering the interaction between liquid compounds for hypergolic reaction, it is important to give special attention WR WKH FRQÂżJXUDWLRQ RI WKH QR]]OHV LQ RUGHU WR SURPRWH JUHDWHU contact area between the hypergolic system components.

Hallit, R.E.A. and Bauerle, G., 2004, “Hypergolic azide fuels with hydrogen peroxide�, U.S. Patents 2004/0221933 A1. Hawkins, T.W. et al., 2011, “Hypergolic fuels�, U.S. Patents 8,034,202 B1. Koppes, W.M. et al., 2010, “Reagents for hypergolic ignition of nitroarenes�, U.S. Patents 7,648,602 B1. Natan, B. et al., 2011, “Hypergolic ignition system for gelled rocket propellant�, World Intellectual Property Organization, WO2011/001435 A1.

REFERENCES Blackburn, J., 2006, “Gas generating system with autoignition deviceâ€?, World Intellectual Property Organization, WO2006/105412 A2. Brown, W.S. et al., 2010, “Low velocity injector manifold for hypergolic rocket engineâ€?, U.S. Patents 2010/0037590 A1. DiSalvo, R., 2012, “High energy, low temperature gelled bi-propellant formulation preparation methodâ€?, U.S. Patents 2012/0073713 A1. Fawls, C.J. et al., 2005, “Propellants and explosives with Ă€RXUR RUJDQLF DGGLWLYHV WR LPSURYH HQHUJ\ UHOHDVH HIÂżFLHQF\´ U.S. Patents 6,843,868 B1. Fisher, S.C., 2009, “Coaxial ignition assemblyâ€?, U.S. Patents 2009/0320447 A1.

412

Sengupta, D., 2008, “High performance, low toxicity hypergolic fuel�, U.S. Patents 2008/0202655 A1. Smith, J.R. et al., 2010, “Hydroxyethylhydrazinium nitrate-acetone formulations and methods of making hydroxyethylhydrazinium nitrate-acetone formulations�, U.S. Patents 2010/0287824 A1. Stevenson, III H.W. et al., 2011, “Hypergolic liquid or gel fuel mixtures�, U.S. Patents 2011/0272071 A1. Thuman, C. et al., 2011, “Method for combating explosivecharged weapon units, and projectile designed for the same�, World Intellectual Property Organization, WO2011/053211 A1. Watkins, W.B., 2004, “Hypergolic fuel system�, U.S. Patents US2004/0177604 A1.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 407-412, Oct.-Dec., 2012

doi: 10.5028/jatm.2012.04041712

Generation of an Atomic Beam by Using Laser Ablation for Isotope Separation Purposes Juliana Barranco de Matos1, MĂĄrcio de Lima Oliveira1, Emmanuela Melo de Andrade Sternberg1, Marcelo Geraldo Destro2, Rudimar Riva2, Nicolau AndrĂŠ Silveira Rodrigues2* Instituto TecnolĂłgico de AeronĂĄutica – SĂŁo JosĂŠ dos Campos/SP – Brazil Instituto de Estudos Avançados – SĂŁo JosĂŠ dos Campos/SP – Brazil

1 2

Abstract: Atomic vapor laser isotope separation has been studied at the Institute for Advanced Studies for nuclear purposes since 1982, and recently it has been questioned about its potentialities for the aerospace area. Many applications from nuclear propulsion to electricity generation and space navigation have been found, which justify the study of isotope separation for aerospace applications. 2ne of the Ney process, and the Âżrst step for atomic vapor laser isotope separation, is the production of a neutral vapor jet. This paper discussed the potentiality of using laser ablation as a tool to generate neutral metal vapor jet for isotope separation purposes. The basis for the discussion is a set of experimental results obtained at the Institute for Advanced Studies. The experiments were described, the results were analyzed using basic theoretical treatment found in the literature, and it was concluded that laser ablation is a potential tool for the generation of a neutral vapor jet for atomic vapor laser isotope separation purposes. Keywords: Laser ablation, Laser isotope separation, Neutral jet generation.

INTRODUCTION Both stable and radioactive isotopes have many important applications in the aerospace area. Nuclear propulsion, based in very compact and highly enriched 235U demanding nuclear reactors, has been pointed as having great potential for deep space navigation (Bennet, 2006). Electricity generation in spacecrafts that travel far from the sun are in general based on radioisotope thermoelectric generator (Bennet, 2006; Flicker et al., 1964). Inertial sensors (accelerometers and gyrometers) QHHG VSHFLDO ORZ ORVVHV ZDYHJXLGHV DQG ÂżEHUV ZKLFK FDQ be produced by combining different Si isotopes (Kato and Lamont, 1977). Lithium niobate is an optical material broadly used in electro-optics devices and circuits used in inertial optical platforms: lithium niobate with low content of 6Li is shown to be less sensitive to cosmic radiation and to have a longer operational life than the ordinary LiNb (Riley, 1999). Magnetic and magneto-optical sensors responsivity can be improved if isotope contents are considered (Itoh et al., 1999; Kamada et al., 2009). Received: 02/05/12

Accepted: 22/08/12

*author for correspondence: nicolau@ieav.cta.br Trevo Coronel Aviador JosÊ Alberto Albano do Amarante, 1 – Putim CEP 12.228-001 São JosÊ dos Campos/SP – Brazil

Isotopes are separated in many different ways, depending on WKH VSHFL¿F LVRWRSH WKH GHVLUHG DPRXQW WKH SURGXFWLRQ SURFHVV and application. The most used isotope separation methods are those based on centrifuges (Beams and Haynes, 1936; Kholpanov et al., 1997), gas diffusion (Naylor and Backer, 1955), electromagnetic methods (Martynenko, 2009), thermal diffusion (Furry et al., 1939; Rutherford, 1986), aerodynamic method (Becker et al., 1967), ion exchange and chemical separation (Calusaru and Murgulescu, 1976; Kim et al., 2001), plasma centrifuge (Prasad and Krishnan, 1987; Del Bosco et al., 1987), ion cyclotron resonance – ICR (Dolgolenko and Muromkin, 2009; Louvet, 1995), atomic vapor laser isotope separation – AVLIS (Schwab et al., 1998; Paisner, 1988), and molecular LIS – MLIS (Schwab et al., 1998; Jensen et al., 1982). The main differences between two distinct isotopes are mass, nuclear volume and nuclear spin. Most of the isotope separation processes are based on mass difference, however, the methods based on lasers, generally called LIS methods rely on the subtle difference on electromagnetic radiation absorption spectra (Mack and Arroe, 1956). The Institute for Advanced Studies (IEAv) has studied isotope separation, both in MLIS and AVLIS, mainly in uranium enrichment for nuclear fuel production (Schwab et al., 1998).

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

413

Matos, J.B. et al.

The isotope separation based on AVLIS process follows three steps: production of a neutral atomic beam; selective photoionization of the desired isotope, and collection of the photoionized atoms. 7KH ¿UVW VWHS GHSHQGV RQ WKH LVRWRSH WR EH VHSDUDWHG D simple resistive heating can cause evaporation in low-melting temperature materials, whereas, for high melting temperature materials, electron beam heating is generally used (Schiller et al., 1983). However, there are refractory materials for which even electron beams cannot produce the desired vapor. Short-laser pulses can remove a fraction of a target surface, generating a plume made of neutral atoms, ions, clusters, and GURSOHWV RI OLTXL¿HG PDWHULDO $PRUXVR et al., 1999; Capitelli et al., 2004; Noll, 2012). Such process is called laser ablation. Near the target surface, both atoms and ions are in excited states and tend to decay to the ground or metastable state as the plume expands (Kools et al., 1992). As far as the neutral fraction can be separated from the rest of the plume, laser ablation could be used as a neutral jet source for AVLIS. All the references mentioned in the last paragraph deal with the behavior of the plasma in the target vicinity. However, the interest for isotope separation is far from the target surface, where the plume is not collisional anymore and most of the ions and neutral atoms have decayed to the ground or metastable states. This paper presents an experimental study in order to investigate the assumption that laser ablation can be used to prepare a neutral atomic jet for AVLIS purposes. Firstly, laser ablation is discussed in the thermal regime, and the relevant parameters are presented. The experiments are described and the results are analyzed using basic theoretical models found in the literature. It is concluded that, under our experimental conditions, laser ablation is indeed a potential method for neutral jet production for further isotope separation, at least when tiny amounts of material are desired. LASER ABLATION Laser ablation is the general designation for the material removal, from a solid or liquid surface, by short laser pulses. In this paper, only the so-called thermal laser ablation will be considered since it corresponds to the present experimental conditions (Amoruso et al., 1999). If a laser pulse illuminates an area A of a solid target, a fraction aA of the pulse will be absorbed. If the target is metallic or a strong absorber, the laser energy will be absorbed in a very thin layer with the thickness given by the optical penetration length. For instance, 414

for metals illuminated by light in the visible, the optical penetration length is typically much smaller than the radiation wavelength (Born and Wolf, 2002). It is reasonable to suppose that all the laser pulse energy is absorbed in the target surface and transmitted to the target volume through heat conduction. During the pulse duration IJ, the heat penetrates the sample a depth given by the thermal diffusion length (Eq. 1): LD = 4κT ,

(1)

where, ț LV WKH WKHUPDO GLIIXVLRQ FRHI¿FLHQW Usually, in thermal ablation experimental conditions, the diameter of the illuminated area is much larger then LD, DQG WKH KHDW FRQGXFWLRQ FDQ EH WUHDWHG DV D µVHPL LQ¿QLWH solid uniformly illuminated’ problem and the target surface temperature, at the end of the laser pulse, will be as in Eq. 2 (Duley, 1976): T (0) = T0 +

2aA I0 ` lx j1/2 , r K

(2)

where, T0: is the target temperature before the laser pulse, I0: is the laser intensity (power/illuminated area), and K: is the thermal conductivity. The mass mE removed from one single laser pulse can be estimated by using calorimetry and neglecting the solid-liquid phase transformation and the temperature dependence on the VSHFL¿F KHDW cE as in Eq. 3: mE =

aA f p , cE DT + LV

(3)

where, İP: is the pulse energy, ǻT: is the temperature variation from the room until the boiling temperature, and LV: is the vaporization enthalpy. EXPERIMENTS Figure 1 presents the basic experimental setup: the laser beam is focused on the sample surface, forming a 45º angle by D PP IRFDO OHQJWK SRVLWLYH TXDUW] OHQV WKH VDPSOH LV ¿[HG to a computer controlled xy table, and the sensor is placed in the plume path, at different distances from the sample.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

*HQHUDWLRQ RI DQ $WRPLF %HDP E\ 8VLQJ /DVHU $EODWLRQ IRU ,VRWRSH 6HSDUDWLRQ 3XUSRVHV

)LJXUH *HQHUDO H[SHULPHQWDO VHWXS

These experiments were performed in vacuum (~10-5 mbar), and three different sensors were used: a mass spectrometer, a SLH]RHOHFWULF SRO\YLQ\OLGHQH GLĂ€XRULGH 3'9) ÂżOP DQG DQ electrostatic probe. Three different lasers were used with the characteristics given in the Table 1. A set of experiments of emission spectroscopy was accomplished in air. In such cases, a fraction of the light emitted by the plume was collected by a quartz lens, coupled to 500 um FRUH RSWLFDO ÂżEHU GHOLYHUHG WR DQ 2FHDQ 2SWLFV VSHFWURPHWHU model HR4000 and later analyzed. Mass spectrometry In this set of experiments, the measuring device was a Pfeiffer quadrupole mass spectrometer model QMS-300, placed either at 10 or 25 cm from the target, with the ion collector placed orthogonally to the plume pathway. The lasers used in these experiments were the CuHBr and the CVL. Stainless steel, nickel, copper, tungsten, and tantalum targets ZHUH DQDO\]HG LQ WZR GLIIHUHQW PHDVXUHPHQWV WKH ÂżUVW ZLWK WKH Table 1. Laser parameters Parameter

CVL

Wavelength (nm)

CuHBr

1G <$* 355

511/578

Pulse width (ns)

40

35

25

Repetition rate (kHz)

5

16

2

Pulse energy (mJ)*

2.5

1

0.23

Peak power (kW)*

60

29

9.2

12.5

16

0.46

Average power (W)* Illuminated area (cm2) Beam quality – M2 Peak power density (W/cm2)** Fluency (J/cm2)

1.1 Ă— 10-4 1.5 Ă— 10-5 6.3 Ă— 10-6 16.7

6

1.7

5.3 Ă— 108

2.0 Ă— 109

1.5 Ă— 109

22

66

37

* maximum values; ** maximum value at target surface.

mass spectrometer ionization sector turned off and the second with the ionization sector turned on. With the ionization off, the ions captured by the mass spectrometer were only those produced in the laser ablation. With the ionization sector on, ions produced by impact of neutral atoms with electrons were added to those produced by laser ablation. For the stainless steel sample and the ionization sector turned off, peaks for Fe and Cr were observed, the main components of steel, and only singly ionized single atoms were present in the spectrograms, or rather, there were no peaks corresponding to ions doubly or highly ionized, not even for particles with the double of the unitary mass. For the ionization sector turned on, the spectra remained relatively the same, only the amplitude increased by a factor of about two. Although it is not possible to obtain quantitative information from this factor, because it is not clear which fraction of the neutral atoms are ionized in the ionization sector, it indicates that the ion and neutral populations have roughly the same order of magnitude. The same behavior was observed with all the remaining samples: only peaks due to single atoms singly ionized were observed. It is known that the plume generated by laser ablation is always followed by droplets; however, they were not seen in the mass spectrograms because the droplet mass was much above the mass spectrometer upper limit (300 amu). Thus, in our experimental conditions, except for the droplets, the monitored plume was mainly made of single atoms (neutral or singly ionized). PVDF sensor The PVDF is a polymer that exhibits pyro and piezoelectric SURSHUWLHV DQG 39') ¿OPV DUH VXLWDEOH IRU WLPH RI ÀLJKW 72) FKDUDFWHUL]DWLRQ LQ ODVHU DEODWLRQ H[SHULPHQWV ,W LV very convenient to measure the plume drift velocity (center of mass velocity) and translational temperature both for neutral or ionized atoms. It is well-accepted that the plume generated by laser ablation of single element targets, far from the target surface, is mainly made of a bunch of atoms, which expand according to a maxwellian velocity distribution with a drift YHORFLW\ VLQFH WKH 39') ¿OP UHVSRQGV WR WKH SOXPH DV D SUHVVXUH WUDQVGXFHU LWV 72) VLJQDO LV JLYHQ E\ (T *LmR et al., 2004): S^ t h v

1 m ` l - j2 E v0 . 5 exp ;2kB TZ t t

(4)

&RQVLGHULQJ WKH 39') VLJQDO DQG ÂżWWLQJ WR (T LW LV possible to obtain the drift velocity v0 and the translational temperature Tz. These experiments were performed with a

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

415

Matos, J.B. et al.

HyBrID-copper laser and Fig. 2 provides a typical PVDF 72) VLJQDO ZLWK WKH VHQVRU SODFHG FP IDU IURP D WXQJVWHQ sample; the solid lines indicate the PVDF signal and the GDVKHG OLQH UHSUHVHQWV WKH EHVW ÂżWWLQJ WR (T 7DEOH JLYHV VRPH W\SLFDO ÂżJXUHV REWDLQHG GXULQJ WKHVH H[SHULPHQWV

and electron temperature were evaluated, considering the hydrodynamic expansion approach (Koopman, 1971). This experiment was repeated with aluminum and tungsten targets, ablated by CVL laser, and for copper samples, ablated by the 1G <$* RQH 7\SLFDO UHVXOWV DUH VKRZQ LQ 7DEOH

)LJXUH 39') VLJQDO VROLG OLQH DQG D EHVW ÂżW IRU (T GDVKHG

Figure 3. Temporal behavior of the probe current in different voltages,

line) for ablation of tungsten with CuHBr laser. Table 2. Plume parameters for ablation of tungsten targets measured

for ablation of tungsten samples with the CuHBr laser. Table 3. Plasma parameters for ablation of different targets and lasers, measured with the electrostatic probe. All the listed

with the PVDF sensor. Target Laser Translational temperature (K) Drift velocity (km/s)

Tungsten CuHBr 8.8 × 104 – 9.1 × 104 4.65 – 4.74

ÂżJXUHV DUH SHDN YDOXHV Target

Copper Aluminum Tungsten Tungsten CVL

CVL

CuHBr

CVL

Ion density (m-3)

3.4Ă—1016

2.3Ă—1015

2.4Ă—1017

1.3Ă—1016

Electrostatic probe

Electron density (m-3)

1.2Ă—1015

3.2Ă—1014

6.3Ă—1015

3.9Ă—1014

The electrostatic probe is convenient to measure drift velocity, translational temperature of ions, ion density, electron GHQVLW\ DQG WHPSHUDWXUH &KXQJ 2QH HOHFWURVWDWLF SUREH PDGH RI D PP ORQJ DQG Č?P GLDPHWHU WXQJVWHQ ZLUH placed transversely to the plume, at distances ranging from 4 to 20 cm from the target, was used to study the plasma generated E\ DEODWLRQ RI WXQJVWHQ WDUJHWV )LUVWO\ WKH 72) VLJQDO RI WKH ions was studied with the probe polarized at a -10 V voltage. Later, the electrostatic probe was used to evaluate the charge densities and electron temperature. Figure 3 shows the probe current signal time behavior for different probe electric potentials in experiments with the CuHBr laser and W targets. The noise around 5 Ă— 10-6 s is from laser electric discharge pulses, and it was taken as reference for triggering the oscilloscope. The peak values of the probe current curves were plotted against the polarization voltage, giving rise to the Langmuir curve. From this curve, the charge densities

Electron temperature (eV)

15

19

28

15

8 – 10

8 – 13

5.4

6 – 10

416

Laser

Drift velocity (km/s)

Emission spectra Laser induced breakdown spectroscopy (LIBS) experiments in air were made with copper, graphite, molybdenum, alumina, and beach sand samples in order to investigate the composition of the expanding plume. The plume light emission in our experimental conditions vanishes for distances larger than 3 or 4 mm and thus the experiments were performed just above the target surface and not at the same distances, as in the case of the PVDF and electrostatic probe experiments. )RU WKH WKUHH ÂżUVW WDUJHWV VLQFH WKH\ ZHUH VLQJOH HOHPHQW samples, the line attribution was made by comparing

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

*HQHUDWLRQ RI DQ $WRPLF %HDP E\ 8VLQJ /DVHU $EODWLRQ IRU ,VRWRSH 6HSDUDWLRQ 3XUSRVHV

WKH PHDVXUHG VSHFWUXP ZLWK D VLPSOLÂżHG V\QWKHWLF RQH considering only the sample constituent element. The synthetic spectrum was built by adding lorentzian curves with peak values given by the Einstein A FRHIÂżFLHQW WDNHQ IURP the National Institute of Standards and Technology transitions database (NIST, 2012), and with the linewidth equals to the instrument resolution (1.5 nm). Figure 4 compares the measured (black) and synthetic (gray) spectra for the copper sample, in 450 to 550 nm. In the case of alumina targets, besides the aluminum and the oxygen, nitrogen and sodium in the synthetic spectra were also considered. The experiments with beach sand were performed in order to examine the separation potentiality of our experimental VHWXS IRU YHU\ FRPSOH[ WDUJHWV 2UGLQDU\ EHDFK VDQG ZDV heat dried, pressed and sintered with the purpose of getting compact samples, which have a very complex composition and are inhomogeneous, i.e., the spectrum depends on the position the laser strikes the sample surface. It was not possible to build a synthetic spectrum because of the complexity and lack of information about the sample composition. We focused our attention to some peaks that are repetitive and very distinct from the background, by comparing their resonance wavelength with the NIST database. Several of the more intense observed lines were due to sodium and silicon, as shown in Fig. 5. With regards to Mo samples, a Jobyn-Yvon spectrometer model TRIAX 550, with a 0.025 nm resolution (at 546 nm), was also used and plasma temperature was measured by means of the Boltzmann plot method (Amoruso et al., 1999). The plasma temperature was about 0.9 eV, in agreement with results found in the literature for spectroscopic measurements (Noll, 2012;

Figure 4. Comparison between measured (black line) and synthetic (gray line) spectra for copper samples.

Figure 5. A typical sand LIBS spectrum. The saturated peak around 355 nm is due to the scattering of the laser beam.

Capitelli et al., 2004), but in contrast with the results obtained in this work with Langmuir probe for other metallic samples. ANALYSIS In order to establish the magnitudes this work refers to, let us consider the experiments performed with tungsten targets and the CuHBr laser. The tungsten properties are: aA = 0.493 for Čœ = 511 nm; K = 1.74 W/(cm ÂşC), Č› = 0.7 cm2/s , atomic mass MW = 183.84 amu, cE = 0.133 J/(g ÂşC), LV = 4.48 kJ/g, and ČĄW = 19.3 g/cm3. The laser parameters are provided in Table 1. With these, T § . 7KLV WHPSHUDWXUH LV much higher than the tungsten boiling point of 5,930 K (Lide, 1996), and before the surface had achieved this temperature level, a fraction of the sample had been evaporated and ejected, starting the formation of the ablation plume. This evaluation was done without taking changes of the thermal parameters with temperature into consideration, and without considering the interaction of the laser beam with the ejected plume. However, the value is in the same order of magnitude as the translational temperature measured, both with the PVDF sensor and the electrostatic probe. It means that the laser pulse energy is in some way delivered to the ejected plume. Using Eq. 3, the mass that is removed in one single pulse is estimated in mE = 1.0 Ă— 10-7 g, which implies that, taking the laser repetition rate of 16 kHz, the ejected mass rate is about 5 g/h. This evaluation requires some care, and some fraction of the removed material expands as clusters and/or droplets. The following calculations assume that all the removed material is PDGH RI DWRPV QHXWUDO RU LRQL]HG 7KXV WKH REWDLQHG ÂżJXUHV must be faced as limit values, which are useful only to provide orders of magnitudes for the analyzed parameters.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

417

Matos, J.B. et al.

If one takes an intermediate value for the expansion velocity (drift velocity) of vD = 5 Ă— 103 m/s, at the end of the laser pulse the plume will expand a distance given by LE = vD IJ § Č?P 7KH SDUWLFOH GHQVLW\ QXPEHU RI SDUWLFOHV SHU XQLW\ of volume) at the end of the laser pulse can estimate if it is assumed that all evaporated material had been expanded to a volume given by a hemisphere with radius LE as in Eq. 5: n=

mE 1 c 2.9 # 1019 cm-3 . mw 2/3rL3E

(5)

The mean free path is given by Eq. 6: Lp =

1 c 560nm, nv c

(6)

where: ÄąC: the collisional cross section was estimated taking the tungsten atomic radius (1,41 Ă…) and thus ÄąC § EDUQ Time between two successive collisions is given by Eq. 7: xC =

Lp c 166ps vT

(7),

where: vT: is the thermal velocity, calculated by taking the temperature of 100.000 K previously estimated. 2U UDWKHU GXULQJ D WLPH SHULRG HTXLYDOHQW WR WKH ODVHU SXOVH duration, more than 200 collisions between particles happen in the plume. Kools et al. (1992), using Monte Carlo calculations, showed that only about four collisions are necessary for thermalization in the expanding plume. Thus, it is reasonable to consider that the plume expands similarly to a gas in equilibrium DW KLJK WHPSHUDWXUH DQG SUHVVXUH FRQÂżQHG WR D VPDOO YROXPH which is suddenly released to expand into vacuum. The particle density decreases as the plume expands and, after some distance, the plume is not collisional anymore. To estimate this distance, it is considered that the particle density decays with the distance from the target surface according to Eq. 8, L 3 n (z) = n^ LEh` zE j

(8)

and that the plume stops being collisional when the mean free path is in the same order of magnitude as the plume size LP, thus substituting Eq. 8 into 6, one has Eq. 9: LNC = n^ LEh vC L3E = 3.1mm.

418

If one considers a 5 km/s expanding velocity, the time to expand until LNC is in the order of 600 ns. Therefore, for the experimental conditions presented in this work, after an expansion of about 3 mm, the plume is not collisional anymore and the interaction between particles from this point on is essentially electrostatic. Basically, two kinds of behavior are expected, for low densities the charged particles behave like free particles and for high densities they KDYH D FROOHFWLYH SODVPD EHKDYLRU 7KH ¿JXUH RI PHULW WKDW allows identifying the particles’ behavior is the Debye Length LDb, given by Eq. 10: LDb = c

f0 kB Te m1/2 . q2 Ne

(10)

Taking the electron densities and temperatures from Table 3, the Debye length ranges from 0.5 to 2.6 mm in the present experimental conditions. Therefore, the plume typical dimensions are in the same order of magnitude as the Debye length and the particles’ behavior is in the transition between the individual particles and plasma behavior regimes. It suggests that the charged particles (ions mainly) can be separated by WKH DSSOLFDWLRQ RI DQ HOHFWULF ÂżHOG EHWZHHQ HOHFWURGHV DSDUW from distances in the range of few millimeters and that the remaining plume fraction will be made of single atoms. The same calculation was repeated for copper and aluminum, and the results, together with the values for WXQJVWHQ DUH SUHVHQWHG LQ 7DEOH 7KH ÂżJXUHV DUH YHU\ FORVH and the same comments made for tungsten are also applicable for copper and aluminum. Table 4. Estimated plume parameters for tungsten, copper, and aluminum, using the same calculation procedure described in “Analysisâ€?. The material constants were taken from Lide (1996), laser parameters from the CVL laser in Table 1 and plasma parameters from Table 3. Parameters Tungsten Copper Temperature at the surface (K)* 1.0Ă—105 1.0Ă—104

Aluminum 1.4Ă—104

Removed mass per pulse (kg/pulse)

1.0Ă—10-10 1.6Ă—10-11 6.7Ă—10-12

Atom density (m-3)* Mean free path (m) LNC (m) Debye length (m)

2.9Ă—1025 5.6Ă—10-7 3.1Ă—10-3 5.0Ă—10-4

1.3Ă—1025 1.5Ă—10-6 1.9Ă—10-6 8.0Ă—10-4

1.3Ă—1025 1.2Ă—10-6 2.1Ă—10-6 1.8Ă—10-3

* at the end of the laser pulse.

(9)

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

*HQHUDWLRQ RI DQ $WRPLF %HDP E\ 8VLQJ /DVHU $EODWLRQ IRU ,VRWRSH 6HSDUDWLRQ 3XUSRVHV

CONCLUSIONS In this work, several materials were evaluated in different experiments of laser ablation, using low energy (~ mJ per pulse), high repetition rate (~ tens of kHz) lasers in the visible and in the near ultraviolet, with pulse width in the range of tens of nanoseconds. The ablation experiments were in the thermal regime, with energy density in the range of tens of J/cm2 and intensities of about 109 W/cm2. The set of results for these experimental conditions leads to the following conclusions: ‡ D VLJQL¿FDQW IUDFWLRQ RI WKH SOXPH JHQHUDWHG E\ ODVHU ablation is made of single atoms (neutral or ionized), even if complex targets are used; ‡ WKH LRQV DQG QHXWUDO DWRPV GHQVLW\ DUH LQ WKH VDPH RUGHU RI magnitude; ‡ IRU GLVWDQFHV JUHDWHU WKDQ IHZ PLOOLPHWHUV WKH SOXPH LV QR longer collisional; ‡ DW GLVWDQFHV ODUJHU WKDQ FP IURP WKH WDUJHW WKH 'HE\H length is such that the charged fraction of the plume can be VHSDUDWHG E\ WKH DSSOLFDWLRQ RI HOHFWURPDJQHWLF ¿HOGV ‡ DEODWLRQ UDWHV RI DERXW J K DUH SRVVLEOH In short, it is possible, using laser ablation, to generate an atomic beam adequate for AVLIS purpose. This is possible even for very complex targets, such as ores. The main limitation is the small amount of material that is removed, limiting the method for the separation of small amounts of material. This is a severe limitation for the separation of materials that are needed in large amounts, such as uranium, however it is adequate for the separation of materials used in photonics or in magneto-optic sensors, which require small amounts of isotopes.

Chemie International – Edition in English, Vol. 6, No. 6, pp 507-518. doi:10.1002/anie.196705071 %HQQHW * / Âł6SDFH 1XFOHDU 3RZHU 2SHQLQJ WKH )LQDO Frontierâ€?, 4th International Energy Convertion Engineering Conference and Exhibit (IECEC), San Diego, California, USA, AIAA, pp. 2006-4191. %RUQ 0 DQG :ROI ( Âł3ULQFLSOHV RI 2SWLFV Electromagnetic Theory of Propagation: Interference and Diffraction of Lightâ€?, 7th ed., Cambridge University Press, 952p. Calusaru, A. and Murgulescu, S., 1976, “Chemical and Ion Exchange Unit for a Cascade of Uranium Isotope Separationâ€?, Naturwissenschaften, Vol. 63, No. 12, pp. 578-579. doi:10.1007/BF00622798 Capitelli, M. et al., 2004, “Laser-induced plasma expansion: theoretical and experimental aspectsâ€?, Spectrochimica Acta: Part B, Vol. 59, No. 3, pp. 271-289. doi:10.1016/j. sab.2003.12.017 &KXQJ 3 0 Âł(OHFWULF SUREHV LQ VWDWLRQDU\ DQG Ă€RZLQJ plasmas: theory and applicationsâ€?, Springer-Verlag, New York, 150p. Del Bosco, E. et al., 1987, “Isotopic enrichment in a plasma centrifugeâ€?, Applied Physics Letters, Vol. 50, No. 24, pp. 1716. doi:10.1063/1.97725 Dolgolenko, D.A. and Muromkin, Y.A., 2009, “Plasma isotope separation based on ion cyclotron resonanceâ€?, Physics Uspekhi, Vol. 52, No. 4, pp. 345-357. doi:10.3367/ UFNe.0179.200904c.0369

REFERENCES Amoruso, S. et al., 1999, “Characterization of laser-ablation SODVPDV´ -RXUQDO RI 3K\VLFV % $WRPLF 0ROHFXODU DQG 2SWLFDO Physics, Vol. 32, No. 14, pp. R131-R172. doi:10.1088/09534075/32/14/201 Beams, J.W. and Haynes, F.B., 1936, “The Separation of Isotopes by Centrifugingâ€?, Physical Review, Vol. 50, pp. 491-492. doi: 10.1103/PhysRev.50.491

'XOH\ : : Âł&22 Lasers: Effects and Applicationsâ€?, Academic Press, New York, 427p. Flicker, H. et al., 1964, “Construction of a promethium-147 atomic batteryâ€?, IEEE Transactions on Electron Devices, Vol. 11, No. 1, pp. 2-8. doi:10.1109/T-ED.1964.15271 Furry, W.H. et al. Âł2Q WKH WKHRU\ RI LVRWRSH VHSDUDWLRQ by thermal diffusionâ€?, Physical Review, Vol. 55, No. 11, pp. 1083-1095. doi:10.1103/PhysRev.55.1083

Becker, E.W. et al., 1967, “Separation of the Isotopes of Uranium by the Separation Nozzle Processâ€?, Angewandte J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

419

Matos, J.B. et al.

*LmR 0 $ 3 et al., 2004, “PVDF sensor in laser ablation H[SHULPHQWV´ 5HYLHZ RI 6FLHQWLÂżF ,QVWUXPHQWV 9RO 1R 12, pp. 5213-5215. doi:10.1063/1.1819556

Mack, E. and Arroe, H., 1956, “Isotope shift in atomic spectra�, Annual Review of Nuclear Science, Vol. 6, pp. 117-128. doi:10.1146/annurev.ns.06.120156.001001

Itoh, N. et al. ³6PDOO RSWLFDO PDJQHWLF ¿HOG VHQVRU WKDW XVHV UDUH HDUWK LURQ JDUQHW ¿OPV EDVHG RQ WKH )DUDGD\ HIIHFW´ $SSOLHG 2SWLFV 9RO 1R SS GRL $2

Martynenko, Y.V., 2009, “Electromagnetic isotope separation method and its heritage�, Physics-Uspekhi, Vol. 52, No. 12, pp. 1266-1272. doi:10.3367/UFNe.0179.200912n.1354

Jensen, R.J. et al., 1982, “Separating isotopes with lasers�, Los Alamos Science, Vol. 3, No. 1, pp. 02-33.

1D\ORU 5 : DQG %DFNHU 3 2 ³(QULFKPHQW FDOFXODWLRQV in gaseous diffusion: Large separation factor�, AIChE Journal, Vol. 1, pp. 95-99. doi:10.1002/aic.690010114

.DPDGD 2 et al., 2009, “Mixed rare earth iron garnet (TbY) ,* IRU PDJQHWLF ÂżHOG VHQVRUV´ -RXUQDO RI $SSOLHG 3K\VLFV Vol. 61, No. 8, pp. 3268-3270. doi:10.1063/1.338877

NIST 2012, “NIST Atomic Spectra Database Lines Form�, Retrieved in Mach 08, 2012, from http://physics.nist.gov/ PhysRefData/ASD/lines_form.html.

.DWR ' DQG /DPRQW 5 * ³,VRWRSLF FKHPLFDO YDSRU deposition of fused silica and high-silica-content glasses for the SURGXFWLRQ RI ORZ ORVV RSWLFDO ZDYHJXLGHV´ $SSOLHG 2SWLFV 9RO 1R SS GRL $2

Noll, R., 2012, “Laser-induced breakdown spectroscopy�, Springer-Verlag, Heidelberg, 543p. doi:10.1007/978-3-64220668-9

Kholpanov, L.P. et al., 1997, “Multicomponent isotope separating cascade with lossesâ€?, Chemical Engineering DQG 3URFHVVLQJ 3URFHVV DQG ,QWHQVLÂżFDWLRQ 9RO 1R pp. 189-193. doi:10.1016/S0255-2701(96)04187-6 Kim, D.W. et al., 2001, “Separation of magnesium isotopes by ion exchange chromatographyâ€?, Journal of Industrial and Engineering Chemistry, Vol. 7, No. 3, pp. 173-177. Kools, J.C.S. et al. Âł*DV Ă€RZ G\QDPLFV LQ ODVHU ablation depositionâ€?, Journal of Applied Physics, Vol. 71, No. 9, pp. 4547-4556. doi:10.1063/1.350772 Koopman, D.W., 1971, “Langmuir probe and microwave measurements of the properties of streaming plasmas generated by focused laser pulsesâ€?, The Physics of Fluids, Vol. 14, No. 8, pp. 1707-1716. doi:10.1063/1.1693667 Lide, D.R., 1996, “CRC Handbook of Chemistry and Physicsâ€?, 76th ed., CRC Press, Boca Raton, USA, 2650p. Louvet, P., 1995, “Device for isotope separation by ion cyclotron resonanceâ€?, Patent US005422481A.

420

Paisner, J.A., 1988, “Atomic Vapor Laser Isotope Separation�, $SSOLHG 3K\VLFV % /DVHUV DQG 2SWLFV 9RO 1R pp. 253-260. doi:10.1007/BF00692883 Prasad, R.R. and Krishnan, M., 1987, “Theoretical and experimental study of rotation in a vacuum arc centrifuge�, Journal of Applied Physics, Vol. 61, No. 1, pp. 113-119. doi:10.1063/1.338976 Riley Jr., J.E., 1987, “The effects of lithium isotopic anomalies on lithium niobate�, Ferroelectrics, Vol. 75, No. 1, pp. 59-62. doi:10.1080/00150198708008209 Rutherford, W.M., 1986, “Separation of Zinc Isotopes by Liquid-Phase Thermal Diffusion�, Industrial & References Engineering Chemistry Process Design and Development, Vol. 25, No. 4, pp. 855-858. doi:10.1021/i200035a003 Schiller, S. et al., 1983, “Electron Beam Technology�, John Wiley & Son, New York, Chichester, Brisbane, Toronto, Singapore, 508p. Schwab, C. et al., 1998, “Laser techniques applied to isotope separation of uranium�, Progress in Nuclear Energy, Vol. 33, No. 1/2, pp. 217-264. doi:10.1016/S0149-1970(97)00100-5

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 413-420, Oct.-Dec., 2012

doi: 10.5028/jatm.2012.04044212

Occurrence of Defects in Laser Beam Welded Al-Cu-Li Sheets ZLWK 7 -RLQW &RQÂżJXUDWLRQ $QGUp /XL] GH &DUYDOKR +LJDVKL1 0LOWRQ 6pUJLR )HUQDQGHV GH /LPD1,2* Instituto TecnolĂłgico de AeronĂĄutica – SĂŁo JosĂŠ dos Campos/SP – Brazil Instituto de Estudos Avançados – SĂŁo JosĂŠ dos Campos/SP – Brazil

1 2

Abstract: In the aerospace industry, laser beam welding has been considered as one of the most promising routes among the new manufacturing processes. Substitution of riveting by laser beam welding of aircraft structures has contributed to weight and cost savings. Concurrently, new aluminum alloys have been developed with the addition of lithium with better mechanical properties and lower density. The Al-3.5%Cu-1.1%Li alloy (AA2198) is one of these new generation alloys. However, laser beam welding of Al-alloys expectations might be greatly reduced by the occurrence of two main defects: SRURVLW\ DQG KRW FUDFNLQJ 3RURVLW\ LV PDLQO\ FDXVHG E\ WKH HQWUDSPHQW RI OLWKLXP JDVHV IROORZHG E\ UDSLG VROLGLÂżFDWLRQ On the other hand, hot cracking happens due to the conjunction of tensile stresses, which are transmitted to the mushy ]RQH E\ WKH FRKHUHQW VROLG XQGHUQHDWK DQG WR DQ LQVXIÂżFLHQW OLTXLG IHHGLQJ WR FRPSHQVDWH IRU WKH YROXPHWULF FKDQJHV 7KLV ZRUN LQWHQGHG WR FRQWULEXWH WRZDUGV WKH NQRZOHGJH RI $$ ZHOGLQJ PHWDOOXUJ\ XWLOL]LQJ D N: \WWHUELXP GRSHG ÂżEHU ODVHU 7KH 7 MRLQW FRQÂżJXUDWLRQ ZHOGV ZHUH SHUIRUPHG DXWRJHQRXVO\ RU ZLWK WKH DGGLWLRQ RI DQ $$ ÂżOOHU ULEERQ $OO the weld beads presented high porosity level, but with a decreasing tendency when welding from both sides. The use of the ÂżOOHU PDWHULDO FRXOG VROYH KRW FUDFNLQJ SUREOHP 7KH EHVW UHVXOWV DUH REVHUYHG XVLQJ WZR UXQV ERWK VLGHV ZLWK ÂżOOHU DQG D VSHHG RI P PLQ DQG SRZHU RI : 7KH 7 SXOO WHQVLOH VWUHQJWK REWDLQHG XQGHU WKHVH FRQGLWLRQV ZDV 03D ZKLFK LV EHORZ WKH WHQVLOH VWUHQJWK RI WKH XQZHOGHG $$ VKHHW EXW KLJKHU WKDQ WKH $$ ZHOGHG LQ VLPLODU FRQGLWLRQV Keywords: Laser, Laser beam welding, Aluminum alloys, Aerospace.

INTRODUCTION In the aerospace industry, the two routes of manufacturing technologies for structures have been constantly improved. One of them is the employment of polymer matrix composite materials in aircraft structures, which has been growing over the years (Mangalgiri, 1999). The other one is the use of conventional metallic materials with enhanced mechanical and physical properties (King et al., 2009). This later could be considered as a safer route due to the very large experience of metallic alloys engineering use. The rising competition between composites and metals took the aluminum alloys producers to develop, jointly with aircraft manufacturers, lighter alloys, with high mechanical strength and high damage tolerance. The aluminum-copperlithium alloy AA2198 is an example of these new generation Received: 11/07/12

Accepted: 04/09/12

DXWKRU IRU FRUUHVSRQGHQFH PVÀLPD#\DKRR FRP EU Trevo Coronel Aviador JosÊ Alberto Albano do Amarante, 1 – Putim CEP 12.228-001 São JosÊ dos Campos/SP – Brazil

alloys. Typically, the AA2198 alloy composition is 3.2% Cu and 1.0% Li, falling in the Al solid solution above 500 °C. Aging at lower temperatures promotes the formation of intermetallics responsible by strengthening effect (Bordesoules, 2007). In addition to these new alloys, materials-joint techniques have been improved aiming at the reduction of weight, costs, and lead-time. Although the riveting process is highly automated, which is largely used by aircraft manufacturers, this process reached its development potential limit, and no VLJQL¿FDQW DGYDQFHV LQ SURGXFWLYLW\ QRU LQ ZHLJKW UHGXFWLRQ can be expected. Thus, many joint techniques that could SURPRWH VLJQL¿FDQW FKDQJHV WR WKH SURGXFWLRQ SURFHVV ZHUH FRQVLGHUHG IRFXVLQJ RQ WKH VSHFL¿F QHHGV RI WKH DHURVSDFH industry, adding low weight and mechanical properties suitable with structural demands during aircraft lifetime operation. Among the available welding processes, friction stir welding (FSW) and laser beam welding (LBW) have presented advances over the past years, becoming attractive for the aerospace industry worldwide.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

421

Higashi, A.L.C., Lima, M.S.F.

LBW already found its place in industrial production, with a market in full expansion. Initially, the automotive industry developed LBW processes for sheets of different thicknesses prior to forming, which are called tailored-blanks welding, and then body-in-white laser welding. The portfolio of available ÀDW DQG VKDSHG SURGXFWV LQFOXGHV DOXPLQXP DQG PDJQHVLXP alloys, presenting productivity and welding quality gains (Pallett and Lark, 2001). Afterwards, the aerospace structure manufacturers began to substitute some riveted panels by laser-welded ones. The utilization of laser as a welding process allows not only weight reductions, but also the development of optimized panels, decreasing the manufacturing lead-time. If compared to the typical riveting speeds (200 to 400 mm/min), the laser welding clearly shows itself more productive, reaching speeds exceeding 6 m/min. Even with more rigorous inspections and SURFHVV FRQWURO LW LV VWLOO SUR¿WDEOH )XUWKHUPRUH WKH VWUXFWXUH become less susceptible to corrosion, since holes in the skin are avoided and gaps in butt joints are eliminated (RÜtzer, 2007). In spite of these advantages, LBW like other fusion methods is subject to common metallurgical problems, such as hot cracking and porosities. The control of welding defects is of utmost importance to control the mechanical properties under the extreme conditions aerospace materials are subjected to. Two of the major problems in fusion welding of aluminum alloys are related to porosity and hot cracks. These problems will be further analyzed. Porosities are intrinsically related to the weld, occurring due to a large number of factors: alloy composition, surface contaminants, improper gas shielding, keyhole collapse, and hydrogen release. In case of alloys with highly volatile elements, such as Li in the present case, boiling could also happen. Pores in Al-Li welds beads had been previously reported (ASM, 1993) as a result of hydrogen contamination leading to interdendritic microporosity. +RW FUDFNLQJ DOVR NQRZQ DV VROLGL¿FDWLRQ FUDFNLQJ LV RQH RI WKH PDMRU GHIHFWV WKDW FDQ RFFXU GXULQJ VROLGL¿FDWLRQ RI metallic alloys. This is the result of inadequate melt feeding initiating micropores and severe deformation leading to the opening and propagation of such defects. This type of LPSHUIHFWLRQ DSSHDUV DW WKH HQG RI WKH VROLGL¿FDWLRQ ZKHQ WKH solid fraction is high (Piwonka and Flemmings, 1966). A large VROLGL¿FDWLRQ LQWHUYDO OHDGV WR D KLJK XQGHU SUHVVXUH DW WKH dendrite roots increasing the tendency to hot cracking. 7KH FUDFNLQJ VXVFHSWLELOLW\ FRHI¿FLHQW SURSRVHG E\ &O\QH and Davies (1981) is formulated as the ratio between the vulnerable time period (tv), and the time available for stress422

relief process (tR), i.e. the time spent in the interdendritic IHHGLQJ VWDJH GHÂżQHG DV WKH LQWHUYDO EHWZHHQ DQG VROLG fraction. Equation 1 presents the hot cracking susceptibility (HCS) followed by Clyne and Davies (1981).

HCS =

tV = t99 - t90 tR t90 - t40

(1)

Since the solid fraction is a function of temperature and DOOR\ FRPSRVLWLRQ WKH PRGLÂżFDWLRQ RI WKH OLTXLG FRPSRVLWLRQ is a suitable way to decrease the vulnerable time. This is usually accomplished when an eutectic forming compound is added to the weld. For example, it is well known that silicon reduces tv LQ DOXPLQXP DOOR\V EHFDXVH WKH VROLGLÂżFDWLRQ LQWHUYDO LV reduced and the fraction of the eutectic phase is increased. Drezet et al. (2008) also proposed that hot cracking could be diminished when two laser sources are used together. The main HIIHFW RI WKHVH KHDW VRXUFHV LV WR FUHDWH D ÂżQH HTXLD[HG UHJLRQ DW the middle of the weld bead, so the liquid permeability increases and the thermal gradient decreases. It has been proved that a process using two laser sources improves the high temperature toughness of the AA6013 aluminum joints (Lima et al., 2001). The use of two laser sources could be unpractical in some weld geometries, but using two weld runs could reduce the WKHUPDO JUDGLHQW ,Q WKH FDVH RI 7 MRLQW FRQÂżJXUDWLRQ W\SLFDO of an aircraft panel, two runs could be envisaged: one at the joint between skin and stringer and another in the opposite face. For this, two challenges must be attained: the laser beam must be very accurately positioned at the interface between WKH SLHFHV DQG DW D FRUUHFW DQJOH DQG WKH ÂżOOHU PDWHULDO PXVW EH inserted in some way it is not obstructing the beam. Therefore, WKH ÂżUVW FKDOOHQJH LV JRLQJ WR EH DFFRPSOLVKHG E\ WKH KLJK TXDOLW\ ÂżEHU ODVHU EHDP 7KH VHFRQG RQH FRXOG EH RYHUFRPH E\ XVLQJ D ÂżOOHU ULEERQ LQVWHDG RI D ÂżOOHU ZLUH DQG E\ LQVHUWLQJ this ribbon directly at the joint intersection. This work intended at contributing to the study of ZHOGDELOLW\ RI WKH $$ DOOR\ XVLQJ D ÂżEHU ODVHU 7KH experimental results of the weldability are missing in the OLWHUDWXUH DQG WKH XVH RI D QHZ ODVHU VRXUFH ÂżEHU ODVHU FRXOG produce a new insight on the matter. The weld geometry is similar to that of a stringer-skin T-joint both autogenous and ÂżOOHG ZLWK DQ $O 6L DOOR\ ULEERQ MATERIALS AND METHODS A 1.6 mm thick aluminum alloy AA2198-T851 sheet was utilized in this work. Its composition is shown in Table 1. The sheet was cut in coupons with 30 x 100 mm dimensions. For

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

2FFXUUHQFH RI 'HIHFWV LQ /DVHU %HDP :HOGHG $O &X /L 6KHHWV ZLWK 7 -RLQW &RQÂżJXUDWLRQ Table 1. AA2198 alloy composition in weight percent (Al as the balance).

Element

Cu

Mg

Li

Ag

Zr

Mn

Si

Zi

Ti

Fe

Other

% wt.

3.50

0.80

1.10

0.50

0.18

0.50

0.08

0.35

0.10

0.10

0.15

Si 11.89

Fe 0.252

Table 2. AA4047 alloy composition in weight percent. Element % wt.

Al 87.83

Cu 0.0015

Mg 0.001

Mn 0.01

ZHOGV SHUIRUPHG ZLWK ÂżOOHU WKH DOXPLQXP DOOR\ $$ ZDV utilized and its composition is shown in Table 2. Wires of 1.0 mm in diameter were cold rolled to ribbons of 1.6 mm of width and 0.2 mm thickness. The ribbons were placed between the sheets DQG ÂżUPO\ DWWDFKHG XVLQJ D EHQFK YLVH LQ D 7 MRLQW FRQÂżJXUDWLRQ as depicted in Fig. 1. Based on previous studies, the angle EHWZHHQ WKH ODVHU EHDP DQG WKH VNLQ VXUIDFH ZDV Âż[HG DW ƒ $ N: FRQWLQXRXV ZDYH ÂżEHU ODVHU SURGXFHG E\ ,3* Co. (USA) was used. The laser radiation is generated in a PP GLDPHWHU ÂżEHU GRSHG ZLWK \WWHUELXP 7KH GRSHG ÂżEHU LV FRQQHFWHG WR D SURFHVV ÂżEHU ZLWK PP GLDPHWHU ZKLFK is then connected to an Optoskand processing head. The focal length was 157 mm with a minimum spot diameter at the focus of 100 mm. 3XUH KHOLXP JDV DW O PLQ Ă€RZ UDWH ZDV XVHG WR SURWHFW the surface against oxidation. The protection gas was delivered through a rounded copper tube of 2 mm internal diameter directly over the irradiated area (Fig. 1). A computer numerical control (CNC) table carries out the sample movement. Right before welding, the sample surface was grounded with a

SiC 600 paper to remove oxidation and then washed with distilled water and ethanol. Microstructural analyses were carried out using optical microscopy (OM) and scanning electron microscopy (SEM). 7KH 20 LV D UHÀHFWHG OLJKW 5HLFKHUW 3RO\YDU *HUPDQ\ equipped with acquisition system and image processing VRIWZDUH 7KH 6(0 LV D =HLVV 0RGHO /(2 9SL *HUPDQ\ The equipment for mechanical tests was an MTS 810 tensile machine (USA) having a loading cell with 250 kN capacity. The mechanical testing was carried out in T-pull mode, as described in Fig. 2. The load is realized by pulling the stringer at constant speed of 1.0 mm/min. The sample dimensions for T-pull testing were: 3(W)x3(H)x2(L) cm. In order to understand the thermal and mechanical EHKDYLRUV GXULQJ ZHOGLQJ D ¿QLWH HOHPHQW DQDO\VLV ZDV SHUIRUPHG XVLQJ WKH (6, *URXS 6\VZHOGŠ VRIWZDUH )UDQFH As the physical properties of AlCuLi alloy are missing in the literature, the simulation had been performed using the constants of an AlSiMg alloy class AA6061. One and two-sided welding conditions were simulated in autogenous condition. In order to reproduce experimental conditions, the simulated sheets were rigidly attached to the borders, and the time between the start of each weld, for the two sides welds, was ten seconds. The mechanical formalism is based on Von Mises strain and stresses (Wikipedia, 2012).

F stringer skin Ă—

)LJXUH ([SHULPHQWDO VHWXS VKRZLQJ DOXPLQXP SDUWV Âż[HG DW WKH

Figure 2.

T-pull mechanical testing schematics. The skin part of the

bench. The white block is an alumina calibrated support,

MRLQW LV DWWDFKHG WR D WDEOH ZLWK WZR VFUHZV Âż[HG FOLSV

and the rounded nozzle is responsible for gas shielding.

The force (F) is applied parallel to the stringer direction.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

423

Higashi, A.L.C., Lima, M.S.F.

(a) Figure 3.

(b)

Optical micrographic images of the weld seams. (a): one side beam, condition: one run – 1,400 W/3 m/min. (b): two runs – 1,200 W/4 m/min.

After a number of free trials, some experimental conditions have been retained for a detailed study. Table 3 presents the experimental conditions for the welds, where the run could be one or two depending if one or both sides were exposed to the beam. The heat input is the ratio of power per speed for each run. RESULTS AND DISCUSSION In the present work, the parameters affecting the heat input provided by the laser, speed (v) and power (P) were studied. In general, the combination of P and v of the welds generated weld beads of reasonably similar dimensions. )RU WKH 7 MRLQW FRQÂżJXUDWLRQ WKH ODVHU EHDP FDPH IURP RQH (Fig. 3a) or two sides (Fig. 3b), however the welded zones were always asymmetric. All samples presented epitaxial growth of grains from the base/molten metal interface WRZDUGV WKH EHDG WRS 7KH VORZHU VROLGLÂżFDWLRQ QH[W WR Table 3. Process parameters. Power (W) 1,200 1,200 1,200 1,200 1,400 1,400 1,400 1,200 424

Speed (m/min.)

Heat input (J/mm)

Condition

2 2 2 2 3 3 3 4

36 36 36 36 28 28 28 18

Autogenous/two runs Autogenous/one run :LWK ÂżOOHU WZR UXQV :LWK ÂżOOHU RQH UXQ Autogenous/one run :LWK ÂżOOHU RQH UXQ :LWK ÂżOOHU RQH UXQ :LWK ÂżOOHU WZR UXQV

the base material promoted the coarser dendrite formation with columnar structure. Near the bead top, where cooling rate was higher, the grains had not preferential orientation SURYLGLQJ HTXLD[LDO JURZWK RI ÂżQHU GHQGULWHV As can be seen in Fig. 3, a great quantity of pores is presented in all weld beads. Some of them presented large toes (Figs. 3a and 3b), which can be explained by the large number of pores within them. Microporosity as much as macro-porosity were present in the welded zone, indicating one or more mechanisms RI SRUH IRUPDWLRQ 3RUHV DUH YHULÂżHG DOO DORQJ WKH H[WHQVLRQ RI the welds, however the volume fraction of pores does not have statistical meaning because of large variations in their density from one cross-section to the other. These pores are mainly linked to the lithium degassing during melting and are frequently associated with poor weldability of Al-Li alloys. The welds with both side seams, as presented in Fig. 3b, showed smaller pores, indicating that the Li vapor had more time to leave the molten pool. Other possible sources of porosity to be considered are surface and gas contaminants. The current careful control RI VXUIDFH ÂżQLVKLQJ GHFUHDVHV WKH SRVVLELOLW\ RI VXUIDFH contaminant, thus having a minor role in the porosity. Additionally, other types of aluminum alloys had been welded in the same experimental conditions (Siqueira et al., 2012), including use of the bench vise and the gas nozzle as presented in Fig. 1. Usually, these welds present only few small pores. Therefore, it is much likely that pores are due to Li degassing and, to an unknown extent, to hydrogen nucleation (ASM, 1993). Figure 4 presents a closer look of a separate pore crosssection using secondary scanning electron microscopy. It

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

2FFXUUHQFH RI 'HIHFWV LQ /DVHU %HDP :HOGHG $O &X /L 6KHHWV ZLWK 7 -RLQW &RQÂżJXUDWLRQ

)LJXUH 3RUH REVHUYHG DW FRQGLWLRQ ZLWK ÂżOOHU : P PLQ one run.

can be seen that the porosity is perfectly spherical with inner VXUIDFH ÂżQHO\ GHFRUDWHG ZLWK GHQGULWH DUPV 7KH UHJLRQ DURXQG WKH REVHUYDEOH FLUFOH SUHVHQWV ÂżQH HTXLD[HG JUDLQV with epitaxial growth from the disc to the surroundings. This observation indicates that pores inoculate the liquid with ORZ HQHUJ\ QXFOHDWLRQ VLWHV WKDW KHOS ÂżQH JUDLQ JURZWK ,Q Fig. 5a it could be seen a pore in the middle of an isolated grain (arrow). Page and Sear (2006) also showed that pores are preferred sites for heterogeneous nucleation of new phases. The same mechanism of metal nucleation around pores is also observed in metal foams. Duarte and Banhart YHULÂżHG WKH QXFOHDWLRQ RI DOSKD JUDLQV DURXQG SRUHV in the foam-processed aluminum alloys classes AlSi7 and $$ $V JUDLQ UHÂżQHUV WKH VPDOO SRUHV FRXOG LQFUHDVH WKH weld seams toughness, particularly in high temperatures in which hot cracks appears. However, the large pores observed here act as stress concentrators and probably hide the positive HIIHFWV RI ÂżQH SRUH LQRFXODWLRQ 7KH XVH RI $O 6L ÂżOOHU VHHPV WR GHFUHDVH WKH WHDU WHQGHQF\ in the fusion zone. The welds performed with laser power of

1,200 W and 2 m/min speed did not present hot cracking with ÂżOOHU DGGLWLRQ XQOLNHO\ WKH DXWRJHQRXV FRQGLWLRQ )LJXUHV D DQG E VKRZ WKH DXWRJHQRXV ZHOG DQG ZHOG ZLWK WKH ÂżOOHU respectively. Thus, the HCS was reduced to this condition ZLWK WKH DGGLWLRQ RI WKH $$ ÂżOOHU ULEERQ $FFRUGLQJ WR WKH current theories (Campbell, 2003), the chemical composition is FKDQJHG UHGXFLQJ WKH YXOQHUDEOH VROLGLÂżFDWLRQ LQWHUYDO ,W LV QRW possible to accurately measure the actual composition of the welded zone using the energy-dispersive X-ray spectroscope of the scanning electron microscope (SEM-EDS), since many alloying elements were well-below 1 weight percent and the second most important alloying element (Li) was too light to be detected. Nevertheless, semiquantitative chemical analyses were performed, and are presented in Fig. 6 for two samples with Al-Si additions. It could be seen that silicon distribution is approximately homogeneous in all areas, but at the bottom region, next to the skin, called “2â€? in Fig. 6. The accumulation of Si in these regions could be explained due to the absence of KLJK OLTXLG FRQYHFWLRQ Ă€X[HV LQ ODWHUDO UHJLRQV RI WKH ZHOG SRRO Through SEM-EDS imaging analyses, the composition of two side-welded beads was obtained. The content of silicon RI WKH ÂżOOHU ZLUH ZKLFK FRPSRVLWLRQ LV DSSUR[LPDWHO\ WKH eutectic Al-12% Si) was diluted in the bead during welding. 7KH PROWHQ PHWDO FRQYHFWLRQ Ă€RZV SHUPLWWHG WKH VROXWHV WR dilute out over the entire bead during welding. $ SRVVLEOH ZD\ WR VWXG\ WKH LQĂ€XHQFH RI FKHPLFDO composition on hot cracking is to compare the ratio of vulnerable to stress-relief times, as presented in Eq. 1. With regards to the same cooling conditions, one could compare the temperature interval, related to tv and tR, between an alloy composed Al-2.9%Cu-1.1%Si (Fig. 6) and another with Al-3.5%Cu. Thermocalc (1994) computations provided the results presented in Table 4, and as can be seen the HCS drops

Ă–

(a)

(b)

)LJXUH +RW FUDFNLQJ LQ WKH ZHOGHG ]RQHV D DXWRJHQRXV ZHOG VHDP FRQGLWLRQ RI : P PLQ E ZHOG VHDP ZLWK ÂżOOHU IUHH RI cracking, condition of 1,200 W/2 m/min.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

425

Higashi, A.L.C., Lima, M.S.F.

Condition 1.4 kW x 3 m/min.

Condition 1.2 kW x 2 m/min.

Region

% Al

% Cu

% Si

Region

% Al

% Cu

% Si

1

96.1

2.9

0.9

1

96.0

2.7

1.3

2

96.3

2.3

1.4

2

94.9

2.8

2.3

3

96.0

3.0

1.0

3

95.9

3.1

1.0

4

95.8

3.3

0.9

4

96.3

2.8

0.9

5

96.1

2.8

1.1

5

96.2

3.2

0.8

Average

96.1

2.9

1.0

Average

95.9

2.9

1.2

)LJXUH (QHUJ\ GLVSHUVLYH ; UD\ VSHFWURPHWU\ FKHPLFDO DQDO\VHV RI WZR ZHOG EHDGV ÂżOOHG ZLWK WKH $O 6L ULEERQ 7KH WDEOHV EHORZ HDFK picture indicate the chemical composition for each region.

IURP WR ZKHQ XVLQJ ¿OOHU PDWHULDO 7KHVH QXPEHUV DUH RQO\ LQGLFDWLYH EHFDXVH WKH UHDO VROLGL¿FDWLRQ LQWHUYDO GHSHQGV on the actual melt composition and cooling conditions. $V +&6 LV OLQNHG WR WKH UDWLR RI WKH VROLGL¿FDWLRQ intervals (Table 4) and the mechanical strains during the ¿QDO VWDJHV RI VROLGL¿FDWLRQ WKHQ RQH QHHG WR HYDOXDWH WKH thermomechanical evolution during welding by computer VLPXODWLRQ 7KH ¿QLWH HOHPHQW PRGHOLQJ ZDV FDUULHG RXW XVLQJ WKH 6\VZHOGŠ VRIWZDUH IRU WKH 7 MRLQW ZHOGLQJ LQ VLPLODU Table 4.

Calculation of temperature intervals in different compositions. T(fs) means temperature in Kelvin at a given solid fraction. HCS: hot cracking susceptibility.

Temperature (K)

:HOGLQJ ZLWK $O6L ÂżOOHU Al-2.9%Cu-1.1%Si

Welding without $O6L ÂżOOHU $O &X

T (fs=99%)

837.04

857.04

T (fs=90%)

869.93

887.01

T (fs=40%)

912.57

919.51

HCS (Equation 1)

0.77

0.92

HCS: hot cracking susceptibility.

426

conditions to the experimental setup. One-side welding temperature and mechanical response were simulated with power of 1,400 W and a speed of 3 m/min. For the simulation of two-side weld, the chosen parameters were power of 1,200 W and speed of 4 m/min. The current thermal inputs were 28 and 18 J/mm per run (Table 3), for one and two-side welds, respectively. These simulation parameters were similar to those experimentally observed in Fig. 3. Figure 7 presents data plots as a function of processing time. For the two-side welds, the second curve begins at ten seconds because the second run started at this time. $V VHHQ LQ )LJ D WHPSHUDWXUH YHUVXV WLPH SUR¿OH ZDV quite similar at the beginning of the welding process. The second run, for the two-side weld, produces a second peak, which after ten seconds attains about 580 °C, approximately the solidus WHPSHUDWXUHV IRU WKH $O &X /L DQG WKH $O 6L ¿OOHUV Indeed, the second run promotes a melt depth up to the opposite surface as shown in Fig. 3b. Since two melting periods are expected, the liquid had additional time for Li degassing in comparison to the one side run. Therefore, less porosity was obtained with two runs.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

2FFXUUHQFH RI 'HIHFWV LQ /DVHU %HDP :HOGHG $O &X /L 6KHHWV ZLWK 7 -RLQW &RQÂżJXUDWLRQ 1000

0.07

900 700

displacements (10-3 cm)

temperature (°C)

0.06

one side two sides

800 600 500 400 300 200

0.05 0.04 0.03 0.02

one side

0.01

100 0 0

5

10

15

two sides

0

20

0

5

time (s)

(a)

15

20

(b)

0.09

0.16

0.08

0.14

one side

0.12

two sides

0.07

stress (MPa)

0.06

-3

Strain (10 )

10 time (s)

0.05 0.04 0.03 0.02

one side

0.01

two sides

0.1 0.08 0.06 0.04 0.02

0

0 0

5

10

15

20

0

5

10

15

20

time (s)

time (s)

(c)

(d)

)LJXUH 6LPXODWLRQ UHVXOWV D WHPSHUDWXUH SURÂżOH DW WKH FHQWHU RI WKH ZHOG ÂżUVW UXQ VLGH E GLVSODFHPHQW RI D QRGH DW WKH PLGGOH EHWZHHQ two sheets. (c) Von Mises strain. (d) Von Mises stresses.

The displacement (Fig. 7b) represents the shift in position during welding of a point at the centerline exactly at the interface between the sheets. The measurement position is UHSUHVHQWHG E\ Âł[´ LQ )LJ $V WKH VKHHWV ZHUH ÂżUPO\ DWWDFKHG to the bench (Fig. 1), these movements were highly constrained leading to residual stresses. The rigid clamping had therefore LQĂ€XHQFHV RQ WKH VWUDLQV DQG VWUHVVHV DV VKRZQ LQ )LJV F DQG 7d. The calculated strain during welding attained 5 x 10-5 for the ÂżUVW UXQ DQG DERXW [ -5 for the second. The most important feature for cracking is the strain rate. A very high strain rate creates porosities at the root of dendrites, thus developing hot cracking (Rappaz et al., 1999). The value attained at the second run was 0.02 s-1. This value is very low and considered safe, at least for the AA6061 aluminum alloy (Drezet et al., 2008). The effect of different weld procedures on the mechanical stresses is presented in Fig. 7d. The low heat input of the twoside method compared to the one-side allowed a lower level of residual stress up to ten seconds. The residual stresses at ten seconds were 0.09 and 0.07 MPa, respectively. After the second run, the difference was even larger, 0.09 and 0.04 MPa.

These stress levels are very low compared to the elastic properties of aluminum alloys and thus the distortion should be very small. Indeed, the T-sets did not show distortions after welding. All these simulation results had been developed using an $$ DOOR\ GDWDEDVH DQG WKH ¿OOHU DGGLWLRQV KDG QRW EHHQ considered. Therefore, the results must be considered only in a qualitative way. Notwithstanding these results, it could be estimated that the T-joint with better chances to be used in DSSOLFDWLRQV LV WKDW ZLWK ¿OOHU DQG WZR UXQV 1RZ RQH QHHG to understand if the observed massive porosity produces an unsuitable weld from the mechanical point of view. The mechanical characterizations of the welds were presented in Figs. 8 and 9. For clarity reasons, the stress is presented in logarithm scale. Figure 8 presents a direct strainVWUHVV FXUYH FRPSDULVRQ EHWZHHQ DQ DXWRJHQRXV DQG ¿OOHU T-joint, when welded from one side to the other. As can be seen, the curves were very similar with a plateau up to 3.2 mm HORQJDWLRQ FRUUHVSRQGLQJ WR WKH ÀH[LRQ RI WKH VNLQ VKHHW DW low stresses. It is easy to see in Fig. 2 that the skin sheet will bend creating a three-point load scheme at the beginning of

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

427

Higashi, A.L.C., Lima, M.S.F. 1000

another aerospace alloy, AA6013, welded in similar T-joint conditions, welded one-side and autogenously. These results are presented in Fig. 10.

autogeneous filler

700 (a)

10

600 500

1 0

1

2

3

4

5

6

7

0.1

400 300 (b)

200

elongation (mm)

Figure 8.

Stress (MPa)

Stress (MPa)

100

Comparison of the mechanical behavior between an

100

(c)

autogeneous and filler-added welded. Conditions: 0

one-side welded (one run), P=1,200 W, v=2 m/min.

0

2

4

6

8

10

12

elongation (mm)

the mechanical testing. The tensile stress and maximum elongation seems to be approximately the same, regardless the use RI ÂżOOHU IRU RQH UXQ MRLQWV The mechanical behavior was completely different when welding from both sides (Fig. 9). Compared to the two-side DXWRJHQRXV ZHOG WKH XVH RI ÂżOOHU WRJHWKHU ZLWK WKH GRXEOH VLGH welding increased the tensile strength from 19 to 178 MPa, and the total elongation from 4.1 to 6.3 mm. The increased toughness, more than ten times, had been linked to the chemical changing of the liquid bath, since the thermomechanical behavior (Fig. 7) was about the same. 1000 autogeneous filler

Stress (MPa)

100

10

Conditions: (a) unwelded AA2198 sheet (maximum attainable condition); (b) Welded on both sides (two runs), P=1,200 W, v=2 m/min; (c) AA6013 aluminum alloy autogenously welded on one side.

The AA2198 welded coupons presented lower tensile strength and total elongation in comparison to the AA2198 unwelded coupon. This is due to the stress concentrator factor caused by the weld bead. Comparing the best results obtained in T-joint welds for AA2198 and AA6013, it could be seen that the tensile strength was much higher in the first case. The AA2198 welded coupon attained 178 MPa, compared to only 46 MPa of the AA6013 case. On the other hand, the total elongations were 9.2 from AA6013 and 2.8 mm for AA2198, indicating a hardening effect of the filler material in the present case. CONCLUSIONS

1 0

1

2

3

4

5

6

7

0.1 elongation (mm)

Figure 9. Comparison of the mechanical behavior between an DXWRJHQHRXV DQG ÂżOOHU DGGHG ZHOGHG &RQGLWLRQV ERWK sides welded (two runs), P=1,200 W, v=2 m/min.

It is worthwhile to compare the best result obtained in the present work with the two cases. Firstly, the AA2198 sheet without welding as the maximum attainable value. Secondly, 428

Figure 10. Comparison of the tensile mechanical behavior.

Even with a careful control of surface preparation, all the AA2198 T-joint welds presented pores, which were linked to the degassing of Li during melting. $GGLQJ D ÂżOOHU ULEERQ RI $$ DOOR\ EHWZHHQ WKH parts to be joined could solve the hot cracking problem. The decrease of the vulnerable to stress relief time during VROLGLÂżFDWLRQ ZDV SRLQWHG RXW DV WKH UHDVRQ IURP WKH ORZHU susceptibility for hot cracking. The results from thermomechanical and chemical analyses, and tensile T-pull strength testing indicated that welded by

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

2FFXUUHQFH RI 'HIHFWV LQ /DVHU %HDP :HOGHG $O &X /L 6KHHWV ZLWK 7 -RLQW &RQÂżJXUDWLRQ

WZR UXQV RQ ERWK VLGHV DQG E\ XVLQJ WKH ÂżOOHU ULEERQ SURGXFH tougher joints. The welds at 2 m/min and 1,200 W under these conditions were showing most promising properties, even in comparison to T-joined autogeneous AA6013 alloy. Because of high pore density, it is safer to consider less critical applications than the aerospace one. Depending on other results, such as fatigue behavior, the AA2198 welded parts could be used, for example, in land transportation systems.

King, D. et al., 2009, “Advanced aerospace materials: past, present and future, Aviation and The Environment�, Vol. 3, pp. 22-27. Lima, M.S.F. et al., 2000, “Advanced laser welding process�, European patent no. 01810986.8. Mangalgiri, P.D., 1999, “Composite materials for aerospace applications�, Bulletin of Materials Science, Vol. 22, pp. 657-664.

ACKNOWLEDGMENTS The authors thank EMBRAER for providing the aluminum sheets, Financiadora de Fundos e Projetos (FINEP) and )XQGDomR GH $PSDUR j 3HVTXLVD GR (VWDGR GH 6mR 3DXOR (FAPESP) for partial funding.

Page, A.J. and Sear, R.P., 2006, “Heterogeneous Nucleation in and out of Pores�, Physical Review Letters, Vol. 97, pp. 065701-1-065701-4.

5()(5(1&(6

Pallett, R.J. and Lark, R.J., 2001, “The use of tailored blanks in the manufacture of constuction components�, Journal of Materials Processing Technology, Vol. 117, pp. 249-254.

ASM – American Society of Materials, 1993, “Metals Handbook – Volume 6: Welding, Brazing, and Soldering�, 10nd ed., Metals Park (Ohio), ASM International, pp. 1392-1393.

Piwonka, T.S. and Flemings M.C., 1966, “Pore formation GXULQJ VROLGLÂżFDWLRQ´ 7UDQVDFWLRQV RI 0HWDOOXUJLFDO 6RFLHW\ AIME, Vol. 236, pp. 1157-1165.

Bordesoules, I. et al., 2007, “Trends in developments of Aluminium solutions for aerospace applications�, In: Proceedings of the European Workshop on Short Distance Welding Concepts for Airframes frames – WEL-AIR, Hamburg, 13-15 june 2007, CD-Rom.

Rappaz, M. et al., 1999, “A new hot tearing criterion�, Metallurgical and Materials Transactions, Vol. 30A, pp. 449-455.

Campbell, J., 2003, “Castingsâ€?, 2nd ed., Oxford: Elsevier Pergamon, 332p. &O\QH 7 : DQG 'DYLHV * - Âł$ 4XDQWLWLYH 6ROLGLÂżFDWLRQ 7HVW IRU &DVWLQJ DQG $Q (YDOXDWLRQ RI &UDFNLQJ in Aluminium-Magnesium Alloysâ€?, The British Foundryman, Vol. 68, pp. 238-254. Drezet, J.M. et al., 2008, “Crack-free aluminium alloy welds using a twin laser process, In: 61st International Conference RI WKH ,QWHUQDWLRQDO ,QVWLWXWH RI :HOGLQJ´ *UD] 6DIHW\ DQG reliability of welded components in energy and processing LQGXVWU\ *UD] $XVWULD 78 *UD] SS

RĂśtzer I., 2005, “Laser-beam welding maker aircraft lighterâ€?, Fraunhofer Magazine, Vol. 1, pp. 36-37. Siqueira, R.H.M. et al., 2012, “Microstructural and Mechanical Characterization of Laser Welded and Heat-Treated AA6013 Aluminum Alloyâ€?, In: Proceedings of XI Brazilian MRS Meeting, CD-Rom. ThermoCalc thermodynamic database, 1994, version J, Stockholm Royal Institute, Sweden. Wikipedia, the free encyclopedia, 2012, Von Mises yield criterion, Retrieved in June 25, 2012, from http://en.wikipedia. org/wiki/Von_Mises_ yield_criterion.

Duarte, I. and Banhart, J., 2000, “A study of aluminium foam formation-kinetics and microstructure�, Acta Materialia, Vol. 48, pp. 2349-2362.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 421-429, Oct.-Dec., 2012

429

doi: 10.5028/jatm.2012.04044412

Multidisciplinary Design Optimization of Sounding Rocket Fins Shape Using a Tool Called MDO-SONDA Alexandre Nogueira Barbosa1*, Lamartine Nogueira Frutuoso GuimarĂŁes2 ,QVWLWXWR GH $HURQiXWLFD H (VSDoR Âą 6mR -RVp GRV &DPSRV 63 Âą %UD]LO ,QVWLWXWR GH (VWXGRV $YDQoDGRV Âą 6mR -RVp GRV &DPSRV 63 Âą %UD]LO

1 2

Abstract: 0XOWLGLVFLSOLQDU\ GHVLJQ RSWLPL]DWLRQ LV D SURPLVLQJ ÂżHOG LQ DHURVSDFH HQJLQHHULQJ +RZHYHU DGYDQFHV LQ WKLV ÂżHOG KDYH QRW EHHQ DSSOLHG \HW WR LPSURYH %UD]LOLDQ VRXQGLQJ URFNHWV VXFK DV WKH 96 7KHUHIRUH WR JLYH D SHUVSHF WLYH RI WKH PXOWLGLVFLSOLQDU\ GHVLJQ RSWLPL]DWLRQ LQ WKLV FRQWH[W WKLV ZRUN SUHVHQWHG D FDVH VWXG\ RI WKLV URFNHW ZKLFK FRQVLVWV RI WKH VKDSH RSWLPL]DWLRQ RI LWV ÂżQV 7R DFKLHYH WKLV JRDO D VSHFLDO WRRO FDOOHG 0'2 621'$ ZKLFK LV WKH PDLQ FRQWULEXWLRQ RI WKLV ZRUN ZDV GHYHORSHG ,WV FXUUHQW YHUVLRQ LQWHUDFWV ZLWK WZR KLJK ÂżGHOLW\ H[HFXWDEOH FRGHV RQH RI DHURG\QDPLFV DQG DQRWKHU RI WUDMHFWRU\ H[SORLWLQJ WKH V\QHUJ\ EHWZHHQ ERWK GLVFLSOLQHV 7KH 0'2 621'$ LV EDVHG RQ D PXOWLREMHFWLYH JHQHWLF DOJRULWKP ZKRVH UHDO RSHUDWRU ZDV RULJLQDOO\ GHVLJQHG LQ WKLV ZRUN %\ XVLQJ WKH SURSRVHG WRRO LW ZDV IRXQG WKDW WKH GUDJ GXH WR WKH URFNHW ÂżQV FRXOG EH UHGXFHG XS WR ZLWKRXW LQFUHDVLQJ WKH FKDQFHV RI DGYHUVH HIIHFWV WKDW FRXOG OHDG WR XQVWDEOH EHKDYLRUV Keywords: 6RXQGLQJ URFNHW 5RFNHW ÂżQ GHVLJQ 0XOWLGLVFLSOLQDU\ GHVLJQ RSWLPL]DWLRQ 0XOWLREMHFWLYH JHQHWLF DOJRULWKPV

INTRODUCTION At the end of the 1990s, among the Brazilian sounding rockets, the VS-40 was presented as one that provides the best conditions for experiments in microgravity (Ribeiro, 1999). Space systems are complex, i.e., their behavior is governed by many distinct but interacting physical phenomena, and multidisciplinary, requiring balance among competing objectives related to safety, reliability, performance, operability, and cost (Rowell and Korte, 2003). Over time, advances in the engineering of complex systems have allowed to more quickly identify feasible solutions and exploit the synergy among the design disciplines (Rowell and Korte, +RZHYHU WKH 96 KDV QRW EHHQ EHQHÂżWHG E\ VXFK advances yet. The interactions between the design disciplines of the VS-40 were processed in a sequential order, in which those disciplines that act early in the conceptual design establish constraints on the others that follow later, leading to a concept without regarding the trade-offs that may exist between the design objectives. The plausible consequence of such sequential methodology is a suboptimal design with Received: 31/07/12

Accepted: 08/10/12

*author for correspondence: nogueiraanb@iae.cta.br 3UDoD 0DUHFKDO (GXDUGR *RPHV Âą 9LOD GDV $FiFLDV &(3 6mR -RVp GRV &DPSRV 63 Âą %UD]LO

respect to the entire project, promoted by low synergy between the design disciplines. 6LQFH ZKHQ WKH ¿UVW 96 ZDV ODXQFKHG WKH methodology that allows exploiting the synergy between its design disciplines has not been used yet for Brazilian sounding rockets. A methodology called multidisciplinary design optimization (MDO) replaces the traditional sequential methodology by synergic interactions between the design disciplines, promoting the overall gain in product’s performance, decreasing the design time (Floudas and Pardalos, 2009). Why should the VS-40 be revised? It promises the best conditions for microgravity experiments, but not widely launched yet such as the VSB-30, also a Brazilian sounding rocket, so that it could be more studied, and perhaps improved E\ FRQVLGHULQJ FROOHFWHG ÀLJKW GDWD 7KH 96 ZDV UHFHQWO\ PRGL¿HG DW WKH *HUPDQ $HURVSDFH &HQWHU '/5 LQ RUGHU WR SURYLGH WKH UHTXLUHG VWDELOLW\ IRU D VSHFL¿F PLVVLRQ EHFDXVH it was not originally designed for carrying a payload with exposed canards, indicating that its design can be altered, if QHFHVVDU\ WR EHQH¿W LWV VWDELOLW\ DQG SHUKDSV LWV SHUIRUPDQFH /DVWO\ LW KDV QRW EHHQ EHQH¿WHG E\ DGYDQFHV LQ WKH HQJLQHHULQJ of complex systems, and it may have some subsystems that could be improved regarding its next launches at Brazilian

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

431

%DUERVD $ 1 *XLPDUmHV / 1 )

territory carrying the Sub-orbital SARA, a Brazilian platform for microgravity experiments. Motivated by a search for VS-40 improvements, the use of the MDO was introduced in Brazilian sounding rockets. Therefore, the objective of this paper was to provide a perspective of the MDO application in this context based on a case study of the VS-40. As case study, the shape optimization RI WKH 96 ÂżQV ZDV SURSRVHG LQ RUGHU WR LPSURYH LWV SHUIRUPDQFH E\ UHGXFLQJ WKH GUDJ GXH WR WKH ÂżQV ZLWKRXW increasing the chances of adverse effects that could lead to unstable behaviors. To perform the optimization, a computer tool called MDO-SONDA (MDO of Sounding Rockets), which was developed by Alexandre Nogueira Barbosa, was XVHG 0'2 621'$ SUHVHQWDWLRQ LQ WKH OLWHUDWXUH ZDV ÂżUVW introduced by this paper. SOUNDING ROCKETS AND MICROGRAVITY ENVIRONMENT Sounding rockets, such as the VS-40, are characterized by WKHLU DSSOLFDWLRQ DQG Ă€LJKW SURÂżOH $FFRUGLQJ WR 0RQWHQEUXFN HW DO (2001), such rockets are constituted of solid fueled motors and a payload that carries instruments to take measurements DQG SHUIRUP VFLHQWLÂżF H[SHULPHQWV GXULQJ D SDUDEROLF Ă€LJKW Thus, the sounding term means taking measurements. In comparison with the VSB-30, the VS-40 bi-stage can provide a wide exposure to the microgravity environment, characterized by a condition where an object is subjected WR D J IRUFH OHVV WKDQ Č?J /D 1HYH DQG &RUUrD -U achieved by moving in free fall, where there are no forces other than gravity acting on the object. Payloads carried by rockets achieve the microgravity environment after the burnout of the rocket when the thrust force is zero and the payload is above the atmosphere. It is assumed that the KĂĄrmĂĄn line, at 100 km above the seawater surface, might be used as a reference for microgravity H[SHULPHQW SXUSRVHV WR GHÂżQH WKH ERXQGDU\ EHWZHHQ WKH atmosphere and the outer space, from which the atmosphere becomes so thin that the drag force could be neglected.

for microgravity experiments with an advantage, the payload recovery operation associated with the VSB-30 is less costly WKDQ ZLWK WKH 96 ZKRVH VSODVKGRZQ LV DSSUR[LPDWHO\ ÂżYH times more distant from the continent-ocean boundary than the VSB-30, demanding more autonomy for the recovery means. From 2004 to 2010, ten VSB-30 campaigns were successfully performed, three of them in the Brazilian territory *DUFLD HW DO , 2011). In contrast to the VSB-30, three VS-40 campaigns has occurred so far, two of them in the Brazilian WHUULWRU\ WKH ÂżUVW RQH LQ 6DQWD 0DULD FDPSDLJQ )LJ D DQG WKH VHFRQG RQH LQ /LYUDPHQWR FDPSDLJQ )LJ E ERWK DW WKH $OFkQWDUD /DXQFK &HQWHU &/$ LQ 0DUDQKmR ,$( 2Q -XQH D PRGLÂżHG 96 FDOOHG 96 0 carrying the Sharp Edge Flight Experiment (SHEFEX) II (Weihs HW DO D D *HUPDQ SURMHFW ZDV VXFFHVVIXOO\ launched at the Andøya Rocket Range in Northern Norway '/5 DQG LW EHFDPH WKH ÂżUVW 96 RSHUDWLRQ LQ DQRWKHU FRXQWU\ )LJ F 7KH 96 0 ÂżQV VKDSH )LJ F LV VLJQLÂżFDQWO\ GLIIHUHQW IURP WKH WZR SUHYLRXV 96 )LJV D DQG E 7KH QHZ ÂżQV ZHUH GHVLJQHG DQG FRQVWUXFWHG IRU 6+()(; ,, DW '/5 GXH WR WKH QHHG RI H[WHQGHG ÂżQV WR compensate for the aerodynamic effects of the small canards at the payload, as can be seen in Fig. 1c (Weihs HW DO , 2008). In 1997, a recovery orbital platform called SARA for supporting short-orbital experiments in microgravity environment was proposed (Moraes and Pilchowski, 1997). ,Q FRPSDULVRQ ZLWK D VXE RUELWDO Ă€LJKW ZKLFK SURYLGHV D few minutes of microgravity conditions, an orbital one can provide more than ten days before reentering the Earth’s DWPRVSKHUH 7KH 6SDFH &DSVXOH 5HFRYHU\ ([SHULPHQW 65( ZKLFK LV DQ ,QGLDQ VSDFHFUDIW ÂżUVW ODXQFKHG LQ LV D YHU\

FACTS ABOUT THE VS-40 In spite of the fact that the VS-40 provides more exposure to microgravity than the VSB-30, since the 21st century began, rather than the VS-40, the VSB-30 has been most frequently XVHG IRU PLFURJUDYLW\ H[SHULPHQWV *DUFLD HW DO , 2011). &HUWDLQO\ EHFDXVH WKH 96% KDV PHW PLVVLRQ UHTXLUHPHQWV 432

(a)

(b)

(c)

Sources: (a) and (b) Institute of Aeronautics and Space, Brazil;

F '/5

Figure 1. VS-40 launches.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

0XOWLGLVFLSOLQDU\ 'HVLJQ 2SWLPL]DWLRQ RI 6RXQGLQJ 5RFNHW )LQV 6KDSH 8VLQJ D 7RRO &DOOHG 0'2 621'$

similar example of such a kind of platform (Reddy, 2007). $OVR DQ H[DPSOH LV WKH 5(; )UHH )O\HU WKH *HUPDQ SURSRVDO for application of SHEFEX derived technology, which is a reusable orbital return vehicle for experiments under microgravity conditions (Weihs HW DO , 2008b). Thereafter, a platform called Sub-orbital SARA, which is part of the road map to achieve the orbital mission purpose of this platform, has been constructed to be launched by a VS-40, supporting an experimental module to be exposed to PLFURJUDYLW\ HQYLURQPHQW /D 1HYH DQG &RUUrD 7KH 96 ZDV RULJLQDOO\ GHVLJQHG IRU ÀLJKW TXDOL¿FDWLRQ of the S44 motor, which constitutes the fourth stage of the %UD]LOLDQ ODXQFK YHKLFOH 9/6 3HUHLUD DQG 0RUDHV -U ,Q ZKHQ WKH ¿UVW 96 ZDV ODXQFKHG WKH 0'2 methodology had recently been presented. 7KH VKDSH RSWLPL]DWLRQ RI WKH 96 ¿QV ZLOO EH SUHVHQWHG as a case study using such methodology to demonstrate its application in the context of Brazilian sounding rockets. However, before presenting the results of the optimization, the main aspects of the MDO-SONDA will be further depicted. MULTIDISCIPLINARY DESIGN OPTIMIZATION OF SOUNDING ROCKETS The MDO-SONDA was conceived to exploit the synergy between the design disciplines of sounding rockets. Among them, those that use physics-based engineering models are: propulsion, aerodynamics, heating, structures, controls, and trajectory. Its current version interacts in batch mode with WZR KLJK ¿GHOLW\ H[HFXWDEOH FRGHV RQH RI DHURG\QDPLFV and another of trajectory. Thus, it can exploit the synergy between these two disciplines. Interacting with at least two disciplines makes the MDO-SONDA able to demonstrate the MDO methodology. Besides, it can support multiobjective problems. It can also investigate the trade-offs between the design objectives. 1st step

2nd

Objective function

interacts with

interacts with

Missile DATCOM software

ROSI software

Aerodynamic discipline

Trajectory discipline

The current version is only prepared for optimization of WKH VKDSH RI URFNHW ÂżQV +RZHYHU LW LV DQ REMHFW RULHQWHG FRGH ZULWWHQ LQ & WKDW SURYLGHV VSHFLÂżF IRUPV FODVVHV DQG REMHFWV to structure proper interfaces for further studies, including the shape optimization of other rocket subsystems, such as DGGLWLRQDO VHW RI ÂżQV QRVH IDLULQJ SURWXEHUDQFHV DQG FRQLFDO transitions between rocket stages of different diameters. The main aspects of the MDO-SONDA are architecture, inputs, outputs, optimization algorithm, and how to proceed with the optimization. Architecture The architecture of the MDO-SONDA is described in two parts: the interaction between the objective function and WZR KLJK ÂżGHOLW\ H[HFXWDEOH FRGHV RQH RI DHURG\QDPLFV DQG another of trajectory (Fig. 2a); and, the interaction between the optimization algorithm and the objective function (Fig. 2b). 7KH KLJK ÂżGHOLW\ H[HFXWDEOH FRGHV DUH PLVVLOH GDWFRP DQG rocket simulation (ROSI). The missile datcom is a widely used semi-empirical aerodynamic prediction code, which estimates aerodynamic forces, moments, and stability derivatives for a wide range RI PLVVLOH FRQÂżJXUDWLRQV DV D IXQFWLRQ RI WKUHH DWPRVSKHULF descriptors: Mach number, altitude, and angle of attack (Sooy and Schmidt, 2005). Its original version was developed in )2575$1 E\ WKH 0F'RQQHOO 'RXJODV &RUSRUDWLRQ /DWHU the FORTRAN 90 version was documented by the U.S. Air Force (Blake, 1998). The ROSI is also a FORTRAN code. It computes the motion of a rigid body in a three-dimensional space, considering also its rotation in yaw, pitch, and roll axes (Ziegltrum, *RPHV ,WV RULJLQDO YHUVLRQ ZDV GHYHORSHG E\ '/5 =LHJOWUXP 6LQFH WKH V WKH 526, KDV EHHQ successfully used for the trajectory calculation of Brazilian sounding rockets. 1st step

assigns values to

Optimization algorithm 3rd

Design variables 2nd feed

feeds 5th Evaluation of each cost function

calls

Objective function

(a)

4th

returns

(b)

Figure 2. Interactions of the MDO-SONDA.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

433

%DUERVD $ 1 *XLPDUmHV / 1 )

The MDO-SONDA calls the executable codes in batch mode, which means to run to completion without manual intervention. The missile datcom provides to ROSI the IROORZLQJ DHURG\QDPLF SURSHUWLHV GUDJ FRHI¿FLHQW &D), QRUPDO IRUFH FRHI¿FLHQW GHULYDWLYH ZLWK DQJOH RI DWWDFN &1Ď), SLWFKLQJ PRPHQW FRHI¿FLHQW GHULYDWLYH ZLWK DQJOH RI DWWDFN &0Ď SLWFKLQJ PRPHQW FRHI¿FLHQW GHULYDWLYH ZLWK SLWFK UDWH &Mq UROOLQJ PRPHQW FRHI¿FLHQW GHULYDWLYH ZLWK UROO UDWH &lp), and center of pressure (Xcp). ,Q DGGLWLRQ 526, XVHV WKH UROO GULYLQJ FRHI¿FLHQW &Oį &lp DQG &Oį DUH SDUDPHWHUV RI HDFK VLQJOH ¿Q WR GHWHUPLQH WKH UROO rate of the rocket. Unfortunately, the missile datcom does not SURYLGH &Oį EXW SURYLGHV WKH UROOLQJ PRPHQW FRHI¿FLHQW &l). To use missile datcom calculation indirectly, it is assumed that &l IRU D YHU\ VPDOO GHÀHFWLRQ DQJOH RI HDFK ¿Q į ž FDQ EH XVHG WR HVWLPDWH &Oį (Eq. 1):

Cld =

2Cl C1 , 0.01c 2d

Outputs (1)

The MDO-SONDA manages the process of each executable code, writes their inputs, and reads their outputs, coordinating their interaction. During the optimization loop, if they freeze for any reason, their processes are, automatically, killed and restarted but with different inputs. First, the MDO-SONDA interacts with missile datcom, obtaining the aerodynamic FRHI¿FLHQWV 7KHQ LW ZULWHV WKH FRHI¿FLHQWV LQWR WKH LQSXW ¿OH of ROSI, which also receives the mass and inertia properties of the rocket, i.e., the changes of mass, center of gravity, moment of inertia and product of inertia, computed by the MDO-SONDA due to spent stage separations, system releases DQG SURSHOODQW FRQVXPSWLRQ DORQJ WKH URFNHW ÀLJKW 2QH PDMRU EHQH¿W RI WKH 0'2 621'$ LV WR SURYLGH D user-friendly interface to insert input values and to check, graphically, outputs of both missile datcom and ROSI. It also SURYLGHV WKH YLVXDOL]DWLRQ RI WKH LQSXW ¿OH RI HDFK H[HFXWDEOH code, which is automatically generated to make sure that there is not any apparent mistake. Inputs The MDO-SONDA inputs can be grouped in three parts. 7KH ¿UVW RQH FRQVLVWV RI LQLWLDO FRQGLWLRQV ÀLJKW HYHQWV DQG URFNHW GH¿QLWLRQV ZKLFK SURYLGH WKH HQWULHV WR HVWLPDWH WKH DHURG\QDPLF FRHI¿FLHQWV DQG WR VLPXODWH WKH URFNHW WUDMHFWRU\ The second are the elements of the optimization problem: GHVLJQ REMHFWLYHV YDULDEOHV DQG FRQVWUDLQWV /DVWO\ WKH WKLUG ones are the optimization algorithm settings. With respect to 434

WKH ¿UVW SDUW W\SLFDO ÀLJKW HYHQWV DUH VWDJH LJQLWLRQ EXUQRXW spent stage separation, nose fairing ejection, and system release. Such events divide the trajectory calculation into phases, since WKH\ SURGXFH DEUXSW FKDQJHV LQ WKH URFNHW FRQ¿JXUDWLRQ )RU LQVWDQFH WKH DHURG\QDPLF FRHI¿FLHQWV DUH JLYHQ DV D IXQFWLRQ of Mach and altitude for each change in rocket geometry, due to the separation of its parts, and jet plume, due to switching a motor on and off. Each phase is characterized by rocket GH¿QLWLRQV ZKLFK GHQRWH WKH SKDVH FRQ¿JXUDWLRQV RI WKH URFNHW 7KXV IRU HDFK RQH URFNHW GH¿QLWLRQV DUH JHRPHWU\ of the body, propulsion data, and mass and inertia properties of each subsystem that still remains in the rocket during the ÀLJKW 8VLQJ WKH +X\JHQV 6WHLQHU WKHRUHP WKH 0'2 621'$ computes the total mass and inertia properties of each phase FRQ¿JXUDWLRQ RI WKH URFNHW

The MDO-SONDA provides an output interface for each executable code and for the optimization results. Using such interfaces, the user can save and analyze later the Paretooptimal solutions by using the features of the output interface for missile datcom and ROSI in order to verify and validate WKH ¿QDO UHVXOWV Optimization algorithm Since it is expected that the objective functions have many local minima and maxima and unknown function’s gradient, the appropriate methods are, traditionally, genetic algorithms and simulated annealing, according to the logic decision for choosing MDO, which was proposed by Rowell DQG .RUWH &RQVLGHULQJ WKH WUDGLWLRQDO DSSURDFK WKH MDO-SONDA is based on a multiobjective nongenerational JHQHWLF DOJRULWKP %DUERVD DQG *XLPDUmHV 7KH nongenerational approach is adequate for multiobjective issues, since it preserves individuals that are closer to the Pareto front 9DOHQ]XHOD 5HQGyQ DQG 8UHVWL &KDUUH 7KH YHUVLRQ RI this genetic algorithm approach, which was used in this work, is based on the proposal of Borges and Barbosa (2000). The nongenerational algorithm starts generating and assessing the LQLWLDO SRSXODWLRQ FRPSXWLQJ WKH ¿WQHVV RI HDFK LQGLYLGXDO DQG UDQNLQJ WKH SRSXODWLRQ DFFRUGLQJ WR LW 7KHQ SUHGH¿QHG quantity of iterations is started, which will be satisfactory if all individuals become nondominated at the completion of the optimization. Each iteration consists of selecting two individuals, denoted by parents, generating their offspring that

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

0XOWLGLVFLSOLQDU\ 'HVLJQ 2SWLPL]DWLRQ RI 6RXQGLQJ 5RFNHW )LQV 6KDSH 8VLQJ D 7RRO &DOOHG 0'2 621'$

LQFOXGHV WZR QHZ VXEMHFWV FRPSXWLQJ WKHLU ÂżWQHVV DQG VHOHFWLQJ WKH QHZ LQGLYLGXDO ZLWK WKH EHVW ÂżWQHVV DQG WHVWLQJ WKH VHOHFWHG individual to decide on his/her inclusion into the population. Despite the denomination given to this genetic algorithm, nongenerational, each iteration denotes a generation, since a new individual can be introduced into the population. In the version used in this work, new individuals are accepted only if they are not bad than the worst individual in the population %DUERVD DQG *XLPDUmHV $OVR WKLV ZRUN XVHG D UHDO RSHUDWRU WKDW SURGXFHV ERWK GLYHUVLÂżFDWLRQ DQG LQWHQVLÂżFDWLRQ of the search for optimal solutions instead of the original binary operators, since the optimization problem of current interest is based on continuous objective functions. The proposed real operator works on a normalized search space. Firstly, appropriate values are assigned to its parameters: FRHIÂżFLHQW RI PXWDWLRQ c), lower bound of mutation (Ninf), and upper bound of mutation (Nsup ZKHUH WKH ÂżUVW SDUDPHWHU is a real number and the last two are integers. Secondly, the operator visits each solution that were previously chosen to JHQHUDWH D GHVFHQGDQW UXQQLQJ WKH IROORZLQJ VWHSV *LYHQ D chosen solution, a variable (Y) of it that is a design variable is randomly chosen to suffer mutation. Thirdly, an integer (N) is randomly generated between Ninf and Nsup, and a real value (p) is randomly generated between zero and one. Finally, the new value of Y derives from the old one plus an increment (m), which is given by Eq. 2:

m=)

- tv if p = 0; t (1 - v), otherwise

(2)

where -k

t = c$e

2

(3)

,Q (T ZKHQ WKH FRHIÂżFLHQW RI PXWDWLRQ c increases, WKH GLYHUVLÂżFDWLRQ RI WKH VHDUFK GRHV WKH VDPH 7KH PRUH GLYHUVLÂżHG WKH PRUH JOREDOL]HG WKH RSWLPL]DWLRQ LV +RZHYHU it is important to establish a compromise between both GLYHUVLÂżFDWLRQ DQG LQWHQVLÂżFDWLRQ LQ RUGHU WR DYRLG H[FHVVLYH HYDOXDWLRQV RI WKH REMHFWLYH IXQFWLRQ LI GLYHUVLÂżFDWLRQ ZHLJKV PRUH WKDQ LQWHQVLÂżFDWLRQ RU SUHPDWXUH FRQYHUJHQFH RWKHUZLVH How to proceed with the optimization The optimization is a trial process. It consists of choosing the preliminary intervals for the design variables. The output interface for optimization results uses a method for analyzing multivariate data, which is called parallel coordinates. This

method consists of parallel lines, vertical and equally spaced, where each line corresponds to a design variable and the maximum and minimum values of each variable are usually scaled to the upper and lower boundaries on their respective OLQHV *ULQVWHLQ HW DO 8VLQJ WKLV DSSURDFK RQH YHUL¿HV graphically, whether the promising region of the search space is reaching the lower and upper bounds or not. Then, if it does, it suggests that the bounds should be extended. Otherwise, it may suggest that the bounds should be more restrictive. Furthermore, the analyses of the optimization results may expose unfeasible conditions that were not considered before in the optimization problem. Thus, the optimization is also a learning process on the self-optimization problem. CASE STUDY This section presents the case study of the VS-40 by using the MDO-SONDA. Firstly, the elements of the optimization SUREOHP ZLOO EH GH¿QHG 7KHQ WKH VHWWLQJV RI WKH PXOWLREMHFWLYH nongenerational genetic algorithm will be presented, and WKH VROXWLRQV WR LPSURYH WKH 96 ¿QV ZLOO EH FRPPHQWHG Finally, a mission analysis considering a hypothetical payload mass to microgravity experiment will be presented on the point of view of the trajectory discipline to evaluate the gain REWDLQHG ZLWK WKH LPSURYHG ¿QV LQ FRPSDULVRQ ZLWK WKH 96 ZLWK LWV RULJLQDO ¿QV WDNLQJ LQWR DFFRXQW WKH LQÀXHQFH RI ZLQG DQG GLVSHUVLRQ IDFWRUV RI WKH 96 RQ LWV ÀLJKW Design problem statement 7KH GHVLJQ LVVXH PD\ EH GH¿QHG DV IROORZV *LYHQ WKH original design of the VS-40 with a payload of 240 kg, and assuming that this mass is the minimum acceptable for this URFNHW WKH JRDO LV WR ¿QG DQ LPSURYHG GHVLJQ IRU LWV WDLO ¿QV To achieve such a goal, two design objectives were pursued: PLQLPL]DWLRQ RI WKH GUDJ IRUFH FDXVHG E\ WKH URFNHW ¿QV and maximization of the shortest interval between critical ÀLJKW HYHQWV ZKLFK DUH WUDQVRQLF VSHHG PD[LPXP G\QDPLF pressure, minimum static margin, and pitch-roll crossing. The second objective is commonly pursued to avoid subjecting the rocket to severe conditions that could induce an unstable behavior. The transonic speed refers to the range of Mach 0.8 to 1.4, in which severe instability can occur due to oscillating shock waves and large acoustic energy release. The maximum dynamic pressure is often related to the point of maximum DHURG\QDPLF ORDG ,QGHHG WKH ¿QV KDYH QHJOLJLEOH LQÀXHQFH on the instants of both the transonic speed and the maximum

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

435

%DUERVD $ 1 *XLPDUmHV / 1 )

G\QDPLF SUHVVXUH 7KHLU UHVSRQVHV DUH VLJQL¿FDQWO\ UHODWHG WR WKH rocket propulsion. The static margin is the position of the center of pressure, where the aerodynamic forces act, minus the position of the center of gravity, both measured with respect to the nose tip as referential and positive in the direction of the rocket tail. If the static margin is negative, that is, the center of pressure is ahead of the center of gravity, the rocket is aerodynamically unstable. If it is positive but too small, it increases the rocket oscillations, which can affect the rocket performance. The pitchroll crossing, that is, the crossing between the pitch and the roll rates, can lead to a physical phenomenon called roll resonance followed by the roll lock-in, where the roll rate deviates from its GHVLUHG SDWK &RUQHOLVVH HW DO , 1979). These two latter critical ÀLJKW HYHQWV DUH VLJQL¿FDQWO\ DIIHFWHG E\ WKH ¿QV RI WKH URFNHW Before proceeding with the comments on the solutions to LPSURYH WKH 96 ¿QV DQ XQREYLRXV TXHVWLRQ ZDV DQVZHUHG ZKHQ DWWHPSWLQJ WR PLQLPL]H WKH GUDJ GXH WR ¿QV GRHV WKH second objective suffer as a result? It is also demonstrated that the MDO methodology can be used to investigate whether design objectives are competing or not, leading to a more comprehensive understanding of the system’s trade-offs. Figure 3 describes the design variables. The VS-40 is a ERG\ WDLO URFNHW FRQ¿JXUDWLRQ ZLWK IRXU LGHQWLFDO WDLO ¿QV DUUDQJHG LQ D FUXFLIRUP JHRPHWU\ ,WV ¿QV KDYH KH[DJRQDO airfoil geometry and two segments. In this case study, only the second segment was subjected to optimization (Fig. 3). Still, the variation of mass and inertia properties related to the shape FKDQJH RI WKH ¿QV ZDV QHJOHFWHG 7KH LQWHUYDOV RI VKDSH YDULDWLRQ RI WKH ¿QV DUH HVWDEOLVKHG LQ 7DEOH ZKLFK GH¿QHV WKH FRQWLQXRXV GHVLJQ VHDUFK VSDFH for optimization.

Table 1. Bounds of the design variables.

Design variable 1 (degrees) 2 (m) 3 (m) 4 (m) 5 6 7 (m)

Nominal /RZHU ERXQG Upper bound 0.6 0.42 0.6 0 0 2.4843 0.7095 0.7095 0.9095 1.2513 1 1.2513 0.348038 0.348038 0.417646 0.799168 0.719 0.959002 0.016783 0.011748 0.016783

The optimization was subjected to the following side FRQVWUDLQWV UROO UDWH ” +] DQG VWDWLF PDUJLQ • FDOLEHUV Such constraints are necessary because excessive roll rate affects the structure, and too small static margin increases oscillations. Both situations can affect rocket performance. Optimization settings and results Table 2 presents the settings of the multiobjective nongenerational genetic algorithm used in MDO-SONDA. It also shows that the neighborhood radius and the graduation IDFWRU DUH SDUDPHWHUV RI WKH ¿WQHVV IXQFWLRQ ZKLFK UHJXODWH the distribution of solutions along the Pareto front (Borges and Barbosa, 2000). Despite the small number of design variables, this case study showed that computational cost could become an issue. A single simulation involving interactions between aerodynamics and trajectory calculations takes 12 seconds LQ D *+] 'XDO &RUH 6LQFH HYDOXDWLRQV RI WKH objective function were required for seven design variables, the optimization took four hours.

b a Var-7

a

Side (i) Side (ii) Note: (ii) is the mirror of (i).

Var-4

Var-4 ˜ 1 Var-5 ˜ Var-6

b Var-4 ˜ Var-5 ˜ Var-6 where 0 d Var-5 d 1

Span station at (*)

0 d Var-6 d 1

Var-2

(*) Var-3

1.2513 m

Second segment

Fin panel

First segment (area = 0.2279 m2)

Var-1 (deflection angle)

)LJXUH 'HVLJQ YDULDEOHV RI WKH WDLO ÂżQ DLUIRLO DQG JHRPHWU\

436

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

Shortest interval between critical flight events (s)

0XOWLGLVFLSOLQDU\ 'HVLJQ 2SWLPL]DWLRQ RI 6RXQGLQJ 5RFNHW )LQV 6KDSH 8VLQJ D 7RRO &DOOHG 0'2 621'$ Table 2. Optimization algorithm settings.

Parameter

Value

Size of the population Number of generations Neighborhood radius *UDGXDWLRQ IDFWRU &RHIÂżFLHQW RI PXWDWLRQ /RZHU ERXQG RI PXWDWLRQ Upper bound of mutation Float-point precision

20 600 2 0.5 1.4 1 6 0.001

We have found a Pareto front, demonstrating that the PLQLPL]DWLRQ RI WKH GUDJ GXH WR ¿QV DQG WKH PD[LPL]DWLRQ RI WKH VKRUWHVW LQWHUYDO EHWZHHQ FULWLFDO ÀLJKW HYHQWV DUH competing objectives (Fig. 4). ,W VHHPV WKDW WKH ¿WQHVV IXQFWLRQ DV SURSRVHG E\ %RUJHV and Barbosa (2000), gave well-distributed points along the Pareto front (Fig. 4). However, despite the fact that population VL]H ZDV ¿[HG DW 7DEOH )LJ RQO\ SUHVHQWV D VHW RI points. Indeed, in some of these points, there is more than one solution with slight differences between them. Optimization results seem to be coherent. The interval between the transonic speed and the maximum dynamic SUHVVXUH HYHQWV LV VHFRQGV QR PDWWHU ZKDW ¿QV DUH XVHG The optimization could not lead to solutions that exceed such LQWHUYDO )LJ $OVR WKH GUDJ GXH WR WKH URFNHW ¿QV FDQ EH reduced up to 29% without increasing the chances of adverse effects that could lead to unstable behaviors (Fig. 4). There are some chances that adverse effects increase when two or more FULWLFDO ÀLJKW HYHQWV RFFXU DW WKH VDPH LQVWDQW )LJXUH VKRZV

9 11

8

Nose tip

10

7 6 5

Pareto-optimal solutions

4 3

Original fins

2 1 0

-8

-7.5

9

Fin profile

8

7

6 5

4 3 2

1

-7 -6.5 -6 -5.5 Drag force caused by fins (kN)

-5

-4.5

Figure 4. Optimization results.

on [-axis the total drag minus its value without computing the ÂżQV LQ WKH GUDJ FRHIÂżFLHQW FDOFXODWLRQ ZKLFK LV N1 Thus, in terms of the total drag, the reduction was up to 5%. Regarding the parallel coordinates graph, the promising area of the search space has reached the limits of almost the totality of the design variables (Fig. 5). In Fig. 5, regarding the line of Var-7, which is related to the WKLFNQHVV RI WKH ÂżQV WKH UHVXOWV VXJJHVW WKDW WKH ORZHU ERXQG KDV WR EH UHGXFHG &HUWDLQO\ WKH ERXQGV KDYH WR EH NHSW ZKHQ they also want to avoid unfeasible solutions. Therefore, the lower bound of Var-7 is kept, assuming that its reduction can lead to structural issues. Table 3 presents a Pareto-optimal solution associated with each point in Fig. 4. It is worth noting, based on Var-3 and Var-4 values in Table 3 and the chord at the base of the VHFRQG VHJPHQW RI WKH ÂżQ SDQHO DQG WKH DUHD RI WKH ÂżUVW RQH

7DEOH 'LPHQVLRQV RI ÂżQV IRU WKH 96 Solution*

Variable 1 (m)

Variable 2 (m)

Variable 3 (m)

Variable 4 (m)

a (m)

b (m)

Variable 7 (m)

Original 1

0.600 0.587

0.000 2.429

0.710 0.793

1.251 1.167

0.652 0.584

0.348 0.382

0.0168 0.0117

2

0.589

1.995

0.787

1.084

0.608

0.426

0.0118

3

0.550

1.995

0.787

1.084

0.597

0.418

0.0118

4

0.526

1.995

0.787

1.084

0.584

0.409

0.0118

5

0.427

1.995

0.787

1.084

0.577

0.409

0.0118

6

0.420

1.766

0.793

1.095

0.610

0.440

0.0117

7

0.420

1.995

0.812

1.095

0.626

0.423

0.0117

8

0.420

1.995

0.842

1.066

0.603

0.416

0.0118

9

0.421

1.995

0.862

1.089

0.622

0.421

0.0118

10 11

0.420 0.422

2.029 1.855

0.862 0.905

1.212 1.196

0.690 0.684

0.470 0.461

0.0117 0.0118

*solutions are ordered as in Fig. 4. J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

437

%DUERVD $ 1 *XLPDUmHV / 1 ) 1

Normalized Interval

Promising region boundary Dominated solutions Original fins Pareto-optimal solutions

0 Var-1

Var-2

Var-3

Var-4

Var-5

Var-6

Var-7

Design variables

Figure 5. Vizualization of the parallel coordinates.

showed in Fig. 3, the Pareto-optimal solutions have from 2.8 to 19.6% more surface than the original panel. Surface area often has more impact than geometry, increasing the drag, despite any attempts to reduce it by choosing an adequate geometry. However, the extended surface area of the Paretooptimal solutions does not seem to cause any disadvantage in FRPSDULVRQ ZLWK WKH RULJLQDO ÂżQV )LJXUH LV HYLGHQFH WKDW WKH RULJLQDO ÂżQV DUH QRW DGHTXDWH 7KH RULJLQDO ÂżQV RI WKH 96 KDYH UHFWDQJXODU SDQHOV )LJ E $PRQJ WKH SDQHO JHRPHWULHV IRU ÂżQV WKH UHFWDQJXODU LV WKH one that provides more drag in supersonic speed, based on equal surface area and span between the geometries (Fleeman, 'HVSLWH WKH UHGXFHG VXUIDFH DUHD RI WKH RULJLQDO ÂżQV LW causes more drag than the Pareto-optimal solution number 11, which has the largest surface area. Among the Pareto-optimal solutions, the drag increases as WKH VXUIDFH DUHD LQFUHDVHV GHPRQVWUDWLQJ WKH VWHDG\ LQĂ€XHQFH of the surface area (Fig. 6). However, the solution number 1 is an outlier, since it causes less drag than solutions from 2 to 7 but it has an area slightly extended with similar geometry (Fig. 4). Solutions are ordered as in Fig. 4.

Magnitude of the drag due to fins (kN)

8

Original solution 7.5

11

7

6.5

7

9

6

6

5.5

5

8

10

1.1

{2,3,4,5} 1 1.15

1.2

1.25

Area of the fin panel (m2)

)LJXUH 'UDJ GXH WR ÂżQV YHUVXV ÂżQ SDQHO DUHD

438

1.3

1.35

Despite the fact that solutions providing the shortest LQWHUYDO EHWZHHQ FULWLFDO ÀLJKW HYHQWV JUHDWHU WKDQ WZR seconds are those safer than the solution number 1, for PLVVLRQ DQDO\VLV WKH LPSURYHG ¿QV ZHUH VHOHFWHG VLQFH LW LV the Pareto-optimal solution that causes the largest reduction of the drag, increasing the rocket’s performance. Mission analysis The proposed mission to be analyzed is characterized by a hypothetical payload of 240 kg, which is carried by the VS-40 to be exposed to microgravity environment. If one suppose the mission is scheduled for December, corresponding to the WUDQVLWLRQ EHWZHHQ WKH GU\ DQG UDLQ\ SHULRGV LQ &/$ &DVWUR and Fisch, 2007), when wind surface reduces gradually with WKH RFFXUUHQFH RI UDLQ WKH RSHUDWLRQ ZLOO EH EHQH¿WHG 7KH goal is to evaluate what is the gain in the performance of the 96 ZLWK WKH LPSURYHG ¿QV LQ FRPSDULVRQ ZLWK LWV RULJLQDO ones considering this hypothetical mission. The maximum expected gain can be estimated without performing any optimization. The trajectory simulation ZLWKRXW FRPSXWLQJ WKH ¿QV LQ WKH GUDJ FRHI¿FLHQW FDOFXODWLRQ provides an expected gain of 2.9% (Fig. 7). Despite the small LQÀXHQFH RI WKH ¿QV RQ WKH SHUIRUPDQFH RI WKH URFNHW LQ PLFURJUDYLW\ DV UHÀHFWHG E\ WKH VPDOO H[SHFWHG JDLQ LW ZDV seen that the conditions of a mission analysis can affect the JDLQ GXH WR LPSURYHPHQW RI WKH URFNHW ¿QV ,JQRULQJ WKH LQÀXHQFH RI WKH ZLQG DQG RI GLVSHUVLRQ IDFWRUV RI WKH 96 RQ LWV ÀLJKW D WRWDO GUDJ UHGXFWLRQ RI XVLQJ WKH LPSURYHG ¿QV FDXVHV DQ HODSVHG ÀLJKW WLPH gain in microgravity of 1.6% (Fig. 7). However, since the VS-40 is an unguided rocket, wind effects and dispersion factors should be considered. The mission analysis consists of taking into account these factors in the evaluation of the 96 FRQ¿JXUDWLRQV RQH ZLWK WKH LPSURYHG ¿QV DQG DQRWKHU

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

0XOWLGLVFLSOLQDU\ 'HVLJQ 2SWLPL]DWLRQ RI 6RXQGLQJ 5RFNHW )LQV 6KDSH 8VLQJ D 7RRO &DOOHG 0'2 621'$

Elapsed flight time in microgravity (s)

1020

The VS-40 with its original fins The VS-40 with improved fins The VS-40 without computing fins drag

1000

980

Gain of 2.9% Gain of 1.6%

960

940

920

900

880

80

80.5

81

81.5

82

82.5

83

83.5

84

84.5

85

Launch elevation (degrees)

)LJXUH (ODSVHG ÀLJKW WLPH FDSDELOLW\ LQ PLFURJUDYLW\ HQYLURQPHQW YDU\LQJ ZLWK ODXQFK HOHYDWLRQ 7KH XSSHU HOHYDWLRQ LV ž DFFRUGLQJ WR &HQWUR GH /DQoDPHQWR GH $OFkQWDUD

ZLWK WKH RULJLQDO ¿QV 7KH ODXQFK D]LPXWK DQG HOHYDWLRQ WKDW SURYLGH WKH GHVLUDEOH SUREDELOLW\ WR SURFHHG EULHÀ\ ZLWK WKH PLVVLRQ DUH ¿UVWO\ REWDLQHG E\ FRQVLGHULQJ WKH ZLQG HIIHFW 7KHQ ¿[LQJ WKH DGHTXDWH ODXQFK D]LPXWK DQG HOHYDWLRQ IRU HDFK 96 FRQ¿JXUDWLRQ WKH WKHRUHWLFDO GHYLDWLRQ RI WKH elapsed time in microgravity is estimated by considering the dispersion factors of the rocket. Finally, the gain in the SHUIRUPDQFH RI WKH 96 ZLWK WKH LPSURYHG ¿QV LV HVWLPDWHG based on the average value of the elapsed time in microgravity, LQ FRPSDULVRQ ZLWK LWV RULJLQDO FRQ¿JXUDWLRQ $ ODUJH SHUFHQWDJH RI WKH WRWDO ZLQG LQÀXHQFH RQ WKH URFNHW RFFXUV YHU\ HDUO\ LQ ÀLJKW 'XULQJ DQ RSHUDWLRQ LQ WKH Brazilian territory, to compensate for the wind effect, it is necessary to adjust the launch azimuth and elevation based on wind data, which are collected few moments before liftoff. Two types of wind sensing devices are provided, rawinsondes to high altitudes and anemometer measurements RI ZLQG VXUIDFH SUR¿OH 7KH SURFHGXUH WR PDNH WKH ODXQFK azimuth and elevation adjustments for sounding rockets, still adopted by the Brazilian launch centers, is based on Hennigh (1964). It consists of determining, for a range of launch elevations, the wind weighting as a function of the altitude, and the splashdown displacements caused by a unit range- and cross-wind, respectively. Such displacements are determined by considering the wind up to an upper limit of the effective atmosphere. The range-wind azimuth is given in the direction of the rocket launch tower, while WKH FURVVZLQG LV QRUPDO WR LW 7KHQ JLYHQ D ZLQG SUR¿OH DV input, the procedure consists of evaluating the ballistic wind, combining data provided by the wind sensing devices with

the wind weighting function, which had been previously calculated. The ballistic wind is hypothetical and constant in GLUHFWLRQ DQG PDJQLWXGH IURP WKH JURXQG OHYHO WR D GH¿QHG upper limit of the effective atmosphere. In practice, the upper limit of the effective atmosphere is roughly 25 km (Hennigh, 1964). Finally, considering the ballistic wind, the splashdown displacement caused by a unit wind, and the assumption that the response of the rocket is linear with the wind velocity, the launch azimuth and elevation are adjusted. However, due to stochastic behavior of the wind, dispersion factors of the rocket, structural issues, geographical constraints, and rocket assumption of the linear response to make the adjustments, WKH IROORZLQJ FRQVWUDLQWV VKRXOG EH FRQVLGHUHG ž”ElA” ž ž”$]A” ž _El&-ElR_” ž DQG _$]A-$]R_” ž ZKHUH ElA and $]A are, respectively, the adjusted elevation and azimuth; and, ElR and $]R are, respectively, the reference elevation and azimuth. 8VLQJ VDPSOHV RI ZLQG SUR¿OHV FROOHFWHG DW &/$ LQ December 2008, obtained with sensors, we have estimated the probability of not violating such constraints for a range of launch azimuth and elevation values, given to one attempt of launch (Fig. 8). Suppose the hypothetical mission cannot exceed two attempts of launch, given that the probability for one attempt (P) can be expressed by Eq. 4: 1

p = 1 - ^1 - Pnh

n

(4)

where, Pn is the probability, between 0 and 1, for n attempts of launch. ,Q RUGHU WR QRW H[FHHG WKH OLPLW RI DWWHPSWV ¿[LQJ Pn at 0.98, for instance, the probability of not violating constraints of launch azimuth and elevation can be at least 0.9 (90%). As the elapsed time in microgravity increases with the launch elevation (Fig. 7), let us select the maximum launch HOHYDWLRQ IRU HDFK 96 FRQ¿JXUDWLRQ DVVRFLDWHG ZLWK of nonviolation of the constraints. Based on Fig. 8, the VS-40 ZLWK LPSURYHG ¿QV FDQ EH ODXQFKHG DW ž DQG ZLWK WKH RULJLQDO ¿QV ž 7KHVH DUH WKH PD[LPXP ODXQFK HOHYDWLRQV 7KH ODXQFK D]LPXWK FDQ EH ¿[HG DW ž IRU ERWK FRQ¿JXUDWLRQV The theoretical deviation of the elapsed time in microgravity LV GHWHUPLQHG E\ XVLQJ 0RQWH &DUORœV PHWKRG ZKLFK FRQVLVWV of varying the dispersion factors, and computing their results on the trajectory of the rocket, assuming a normal distribution RQ WKHLU YDULDWLRQ LQWHUYDO ZKLFK LV GH¿QHG E\ WKHLU UHVSHFWLYH error. The aerodynamic coefficients are, for instance,

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

439

%DUERVD $ 1 *XLPDUmHV / 1 )

50

70 60 50 40 30 20 10

100

40

90

30

90

10 20 30 40 50 60 70

10 20 30 40 50 60

80 80.5 81 81.5 82 82.5 83 83.5 84 84.5 85 Launch elevation (degrees)

10

90

45

35

35 30

55

80

80

40

80

60

20 30 400 5 60 70

10 20 30 40 50 60 70

50 45

Launch azimuth (degrees)

80

65

90

55

70

60

70

60 50 4 300 20 10

80

65

90

Launch azimuth (degrees)

70

75

70

80

75

80 80.5 81 81.5 82 82.5 83 83.5 84 84.5 85 Launch elevation (degrees)

(a)

(b)

Figure 8. Probability of not violating constraints of launch azimuth and elevation adjustment to compensate for the wind effect (%), given to RQH DWWHPSW RI ODXQFK D 96 ZLWK LWV RULJLQDO ÂżQV E 96 ZLWK WKH LPSURYHG ÂżQV

dispersion factors to be considered. Studies that evaluate the accuracy of the missile datcom compared to experimental wind tunnel data shows that the results for aerodynamic drag are predicted by missile datcom with an error, whose magnitude is less than 20% for a variety of rocket geometries (Sooy and Schmidt, 2005). At transonic speeds, where boundary layer shock interaction takes place, missile datcom does not have the capability to accurately represent such kind of interaction. Table 4 presents the dispersion factors that were assumed to calculate the deviation of the elapsed time in microgravity. Table 4. Dispersion factors error for each rocket stage. Error First stage Second stage

Dispersion factor

Thrust variation (%)

Âą0.5 Âą3.0 Âą2.0 Âą3.0

Âą3.0

Thrust misalignment in pitch and yaw (degrees)

Âą0.1

Âą0.1

Âą20.0 Âą1.0 Âą0.01

Âą20.0 Âą1.0 Âą0.01 Âą2.0

/DXQFKHU HOHYDWLRQ HUURU GHJUHHV

/DXQFKHU D]LPXWK HUURU GHJUHHV

Head and cross wind (m/s)

Aerodynamic drag (%) Weight variation (%) Fin misalignment (degrees) Ignition time variation (s)

–

– – –

No predominant wind speed and direction have been considered in the calculation of the deviation of the elapsed time in microgravity. Table 5 presents the deviation of the elapsed time in microgravity. 440

Table 5. Average value and error of the elapsed time in microgravity. /DXQFK HOHYDWLRQ (degrees) 81.5 82

Elapsed time in microgravity (s) :LWK RULJLQDO ÂżQV :LWK LPSURYHG ÂżQV 922Âą138 939Âą134 932Âą138 949Âą129

&RQVLGHULQJ WKH PD[LPXP ODXQFK HOHYDWLRQV WKH HODSVHG WLPH JDLQ LQ PLFURJUDYLW\ SURYLGHG E\ WKH LPSURYHG ÂżQV FDQ increase from 1.6 to 2.9% (Table 5). As previously discussed, the expected gain does not seem to justify any attempt of FKDQJLQJ WKH ÂżQV RI WKH 96 %HVLGHV WKH H[SHFWHG HUURU LV DSSUR[LPDWHO\ ÂżYH WLPHV WKH JDLQ LQ PLFURJUDYLW\ 7DEOH 2Q the other hand, it was demonstrated that the factors associated with the mission analysis could affect the gain evaluation. It is expected that, by involving more subsystems and design GLVFLSOLQHV LQ IXWXUH ZRUNV VLJQLÂżFDQW LPSURYHPHQWV LQ WKH Brazilian sounding rockets can be demonstrated regarding different applications, besides their application in microgravity experiments. FUTURE WORKS In future works, at least four lines of development should be considered. First, new functionalities may be added to the MDO-SONDA. Interfaces might be created for graphical FRPSDULVRQV RI WKH DHURG\QDPLF FRHIÂżFLHQWV EHWZHHQ SKDVH FRQÂżJXUDWLRQV ' YLVXDOL]DWLRQ RI WKH URFNHW DQG FXVWRPL]HG plots of the trajectory parameters. The user should be able to customize the optimization problem and to set the interaction

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

0XOWLGLVFLSOLQDU\ 'HVLJQ 2SWLPL]DWLRQ RI 6RXQGLQJ 5RFNHW )LQV 6KDSH 8VLQJ D 7RRO &DOOHG 0'2 621'$

ZLWK D QHZ KLJK ¿GHOLW\ H[HFXWDEOH FRGH E\ XVLQJ DQ LQWHUIDFH LQVWHDG RI DGGLQJ WR RU UHSODFLQJ D VSHFL¿F VXEURXWLQH LQ MDO-SONDA. This latter should be able to recalculate the mass and inertia properties of the rocket considering the change of the shape that is being optimized. Data-mining methods might be included in the future to assist the user on searching for trade-offs, when the number of design variables and objectives are such that the traditional methods of data visualization are not enough to make them explicit. Also, the MDO-SONDA should be compared with other codes. 6HFRQG PRUH KLJK ¿GHOLW\ FRGHV PD\ EH OLQNHG WR MDO-SONDA, involving more design disciplines. For instance, teamwork involving experts in propulsion and VWUXFWXUH PLJKW SURYLGH UHVSHFWLYHO\ VSHFL¿F FRGHV WR generate the thrust curve from the propellant variables and to estimate the structural resistance of the rocket against DHURG\QDPLF ORDGV GXULQJ WKH ÀLJKW )XUWKHUPRUH DQ DQDO\VLV FDQ EH SHUIRUPHG WR VWXG\ WKH LQÀXHQFH RI WKH HUURU RI WKH KLJK ¿GHOLW\ FRGHV RQ WKH GHVLJQ RSWLPL]DWLRQ Third, the optimization mechanisms may be more GLYHUVL¿HG DQG VRSKLVWLFDWHG 0HPHWLF DOJRULWKPV DUH WKH combination of two or more metaheuristics, cooperating or competing with each other, and surrogate models might improve the overall performance of the optimization by reducing the number of objective function evaluations. Parallel computing might be used together with such approaches for large-scale optimization problems. The search for appropriate parameter values related to the optimization mechanisms are an issue for future works. Finally, with respect to the last line of development to be seen in future, two or more subsystems may be redesigned, simultaneously, to improve the rocket, for instance, two or more VHWV RI ¿QV ¿QV DQG QRVH IDULQJ DQG VR RQ 6HQVLWLYLW\ DQDO\VLV can be executed to investigate the impact of any variations of the design variables on the its objectives. In addition, two or more missions with respect to the same rocket may be simultaneously considered at the same optimization process.

why it should be revised. Before commenting the results of the optimization, the main aspects of the MDO-SONDA were depicted. It was found that the minimization of the drag due WR ÂżQV DQG WKH PD[LPL]DWLRQ RI WKH VKRUWHVW LQWHUYDO EHWZHHQ FULWLFDO Ă€LJKW HYHQWV DUH FRPSHWLQJ REMHFWLYHV OHDGLQJ WR D PRUH comprehensive understanding of the VS-40 trade-offs. The drag GXH WR WKH URFNHW ÂżQV FRXOG EH UHGXFHG XS WR DQG ZLWK DQ LQWHUYDO RI DW OHDVW RQH VHFRQG EHWZHHQ FULWLFDO Ă€LJKW HYHQWV in order to avoid adverse effects that could lead to unstable behaviors. However, in terms of the total drag, the reduction was XS WR FDXVLQJ DQ HODSVHG Ă€LJKW WLPH JDLQ LQ PLFURJUDYLW\ RI ZLWKRXW LJQRULQJ WKH LQĂ€XHQFH RI WKH ZLQG DQG WKH GLVSHUVLRQ factors of the rocket. Despite the small gain, it was demonstrated that the factors associated with the mission analysis could affect the gain evaluation. Finally, four lines of development for future works were suggested: the addition of new functionalities to MDO-SONDA; the participation of more design disciplines, FRQWULEXWLQJ ZLWK WKHLU KLJK ÂżGHOLW\ FRGHV WKH LPSURYHPHQW RI the optimization mechanisms, adding sophisticated methods, such as surrogate models; and the simultaneous optimization of two or more subsystems of the rocket. REFERENCES %DUERVD $ 1 DQG *XLPDUmHV / 1 ) Âł,QYHVWLJDWLQJ WKH (IÂżFLHQF\ RI WKH 6XUURJDWHV %DVHG RQ 1HXUDO 1HWZRUNV in Assisting Multi-objective Optimization of Test-problems 3HUIRUPHG E\ D 1RQ JHQHUDWLRQDO *HQHWLF $OJRULWKP´ ,Q 3URFHHGLQJV RI WKH UG ,QWHUQDWLRQDO &RQIHUHQFH RQ Engineering Optimization, Rio de Janeiro. %ODNH : % Âł0LVVLOH 'DWFRP 8VHUÂśV 0DQXDO Âą )RUWUDQ 5HYLVLRQ´ :ULJKW 3DWWHUVRQ $LU )RUFH %DVH 2KLR 86$ %RUJHV & & + DQG %DUERVD + - & Âł$ QRQ JHQHUDWLRQDO JHQHWLF DOJRULWKP IRU PXOWLREMHFWLYH RSWLPL]DWLRQ´ LQ SURFHHGLQJV RI WKH &RQJUHVV RQ (YROXWLRQDU\ &RPSXWDWLRQ /D -ROOD SS

CONCLUSIONS In this paper, a MDO application in the context of Brazilian sounding rockets was demonstrated. As case study, the shape RSWLPL]DWLRQ RI ÂżQV RI WKH 96 ZDV SUHVHQWHG UHJDUGLQJ LWV next launches at the Brazilian territory to perform microgravity experiments. This paper began by introducing the concepts of sounding rockets and the microgravity environment, which was followed by presenting facts about the VS-40, and explaining

&DVWUR / & DQG )LVFK * ³(VWXGR GR 0HLR $PELHQWH $WPRVIpULFR 3URGX]LGR SDUD $WHQGHU R /DQoDPHQWR GR 96% 9 ´ ,QVWLWXWR GH $HURQiXWLFD H (VSDoR 6mR -RVp GRV &DPSRV 57 ) S &HQWUR GH /DQoDPHQWR GH $OFkQWDUD ³0DQXDO GH 6HJXUDQoD 2SHUDFLRQDO GR &HQWUR GH /DQoDPHQWR GH $OFkQWDUD´ 1R 0$1 6*2 %UD]LO

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

441

%DUERVD $ 1 *XLPDUmHV / 1 )

&RUQHOLVVH - : HW Dl Âł5RFNHW 3URSXOVLRQ DQG 6SDFHĂ€LJKW '\QDPLFV´ 3LWPDQ /RQGRQ S )OHHPDQ ( / Âł7DFWLFDO 0LVVLOH 'HVLJQ´ QG HGLWLRQ AIAA, Reston, 468 p. )ORXGDV & $ DQG 3DUGDORV 3 0 Âł(QF\FORSHGLD RI 2SWLPL]DWLRQ´ QG HGLWLRQ 6SULQJHU 1HZ <RUN S *DUFLD $ HW Dl Âł96% VRXQGLQJ URFNHW KLVWRU\ RI Ă€LJKW SHUIRUPDQFH´ -RXUQDO RI $HURVSDFH 7HFKQRORJ\ DQG Management, Vol. 3, No. 3, pp. 325-330. *HUPDQ\ÂśV 1DWLRQDO 5HVHDUFK &HQWHU IRU $HURQDXWLFV DQG 6SDFH '/5 Âł([SHULPHQWV RQ 6+()(; ,, VXFFHVVIXO´ '/5 3RUWDO ZHE VLWH 5HWULHYHG LQ -XO\ IURP KWWS www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_ read-4100/. *RPHV 5 0 Âł7UDMHFWRU\ FDOFXODWLRQ XVLQJ WKH 526, SURJUDP Âą 1RPLQDO 7UDMHFWRU\ DQDO\VLV´ 7HFKQLFDO 5HSRUW ASE-RT-010-2004, Institute of Aeronautics and Space, Brazil. *ULQVWHLQ * HW Dl Âł+LJK 'LPHQVLRQDO 9LVXDOL]DWLRQV´ In: Proceedings of the Visual Data Mining Workshop, San Francisco, USA. +HQQLJK . ( Âł)LHOG :LQG :HLJKWLQJ DQG ,PSDFW 3UHGLFWLRQ IRU 8QJXLGHG 5RFNHWV´ 1DWLRQDO $HURQDXWLFV and Space Administration (NASA), Washington, NASA TN D-2142, 22 p. ,QVWLWXWR GH $HURQiXWLFD H (VSDoR ,$( Âł2 )RJXHWH GH VRQGDJHP 96 ´ 6mR - GRV &DPSRV %UD]LO 5HWULHYHG LQ 2FWREHU IURP ZZZ LDH FWD EU "DFWLRQ YV /D 1HYH $ DQG &RUUrD -U ) $ Âł6$5$ ([SHULPHQW Module: An Interdisciplinary Project through Partnership ZLWK WKH ,QVWLWXWH RI $HURQDXWLFV DQG 6SDFH´ ,Q 3URFHHGLQJV RI WKH ,QWHUQDWLRQDO &RQIHUHQFH RQ (QJLQHHULQJ (GXFDWLRQ Oslo, Norway. Montenbruck, O. HW Dl Âł*36 7UDFNLQJ RI 6RXQGLQJ 5RFNHWV Âą $ (XURSHDQ 3HUVSHFWLYH´ ,Q 3URFHHGLQJV RI WKH 1st ESA Workshop on Satellite Navigation User Equipment Technologies, Noordwijk, Holland.

442

0RUDHV -U 3 DQG 3LOFKRZVNL + 8 ³3ODWDIRUPD 2UELWDO SDUD ([SHULPHQWDomR HP $PELHQWH GH 0LFUR *UDYLGDGH´ ,Q 3URFHHGLQJV RI WKH ;,9 &RQJUHVVR %UDVLOHLUR GH (QJHQKDULD Mecânica, Bauru-SP, Brazil, Vol. 1, 9 p. 3HUHLUD $ / DQG 0RUDHV -U 3 ³(QVDLRV $HURGLQkPLFRV HP 9{R GR )RJXHWH 6XERUELWDO 96 ´ LQ SURFHHGLQJV RI WKH ;9 &RQJUHVVR 1DFLRQDO GH (QJHQKDULD 0HFkQLFD 1DWDO Brazil. Retrieved in July 6, 2012, from http://pintassilgo2. LSHQ EU ELEOLRWHFD FG FRQHP ,& SGI 5HGG\ . 3 - ³+\SHUVRQLF )OLJKW DQG *URXQG 7HVWLQJ $FWLYLWLHV LQ ,QGLD´ ,Q 3URFHHGLQJV RI WKH WK $XVWUDODVLDQ )OXLG 0HFKDQLFV &RQIHUHQFH *ROG &RDVW $XVWUDOLD 5LEHLUR 7 6 ³9HtFXORV /DQoDGRUHV GH 6DWpOLWHV ¹ &HQiULR $WXDO H )XWXUR´ 3DUFHULDV (VWUDWpJLFDV 1R SS 235-247. 5RZHOO / ) DQG .RUWH - - ³/DXQFK 9HKLFOH 'HVLJQ and Optimization Methods and Priority for the Advanced (QJLQHHULQJ (QYLURQPHQW´ 1DWLRQDO $HURQDXWLFV DQG Space Administration (NASA), Hampton, Virginia, NASA/ TM-2003-212654, 29 p. 6RR\ 7 - DQG 6FKPLGW 5 = ³$HURG\QDPLF 3UHGLFWLRQV &RPSDULVRQV DQG 9DOLGDWLRQV 8VLQJ 0LVVLOH '$7&20 DQG $HURSUHGLFWLRQ $3 ´ -RXUQDO RI 6SDFHFUDIW DQG Rockets, Vol. 42, No. 2, pp. 257-265. 9DOHQ]XHOD 5HQGyQ 0 DQG 8UHVWL &KDUUH ( ³$ QRQ JHQHUDWLRQDO *HQHWLF $OJRULWKP IRU PXOWLREMHFWLYH RSWLPL]DWLRQ´ ,Q 3URFHHGLQJV RI WKH WK ,QWHUDQWLRQDO &RQIHUHQFH RQ *HQHWLF $OJRULWKPV 6DR 0DWHR SS Weihs, H. HW Dl D ³7KH 6KDUS (GJH )OLJKW ([SHULPHQW 6+()(; ,, D 0LVVLRQ 2YHUYLHZ DQG 6WDWXV´ ,Q 3URFHHGLQJV of the AIAA 15th Space Planes and Hypersonic Systems and 7HFKQRORJLHV &RQIHUHQFH 2KLR 86$ Weihs, H. HW Dl E ³.H\ ([SHULPHQWV ZLWKLQ WKH 6KHIH[ ,, 0LVVLRQ´ ,Q 3URFHHGLQJV RI WKH WK ,QWHUQDWLRQDO $VWURQDXWLFDO &RQJUHVV *ODVJRZ 6FRWODQG =LHJOWUXP : ³$QDO\VLV DQG 6SHFL¿FDWLRQ RI 7UDMHFWRU\ 3URJUDP 526, ,QSXW 3URJUDP :(,*+7 3ORW 3URJUDP 526,3/27´ ')9/5 71 9RO

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 431-442, Oct.-Dec., 2012

doi: 10.5028/jatm.2012.04044012

6WXGLHV RQ WKH IQÀXHQFH RI THVWLQJ 3DUDPHWHUV RQ D\QDPLF DQG TUDQVLHQW 3URSHUWLHV RI CRPSRVLWH 6ROLG RRFNHW 3URSHOODQWV UVLQJ D D\QDPLF 0HFKDQLFDO $QDO\]HU 9LODV :DQL 0HKLODO 6XQLO -DLQ 3UDYHHQ 3UDNDVK 6LQJK %LNDVK %KDWWDFKDU\D High Energy Materials Research Laboratory – Pune – India Abstract: Dynamic mechanical analysis is a unique technique that measures the modulus and damping of materials as they are deformed under periodic stress. Propellants, which are viscoelastic in nature, are subjected to time, temperature, and frequency effects during the analysis to determine their dynamic and transient properties. The choice of parameters during the experiments like temperature, frequency, strain (%), and stress level is very crucial to the results obtained since the propellant behaves differently under different conditions. A series of experiments like strain and temperature ramp/ frequency sweeps, creep, stress relaxation, etc. have been conducted using high burning rate composite propellant (burn rate ~20 mm/s at 7,000 kPa), in order to determine the precise effects of such parameters on the results obtained. The evaluated data revealed that as the temperature increases the storage modulus, loss modulus, and tan delta curves with respect to the frequency shift towards the lower side. Moreover, there is equivalency between the increase in the temperature and the decrease in the frequency, which can be used for the time-temperature superposition principles. Further, in transient tests, the relaxation modulus has been found to decrease when increasing strain levels in the given time range. Also, relaxation modulus versus time curves were found to shift towards the lower side with increasing temperature while creep compliance decreases with the increase in stress and decrease in temperature. The glass transition value of the composite propellant increases when there is an increase in the heating rate. Keywords: Glass transition temperature, Storage modulus, Loss modulus, Polybutadiene, Viscoelastic properties.

INTRODUCTION Composite propellants are being used in several missile applications, which basically contain ammonium perchlorate – AP (from 65 to 70%), a metallic fuel like aluminium powder (15 to 20%), and a liquid binder such as hydroxyl terminated polybutadiene – HTPB (10 to 15%) along with certain process aids and diisocyanate based curatives (Boyars and Klager, 1969). Due to the presence of polymeric binder, propellants are viscoelastic in nature. Vibrational methods are used in order to determine the dynamic mechanical properties of such materials. These vibrational tests measure the deformation of the material to periodic forces. From these dynamic mechanical tests, different variables are obtained, such as: storage modulus (Âś ORVV PRGXOXV (´ DQG ORVV IDFWRU WDQ ÄŻ 6WRUDJH Received: 06/07/12

Accepted: 08/08/12

*author for correspondence: drmehilal@yahoo.co.in +(05/ 6XWDUZDGL 3XQH Âą Âą 0DKDUDVKWUD Âą ,QGLD

modulus is related with the energy stored during deformation, and loss one is associated with the dissipation of the energy as heat. From the ratio of the loss to storage moduli, loss factor is obtained, and it represents the damping capacity of the material. Thus, dynamic mechanical analysis is a technique that measures the modulus and damping of materials as they are deformed under periodic strain or stress (Ferry, 1980; Groves et al., 1992; Foreman, 1997; Morton et al., 1969). Propellants, which are viscoelastic in nature, are subjected to time, temperature, and frequency effects during the analysis to determine their dynamic mechanical property data (Tod, 1987; Hanus, 2001). The material properties that can be measured by this technique in addition to storage and loss moduli, and WDQ ÄŻ DUH JODVV WUDQVLWLRQ 7J VRIWHQLQJ WHPSHUDWXUH GHJUHH of cure, creep, stress relaxation, and so on. Exhaustive literature survey reveals that a number of studies have been carried out to evaluate the effects of binders,

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

443

Wani,V. et al.

humidity, and composition on the dynamic mechanical properties of propellants, viz. Bhagawan et al. (1995) studied the dynamic mechanical properties of different binders and corresponding propellants in terms of storage modulus and WDQ ÄŻ WKH\ ZHUH +73% &73% 3%$1 +() DQG ,652 SRO\RO 6XFK DXWKRUV IRXQG WKDW SRO\EXWDGLHQH ELQGHUV H[KLELWHG ORZHVW 7J YDOXH DURXQG ƒ& ZKLOH ,652 SRO\RO had the highest one (~ -20 °C) and the propellants had higher moduli than their corresponding binders at any temperature. Cogmez et al. (1999) also attempted to compare the dynamic data of two HTPB-based propellants with different solid compositions, viz., one with 87% solid loading having 16% Al as metallic fuel, and the other with 86% solid loading without metallic fuel; the former propellant was found to be less stiffer and more dissipative than the latter at higher temperatures. 6WXGLHV KDYH DOVR EHHQ SHUIRUPHG RQ WKH WUDQVLHQW SURSHUWLHV like creep and stress relaxation by Mohandas et al. (2000), who studied the effect of humidity on the transient properties of propellants having the standard composition of HTPB/ Al/AP. It was found that when propellant is exposed to high relative humidity (RH) levels, the creep strain increases and equilibrium stress during stress relaxation decreases by a factor of two. Further to this, Musanic (2002) studied double-based propellants and the effect of testing parameters like frequency, heating rate, length to thickness ratio, etc. on their dynamic PHFKDQLFDO SURSHUWLHV VWRUDJH PRGXOXV ORVV PRGXOXV WDQ ÄŻ However, little work has been carried out to study the effect of various testing parameters on the dynamic as well as transient properties of composite propellants, which are YHU\ VLJQLÂżFDQW VLQFH G\QDPLF PHFKDQLFDO DQDO\]HU '0$ DQDO\VLV UHVXOWV PD\ GHSHQG VLJQLÂżFDQWO\ RQ WKH FRQGLWLRQV used during the experiment, i.e., heating rate, frequency, stress/strain level applied, temperature, and so on. Therefore, in the present study, an exhaustive data set was generated to determine the effect of various parameters like frequency, heating rate, strain (%), stress level, temperature on the dynamic and transient properties of composite propellants using different DMA test methods such as: ‡ '0$ PXOWL VWUDLQ VWUDLQ VZHHS ‡ '0$ PXOWL IUHTXHQF\ VWUDLQ Âą LVRWKHUPDO WHPSHUDWXUH frequency sweep; ‡ '0$ PXOWL IUHTXHQF\ VWUDLQ Âą WHPSHUDWXUH UDPS frequency sweep; ‡ 6WUHVV UHOD[DWLRQ ‡ &UHHS

444

In the following section, the effect of the previously mentioned parameters will be reported. (;3(RI0(NT$/ The experiments were carried out using high burning rate composite solid propellants having the following composition: HTPB, AP with tetra-modal distribution, Al and other additives with toluene diisocyanate (TDI) as the curative. The testing samples were cut from the propellant block in the form of rectangular bars containing the following dimensions: 60 x 12.5 x 3 mm. All dynamic mechanical measurements were carried out on TA Instruments Dynamic Mechanical Analyser 4 7$ ,QVWUXPHQWV 86$ 7KH GLIIHUHQW H[SHULPHQWV ZHUH performed on dual cantilever clamp varying the frequency, temperature, stress, and strain levels. 9DULDWLRQ RI G\QDPLF PHFKDQLFDO SURSHUWLHV ‡ '0$ PXOWLVWUDLQ VWUDLQ VZHHS WKH VDPSOH ZDV WHVWHG DW 35 ÂşC with amplitude increasing linearly from 0.5 to 50 Č?P DW GLIIHUHQW IUHTXHQFLHV 7KH HIIHFW RI IUHTXHQF\ RQ WKH storage modulus was determined by plotting a graph of storage modulus versus strain. ‡ '0$ PXOWLIUHTXHQF\ VWUDLQ LVRWKHUPDO WHPSHUDWXUH frequency sweep: the sample was given a series of strains at three frequencies viz., 3.5, 11, 35 Hz at 35 ÂşC and the effect of strain levels was evaluated on modulus by plotting a graph of storage modulus versus frequency. ‡ '0$ PXOWLIUHTXHQF\ VWUDLQ LVRWKHUPDO WHPSHUDWXUH frequency sweep: the sample was given a constant strain of 0.5% at three frequencies (3.5, 11 and 35 Hz), while varying the temperatures for subsequent tests to determine the effect RI WHPSHUDWXUH RQ VWRUDJH PRGXOXV ORVV PRGXOXV DQG WDQ ÄŻ ‡ '0$ PXOWLIUHTXHQF\ VWUDLQ WHPSHUDWXUH UDPS IUHTXHQF\ sweep: samples were given a constant strain of 0.01%, and temperature increased from 35 to 85 ÂşC at the heating rates of 1, 2, and 10 ÂşC/minutes, at the same time the frequencies were varied to determine the frequency effect on storage modulus by plotting a curve of storage modulus versus temperature. 9DULDWLRQ RI WUDQVLHQW SURSHUWLHV ‡ 6WUHVV UHOD[DWLRQ DW GLIIHUHQW VWUDLQV VDPSOHV ZHUH ORDGHG under various strain levels at 35 ÂşC for 30 minutes, and their relaxation moduli were determined.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

6WXGLHV RQ WKH ,QĂ€XHQFH RI 7HVWLQJ 3DUDPHWHUV RQ '\QDPLF DQG 7UDQVLHQW 3URSHUWLHV RI &RPSRVLWH 6ROLG 5RFNHW 3URSHOODQWV 8VLQJ DÂŤ

‡ 6WUHVV UHOD[DWLRQ DW GLIIHUHQW WHPSHUDWXUHV VDPSOHV ZHUH loaded under 0.1% strain level at a series of temperatures ranging from 35 to 85 ºC for 30 minutes, and their relaxation moduli were also determined. ‡ &UHHS DW GLIIHUHQW VWUHVV VDPSOHV ZHUH ORDGHG XQGHU YDULRXV stress levels at 35 ºC for a ten-minute creep time with 20 minutes of recovery, being their creep compliances compared. ‡ &UHHS DW GLIIHUHQW WHPSHUDWXUHV DW 03D VWUHVV DW D ten-minute creep time and 20-minute recovery time: samples were loaded under 1 MPa stress level at a series of temperatures ranging from 35 to 85 ºC for 30 minutes (10-minute creep time and 20-minute recovery time), and their creep compliances were determined. R(6U/T6 $ND DI6CU66ION All the analyses were carried out on high burning rate composite solid propellant (burn rate ~20 mm/s at 7,000 kPa) using different test methods of DMA and varying parameters like temperature, frequency, heating rate, and stress/strain levels. A typical DMA curve of high burning rate composite solid propellant is shown in Fig. 1, wherein the composite propellant was given an oscillation strain of 0.01% with 2 ºC / minutes heating rate at 11 Hz frequency. It is clear from Fig. 1 that the tan delta maximum is at -62.1 ºC, which is taken to be the Tg temperature. The effects of various parameters like temperature, frequency, strain, stress and heating rate on such sample being tested for various dynamic and transient properties like storage modulus, loss

PRGXOXV WDQ ÄŻ UHOD[DWLRQ PRGXOXV DQG FUHHS FRPSOLDQFH are described in details. IQĂ€XHQFH RI WHPSHUDWXUH RQ WKH G\QDPLF DQG WUDQVLHQW SURSHUWLHV The dynamic properties of the high burning rate composite propellant were studied using dual cantilever clamp at an oscillatory strain of 0.5% at a heating rate of 2 ÂşC/minutes, with temperatures ranging from 35 to 80 ÂşC at several frequencies. The results for the variation of storage modulus, loss modulus, WDQ ÄŻ ZLWK IUHTXHQF\ IRU GLIIHUHQW WHPSHUDWXUHV DUH VKRZQ LQ Figs. 2 to 4, respectively. It is clear from Figs. 2 to 4 that as the temperature increases the storage modulus versus frequency, loss modulus versus IUHTXHQF\ DQG WDQ ÄŻ versus frequency curves shift towards the lower side since the temperature decreases the chains become stiffer and less mobile leading to an increase in the modulus. This also supports the fact that an increase in the temperature is equivalent to a decrease in the frequency. The transient tests of creep were also carried out for the high burning rate composite propellants using dual FDQWLOHYHU FODPS DW D Âż[HG VWUHVV RI 03D DW WZR GLIIHUHQW temperatures, viz., 65 and 75 ÂşC. The results obtained are presented in Fig. 5, which reveals that the creep compliance/ strain increases with the increase in the temperature at a given time range. This might be due to the higher strains induced in WKH VDPSOH EHFDXVH RI KLJKHU WHPSHUDWXUHV IRU D Âż[HG VWUHVV leading to a decrease in the modulus and hence increase in the compliance that is the reciprocal of modulus.

Figure 1. DMA result for a standard sample at 11 Hz with 0.01% oscillatory strain at heating rate of 2 ÂşC/minutes.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

445

Wani,V. et al.

)LJXUH 6WRUDJH PRGXOXV versus frequency for different temperatures at 0.5% strain.

Figure 3. Loss modulus versus frequency for different temperatures at 0.5% strain.

Figure 4. Tan delta versus frequency for different temperatures at 0.5% strain.

446

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

6WXGLHV RQ WKH ,QÀXHQFH RI 7HVWLQJ 3DUDPHWHUV RQ '\QDPLF DQG 7UDQVLHQW 3URSHUWLHV RI &RPSRVLWH 6ROLG 5RFNHW 3URSHOODQWV 8VLQJ D«

Figure 5. Creep compliance versus time at 1 MPa stress at different temperatures.

The transient tests of stress relaxation were also carried out XVLQJ GXDO FDQWLOHYHU FODPS DW D ¿[HG VWUDLQ OHYHO RI VWUDLQ at different temperatures, viz. 35, 40, 45 and 50 ºC. The results obtained are shown in Fig. 6, which shows that relaxation modulus versus time curves shift towards the lower side (the relaxation modulus decreases) as temperature increases. This might be due to the fact that at higher temperatures the SRO\PHULF +73% FKDLQV EHFRPH PRUH PRELOH DQG PD\ ÀRZ to bear the strain applied resulting in rapid decrease in stress and modulus. IQÀXHQFH RI IUHTXHQF\ RQ WKH G\QDPLF DQG WUDQVLHQW SURSHUWLHV 7KH IUHTXHQF\ LQÀXHQFH RQ '0$ IURP WKH KLJK EXUQLQJ rate composite propellant was analysed using dual cantilever clamp at different frequencies, viz, 0.1, 0.2, 1, 2, 3.5, 4.6,

11,35 Hz and so on, at a heating rate of 3 ºC/minutes with an oscillatory strain of 0.01%, and the results obtained are presented in Figs. 7 and 8, respectively. It is clear from Fig. 7 that as the frequency increases, the storage modulus versus temperature curves shifts upwards indicating an increase in the storage modulus with the increase in the frequency. It is also clear from Fig. 8 that as the frequency increases, the storage modulus versus strain curves shift towards the upper side, that is, the storage modulus values increase with the frequency. This may be due to the fact that increase in the frequency (equivalent to decrease times) freezes the chain movements resisting intermolecular slippage, and leading to D VWLIIHU EHKDYLRXU DQG KHQFH LQFUHDVLQJ WKH PRGXOXV 1DLU et al., 2009; Young and Lovell, 1991). It should be noted that storage modulus versus temperature curves at various frequencies can be shifted using timeWHPSHUDWXUH VXSHUSRVLWLRQ 776 SULQFLSOH WR GHWHUPLQH WKH

Figure 6. Relaxation modulus versus time at different temperatures at 0.1% strain.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

447

Wani,V. et al.

)LJXUH 6WRUDJH PRGXOXV versus temperature at different frequencies at 0.01% strain.

)LJXUH 6WRUDJH PRGXOXV versus strain in different frequencies at 35 ÂşC.

master curve at a single reference temperature, thus increasing the frequency range in which the sample properties can be known beyond the frequency range, where the sample was WHVWHG 7KH 776 SULQFLSOH VWDWHV WKDW DQ LQFUHDVH LQ IUHTXHQF\ has the same effect on the measured viscoelastic property as decreases in temperature or in time. The amount of shifting along the horizontal (x-axis) of each curve to align with the reference WHPSHUDWXUH FXUYH LQ D W\SLFDO 776 SORW LV JHQHUDOO\ GHVFULEHG by the Williams-Landel-Ferry (WLF) equation (Eq. 1): log aT =- C1 ^T - T0h / 6C2 + ^T - T0h@

where C1 and C2 are constants, T0 is the reference temperature (K), T is the measurement temperature (K), and aT is the shift factor. 448

(1)

The WLF equation is typically used to describe the time/ temperature behaviour of polymers in the Tg region, and it has been reported in the literature to predict the performance of polymers (Foreman, 1997). IQĂ€XHQFH RI VWUDLQ OHYHO RQ WKH G\QDPLF DQG WUDQVLHQW SURSHUWLHV 7KH LQĂ€XHQFH RI VWUDLQ OHYHO RQ WKH G\QDPLF SURSHUWLHV RI the high burning rate composite propellant was tested using dual-cantilever clamp at 35 ÂşC at frequencies from 3.5 to 35 Hz at various strains, ranging from 0.001 to 3% strain, and the results obtained are shown in Fig. 9. It is clear from Fig. 9 that as the strain applied on the sample increases the storage modulus versus frequency curves shift downwards, that is, the storage modulus decreases on increasing the oscillatory strain. This is well-supported by the fact that the

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

6WXGLHV RQ WKH ,QÀXHQFH RI 7HVWLQJ 3DUDPHWHUV RQ '\QDPLF DQG 7UDQVLHQW 3URSHUWLHV RI &RPSRVLWH 6ROLG 5RFNHW 3URSHOODQWV 8VLQJ D«

)LJXUH 6WRUDJH PRGXOXV versus frequency for different strains at 35 ºC.

elastic component of a material is obtained by the stress ratio from each strain, therefore, if the strain increases, the storage modulus will drop. The effect of strain level was also studied on the stress relaxation behaviour of the high burning rate composite propellant using dual cantilever clamp at 35 ºC with strains varying from 0.01 to 2% for 40 minutes each. The results obtained can be seen in Fig. 10, which shows that the relaxation modulus decreases with increasing strain levels in the given time range, a quite obvious fact since the modulus is obtained by stress ratio from strain, as the strain increases the modulus decreases. IQÀXHQFH RI VWUHVV OHYHO RQ WKH G\QDPLF DQG WUDQVLHQW SURSHUWLHV The effect of stress applied on the composite propellant when it is subjected to creep was determined by testing the

samples in dual cantilever clamp at 35 ºC for a ten-minute period with the stress applied varying from 0.1 to 3 MPa and measuring the corresponding creep compliances. A plot of creep compliance versus time for high burning rate composite propellant under creep subjected to different stress levels at 35 ºC is shown in Fig. 11, which infers that as the stress level increases the creep compliance versus time curve shifts downwards, that is, the creep compliance decreases ZLWK LQFUHDVH LQ VWUHVV 6LQFH WKH FUHHS FRPSOLDQFH LV WKH reciprocal of modulus and this is the ratio of stress by strain, therefore, as the stress level increases the modulus increases accordingly, leading to decrease in the compliance. Fig. 11 also reveals that the difference between creep compliance for stress values around 0.1 and 0.5 MPa is more than the difference between the creep compliance for stress values around 2 and 3 MPa. This may be accounted to the fact that at higher stress values the material is strained beyond

Figure 10. Relaxation modulus versus time for different strains at 35 ºC.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

449

Wani,V. et al.

Figure 11. Creep compliance versus time in different stress levels at 35 ÂşC.

its viscoelastic limit, and a permanent set appears in the material so there is only marginal enhancement in modulus for higher stress values. IQÀXHQFH RI KHDWLQJ UDWH RQ WKH G\QDPLF DQG WUDQVLHQW SURSHUWLHV ,Q RUGHU WR GHWHUPLQH WKH LQÀXHQFH RI KHDWLQJ UDWH WKH tests were carried out using different heating rates, i.e., 1, 2, 5 and 10 (ºC/minutes) at three frequencies (3.5, 11, 35 Hz) from -80 to 80 ºC at a sinusoidal strain of 0.01%. The results obtained for the heating rates 1, 2 and 10 ºC/minutes are VKRZQ LQ )LJV WR ,W LV FOHDU IURP VXFK ¿JXUHV WKDW as the heating rate increases, the curves shift towards the higher temperature side. The values for E’, E�, and tan delta obtained are higher at higher heating rates. Also, the value of

Tg increases as the heating rate increases, as shown in Fig. 14. Tg at 1 ºC/minute heating rate is around -65 ºC, while at ž& PLQXWH KHDWLQJ UDWH LV DURXQG ž& +RZHYHU WKH WDQ į peak (for the value of Tg) starts diminishing at a 5 ºC/minute heating rate. It is clear from Fig. 14 that at a 10 ºC/minute KHDWLQJ UDWH WKH VDPSOH GRHV QRW VKRZ DQ\ SHDN LQ WDQ į versus the temperature curve. This may be because the heat transfer from the furnace to the sample is not instantaneous, but depends on the conduction, convection, and radiation that can occur within the DMA instrument. Thus, a thermal lag is present between the sample and the furnace, and as higher the rate of heating, the greater this lag is likely to be present. Therefore, at a 10 ºC/minute heating rate, the sample is not able to acquire the required temperature in such a short term, thereby no peak is observed. Hence, lower heating rates (up to 3 ºC/minutes) are preferred to get accurate results.

)LJXUH ,QĂ€XHQFH RI KHDWLQJ UDWH RQ VWRUDJH PRGXOXV DW +] IUHTXHQF\

450

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

6WXGLHV RQ WKH ,QĂ€XHQFH RI 7HVWLQJ 3DUDPHWHUV RQ '\QDPLF DQG 7UDQVLHQW 3URSHUWLHV RI &RPSRVLWH 6ROLG 5RFNHW 3URSHOODQWV 8VLQJ DÂŤ

)LJXUH ,QĂ€XHQFH RI KHDWLQJ UDWH RQ ORVV PRGXOXV DW +] IUHTXHQF\

)LJXUH ,QĂ€XHQFH RI KHDWLQJ UDWH RQ WDQ GHOWD DQG JODVV WUDQVLWLRQ DW +] IUHTXHQF\

CONC/U6ION6 7KH LQĂ€XHQFH RI YDULRXV SDUDPHWHUV OLNH WHPSHUDWXUH frequency, strain/stress levels, heating rate on the dynamic, and transient properties of high burning rate composite propellant was studied successfully. The results revealed that H[SHULPHQWDO SDUDPHWHUV KDYH VLJQLÂżFDQW LQĂ€XHQFH RQ '0$ results. Data also showed that increase in the frequency has the same effect on the measured viscoelastic property as decrease in temperature or decrease in the time. An increase in the stress or a decrease in the temperature leads to decrease in the creep compliance, while an increase in the strain or increase in the temperature directs to decrease in the relaxation modulus. Also, an increase in the heating rate or in the frequency shifts

DMA curves to higher temperatures. Very high heating rates (~10 ÂşC/minutes) get inaccurate results. Therefore, to obtain accurate results, lower heating rates, which cannot be higher than 3 ÂşC/minutes, are preferred. Moreover, dynamic and transient properties determined at different parameters may be used to: characterize the propellant material, get the shift factors (aT) from multifrequency strain curves at different temperatures using WLF model, develop the master curve for the propellant at the required reference temperature and be used to predict the performance of the propellant over a lifetime of its application.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

451

Wani,V. et al.

$C.NO:/(D*(0(NT6 $XWKRUV WKDQN 6ZDWL 6DFKDGHYD IRU KHU ZKROH KHDUWHG VXSSRUW GXULQJ WKLV VWXG\ LQ WKH ÂżHOG RI WHVWLQJ SURSHOODQWV parameters. REFERENCES %KDJDZDQ 6 6 et al. Âł9LVFRHODVWLF %HKDYLRXU RI 6ROLG 3URSHOODQWV EDVHG RQ 3RO\PHULF %LQGHUV´ 'HIHQFH 6FLHQFH -RXUQDO 9RO 1R SS Boyars, C. and Klager, K., 1969, “Propellants, Manufacturing, +D]DUGV DQG 7HVWLQJ´ $PHULFDQ &KHPLFDO 6RFLHW\ Washington D.C, 88p. Cogmez, A. et al., 1999, “Comparison of two HTPB based composite propellants by dynamic mechanical analysisâ€?, Proceedings of the 30th International Conference of ICT, Karlsruhe, V29 pp. 1-12 or 29-1 to 29-12. Ferry, J.D., 1980, “Viscoelastic Properties of Polymersâ€?, 3rd (G -RKQ :LOH\ 6RQV &KDSWHU SS Foreman, J., 1997, “Dynamic mechanical analysis of polymersâ€?, American Laboratory, pp. 198-206. Groves, I.F. et al., 1992, “Dynamic mechanical analysis – A versatile technique for the viscoelastic characterization of materialsâ€?, International Labmate, Vol. 17, Issue 2, TA070.

452

Hanus, M., 2001, “Dynamic mechanical analysis of composite VROLG URFNHW SURSHOODQWV´ 3URFHHGLQJV RI WKH ,9 VHPLQDU Âł1HZ trends in research of energetic materials, Czech Republic, pp. 112-121. Mohandas, C.V. et al. Âł6WXGLHV RQ WKH HIIHFW RI KXPLGLW\ RQ &UHHS DQG 6WUHVV 5HOD[DWLRQ %HKDYLRXU RI FRPSRVLWH +73% based propellantâ€?, 3rd ,QWHUQDWLRQDO 6HPLQDU RQ +LJK (QHUJ\ Materials Conference and Exhibit, Thiruvananthapuram, India. Morton, M. et al., 1969, “Dynamic Response and Damping behaviour of heterogeneous polymersâ€?, Technical report AFML-TR-67-408 Part – II. 0XVDQLF 6 0 Âł,QĂ€XHQFH RI WHVWLQJ FRQGLWLRQV RQ results of dynamic mechanical analysis of double base rocket SURSHOODQWV´ 3URFHHGLQJV RI WKH ,9 VHPLQDU Âł1HZ WUHQGV LQ research of energetic materialsâ€?, Czech Republic. 1DLU 7 0 et al., 2009, “Dynamic Mechanical Analysis of (WK\OHQH 3URS\OHQH 'LHQH 0RQRPHU 5XEEHU DQG 6W\UHQH Butadiene Rubber Blendsâ€?, Journal of Applied Polymer 6FLHQFH 9RO SS Tod, D.A., 1987, “Dynamic mechanical analysis of propellantsâ€?, Proceedings of 18th international conference of ICT, Karlsruhe, V 44 pp. 1-14 or 44-1 to 44-14. Young, R.J. and Lovell, P.A., 1991, Introduction to Polymers, 2nd HG 1HOVRQ 7KRUQHV &KHOWHQKDP 8.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 443-452, Oct.-Dec., 2012

GRL MDWP

Kinematic Analysis of the Deployable Truss Structures for Space Applications Xu Yan1*, Guan Fu-ling1, Zheng Yao1, Zhao Mengliang1,2 Zhejiang University, Hangzhou – China Shanghai JiangNan Architectural Design Institute – China

2

Abstract: Deployable structure technology has been used in aerospace and civil engineering structures very popularly. This paper reported on a recent development of numerical approaches for the kinematic analysis of the deployable truss structures. The dynamic equations of the constrained system and the computational procedures were summarized. The driving force vectors of the active cables considering the friction force were also formulated. Three types of macroelements used in deployable structures were described, including linear scissor-link element, multiangular scissor element, and rigid-plate element. The corresponding constraint equations and the Jacobian matrices of these macroelements were formulated. The accuracy and efÂżciency of the proposed approach are illustrated with numerical e[amples, including a double-ring deployable truss and a deployable solar array. Keywords: Kinematic analysis, Deployable truss structures, Macroelements, Deployable solar array.

LIST OF SYMBOLS T X M

Q ĭi A h1, h2, ‌, hp

ČĄ T(Č™) f(Č™) N(Č™) , r

Kinetic energy of the system; Generalized coordinate vector; Inertia or mass matrix; First order time derivative of X; Vector that includes external and velocity dependent inertia force; Geometrical constrain equations; Jacobian matrix of constrain equations; p independent displacement modes of rigidbody movement; Row vector consists on these combined FRHIÂżFLHQWV LQ (T Length density of the active cable; Internal force vector; Friction force vectors in the contact point; Pressure force vectors in the contact point; Velocity and acceleration of cable length variety; Radius of the pulley;

5HFHLYHG

$FFHSWHG

DXWKRU IRU FRUUHVSRQGHQFH [\]V#]MX HGX FQ 6FKRRO RI $HURQDXWLFV DQG $VWURQDXWLFV =KHMLDQJ 8QLYHUVLW\ Zheda Road – Xihu – Hangzhou, Zhejiang – China

ÄŽ Čœ Č? Č™k , Č™k–1 Čœij

Half angle between the two active cable element nearby the point; Direction cosine of the cable element; '\QDPLF IULFWLRQ FRHIÂżFLHQW Start and end angle according to contact region; 'LUHFWLRQ FRVLQH RI WKH XQLSOHWV LM

INTRODUCTION Deployable truss structures have been applied in many applications, such as solar arrays, masts and antennas (Meguro et al., 2003) that have small-stowed volumes during launch, and are deployed by certain means to assume LWV SUHGHWHUPLQHG VKDSH DFFXUDWHO\ LQ RUELW 7UDGLWLRQDOO\ a deployable truss structure consists of a large number of struts and kinematic pairs, which are simple, such as revolute MRLQWV VOLGLQJ KLQJHV 7DNDPDWVX DQG 2QRGDI JHDUV and pantograph struts (Cherniavsky et al. 7KLV W\SH RI deployable structure has many advantages, including lighter weight, higher precision, smaller launch volume, and higher UHOLDELOLW\ IRU GHSOR\PHQW 7KHUH LV D ODUJH DPRXQW RI SXEOLVKHG OLWHUDWXUH RQ FRQVWUDLQHG ULJLG DQG ÀH[LEOH ERG\ G\QDPLFV ZKLFK IRFXVHG on building the dynamic model, solving the differential HTXDWLRQV DQG NLQHPDWLF VLPXODWLRQ 0DQ\ VWXGLHV KDYH

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

453

<DQ ; et al

only addressed simple beams and rigid bodies, which are QRW FRPSOLFDWHG GHSOR\DEOH VWUXFWXUHV %D\R DQG /HGHVPD SUHVHQWHG D QHZ LQWHJUDWLRQ PHWKRG IRU FRQVWUDLQHG PXOWLERG\ G\QDPLFV )LVHWWH DQG 9DQHJKHP XVHG the coordinate partitioning method of constrained Jacobian PDWUL[ WR DQDO\]H WKH PXOWLERG\ V\VWHP $Q RUWKRQRUPDO tangent space method for constrained multibody systems ZDV SURSRVHG E\ %ODMHU LQ ZKLFK WKH LQGHSHQGHQFH basis vector of the tangent space of constrained surface QHHGV WR EH FDOFXODWHG 2UWKRJRQDO PDWUL[ WULDQJXODUL]DWLRQ 45 GHFRPSRVLWLRQ .LP DQG 9DQGHUSORHJ VLQJXODU YDOXH GHFRPSRVLWLRQ 6LQJK DQG /LNLQV DQG GLIIHUHQWLDEOH QXOO VSDFH PHWKRG /LDQJ DQG /DQFH ZHUH XVHG WR REWDLQ VXFK EDVLV YHFWRUV 6RPH DXWKRUV KDYH investigated the mechanism characteristics of deployable truss and tensegrity structures in their literatures (Calladine DQG 3HOOHJULQR <RX %DH et al. (2000) SURSRVHG DQ HIÂżFLHQW LPSOHPHQWDWLRQ DOJRULWKP IRU UHDO WLPH VLPXODWLRQ RI WKH PXOWLERG\ YHKLFOH G\QDPLFV PRGHOV Newton chord method was employed to solve the equations RI PRWLRQ DQG FRQVWUDLQWV 8VLQJ WKH ÂżQLWH SDUWLFOH PHWKRG )30 <X DQG /XR SUHVHQWHG D PRWLRQ DQDO\VLV approach of deployable structures based on the straight- and DQJXODWHG URG KLQJHV .LQHPDWLF DQG G\QDPLF DQDO\VLV DQG control methods of the hoop truss deployable antenna were LQYHVWLJDWHG E\ /L 7KLV SDSHU UHSRUWV D UHFHQWO\ FRQGXFWHG HIIRUW WKDW systematically addressed a kinematic analysis method of deployable truss structure based on macroelements, in which WKH IULFWLRQ IRUFH ZDV FRQVLGHUHG

where X: is the generalized coordinate vector, and M LV WKH LQHUWLD RU PDVV PDWUL[ 7KH ÂżUVW /DJUDQJH HTXDWLRQ LV SUHVHQWHG DV (T ^dX hT c d 2To - 2T - Q m = 0 2X dt 2X

(2)

where Q: is the vector that includes the external and velocity dependent inertia force, LV WKH ÂżUVW RUGHU WLPH GHULYDWLYH RI X %\ VXEVWLWXWLQJ (T LQWR WKH G\QDPLF HTXDWLRQ FDQ EH GHWHUPLQHG DV (T dX T ^ MXp - Qh = 0

(3)

%HFDXVH WKHUH DUH PDQ\ FRPSOLFDWHG FRQVWUDLQV LQ WKH deployable truss structures, the vector dX, according to the JHQHUDOL]HG FRRUGLQDWH YHFWRU LV GHSHQGHQW &RQVLGHULQJ DOO types of constrains of the entire structures, the geometrical FRQVWUDLQ HTXDWLRQV DUH IRUPXODWHG DV (T Ui ^ X h = 0; i = 1, 2, g, s

Since all constrains of the deployable structure are constant with time t during the deployment process, the derivative of WKH FRQVWUDLQW HTXDWLRQV SURYLGH WKH -DFRELDQ PDWUL[ (T AXo = 0

EQUATIONS OF MOTION CONSIDERING DRIVING CONDITIONS Dynamic equations for the constrained system 7KH G\QDPLF HTXDWLRQV IRU WKH FRQVWUDLQHG V\VWHP DQG WKH FRPSXWDWLRQDO SURFHGXUHV DUH VXPPDUL]HG LQ WKLV VHFWLRQ For the deployable spatial structure, the dependent Cartesian coordinates are used as generalized ones for the dynamic HTXDWLRQ 7KH PDVV DQG YHORFLW\ RI WKH VWUXWV DUH UHGXFHG WR two revolute joints at the two ends, and the kinetic energy of WKH V\VWHP LV GHÂżQHG DV (T 1 T = Xo T MXo 2

454

(5)

where A: is the corresponding Jacobian matrix of constraint HTXDWLRQV 7KH YHORFLW\ HTXDWLRQ (T LV VROYHG E\ WKH JHQHUDOL]HG LQYHUVH PDWUL[ PHWKRG (T Xo = ao 1 h1 + ao 2 h2 + gao p h p = Hao

where h , h2, ‌ , hp: are p independent displacement modes of the rigid-body movement, : is a row vector that consists of these combined FRHI¿FLHQWV (T

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

.LQHPDWLF $QDO\VLV RI WKH 'HSOR\DEOH 7UXVV 6WUXFWXUHV IRU 6SDFH $SSOLFDWLRQV

o o Xp = Hap - A+ AX

%\ UHSODFLQJ (TV DQG LQWR WKH G\QDPLF HTXDWLRQ (T WKH IROORZLQJ ÂżQDO G\QDPLF HTXDWLRQV DUH REWDLQHG (TV DQG Xo = Hao o ao - H T Q = 0 H T MHap - H T MA+ AH

With the initial condition: Xt = 0 = X0, Xo t = 0 = Xo 0

When the initial displacement and velocity vectors are known, the vector t=0 LQ (T FDQ EH REWDLQHG %\ WKHVH LQLWLDO YDOXHV 1HZPDUNœV PHWKRG LV HPSOR\HG WR VROYH WKH ¿QDO G\QDPLF HTXDWLRQV (T WKHUHIRUH GLVSODFHPHQW YHORFLW\ and acceleration of the deployable process in each time step FDQ DOVR EH GHWHUPLQHG 7KH QXPHULFDO DSSURDFK FRPSXWDWLRQDO SURFHGXUH LV YHU\ simple and can be summarized as follows: ‡ DOO LQLWLDO LQSXW GDWHV RI WKH HQWLUH VWUXFWXUH DQG QXPHULFDO simulation, such as the coordinates of the joints, structural topology, constraint conditions, driving mechanisms, boundary conditions and the length of time step, and so on, are provided; ‡ DW DQ\ WLPH VWHS n, the mass matrix and driving force vectors are formed; ‡ WKH -DFRELDQ PDWUL[ DQG WKH ¿UVW RUGHU GHULYDWLYH RI WKH Jacobian matrix are formulated; ‡ WKH JHQHUDOL]HG LQYHUVH PDWUL[ DQG EDVLV YHFWRU RI QXOO space of are determined; ‡ LI PDWUL[ has full column, the rank will be estimated, if so go to the ninth step; ‡ WKH GLIIHUHQWLDO G\QDPLF HTXDWLRQV DUH FDOFXODWHG DQG WKH displacement, velocity, and acceleration of all joints are obtained; ‡ XSGDWH WKH SRVLWLRQV RI DOO MRLQWV DQG FKHFN ZKHWKHU WKH ORFNHG FRQGLWLRQV RI WKH VWUXFWXUH LV VDWLV¿HG LI WKH\ DUH not, go to the second step; otherwise, go to the ninth step; ‡ LI WKH SHULRG LV OHVV WKDQ WKH HQGLQJ WLPH JR WR WKH VHFRQG step, otherwise, the analysis should be stopped; ‡ WKH DQDO\VLV LV VWRSSHG DQG WKH RXWSXW GDWHV DUH UHDG\ IRU SRVW SURFHVV

Active cable driving and friction 7KH SXUSRVH RI WKLV VHFWLRQ LV WR IRUPXODWH WKH GULYLQJ force vectors of the active cables, which forms the term Q in WKH G\QDPLF HTXDWLRQV 'ULYH HQHUJ\ RI WKH GHSOR\DEOH WUXVV VWUXFWXUH FRPHV IURP WKH HOHFWULFDO PRWRU :KHQ WKH DFWLYH cables are driven by the motor, the cable length becomes VKRUWHU DQG WKH VWUXFWXUH LV GHSOR\HG 7KH GULYLQJ IRUFHV LQ the active cables will become smaller after it loops over the pulley, so the Coulomb friction law is employed to consider WKH IULFWLRQ EHWZHHQ WKH DFWLYH FDEOHV DQG WKH SXOOH\ )LJ 7KH SUHWHQVLRQ IRUFH RI WKH DFWLYH FDEOH LQ WKH IUHH HQG is assumed as T &RQVLGHULQJ WKH IULFWLRQ IRUFHV EHWZHHQ WKH active cable and the pulley in the joints, driving forces of the cables in each deployable element are T2, ‌, Tk, ‌, Tn LQ WXUQ 7KHUHIRUH WKHUH DUH T > ‌ > Tk > ‌ > Tn. 7KH HODVWLF GHIRUPDWLRQV RI WKH DFWLYH FDEOHV DUH LJQRUHG and a microarc element ds in the contact point between the FDEOH DQG WKH SXOOH\ LV DQDO\]HG DV VKRZQ LQ )LJ 7KH length density of the active cable is ȥ and the internal force vector is denoted as T(ș 7KH IULFWLRQ DQG SUHVVXUH IRUFH vectors in the contact point are denoted as f (ș) and N (ș), UHVSHFWLYHO\ 7KH HTXLOLEULXP HTXDWLRQV RI WKH PLFURDUF

(a) contact domain

(b) microarc element )LJXUH $FWLYH FDEOH UXQV RYHU D SXOOH\

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

455

<DQ ; et al

HOHPHQW DUH REWDLQHG DV LQ (T T^i + di h cos di - T^i h - f^i h = ČĄdslp * lo2 T^i + di h sin di = N^i h + ČĄds r

%\ XWLOL]LQJ WKH ÂżUVW HTXDWLRQ RI (TV DQG (T LV the result:

where and : are the velocity and acceleration of cable length variety, r: is the radius of the pulley, ÄŽ: is the half angle between the two active cable elements QHDUE\ WKH SRLQW DV VKRZQ LQ )LJ

7KHQ WKHUH LV (T

(T LV GLYLGHG E\ dČ™ and the limit is gotten by dČ™ Äş . %\ XVLQJ (T LW \LHOGV (T dT = nT + ^ prlp - nplo2h di

7KH VWDUW DQG HQG DQJOHV DFFRUGLQJ WR FRQWDFW UHJLRQ DUH provided as șk and șk ¹ 7KH GH¿QLWH LQWHJUDO UHVXOW RI (T LV ZULWWHQ DV (T

#TT

k-1

k

)LJXUH $FWLYH FDEOHV LQ WZR DGMDFHQW GHSOR\DEOH HOHPHQWV

7KHQ WKH YHORFLW\ DQG DFFHOHUDWLRQ RI FDEOH OHQJWK YDULHW\ and ZHUH IRUPXODWHG )RU WKH DFWLYH FDEOH HOHPHQW ij in a GHSOR\DEOH HOHPHQW WKH OHQJWK FDQ EH H[SUHVVHG DV (T 6^ Xi - X jhT ^ Xi - X jh@2 = l 1

ik -1 dT = # di 2 p o ^ h + ik nT ČĄrl nČĄl

6ROYLQJ VXFK HTXDWLRQV LW ZLOO \LHOG (T

nTk - 1 + ^ ČĄrlp - nČĄlo2h = e n^i nTk + ^ ČĄrlp - nČĄlo2h

k - 1 - i kh

7KHUH LV Č™k Âą – Č™k = ĘŒ – 2Č•, and the relation of the internal force of cable in two adjacent deployable elements can be REWDLQHG (T

'LIIHUHQWLDWLQJ (T IRU WKH ÂżUVW DQG VHFRQG WLPHV (TV DQG ZHUH GHWHUPLQHG Xo i lo = m^ Xo j - Xo ih = 6- m m @) o 3 Xj

nTk - 1 + ^ ČĄrlp - nČĄ lo2h = e n^r - 2bh nTk + ^ ČĄrlp - nČĄ lo2h

(20)

%\ XWLOL]LQJ (T WKH IULFWLRQ IRUFH EHWZHHQ WKH DFWLYH cable and the pulley in the joint j LV REWDLQHG (T

where Čœ = 1 (Xj – Xi)7 LV WKH GLUHFWLRQ FRVLQH RI WKH FDEOH HOHPHQW l 7KH 9LVFRXV DQG &RXORPE IULFWLRQ ODZV FDQ EH FRPELQHG into equations of motion, being the second one employed:

fk - 1 = Tk - 1 - Tk

where Č? LV WKH G\QDPLF IULFWLRQ FRHIÂżFLHQW 456

7KH JHQHUDOL]HG GULYLQJ IRUFH RI D GULYLQJ FDEOH HOHPHQW LV DV (T Q ce = " Qie Q ej ,

T

f^i h = Č? N^i h

(22)

Such force of the vector Q of the entire structure is obtained E\ DVVHPEOLQJ WKH (T IRU HDFK HOHPHQW

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

.LQHPDWLF $QDO\VLV RI WKH 'HSOR\DEOH 7UXVV 6WUXFWXUHV IRU 6SDFH $SSOLFDWLRQV

JACOBIAN MATRICES OF THE MACROELEMENTS In this section, some deployable macroelements are investigated, and the corresponding Jacobian matrices are IRUPXODWHG 7KH HTXDWLRQV RI WKH FRQVWUDLQWV DQG WKH -DFRELDQ matrices for a constant distance constraint on the members, the position constraint of the sleeve element, the angle constraint of the revolute joints and of synchronize gears have EHHQ SUHVHQWHG LQ PDQ\ UHIHUHQFHV )RU WKH VDNH RI EUHYLW\ the formulations are not fully developed here, therefore see Nagaraj et al. =KDR DQG *XDQ IRU GHWDLOV Linear scissor-link element /LQHDU VFLVVRU OLQN HOHPHQW 6/( LV D W\SH RI IXQGDPHQWDO macroelement in the deployable truss structures, where two pairs RI VWUXWV DUH FRQQHFWHG WR HDFK RWKHU DW D SLYRW SRLQW 2 WKURXJK D UHYROXWH MRLQW VKRZQ LQ )LJ ,W DOORZV WZR SDLUV RI VWUXWV to rotate freely around the axis perpendicular to their common SODQH EXW UHVWUDLQV DOO RWKHU GHJUHHV RI IUHHGRP $W WKH VDPH WLPH WKHLU HQGSRLQWV DUH KLQJHG WR WKH RQHV RI RWKHU HOHPHQWV $V FDQ EH VHHQ LQ )LJ WKH DQJOH EHWZHHQ OLQNV il and oi is GHÂżQHG DV WKH GHSOR\ DQJOH ÄŽ RI 6/( :KHQ WKH PDFURHOHPHQW LV GHSOR\HG WKLV GHSOR\ DQJOH EHFRPHV ODUJHU 7KHUH DUH WZR FRQVWDQW GLVWDQFH FRQVWUDLQW HTXDWLRQV RI WKH uniplets ij and lk, and the Jacobian matrix is formulated as (T - mijT mijT 0 0 G A1e = = 0 0 - m Tkl m Tkl

(23)

FRQVWUDLQW HTXDWLRQ LV DV (T ^ X i - X jh

a a + Xi = ^ Xk - Xlh + Xl a^1 + kh a^1 + kh

7KH XSSHU HTXDWLRQ LV VLPSOLÂżHG WR WKH IROORZLQJ IRUP (T kXi + X j - kXk - Xl = 0

(25)

Differentiating it with respect to X, therefore the Jacobian matrix is obtained:

A2e = " kI3 # 3 I3 # 3 - kI3 # 3 - I3 # 3 , %HFDXVH ÂżYH UHYROXWH MRLQWV DUH FRSODQDU GXULQJ WKH deployment process, the planar equation is the constraint HTXDWLRQV RI WKH PDFURHOHPHQW (T ^rij # rikh : ril = 0

When differences are compared with respect to X, the -DFRELDQ PDWUL[ LV REWDLQHG (T A3e = "^ril # rjk - rij # rikh1 # 3 ^rik # rilh1 # 3 ^rij # rilh ^rij # rikh1 # 3 ,

)RU WKH SODQDU 6/( WKH URZ QXPEHU RI WKH -DFRELDQ PDWUL[

A3e Ae = A3e LV A3e

Planar multiangular scissor element

where the direction cosine of the uniplets ij is

It is assumed that the length of oi, ok are a and the length of oj, ol are k*a 7ZR SDLUV RI XQLSOHWV DUH FRQQHFWHG WR HDFK other at the point o 'XULQJ WKH GHSOR\PHQW SURFHVV WKH relative position of the connection point o LV LQYDULDEOH 7KH

Planar multiangular scissor element, as illustrated in )LJ LV DQRWKHU W\SH RI PDFURHOHPHQW XVHG LQ WKH GHSOR\DEOH truss structures, in which the uniplets ij and lk are not aligned at an intermediate point O %DVHG RQ WKH FRQGLWLRQ RI WZR FRQJUXHQW WULDQJOHV WKH constraint equations of the planar multiangular scissor

)LJXUH /LQHDU VFLVVRU OLQN HOHPHQW

)LJXUH 3ODQDU PXOWLDQJXODU VFLVVRU HOHPHQW

Čœij = 1 (Xj – Xi), like the kl XQLSOHWV Lij

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

457

<DQ ; et al

element include: ‡ IRXU WUXVV PHPEHUV io, jo, ko and lo of the macroelement are considered and there are four constant distance constraint equations; ‡ WZR GXPP\ WUXVV PHPEHUV ij and lk are added to the macroelement; thus, there are two constant distance constraint equations; ‡ ¿YH SRLQWV DUH FRSODQDU DQG WKH SODQDU HTXDWLRQ LV constraint, which can be formulated by the same method DV DOUHDG\ PHQWLRQHG For the planar multiangular scissor element, the row number of the Jacobian matrix Ae LV HLJKW Rigid-plate element Planar rigid-plate element is a type of macroelement used LQ VRODU DUUD\V $ IRXU QRGH ULJLG SODWH HOHPHQW ijkl is shown in )LJ ZKLFK LV FRQQHFWHG WR RWKHU PHPEHUV DW FRUQHU SRLQWV WKURXJK D UHYROXWH MRLQW 7KH PDVV SURSHUW\ RI WKH PDFURHOHPHQW LV UHGXFHG WR D ¿QLWH QXPEHU RI SRLQWV 7KH ULJLG SODWH HOHPHQW LV VXEVWLWXWHG ZLWK DQ HTXLYDOHQW JULG RI YLUWXDO ULJLG VWUXWV 7KH IUHHGRP degree of the element is analyzed: the degree of freedom of four spatial points i, j, k, l LV $IWHU WKH OHQJWK FRQVWUDLQWV RI six struts are appended, the total degree of freedom becomes VL[ ZKLFK LV HTXDO WR WKDW RI WKH ULJLG SODWH HOHPHQW Six struts ij, jk, kl, li, ik and jl of the element are considered, DQG WKHUH DUH VL[ FRQVWDQW GLVWDQFH FRQVWUDLQW HTXDWLRQV )RU the planar-plate element, the row number of the Jacobian matrix Ae LV VL[

DQWHQQDV WKH IXOO GHSOR\HG IROGHG FRQÂżJXUDWLRQ RI ZKLFK DUH VKRZQ LQ )LJ 7ZR DGMDFHQW GHSOR\DEOH HOHPHQWV RI WKH RXWHU DQG LQQHU ULQJ DUH VKRZQ LQ )LJ ZKLFK DUH TXDGULODWHUDO HOHPHQWV ZLWK D GLDJRQDO VOHHYH HOHPHQW 7KH DFWLYH FDEOHV SDVV WKURXJK WKH GLDJRQDO VOHHYHV :KHQ WKH DFWLYH FDEOH is deployed by a motor and becomes shorter, the diagonal VOHHYHV $( DQG &( FRQWUDFW 7KHQ WKH GHSOR\DEOH HOHPHQWV DUH GHSOR\HG :KHQ WKH OHQJWKV RI WKH GLDJRQDO VOHHYHV $( DQG &( DUH HTXDO WR D GHVLJQHG YDOXH WKH GHSOR\PHQW RI WKH HOHPHQWV LV VWRSSHG Several planar truss elements can make a closed loop by DUUDQJLQJ WKHP VLGH E\ VLGH 7KH SODQDU WUXVV HOHPHQWV DUH DOVR XVHG LQ FRQQHFWLQJ WKH LQQHU DQG RXWHU ORRSV 7KH VWUXFWXUH topology is determined and the major design parameters of the WUXVV DUH LQFOXGHG WKH VLGH QXPEHU RI WKH ULQJ LV WKH WUXVV DSHUWXUH LV P WKH WUXVV KHLJKW LV P WKH OHQJWK RI WKH FKRUG VWUXWV LQ WKH RXWHU ULQJ LV P DQG WKH OHQJWK RI WKH FKRUG VWUXWV LQ WKH LQQHU ULQJ LV PP

D GHSOR\HG FRQÂżJXUDWLRQ

E IROGHG FRQÂżJXUDWLRQ

)LJXUH 'RXEOH ULQJ GHSOR\DEOH WUXVV

)LJXUH 5LJLG SODWH HOHPHQW

NUMERICAL EXAMPLES

)LJXUH 'HSOR\PHQW SURFHVV RI GHSOR\DEOH WUXVV HOHPHQWV

Double-ring deployable truss

7KH QXPEHULQJ RI WKH WUXVV MRLQWV LV VKRZQ LQ )LJ 7KH PRWLRQ SURFHVV RI WKH GRXEOH ULQJ GHSOR\DEOH WUXVV ZDV simulated by the program developed based on numerical DSSURDFKHV 7KH PDVV RI HDFK UHYROXWH MRLQW LV NJ

A type of double-ring deployable truss based on quadrilateral elements is investigated for large-size mesh 458

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

.LQHPDWLF $QDO\VLV RI WKH 'HSOR\DEOH 7UXVV 6WUXFWXUHV IRU 6SDFH $SSOLFDWLRQV

)LJXUH 1XPEHULQJ RI WKH WUXVV MRLQWV

)LJXUH $FWLYH FDEOHV

7KH DFWLYH FDEOHV ORFDWHG LQ WKH PRGHO DUH VKRZQ LQ )LJ 7KH HODVWLF GHIRUPDWLRQV RI WKH DFWLYH FDEOHV DUH QHJOHFWHG DQG D FRQVWDQW 1 GULYLQJ IRUFH RI WKH DFWLYH FDEOHV LQ DOO FRQ¿JXUDWLRQV LV DVVXPHG 7R GHSOR\ WKH WUXVV VXFFHVVIXOO\ WKH G\QDPLF IULFWLRQ FRHI¿FLHQW ȝ between the active cables and the SXOOH\ LV UHTXLUHG WR EH VPDOO WKH UHDO YDOXH RI ZKLFK LV GLI¿FXOW WR EH PHDVXUHG ,W LV JLYHQ WR EH D VPDOO GHIDXOW YDOXH LQ WKLV VLPXODWLRQ ZRUN 7KH OHQJWK RI WLPH VWHS LQ WKH VLPXODWLRQ LV

VHFRQG 7KH WUXVV VWDUWV WR PRYH E\ DFWLYH FDEOHV DQG UHDFKHV D VWDWLF ¿QDO FRQ¿JXUDWLRQ DW ODVW ZKLFK LV VKRZQ LQ )LJ When the lengths of the diagonal sleeves are equal to a designed value, the locked constraint conditions of the sleeves work and WKH VLPXODWLRQ VWRSV ,W WDNHV VHFRQGV WR EH IXOO\ GHSOR\HG 7KH FRRUGLQDWH YDULDWLRQV RI MRLQWV DQG LQ WKH GHSOR\DEOH WUXVV DUH VKRZQ LQ )LJ ZKLFK FDQ GHVFULEH WKH YDULDWLRQV RI FRQ¿JXUDWLRQV GXULQJ WKH VWUXFWXUDO PRWLRQ LQ GHWDLOV

D W VHFRQG

G W VHFRQGV

E W VHFRQGV

F W VHFRQGV

H W VHFRQGV

)LJXUH 0RWLRQ SURFHVV RI WKH GHSOR\DEOH WUXVV

(a) x axes coordinate

(b) y axes coordinate

)LJXUH &RRUGLQDWH YDULDWLRQV RI MRLQWV DQG

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

459

<DQ ; et al

,Q WKH IXOO\ GHSOR\HG FRQ¿JXUDWLRQ WKH FRRUGLQDWHV RI SRLQWV DQG DUH UHVSHFWLYHO\ DQG +RZHYHU WKH UHIHUHQFH FRRUGLQDWHV RI WKH GHSOR\HG FRQ¿JXUDWLRQ which are obtained from the geometric equation of this FRQ¿JXUDWLRQ DUH DQG 7KH PD[LPXP HUURU LV 7KHUHIRUH WKH PHWKRG FDQ VLPXODWH WKH PRWLRQ EHKDYLRU RI WKH GHSOR\DEOH WUXVV HIIHFWLYHO\ DQG DFFXUDWHO\ Deployable sail arrays )LJXUH 6FDOH PRGHO RI WKH GHSOR\DEOH VDLO DUUD\

$ VFDOH PRGHO RI GHSOR\DEOH VDLO DUUD\ EDVHG RQ 6/(V LV SUHVHQWHG LQ )LJ 7KH VDLO DUUD\ FRQVLVWV RI HLJKW 6/( PDFURHOHPHQWV DQG HLJKW ULJLG SODWH PDFURHOHPHQWV 7KH 6/( macroelements are dynamic machines during deployment and VXSSRUW VWUXFWXUH DIWHU GHSOR\PHQW 7KH ULJLG SODWH HOHPHQWV DUH VDLO DUUD\ GHFN DQG WKHVH YHUWLFDO VWUXWV VXFK DV DQG DUH VOHHYH HOHPHQW 7KHUH DUH WZR DFWLYH FDEOHV LQ WKH VDLO DUUD\ LQ ZKLFK FDQ EH VHHQ LQ )LJ 2QH RI WKHP ZKLFK LV ¿UPO\ FRQQHFWHG WR MRLQW UXQV RYHU D SXOOH\ DW MRLQW ]LJ]DJV GRZQ WKH 6/( IROORZLQJ WKH URXWH VKRZQ LQ WKH ¿JXUH LW UXQV RYHU D SXOOH\ DW each kink) and, after passing over a pulley at joint 2, is connected WR WKH PRWRUL]HG GUXP ORFDWHG EHORZ WKH EDVH 7KH RWKHU DFWLYH FDEOH LV DUUDQJHG E\ WKH VDPH PHWKRG 7KH HODVWLF GHIRUPDWLRQ RI WKH DFWLYH FDEOHV LV QHJOHFWHG DQG D FRQVWDQW 1 GULYH IRUFH RI WKH DFWLYH FDEOHV LQ DOO FRQ¿JXUDWLRQV LV DVVXPHG )L[HG ERXQGDU\ FRQGLWLRQV DUH XVHG DW MRLQWV DQG DQG WKH WUDQVODWLRQ DORQJ [ GLUHFWLRQ RI MRLQWV DQG DUH ¿[HG 7KH

D W VHFRQGV

VWUXFWXUH LV GHSOR\HG IURP WKH QHDUO\ ÀDW FRQ¿JXUDWLRQ Į = WR WKH ¿QDO RQH Į = DV VKRZQ LQ )LJ 7KH PDVV RI HDFK UHYROXWH MRLQW LV NJ DQG WKDW RI MRLQWV LQ WKH ULJLG SODWH PDFURHOHPHQWV LV NJ $ WLPH VWHS dt s is used in WKH VLPXODWLRQ 7KH PRWLRQ EHKDYLRU RI WKH VDLO DUUD\ VWUXFWXUH ZDV VLPXODWHG E\ WKH VDPH SURJUDP 7KH VDLO DUUD\ VWDUWV WR PRYH E\ DFWLYH FDEOHV DQG UHDFKHV D VWDWLF ¿QDO FRQ¿JXUDWLRQ DV VKRZQ LQ )LJ :KHQ WKH OHQJWKV RI WKH YHUWLFDO VOHHYHV are equal to a designed value, the locked constraint conditions RI WKH VOHHYHV ZRUN DQG WKH VLPXODWLRQ VWRSV 7KH GHSOR\PHQW WLPH RI WKH VWUXFWXUH LV VHFRQGV 7KH FRRUGLQDWH YDULDWLRQV RI SRLQW LQ WKLV PRGHO ZLWK WLPH DUH VKRZQ LQ )LJ ZKLFK FDQ GH¿QH WKH YDULDWLRQV RI FRQ¿JXUDWLRQV GXULQJ WKH VWUXFWXUDO PRWLRQ LQ GHWDLOV ,Q WKH ¿QDO FRPSOHWHO\ GHSOR\HG FRQ¿JXUDWLRQ WKH FRRUGLQDWHV RI SRLQWV DQG DUH UHVSHFWLYHO\ DQG

E W VHFRQGV

G W VHFRQGV

F W VHFRQGV

H W VHFRQGV

)LJXUH 0RWLRQ SURFHVV RI WKH GHSOR\DEOH VDLO DUUD\V

460

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

.LQHPDWLF $QDO\VLV RI WKH 'HSOR\DEOH 7UXVV 6WUXFWXUHV IRU 6SDFH $SSOLFDWLRQV 4.5

0.6

4

0.5

3.5

0.4 y-coordinate (m)

x-coordinate (m)

3 2.5 2 1.5

0.3 0.2 0.1

1 0

0.5 0

-0.1

0

20

40

60

80

100

120

140

0

20

40

60

80

100

120

140

Time (s)

Time (s)

(a) x axes coordinate

(b) y axes coordinate

)LJXUH &RRUGLQDWH YDULDWLRQV RI MRLQW

ZKLOH WKH UHIHUHQFH FRRUGLQDWHV RI WKHVH SRVLWLRQV RQ WKH GHSOR\HG FRQÂż JXUDWLRQ ZKLFK DUH REWDLQHG IURP WKH JHRPHWULF HTXDWLRQ RI WKLV FRQÂż JXUDWLRQ DUH DQG 7KH PD[LPXP HUURU LV 7KHUHIRUH WKH PHWKRG FDQ VLPXODWH WKH PRWLRQ EHKDYLRU RI WKH GHSOR\DEOH VDLO DUUD\ HIIHFWLYHO\

REFERENCES

CONCLUSIONS

%D\R ( DQG /HGHVPD 5 ³$XJPHQWHG /DJUDQJLDQ DQG mass-orthogonal projection method for constrained multibody G\QDPLFV´ 1RQOLQHDU '\QDPLFV 9RO SS

7KLV SDSHU SUHVHQWV D QXPHULFDO DSSURDFK IRU NLQHPDWLF DQDO\VLV RI WKH GHSOR\DEOH WUXVV VWUXFWXUHV 7KH GULYLQJ forces of active cables are combined with the equations of PRWLRQ 7KH IULFWLRQ EHWZHHQ DFWLYH FDEOHV DQG WKH SXOOH\ LV FRQVLGHUHG 7KUHH NLQGV RI PDFURHOHPHQWV XVHG LQ GHSOR\DEOH VWUXFWXUHV DUH GHVFULEHG 7KH FRUUHVSRQGLQJ FRQVWUDLQW equations and Jacobian matrices of the macroelements are IRUPXODWHG $ GRXEOH ULQJ GHSOR\DEOH WUXVV DQG D GHSOR\DEOH VRODU DUUD\ VWUXFWXUH DUH VHOHFWHG DV QXPHULFDO H[DPSOHV 7KH deployment process and dynamic parameters at each time step can be simulated for evaluating the deployment behaviors of WKH VWUXFWXUH 5HVXOWV RI WKH QXPHULFDO VLPXODWLRQ VKRZ WKDW the capabilities of this method in the motion analysis are of FRPSOH[ GHSOR\DEOH WUXVV VWUXFWXUHV 7KH RULJLQ RI WKH Âż QDO error in the time step of the simulation is too large to stop WKH VLPXODWLRQ QHDUE\ WKH UHIHUHQFH FRQÂż JXUDWLRQ 7R DFKLHYH KLJKHU VLPXODWLRQ DFFXUDF\ WKH WLPH VWHS QHHGV WR EH VPDOOHU %DVHG RQ WKH UHVHDUFKHV LQFOXGHG LQ WKLV SDSHU IXWXUH works are suggested: the reliability analysis of the deployment process can be researched; and deployment control of the GHSOR\DEOH WUXVV DQWHQQDV QHHGV WR EH LQYHVWLJDWHG

%DH ' 6 et al., 2000, “An explicit integration method for real time simulation of multibody vehicle models�, &RPSXWHU 0HWKRGV LQ $SSOLHG 0HFKDQLFV DQG (QJLQHHULQJ 9RO SS

%ODMHU : Âł$Q RUWKRQRUPDO WDQJHQW VSDFH PHWKRG for constrained multibody systemsâ€?, Computer Methods In $SSOLHG 0HFKDQLFV $QG (QJLQHHULQJ 9RO SS &DOODGLQH & 5 DQG 3HOOHJULQR 6 Âł)XUWKHU UHPDUNV RQ Âż UVW RUGHU LQÂż QLWHVLPDO PHFKDQLVPV´ ,QWHUQDWLRQDO -RXUQDO RI 6ROLGV DQG 6WUXFWXUHV 9RO SS &KHUQLDYVN\ $ * et al., 2005, “Large deployable space antennas based on usage of polygonal pantographâ€?, Journal of $HURVSDFH (QJLQHHULQJ 9RO SS )LVHWWH 3 DQG 9DQHJKHP % Âł1XPHULFDO LQWHJUDWLRQ of multibody system dynamic equations using the coordinate partitioning method in an implict Newmark schemeâ€?, &RPSXWHU 0HWKRGV LQ $SSOLHG 0HFKDQLFV DQG (QJLQHHULQJ 9RO SS

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

461

<DQ ; et al

.LP 6 6 DQG 9DQGHUSORHJ 0 - Âł45 GHFRPSRVLWLRQ for state space representation of constrained mechanical G\QDPLF V\VWHPV´ -RXUQDO RI 0HFKDQLVPV 7UDQVPLVVLRQV DQG $XWRPDWLRQ LQ 'HVLJQ 9RO SS /L 7 - Âł'HSOR\PHQW DQDO\VLV DQG FRQWURO RI GHSOR\DEOH VSDFH DQWHQQD´ $HURVSDFH 6FLHQFH DQG 7HFKQRORJ\ 9RO SS /LDQJ & * DQG /DQFH * 0 Âł$ GLIIHUHQWLDEOH QXOO space method for constrained dynamic analysisâ€?, Journal RI 0HFKDQLVPV 7UDQVPLVVLRQV DQG $XWRPDWLRQ LQ 'HVLJQ 9RO SS 0HJXUR $ et al., 2003, “Key technologies for high-accuracy ODUJH PHVK DQWHQQD UHĂ€HFWRUV´ $FWD $VWURQDXWLFD 9RO SS 1DJDUDM % 3 et al. Âł.LQHPDWLFV RI SDQWRJUDSK PDVWV´ 0HFKDQLVP DQG 0DFKLQH 7KHRU\ 9RO SS 1DJDUDM % 3 et al. Âł$ FRQVWUDLQW -DFRELDQ EDVHG approach for static analysis of pantograph mastsâ€?, Computers DQG 6WUXFWXUHV 9RO SS

462

6LQJK 5 3 DQG /LNLQV 3 : Âł6LQJXODU YDOXH decomposition for constrained dynamical systemsâ€?, Journal RI $SSOLHG 0HFKDQLFV 9RO SS 7DNDPDWVX . $ DQG 2QRGDI - Âł1HZ GHSOR\DEOH WUXVV concepts for large antenna structures or solar concentratorsâ€?, -RXUQDO RI 6SDFHFUDIW 9RO SS <RX = Âł'HSOR\DEOH VWUXFWXUH RI FXUYHG SURÂżOH IRU VSDFH DQWHQQDV´ -RXUQDO RI $HURVSDFH (QJLQHHULQJ 9RO SS <X < DQG /XR < Âł0RWLRQ DQDO\VLV RI GHSOR\DEOH VWUXFWXUHV EDVHG RQ WKH URG KLQJH HOHPHQW E\ WKH ÂżQLWH SDUWLFOH methodâ€?, Proceedings of the Institution of Mechanical (QJLQHHUV 3DUW * -RXUQDO RI $HURVSDFH (QJLQHHULQJ 9RO SS =KDR 0 / DQG *XDQ ) / Âł.LQHPDWLF DQDO\VLV RI deployable toroidal spatial truss structures for large mesh antennaâ€?, Journal of the International Association for Shell DQG 6SDWLDO 6WUXFWXUHV 9RO SS

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 453-462, Oct.-Dec., 2012

doi: 10.5028/jatm.2012.04044912

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying the Wind Pattern at Centro de Lançamento de Alcântara Ana Cristina Avelar 1*, FabrĂ­cio Lamosa Carneiro Brasileiro2 , Adolfo Gomes Marto1, Edson R. Marciotto1, Gilberto Fisch1, Amanda Fellipe Faria1 Instituto de AeronĂĄutica e Espaço – SĂŁo JosĂŠ dos Campos/SP – Brazil Universidade Paulista – SĂŁo JosĂŠ dos Campos/SP – Brazil

1 2

Abstract: Centro de Lançamento de Alcântara is the main Brazilian launching center. In spite of presenting several desirable aspects, due to its proximity to the Equator, it has a peculiar topography because of the existence of a coastal cliff, Zhich modiÂżes the characteristics of the atmospheric boundary layer. 7his may affect rocNet launching operations, especially Zhen associated Zith safety procedures. 7his ZorN is a continuation of previous experimental studies about the airĂ€oZ pattern at this launching center. An improved Zay of simulating the atmospheric boundary layer in a short test section Zind tunnel using passive methods is presented here. It is also presented a preliminary analysis of the airĂ€oZ pattern in Centro de Lançamento de Alcântara, at speciÂżc positions as the edge of cliff and around the mobile integration toZer, from Zind tunnel measurements using particle image velocimetry. 7hree values of 5eynolds number, based on the coastal cliff height, l, ranging from 6.8Ă—105 to 2.0Ă—106, were considered. Keywords: Atmospheric Flow, Wind 7unnel, Boundary Layer, Centro de Lançamento de Alcântara.

LIST OF SYMBOLS AND NOMENCLATURES

INTRODUCTION

ÄŽ CLA ABL ÄŻ H IBL Iu l MIT PIV

The majority of the Brazilian rockets are launched from the Centro de Lançamento de Alcântara (CLA), which has a privileged geographical location, 2Âş 18’S that enables the operation of suborbital vehicles and satellites with safety launchings in several directions over the Atlantic Ocean (Pires et al., 2008; Avelar et al., 2010; Fisch et al., 2010, Pires et al. 2010). An effective use of the launch opportunities at CLA is possible due to the climate conditions with a ZHOO GHÂżQHG UDLQ UHJLPH DQG ZLQGV RI WROHUDEOH LQWHQVLW\ DQG QR VLJQLÂżFDQW WHPSHUDWXUH YDULDWLRQV ,Q DGGLWLRQ ORZ demographical density allows the displacement of several sites for launching or logistic support. However, despite the many favorable aspects, mainly because of its proximity to the Equator, the launching center has a peculiar topography due to the existence of a coastal cliff with 40m height (Fig. 1), which can modify the atmospheric boundary layer (ABL) characteristics and consequently affect the safety of rocket launching operations, since the rockets launching pad and the place where the space vehicles are assembled, i.e., mobile integration tower (MIT), are located around 150 to 200m from the border, respectively. Another important physical feature occurrence at the CLA is the formation of an internal boundary layer (IBL) as a consequence of the surface

3RZHU ODZ HTXDWLRQ FRHI¿FLHQW Centro de Lançamento de Alcântara Atmospheric Boundary Layer Boundary layer thickness Wind tunnel height Internal boundary layer Turbulence intensity Coastal cliff height Mobile integration tower Particle image velocimetry Aeronautic Wind Tunnel of Institute of AeronauTA-2 tics and Space u(z) LRJDULWKPLF YHORFLW\ SUR¿OH U(z),U(zr ) Mean velocities corresponding to heights z and zr Uinf Free stream velocity Friction velocity u* zr Reference height W Wind tunnel width Received: 04/09/12

Accepted: 10/10/12

*author for correspondence: anacristina.avelar@gmail.com Praça Marechal Eduardo Gomes, 50 – Vila das AcĂĄcias CEP 12228-904 – SĂŁo JosĂŠ dos Campos/SP – Brazil

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

463

Avelar, A.C. et al.

roughness variation, from ocean surface to continental terrain. The wind blowing from the oceanic smooth surface interacts with the low woodland vegetation modifying itself with the formation of an IBL (Pires, 2009), which makes the study of WKH PHWHRURORJLFDO FRQGLWLRQV DQG ZLQG ÀRZ SDWWHUQ LQ WKLV region even more important.

Figure 1. A general view of Centro de Lançamento de Alcântara.

The simulation of an ABL in a wind tunnel with short-test section is quite complicated and there are several methods for this purpose discussed in the literature (Counihan, 1969). A simple way of generating thick boundary layers is by using passive methods (Barbosa et al., 2002; Loredo-Souza et al. LQ ZKLFK WKH ÀRZ LV IRUFHG WR SDVV WKURXJK a combination of spires, wedges or grids together with roughness elements distributed on the wall. Ten possible ways of simulating neutral, stable, and unstable atmospheric conditions in different wind tunnel types were described in Hunt and Fernholz (1975). A short review of the techniques used to thicken the boundary layer was presented by Barbosa et al. (2002). Besides, thickening devices with sophisticated geometry were described by Ligrani et al. (1979 and 1983). 8QOXFNLO\ WKHVH PHWKRGV DUH QRW VWUDLJKWIRUZDUG IURP D ÀXLG PHFKDQLFV SRLQW RI YLHZ WR DOORZ VLPSOL¿HG DQG DIIRUGDEOH designs, which have motivated researchers to choose satisfactory geometries by trial and error. ABL physics is very complex, and the main reason for WKLV FRPSOH[LW\ LV WKH LQWHUDFWLRQ EHWZHHQ WKH DLUÀRZ DQG the surface, which occurs primarily through mechanical and thermal mechanisms. The mechanical interaction arises from the friction caused by the wind against the ground surface, ZKLFK FDXVHV WKH ZLQG WR EH VKHDUHG FUHDWLQJ D ZLQG SUR¿OH and associated turbulence. In the absence of thermal process, the ABL is said to be neutral, and a logarithmic velocity 464

SURÂżOH u(z), characterized by the friction velocity u* and the terrain roughness height zo, is expected to be found (LoredoSouza et al., 2004). According to Barbosa et al. (2000), for wind speeds higher than 10m/s, the turbulence produced E\ WKH Ă€RZ VKHDU LV PXFK JUHDWHU WKDQ WKDW SURGXFHG E\ WKH buoyancy, therefore thermal effects become negligible. This is the case of CLA, where strong winds are observed during the dry season, from July to December. The ABL and atmospheric Ă€RZ SDWWHUQ LQ WKH &/$ UHJLRQ KDV DOUHDG\ EHHQ VWXGLHG from observations, numerical simulations, and wind tunnel measurements (Pires et al., 2008; Avelar et al., 2010; Fisch et al., 2010; Marciotto et al., 2012) The present work is an extended version of a paper recently presented at the fourth AIAA Atmospheric and Space Environments Conference, in New Orleans, from 25 to 28 June 2012, Avelar et al. (2012), and it is also a continuation of a previous study (Avelar et al., 2010), in which the procedures for a boundary layer simulation in a short-test section wind tunnel (TA-2) were described and some preliminary results RI Ă€RZ PHDVXUHPHQWV XVLQJ WKH SDUWLFOH LPDJH YHORFLPHWU\ 3,9 WHFKQLTXH ZLWK D VLPSOLÂżHG WRSRJUDSK\ PRGHO RI WKH CLA region, were presented. Herein, the ABL was simulated using a combination of spires, barrier, and bottom wall surface roughness. The results FRQÂżUPHG WKH SRVVLELOLW\ RI FUHDWLQJ DQ $%/ LQ WKH DHURQDXWLF wind tunnel, TA-2, of the Instituto de AeronĂĄutica e Espaço, in Brazil, without using screens downstream of the spires, as in a previous work (Avelar et al., 2010). Three values of Reynolds number (5el) based on the coastal cliff height, l, ranging from 6.8Ă—105 to 2.0Ă—106 were considered. The SXUSRVH RI LQYHVWLJDWLQJ WKH LQĂ€XHQFH RI WKLV Ă€RZ SDUDPHWHU ZDV WR YHULI\ LI WKH Ă€RZ SDWWHUQ PDLQO\ EHKLQG WKH 70, LV sensitive to small Reynolds number variations. In addition, turbulence measurements from hot-wire techniques have been conducted. Some stereo PIV velocity measurements for the values of Reynolds number considered were also conducted, showing strong recirculation regions behind the TMI, and it ZDV YHULÂżHG WKDW WKH ZLQG Ă€RZ SDWWHUQ LV QRW YHU\ VHQVLWLYH WR small variations of this parameter. METHODOLOGY :LQG YHORFLW\ SURÂżOHV (PSLULFDO ODZV FDQ EH XVHG WR UHSUHVHQW WKH ZLQG SURÂżOH inside the ABL, for example, the logarithmic and power law equations (Arya, 2001). According to the logarithmic law,

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying the Wind Pattern at Centro de Lançamento de Alcântara

the vertical variation of the horizontal wind velocity, U, from the surface up to 100 to 150 m, which corresponds to the VXSHUÂżFLDO ERXQGDU\ OD\HU PD\ EH UHSUHVHQWHG E\ (T U^ z h = `

u) j c z r m ln z0 k

(1)

where, u*: is the friction velocity, N: is the Von Kårmån constant, z0: is the mean terrain roughness, and zr: is assumed to be 10m, which is the height suggested by the World Meteorology Organization to represent the horizontal wind surface. The friction velocity, u*, is dependent on the wall shear stress, IJw, consequently being a measure of the logarithmic declivity close to the wall (Loredo-Souza et al., 2004). Such HTXDWLRQ KDV D EHWWHU DSSUR[LPDWLRQ RI WKH ZLQG SUR¿OH FORVH to the surface, however it is extensively employed also in the surface layer up to about 100m above sea level (Garratt, 1994). 7KH SRZHU ODZ HTXDWLRQ FDQ EH GH¿QHG E\ (T a U^ z h = c zr m zref U^ zref h

(2)

where, U(zref ): is the mean velocity correspondent to a reference height zref . The exponent Ď is a characteristic of the type of terrain. It varies from 0.11 for smooth surface as lakes and the ocean to 0.34 for cities with high density of buildings. For the ocean surface, some studies consider Ď between 0.11 (Hsu et al., 1994; Barbosa et al., 2002) and 0.15 (Blessmann, 1973). Although commonly used, the power law equation has some drawbacks, which were pointed out by Loredo-Souza et al. (2004). Since this equation is valid for any value of zr, the top of the ABL is not recognized in this model. The second issue is that in spite of providing a good representation of the PHDQ YHORFLW\ SUR¿OH WKLV DSSURDFK GRHV QRW KDYH D WKHRUHWLFDO MXVWL¿FDWLRQ )LQDOO\ WKH SRZHU ODZ HTXDWLRQ KDV D JRRG adjustment in Ekman’s layer, but not into the surface layer. In the present work, the power law equation was used LQVWHDG RI WKH ORJDULWKPLF RQH EHFDXVH RI WKH GLI¿FXOWLHV LQ obtaining z0 and u*. In fact, according to Hsu (1988), in situ measurements of the aerodynamic roughness length are not

always possible since it is related to both the wind speed and the wave characteristics of the ocean. The value of 0.11 for the exponent ÄŽ was assumed in the power law equation. Wind tunnel atmospheric boundary layer modeling The experiments were conducted in TA-2, which is a closed-circuit aeronautic subsonic wind tunnel. Its test section has a 2.10m height, H, and 3.00m width, W. A 1,600 HP motor produces a maximum speed of 120m/s through the test section. Spires, roughness elements, and a barrier positioned downstream of spires were used for simulation of a thick boundary layer. The VSLUHV FRQVLVW RI WULDQJXODU VWHHO SODWHV Âż[HG DW WKH WHVW VHFWLRQ entrance. The combination of these elements generates the ERXQGDU\ OD\HU SURÂżOH LQ WKH VHFWLRQ WHVW 7KH VSLUH GLPHQVLRQV depend on the desired boundary layer characteristics and on the wind tunnel size, and they were calculated following the methodology proposed by Blessmann (1973). For the boundary layer formation, initially, a set of 180 small blocks with 80Ă—80Ă—20mm was displaced on the wind tunnel bottom wall separated by 150mm. A 200mm high barrier was positioned 350mm downstream of the spires. 1HYHUWKHOHVV GLIIHUHQW FRQÂżJXUDWLRQV REWDLQHG E\ UHPRYLQJ the barrier and spires, or changing the density of the roughness elements were tried as well. Two multi-manometers, with Pitot tubes for dynamic pressure measurements installed along its KHLJKW )LJ ZHUH XVHG IRU PRQLWRULQJ WKH YHORFLW\ SURÂżOHV in the boundary layer. The tallest multi-manometer (rake 1) has 15 Pitot tubes equally distributed along its extension and spaced by 13mm. The smallest one (rake 2) has 16 Pitot tubes. The 11 lowest Pitot tubes are spaced by 5mm and the ÂżYH KLJKHVW RQHV E\ PP )RU HDFK FRQÂżJXUDWLRQ WKH $%/ YHORFLW\ SURÂżOH ZDV FRPSDUHG ZLWK D SRZHU ODZ SURÂżOH ZLWK

Rake 1

Rake 2

Figure 2. Multi-manometer with Pitot tubes.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

465

Avelar, A.C. et al.

a=0.11, which was assumed to be the closest of what is found over the ocean (Hsu et al., 1994). The positions where dynamic pressure measurements were carried out are represented in Fig. 3.

during the experiment, was also used. Because of a physical limitation of this device, the highest vertical position where turbulence measurements were conducted was 765mm. Particle Image Velocimetry measurements

Mobile Integration Tower MIT

Roughness elements

P5 500 530

P7 710

Spires

P4 P1

P6

Wind

Barrier

1030 P2 P3

Coastal Cliff Position 350 mm

Figure 3. Positions in test section in which dynamic pressures values were measured with the multi-manometer.

The circle in Fig. 3 is located in the middle of the test section. The distance between the spires and wind tunnel central line was of 7,860mm. Turbulence measurements Turbulence measurements were performed for the freestream velocity of, approximately, 40m/s. Mean velocity SURÂżOHV DQG WXUEXOHQFH LQWHQVLW\ OHYHOV ZHUH REWDLQHG XVLQJ a constant temperature hot-wire anemometer, from Dantec Dynamics. These measurements were conducted only in the middle of the wind tunnel test section, in the location indicated as P1 in Fig. 3, after the simulation of the atmospheric boundary layer. It was used a straight golden-plated wire probe (55P01). For data collection, a sample rate of 10kHz was used. The measurements were conducted in several vertical positions. A manually controlled device (Fig. 4), which allowed the vertical displacement of the hot-wire probe

$IWHU WKH $%/ VLPXODWLRQ D VLPSOLÂżHG PRGHO RI WKH &/$ topography was installed in the TA-2 test section, and PIV measurements were conducted at the edge of the coastal cliff and around the MIT. In the present study, the coastal cliff slope angle was assumed as 70Âş with the horizontal plane, and this value was then reproduced in the model. However, since this inclination angle is not constant along the coastal cliff length, as a continuation of the present analysis, other inclinations will be further considered. 7KH PHDQ Ă€RZ YHORFLW\ ZDV PHDVXUHG XVLQJ D 'DQWHF Dynamics two-dimensional PIV system (Fig. 5). The system was a double-cavity pulsed laser, Nd:Yag, 15Hz, with an output power of 200mJ per pulse at the wavelength of 532 nm (New Wave Research, Inc.) and two HiSense 4M CCD camera, built by Hamamatsu Photonics, Inc. with acquisition rate of 11Hz, VSDWLDO UHVROXWLRQ RI ĂŽ SL[HOV DQG Č?P SL[HO SLWFK A Nikon f# 2.8 lenses with 105mm of focal length was used. The laser sheet was shot from the wind tunnel top wall, which was replaced by a glass window, and such sheet was produced using cylindrical lens placed at the end of an articulated optical arm, which transmits the laser from its source to the region of focus (ROF). This arm was used to allow the laser sheet displacement over the model. The red circles in Fig. 5 indicate locations where PIV measurements were conducted, at the edge of the cliff and around the TMI.

Figure 5. Particle image velocimetry measurements.

Figure 4. Hot-wire probe in the TA-2 test section.

466

7KH ÀRZ ZDV VHHGHG ZLWK WKHDWULFDO IRJ SRO\HWK\OHQH glycol water-solution) generated by a Rosco Fog Generator placed inside the wind tunnel diffuser. The digital camera ZDV PRXQWHG RQ D 'DQWHF 6FKHLPSÀXJ &DPHUD 0RXQWV ¿[HG

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying the Wind Pattern at Centro de Lançamento de Alcântara

on an aluminum trail supported by a three-axis-positioning device. The number of image pairs captured per second was 5.6, and around 200 image pairs, from each camera, were averaged for one measurement condition. The instantaneous images were processed using the adaptive correlation option of the commercial software Dynamic Studio, developed by Dantec Dynamics. A 32×32- pixel interrogation window with 50% overlap and moving average validation was used. 7KH PRGHO ZDV EXLOW LQ ZRRG DQG SDLQWHG LQ ÀDW EODFN WR PLQLPL]H ODVHU UHÀHFWLRQV RESULTS AND DISCUSSION %RXQGDU\ OD\HU YHORFLW\ SUR¿OHV The configurations tested for the boundary layer JHQHUDWLRQV DQG WKH YHORFLW\ SUR¿OHV REWDLQHG DUH SUHVHQWHG LQ )LJV WR 7KH ¿UVW WKUHH FRQ¿JXUDWLRQV UHPRYLQJ WKH spires, the barrier and the roughness elements were only

tested to illustrate the role of these devices for an appropriated ERXQGDU\ OD\HU SUR¿OH VLPXODWLRQ As can be noticed from Figs. 6 to 10, the spires have a major UROH LQ GH¿QLQJ WKH ERXQGDU\ OD\HU SUR¿OH +RZHYHU ZLWKRXW the roughness element, the generation of a thick boundary layer is not possible. The barrier has the purpose of generating D GH¿FLW RI PRPHQWXP LQ WKH OHYHO RI WKH ÀRRU FRQWULEXWLQJ IRU WKH YHORFLW\ SUR¿OH DGMXVWPHQW FORVH WR WKH ERWWRP VXUIDFH )LJXUH SUHVHQWV WKH YHORFLW\ SUR¿OH REWDLQHG IRU FRQ¿JXUDWLRQ ,9 LQ ZKLFK WKH EDUULHU WKH VSLUHV DQG DOO WKH 180 wood blocks were used. These results seem to indicate WKDW DQ HQKDQFHPHQW LQ WKH PRPHQWXP GH¿FLW ZDV QHFHVVDU\ With this purpose, wood strips perpendicularly to the spires were added, as shown in Fig. 14. By adding the three horizontal strips, as observed in )LJ WKH YHORFLW\ SUR¿OH LV FORVHU WR WKH SRZHU ODZ SUR¿OH with the exponent 0.11. Comparing Fig. 15 and 17 and observing the correspondent YHORFLW\ SUR¿OHV LW FDQ EH REVHUYHG WKDW PRGLI\LQJ WKH

0.80

U = 20 m/s 0.60

U = 30 m/s

y/ÄŻ

U = 40 m/s Power Law - 0,11

0.40

0.20

0.00 0.00

)LJXUH &RQÂżJXUDWLRQ , Âą EDUULHU DQG URXJKQHVV HOHPHQWV

0.20

0.40

0.60

U / Uinf

0.80

1.00

1.20

1.00

1.20

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ ,

1.20

1.00

U = 20 m/s 0.80

U = 30 m/s

y/ÄŻ

U = 40 m/s 0.60

Power Law = 0.11

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

U / Uinf )LJXUH &RQÂżJXUDWLRQ ,, Âą VSLUHV DQG KRUL]RQWDO VWULSV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ ,,

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

467

Avelar, A.C. et al.

1.20

1.00

U = 10 m/s U = 20 m/s

0.80

U = 30 m/s

y/ÄŻ

U = 40 m/s 0.60

Power Law - 0.11

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.00

1.20

1.00

1.20

U / Uinf )LJXUH &RQÂżJXUDWLRQ ,,, Âą VSLUHV DQG URXJKQHVV HOHPHQWV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ ,,,

1.20

1.00

U = 20 m/s

y/ÄŻ

0.80

U = 30 m/s U = 40 m/s Power Law - 0.11

0.60

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

U / Uinf )LJXUH &RQÂżJXUDWLRQ ,9 Âą VSLUHV EDUULHU DQG URXJKQHVV HOHPHQWV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ ,9

1.20

1.00

U = 20 m/s U = 30 m/s U = 40 m/s Power Law - 0,11

y/ÄŻ

0.80

0.60

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

U / Uinf )LJXUH &RQÂżJXUDWLRQ 9 Âą EDUULHU DQG URXJKQHVV HOHPHQWV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ 9

URXJKQHVV HOHPHQW GHQVLW\ D ÂżQH DGMXVWPHQW LQ WKH ERXQGDU\ OD\HU SURÂżOH FDQ EH REWDLQHG Figures 18 to 21 were included to show some velocity SURÂżOHV LQ GLIIHUHQW SRVVLWLRQV LQ 7$ WHVW VHFWLRQ )LJ shows that the wind tunnel lateral walls do not affect

VLJQLÂżFDWLYHO\ WKH ERXQGDU\ OD\HU YHORFLW\ SURÂżOH )LJXUH VKRZV WKH FRQÂżJXUDWLRQ XVHG LQ D SUHYLRXV study, Avelar et. al, 2010, for the boundary layer formation in the same wind tunnel, and Fig. 23 presents the velocity SURÂżOH REWDLQHG

468

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying the Wind Pattern at Centro de Lançamento de Alcântara

1.20

1.00

U = 20 m/s U = 30 m/s

y/ÄŻ

0.80

U = 40 m/s Power Law - 0,11

0.60

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.00

1.20

U / Uinf

)LJXUH &RQÂżJXUDWLRQ 9, Âą EDUULHU URXJKQHVV HOHPHQWV DQG VWULSV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ 9,

1.20

1.00

U = 20 m/s U = 30 m/s U = 40 m/s

0.80

y/ÄŻ

Power Law - 0.11 0.60

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

U / Uinf

)LJXUH &RQÂżJXUDWLRQ 9,, Âą EDUULHU URXJKQHVV HOHPHQWV DQG VWULSV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ 9,,

Measurement close to the lateral wall of the wind tunnel.

1.20

1.00

U = 20 m/s U = 30 m/s

0.80

U = 40 m/s

y/ÄŻ

Power Law - 0.11

0.60

0.40

0.20

0.00 0.00

0.20

0.40

0.60

0.80

1.00

1.20

U / Uinf )LJXUH &RQÂżJXUDWLRQ 9,,, Âą EDUULHU URXJKQHVV HOHPHQWV DQG VWULSV

)LJXUH 9HORFLW\ SURÂżOHV IRU FRQÂżJXUDWLRQ 9,,,

Measurement close to the mobile integration tower site.

It can be observed that whenever the power-law is well IROORZHG WKH GLPHQVLRQOHVV ZLQG VSHHG SURÂżOHV FROODSVH WR D

VLQJOH FXUYH VKRZLQJ WKDW WKHUH LV QR ÀRZ UHJLPH FKDQJH IRU the range of speed studied (from 20 to 40m/s).

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

469

Avelar, A.C. et al. 1600 1400

Theoretical

1200

U = 27 m/s

y/ÄŻ

1000

Expon. (U=27m/s)

800 600 400 200 0 0

0.2

0.4

0.6

0.8

1

1.2

U / Uinf

)LJXUH 9HORFLW\ SURÂżOHV IURP )LJ )LJXUH &RQÂżJXUDWLRQ XVHG LQ $YHODU et al. (2010).

0.7

Turbulence measurement results Table 1 shows the intensity turbulence, Iu, measured for various vertical positions and associated h į ratio in the central position of the TA-2 test section, where h is the distance from the ZLQG WXQQHO ÀRRU 7KHVH WXUEXOHQFH PHDVXUHPHQWV ZHUH WDNHQ IRU the wind tunnel velocity of 40m/s. The turbulence measurements ZHUH FRQGXFWHG IRU WKH FRQ¿JXUDWLRQ VKRZQ LQ )LJ 7KH WXUEXOHQFH SUR¿OH FRUUHVSRQGHQW WR WKH YDOXHV presented in Table 1 is presented in Fig. 24.

y/ÄŻ

0.6 0.5 0.4 0.3 0.2 0.1

2

6

10

14

Iu (%) )LJXUH 7XUEXOHQFH SURÂżOH LQ 7$ WHVW VHFWLRQ Âą ORFDWLRQ 3

Table 1. Turbulence intensity measurements. Measurement position

y (mm)

Iu (%)

y ÄŻ

P1 P2 P3 P4 P5 P6 P8 P9

765 665 565 465 365 315 215 165

4.6 4.9 5.3 6.1 6.7 7.9 9.1 10.0

0.66 0.57 0.48 0.40 0.31 0.23 0.18 0.14

The turbulence intensity values measured in the generated boundary layer, represented in Fig. 24, are in agreement with the values encountered by Wittwer et al. (2012), who experimentally studied CLA small scale models, 1:400 in the wind tunnel “Joaquim Blessmannâ€? of the laboratory LAC / UF5*6, in Porto Alegre, Brazil. In this study, mean DQG XQVWHDG\ Ă€RZ FKDUDFWHULVWLFV ZHUH HYDOXDWHG XVLQJ WKH hot-wire anemometer technique. From Table 1 and Fig. 24, it can be observed that the WXUEXOHQFH SURÂżOH KDV DQ H[SHFWHG EHKDYLRU ZLWK KLJK WXUEXOHQFH LQWHQVLW\ FORVH WR WKH ZLQG WXQQHO Ă€RRU 7KH 470

frequency spectrums, for each vertical position where turbulence measurement were conducted, are shown in Fig. 25. From Fig. 25, it can be observed that in the inertial range the -5/3 Kolmogorov’s law is followed by all curves.

Figure 25. Turbulence spectrum for P1 to P10.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying the Wind Pattern at Centro de Lançamento de Alcântara

Particle Image Velocimetry results A schematic representation of the CLA wind tunnel model is shown in Fig. 26. The squares numbers 1 and 2 indicate the positions over the model surface, in which the PIV measurements ZHUH FDUULHG RXW ,Q )LJ 3,9 YHORFLW\ ÀRZ PDSV DUH SUHVHQWHG for the cliff slope of 70º and wind incidence direction of 0º.

2 1 (a) 5el =6.8Ă—105

Figure 26. Schematic representation of the Centro de Lançamento de Ă‚lcantara physical model.

(b) 5el =1.4Ă—106 (a) 5el =6.8x105

(b) 5el =1.4x106 (c) 5el =2.0Ă—106 Figure 27. Particle image velocimetry results for the edge of cliff, square number 1, for different 5el values.

Figure 28. Particle image velocimetry results around the mobile integration tower for different 5el values.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

471

Avelar, A.C. et al.

The PIV measurements were carried out with the SXUSRVH RI LQYHVWLJDWLQJ WKH LQÀXHQFH RI VPDOO YDULDWLRQ RI 5H\QROGV QXPEHU LQ WKH VLPXODWHG ÀRZ SDWWHUQ DQG DOVR WR JHW LQVLJKWV DERXW WKH WKUHH GLPHQVLRQDO EHKDYLRU RI WKH ÀRZ in CLA region. From Figs. 27 and 28, it can be observed an DFFHOHUDWLRQ RI WKH ÀRZ LQ WKH HGJH RI WKH FOLII DQG DOVR LQ 0,7 ¿UVW FRUQHU +RZHYHU DV WKH ÀRZV LQ WKHVH UHJLRQV DUH already separated, the Reynolds number seems not to play an important role. In fact, according to Larose and D’Auteuil (2006), it is expected that bluff bodies with sharp edges, which is the case of MTI, the aerodynamics characteristics are almost insensitive to Reynolds Number as long as this parameter reaches 10,000. It can be pointed out also that the IBL seems to grow asymptotically. CONCLUSIONS

REFERENCES Arya, S.P., 2001, “Introduction to Micrometeorologyâ€?, Academic Press, USA, 2001, 2nd edition. Avelar, A.C. et al., 2012, “Atmospheric Boundary Layer Simulation in a Wind Tunnel for Analysis of the Wind Flow at the Centro de Lançamentode Alcântaraâ€?, 4th AIAA Atmospheric and Space Environments Conference 25-28, New Orleans, Louisiana, AIAA paper 2012-2930. Avelar, A.C. et al., 2010, “Simulation of the Atmospheric Boundary Layer in a Closed Circuit Wind Tunnel with Short Test Sectionâ€?, 27th AIAA Aerodynamic Measurement Tecnology and Ground Testing Conference, Chicago, AIAA paper AIAA-2010-4343.

Following a previous study on the simulation of the ABL in a short-test section wind tunnel, a combination of passive turbulence generators were tested in the present work. Good DJUHHPHQW EHWZHHQ WKH ERXQGDU\ OD\HU YHORFLW\ SUR¿OHV JHQHUDWHG DQG WKH SRZHU ODZ SUR¿OH ZDV REVHUYHG ZKHQ horizontal strips were added perpendicularly to the spires in the conventional setup (roughness, barrier, and spires). Whenever the power-law is well-followed, the dimensionless wind speed SUR¿OHV FROODSVH WR D VLQJOH FXUYH VKRZLQJ WKDW WKHUH LV QR ÀRZ regime change for the range of speed studied (from 20 to 40m/s). 3,9 PHDVXUHPHQWV SURYLGHG WKH YHFWRU YHORFLW\ ¿HOG around the step corner, representing the coastal cliff, and around the MIT. For the range of Reynolds number tested, QR VLJQL¿FDQW YDULDWLRQV ZHUH REVHUYHG RQ WKH FLUFXODWLRQ pattern. In both cases, a very turbulent wake was downstream observed. A future analysis of this research will compare wind WXQQHO VLPXODWLRQ ZLWK DFWXDO ÀRZ REVHUYDWLRQV

Barbosa, P.H.A. et al., 2000, “Simulation of atmospheric ERXQGDU\ OD\HU Ă€RZV LQ VKRUW ZLQG WXQQHOV´ 3URFHHGLQJV RI do XI CBMET 2000, Rio de Janeiro, Brazil.

ACKNOWLEDGMENTS

Fisch, G. et al., 2010, “The Internal Boundary Layer at the Alcântara Space Center: Winds Measurements, Wind Tunnel Experiments and Numeric Simulations,â€? Proceedings of the Fifth International Symposium on Computational Wind Engineering (CWE2010) Chapel Hill, North Carolina, USA May 23-27.

The authors would like to thank the technicians JosÊ RogÊrio Banhara and JosÊ Ricardo Carvalho de Oliveira, the Engineers Alfredo Canhoto, Wellington dos Santos and Matsuo Chisaki, Ana Clara Dias Barbosa and Tailine Corrêa for their valuable help to this research. Also, to the Agência Espacial Brasileira (AEB), the Conselho 1acional de 'esenvolvimento Cientt¿co e 7ecnolygico (CNPq) under the Grants 559949/2010-3, PQ 303720/2010-7 (Fisch), Universal 471143/2011-1 (Marciotto), and the Fundaçmo de Amparo j 3esquisa do Estado de 6mo Paulo IRU WKHLU ¿QDQFLDO VXSSRUW 472

Barbosa, P.H.A. et al., 2002, “Wind Tunnel Simulation of Atmospheric Boundary Layer Flowsâ€?, Journal of the Brazilian Society of Mechanical Sciences, Vol. 24, No. 3, pp. 177-185. Blessmann, J., 1973, “Simulação da estrutura do vento natural em um tĂşnel de vento aerodinâmicoâ€?, Tese (Doutor em CiĂŞncias), Instituto TecnolĂłgico da AeronaĂştica – ITA, SĂŁo JosĂŠ dos Campos, Brazil, 169 p. Counihan, J., 1969, “An improved method of simulating an atmospheric boundary layer in a wind tunnelâ€?, Atmospheric Environment, Vol. 3, pp. 197-214.

Garratt, J.R., 1994, “The Atmospheric Boundary Layer�, Cambridge University Press, Cambridge, USA, 316 p. H’su, S.A., 1988, “Coastal Meteorology�, Academic Press, San Diego, 260 p.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

Wind Tunnel Simulation of the Atmospheric Boundary Layer for Studying the Wind Pattern at Centro de Lançamento de Alcântara

Hsu, A.S. et al., 1994, “Determining the Power-Law Wind3URÂżOH ([SRQHQW XQGHU 1HDU 1HXWUDO 6WDELOLW\ &RQGLWLRQV DW Seaâ€?, Journal of Applied Meteorology, Vol. 33, No. 6, pp. 757-765. Hunt, J.C.R. and Fernholz, H., 1975, “Wind-tunnel simulation of the atmospheric boundary layer: a report on Euromech 50â€?, The Journal of Fluid Mechanics, Vol. 70, pp. 543-559. Vol. 7, pp. 361-366. Larose, G. and D’Auteuil, A. 2006, “On the Reynolds number sensitivity of the aerodynamics of bluff bodies with Sharp edgesâ€?, Journal of Wind Engineering and Industrial Aerodynamics, Vol. 94, pp. 365-376. Ligrani, P.M. et al., 1979, “The Thermal and Hydrodynamic Behavior of Thick Rough-Wall Turbulent Boundary Layersâ€?, Report No HMT-29, Stanford University. Ligrani, P.M. et al. Âł$UWLÂżFLDOO\ 7KLFNHQHG 7XUEXOHQW Boundary Layers for Studying Heat Transfer and SkinFriction on Rough Surfacesâ€?, Journal of Fluids Engineering, Vol. 105, pp. 146-153. Loredo-Souza, A.C. et al., 2004, “Simulação da Camada Limite AtmosfĂŠrica em TĂşnel de Vento,â€? TurbulĂŞncia, Vol. 4, pp. 137-160.

Marciotto, E.R. et al., 2012, “Characterization of Surface Level Wind at the Centro de Lançamento de Alcântara for Use in Rocket Structure Loading and Dispersion Studiesâ€?, Journal of Aerospace Technology and Management, Vol. 4, No. 1, pp. 69-79. Pires, L.M.B. et al., 2008, “Experimentos em TĂşnel de Vento da Camada Limite Interna no Centro de Lançamento de Alcântaraâ€?, Proceedings of Escola de Primavera de Transição e TurbulĂŞncia, EPTT 2008, SĂŁo Carlos, SĂŁo Paulo, Brazil. Pires, L.B.M., 2009, “Estudo da Camada Limite Interna Desenvolvida em FalĂŠsias com Aplicação para o Centro de Lançamento de Alcântaraâ€?, Tese (Doutorado em Meteorologia), National Institute for Space Research, SĂŁo JosĂŠ dos Campos, SĂŁo Paulo, Brazil, 150 p. Pires, L.B.M. et al., 2010, “Atmospheric Flow Measurements Using the PIV and HWA Techniquesâ€?, Journal of Aerospace Technology and Management, Vol. 2, No. 2, pp. 127-136. Wittwer, A. R., et al., 2012, “Avaliação Experimental do Escoamento AtmosfĂŠrico no Centro de Lançamento GH $OFkQWDUD 8VDQGR 0RGHORV 7RSRJUiÂżFRV HP (VFDOD Reduzidaâ€?, Proceedings of the VIII Escola de Primavera de Transição e TurbulĂŞncia, 24 a 28 de setembro de 2012, SĂŁo Paulo – SP, Brazil.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 463-473, Oct.-Dec., 2012

473

GRL MDWP

Propeller-induced Effects on the Aerodynamics of a Small Unmanned Aerial Vehicle Adnan Maqsood*1, Foong Herng Huei2, Tiauw Hiong Go2 1DWLRQDO 8QLYHUVLW\ RI 6FLHQFHV DQG 7HFKQRORJ\ ¹ ,VODPDEDG ¹ 3DNLVWDQ Nanyang Technological University – Singapore

1 2

Abstract: The present paper has discussed investigations about the propeller slipstream effects on the aerodynamics of a generic unmanned air vehicle platform in the wind tunnel for a broad advance ratio range. The propeller-induced effects IRU VPDOO XQPDQQHG DLU YHKLFOHV DUH PRUH VLJQL¿FDQWO\ SURQRXQFHG WKDQ JHQHUDO DYLDWLRQ DLUFUDIW EHFDXVH RI WKHLU KLJK propeller-diameter-to-wing-span-ratio. The stall angle of attack of the small unmanned air vehicle is generally delayed under slipstream effects. The study evaluated the shift in stall angle of attack as a function of propeller-diameter-to-wingspan and advance ratios of the propeller. The aerodynamics of the unmanned air vehicle platform is estimated through wind-tunnel experiments. The study reported in this paper is part of an effort to develop the framework for the analysis RI SURSHOOHU ZLQJ LQWHUDFWLRQ IRU VPDOO PLFUR XQPDQQHG DLU YHKLFOHV DW DQ HDUO\ GHVLJQ VWDJH 6SHFL¿FDOO\ WKH VOLSVWUHDP effects on the aerodynamics of a generic small unmanned air vehicle are studied in the wind tunnel for the shift in the aircraft stall angle of attack. The lift-curve slope of the aircraft is independent from the variation of advance ratio. The VWDOO FKDUDFWHULVWLFV VKRZ VWURQJ GHSHQGHQFH RQ WKH DGYDQFH UDWLR 7KHUHIRUH WKH UHODWLRQVKLS LV PRGHOHG DFFXUDWHO\ using inverse-quadratic relationship. This empirical trend of the stall behavior with advance ratio can be useful in the DQDO\VLV DQG VLPXODWLRQ RI WKH UHVXOWLQJ ÀLJKW DQG HVWLPDWLRQ RI SHUIRUPDQFH HQYHORSHV Keywords: 8QPDQQHG DLU YHKLFOH 3URSHOOHU LQWHUDFWLRQ 3RZHUHG WHVWLQJ :LQG WXQQHO WHVWLQJ

INTRODUCTION The demand for customized small-scale unmanned air YHKLFOHV 8$9 WR H[HFXWH GLIIHUHQW PLVVLRQ SUR¿OHV KDV LQFUHDVHG RYHU WKH \HDUV 6LJQL¿FDQW HIIRUWV DUH XQGHUZD\ WR HQKDQFH WKH ÀLJKW HQYHORSH RI VXFK 8$9 2QH RI WKHP LV WKH LQFRUSRUDWLRQ RI KRYHU FDSDELOLW\ LQ ¿[HG ZLQJ DLUFUDIW GHVLJQV 5HDGHUV PD\ ¿QG WKH DVVRFLDWHG GHYHORSPHQW RI such platforms in Taylor and Thomas Cord (2003), Green and 2K )UDQN HW DO 6WRQH HW DO 0DTVRRG DQG *R 'XULQJ KRYHU VORZ IRUZDUG ÀLJKW SKDVH WKH DLUFUDIW ÀLHV DW KLJK SRZHU ORZ YHORFLW\ ÀLJKW FRQGLWLRQ ZKLFK FRUUHVSRQGV WR ORZ DGYDQFH UDWLR RI WKH SURSHOOHU )RU WKH ¿[HG ZLQJ IRUZDUG ÀLJKW WKH DLUFUDIW ÀLHV DW KLJK DGYDQFH UDWLRV ORZ SRZHU DQG KLJK YHORFLW\ 7KH ÀLJKW HQYHORSH RI KRYHU FDSDEOH ¿[HG ZLQJ GHVLJQV FDQ JHQHUDOO\ span from zero to substantially high advance ratios. In an 5HFHLYHG

$FFHSWHG

DXWKRU IRU FRUUHVSRQGHQFH DGQDQ#UFPV QXVW HGX SN 5HVHDUFK &HQWHU IRU 0RGHOLQJ DQG 6LPXODWLRQ 1DWLRQDO 8QLYHUVLW\ RI 6FLHQFHV DQG 7HFKQRORJ\ + ,VODPDEDG 3DNLVWDQ

H[SHULPHQW ZLWK OLPLWHG DGYDQFH UDWLR UDQJH IURP WR DQG IUHH VWUHDP YHORFLW\ RI P V :LWNRZVNL et al. D E KDYH REVHUYHG WKDW WKH DHURG\QDPLF EHKDYLRU RI WKH DLUFUDIW VLJQL¿FDQWO\ FKDQJHV ZLWK WKH FKDQJH LQ DGYDQFH UDWLR 7KLV REVHUYDWLRQ KRZHYHU LV QRW ZHOO IROORZHG E\ RWKHU UHVHDUFKHUV 2QO\ YHU\ IHZ VWXGLHV DGHTXDWHO\ DGGUHVV WKH prop-stream effects over the broader range of advance ratios DQG WKXV VXFK WRSLF PD\ VWLOO EH FRQVLGHUHG DV D PLVVLQJ OLQN LQ OLWHUDWXUH )HZ VWXGLHV 6WRQH HPSKDVL]H RQ WKH LPSRUWDQFH RI SURS ZLQJ LQWHUDFWLRQ DW ]HUR ORZ WUDQVODWLRQDO YHORFLWLHV ORZ DGYDQFH UDWLR 7KH ZRUN FDUULHG RXW E\ Stone (2002) comprises numerical modeling and is based on superimposition of prop-stream in numerical panel methods. The prop-stream effects for the small/mini UAV have DQRWKHU SURQRXQFHG LPSOLFDWLRQ )RU D ODUJH VFDOH DLUFUDIW WKH SURSHOOHU GLDPHWHU WR ZLQJ VSDQ UDWLR d/b) is relatively VPDOO JHQHUDOO\ UDQJLQJ IURP WR )RU VPDOO PLFUR 8$9V KRZHYHU WKH LW FDQ YDU\ IURP WR LQGLFDWLQJ that the diameter of the propeller is often comparable to the ZLQJVSDQ RI WKH 8$9V $V D UHVXOW WKH ÀRZ RYHU WKH ZLQJV IRU

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 475-480, Oct.-Dec., 2012

475

0DTVRRG $ et al.

VXFK YHKLFOHV LV KHDYLO\ LQÀXHQFHG E\ WKH SURSHOOHU LQGXFHG ÀRZV &OHDUO\ IRU KLJKHU d/b YDOXHV WKH SRZHU HIIHFW LV PRUH VLJQL¿FDQW WR WKH RYHUDOO DHURG\QDPLF EHKDYLRU RI WKH DLUFUDIW 2QH RI WKH LPSRUWDQW DHURG\QDPLF EHKDYLRU FKDQJHV ZLWK SRZHU HIIHFWV LV RQ WKH OLIW FKDUDFWHULVWLFV ZLWK WKH DQJOH RI DWWDFN :LWNRZVNL et al. D REVHUYHG WKH OLIW FXUYH VORSH decreases as the advance ratio of the propeller increased. The SHUFHQWDJH GHFUHDVH RI WKH OLIW VORSH LV GRFXPHQWHG DV IRU DGYDQFH UDWLR RI DQG d/b in the range of 0.16 to 0.3. 7KH SRZHU HIIHFWV RQ WKH VWDOO FKDUDFWHULVWLFV DUH DOVR IRXQG WR EH VLJQL¿FDQW 5DOVWRQ DQG +XOWEHUJ UHSRUWHG WKDW IRU D JHQHUDO DYLDWLRQ DLUFUDIW WKH VWDOO DQJOH LV VLJQL¿FDQWO\ GHOD\HG diminished as the advance ratio of the propeller is decreased KLJK SRZHU ORZ VSHHG ÀLJKW 1XOO et al. DOVR REVHUYHG WKH FKDQJH LQ WKH VWDOO DQJOH RI WKH DLUFUDIW ZLWK WKDW LQ DGYDQFH UDWLR EXW GLG QRW TXDQWLI\ WKH SKHQRPHQRQ LQ WKHLU H[SHULPHQWDO LQYHVWLJDWLRQV ,W VHHPV WKDW D TXDQWL¿FDWLRQ RI SRZHU HIIHFWV RQ VWDOO DQJOH RI DWWDFN LV QHFHVVDU\ IRU ÀLJKW G\QDPLF VLPXODWLRQV as part of the aircraft design and development. The study reported in this paper is part of an effort to GHYHORS WKH IUDPHZRUN IRU WKH DQDO\VLV RI SURSHOOHU ZLQJ interaction for small/micro UAVs at an early design stage. 6SHFL¿FDOO\ WKH VOLSVWUHDP HIIHFWV RQ WKH DHURG\QDPLFV RI D KRYHU FDSDEOH JHQHULF VPDOO 8$9 DUH VWXGLHG LQ WKH ZLQG tunnel for a broad advance ratio range. The propeller effects RQ WKH OLIW FXUYH VORSH DQG VWDOO DQJOH RI DWWDFN SDWWHUQ DUH DOVR VWXGLHG 7KH SUHVHQW ZRUN DOVR SURYLGHV GLUHFWLRQV IRU IXUWKHU investigations involving various design parameters. EXPERIMENTAL SETUP AND TESTING 7KH DLUFUDIW WKDW LV VKRZQ LQ )LJ LV WKH VDPH SODWIRUP XVHG IRU WKH WUDQVLWLRQ ÀLJKW DQDO\VLV 0DTVRRG DQG *R ,W KDV D VWDQGDUG WUDFWRU W\SH SURSXOVLRQ V\VWHP ZLWK d/b RI 7KLV DOORZV SURSHOOHU LQGXFHG ÀRZV WR EH JHQHUDWHG RYHU D ODUJH SRUWLRQ RI WKH ZLQJV 7KH VPDOO 8$9 LV VSHFL¿FDOO\ GHVLJQHG to maneuver in tight spaces and can hover over the target area RI LQWHUHVW 7KH VSDQ DQG OHQJWK RI WKH DLUFUDIW DUH P 7KH DLUIRLO IRU WKH UHFWDQJXODU ZLQJ DQG KRUL]RQWDO WDLO LV 1$&$ 7KH ZLQG WXQQHO PRGHO LV IDEULFDWHG IURP $OXPLQXP T6061 at Nanyang Technological University (NTU). 7KH H[SHULPHQW ZDV FDUULHG RXW DW D ORZ WXUEXOHQFH FORVHG FLUFXLW ZLQG WXQQHO DW 1DQ\DQJ 7HFKQRORJLFDO 8QLYHUVLW\ 178 7KH RSHUDWLQJ VSHHG RI WKH ZLQG WXQQHO UDQJHV IURP WR P V ,WV KLJK FRQWUDFWLRQ UDWLR RI ZLWK D UHFWDQJXODU LQOHW FRQWUDFWLRQ FRQH DV ZHOO DV WKH LQVWDOOPHQW RI WKUHH DQWL WXUEXOHQFH VFUHHQV ZLWK GLIIHUHQW PHVKHV DUH VSHFL¿FDOO\ 476

)LJXUH 9LHZ RI WKH XQPDQQHG DLU YHKLFOH ZLWK PRWRU LQVWDOOHG

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ÂżFLHQWV SUHVHQWHG LQ WKLV ZRUN KDYH DOO EHHQ FRUUHFWHG IRU ZLQG WXQQHO EORFNDJH HIIHFWV VROLG EORFNDJH ZDNH EORFNDJH DQG VWUHDPOLQH FXUYDWXUH DFFRUGLQJ WR WKH WHFKQLTXHV SUHVHQWHG E\ %DUORZ et al. (1999). The PDJQLWXGH RI WKH EORFNDJH HIIHFWV LQFUHDVHV ZLWK WKH LQFUHDVH LQ WKH DQJOH RI DWWDFN 7KH PDJQLWXGH RI EORFNDJH FRUUHFWLRQV IRU PRVW RI WKH VFHQDULRV LV IRXQG WR EH OHVV WKDQ 7KH SURSHOOHU XVHG LQ WKH H[SHULPHQW ZDV D Âł [ ĆŽ WKLQ WZR EODGHG SURSHOOHU GULYHQ E\ D EUXVKOHVV $;, electric motor through the TahmazoÂŽ 3UR & 0D[ 6 electronic speed controller (ESC). The control signal from D SHUVRQDO FRPSXWHU 3& WR WKH (6& ZDV VHQW WKURXJK WKH PololuÂŽ 6HULDO 6HUYR &RQWUROOHU LQWHUIDFH 7KH FRQWURO VLJQDO IURP WKH 3& FDQ YDU\ IURP WR ELWV 7KH UHYROXWLRQ UDWH RI WKH SURSHOOHU ZDV FDOLEUDWHG DJDLQVW WKH FRQWURO VLJQDO 7R SRZHU WKLV VHWXS D *: ,QVWHN 36+ $ JURXQG EDVHG GLUHFW FXUUHQW '& VRXUFH ZDV XVHG 7KH PD[LPXP SRZHU VXSSOLHG WR WKH PRWRU ZDV : 9 $ DW DQ\ LQVWDQW during testing. The schematic of the propulsion system setup IRU WKH H[SHULPHQW LV VKRZQ LQ )LJ The relationship of the propeller driven propulsion system is developed from the velocity of the aircraft, the blade-pitch DQJOH RI WKH SURSHOOHU DQG WKH DGYDQFH UDWLR )RU WKH Âż[HG

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 475-480, Oct.-Dec., 2012

Propeller-induced Effects on the Aerodynamics of a Small Unmanned Aerial Vehicle

)LJXUH 6FKHPDWLF RI WKH SURSXOVLRQ V\VWHP DQG LWV FRQWUROOHU

J=

V3 N#D

(1)

ZKHUH VÂ’ : is the true airspeed of the aircraft in m/s, N: is the number of revolutions per second of the propeller, and D: is the diameter of the propeller. 7KH DGYDQFH UDWLR (T FDQ EH YDULHG HLWKHU E\ FKDQJLQJ WKH IUHH VWUHDP YHORFLW\ LQ WKH ZLQG WXQQHO RU WKH UHYROXWLRQ UDWH RI WKH SURSHOOHU %RWK DSSURDFKHV KDYH FHUWDLQ OLPLWDWLRQV The change in the free-stream velocity causes variation in WKH 5H\QROGV QXPEHU RI WKH H[SHULPHQWDO GDWD ZKRVH HIIHFW LQFUHDVHV ZLWK WKH DGGLWLRQ LQ WKH YHORFLW\ HQYHORSH RI WKH WHVWLQJ )RU VPDOO 8$9 DSSOLFDWLRQV WKH YHORFLW\ HQYHORSH LV VPDOO DQG WKHUHIRUH WKH HIIHFWV DUH JHQHUDOO\ QRW VLJQLÂżFDQW +RZHYHU DSSURSULDWH FKHFNV DUH UHTXLUHG WR UHPRYH WKH HIIHFW RI 5H\QROGV QXPEHU LQ WKH H[SHULPHQWDO GDWD 2Q WKH RWKHU KDQG WKH LQFUHDVH LQ WKH 530 RI WKH SURSHOOHU FDQ HYHQWXDOO\ OHDG WKH SURSHOOHU WLS WR UHDFK VRQLF VSHHGV ,Q WKLV ZRUN GDWD ZHUH FROOHFWHG DW FRQVWDQW 530 ZKLFK FRUUHVSRQG WR

WKURWWOH VHWWLQJ DQG VHYHUDO YHORFLWLHV UDQJHG IURP WR P V *HQHUDOO\ WKH DLUFUDIW ÀLHV DW ORZHU WKURWWOH VHWWLQJV EXW WKH SUHVHQWHG VHULHV RI WHVWV ZHUH FRQGXFWHG DW PD[LPXP throttle setting to delineate the maximum effects of propellerLQGXFHG ÀRZV 7KH UHODWLRQVKLS EHWZHHQ WKH DGYDQFH UDWLR RI ¿[HG SLWFK SURSHOOHU DQG IUHH VWUHDP YHORFLW\ LV RI OLQHDU behavior (Ralston and Hultberg, 2010), and this is also REYLRXV IURP (T 7KH XQSRZHUHG OLIW FRHI¿FLHQW LV SORWWHG DJDLQVW WKH DQJOH RI DWWDFN IRU YDULRXV 5H\QROGV QXPEHUV LQ )LJ ,W FDQ EH observed that the lift-curve slope is practically independent RI 5H\QROGV QXPEHU 0RUHRYHU WKH VWDOO DQJOH RI DWWDFN LV constant across the complete Reynolds number variation from

Coefficient of Lift

pitch propeller, the advance ratio is the primary entity to describe the relationship. The advance ratio (J) of the propeller LV GHÂżQHG DV WKH UDWLR EHWZHHQ WKH GLVWDQFH WKH SURSHOOHU DGYDQFHV IRUZDUG GXULQJ RQH UHYROXWLRQ DQG WKH GLDPHWHU RI WKH SURSHOOHU 0DWKHPDWLFDOO\ LW FDQ EH H[SUHVVHG DV LQ (T

1 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0

Re = 0.05 Million Re = 0.08 Re = 0.113 Re = 0.128 Re = 0.147 Re =0.156 Re = 0.166

0

2

4

6

8

10

12

Angle of Attack, degrees

)LJXUH 8QSRZHUHG OLIW FRHIÂżFLHQW IRU WKH WHVW XQSRZHUHG Reynolds number range.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 475-480, Oct.-Dec., 2012

477

0DTVRRG $ et al.

Laero = Ltotal - L prop Daero = Dtotal + D prop

(2)

)LJXUH 7KUXVW YDULDWLRQ ZLWK WKH FKDQJH LQ WKH DGYDQFH UDWLR

RESULTS AND DISCUSSION ,Q WKLV VHFWLRQ WKH UHVXOWV IURP SRZHUHG WHVWLQJ DUH GLVFXVVHG $V PHQWLRQHG HDUOLHU WKH VWXG\ ZDV UHVWULFWHG WR ORQJLWXGLQDO SODQH DQG WKH HIIHFW RI VZLUO RQ WKH ODWHUDO GLUHFWLRQDO IRUFHV DQG PRPHQWV ZDV RXW RI WKH VFRSH RI WKH VWXG\ 7KH PLQRU YDULDWLRQV LQ SRZHUHG GDWD FDQ EH DWWULEXWHG WR WKH SURSHOOHU URWDWLRQ ZKHWKHU WKH ZLQJV DUH EHKLQG DQ XSZDUG RU GRZQZDUG PRYLQJ EODGH 7KH UHVXOWDQW aerodynamic characteristics on both sides of the fuselage ZLOO GLIIHU VOLJKWO\ 7KH WUHQG IRU WKH FRHIÂżFLHQW RI OLIW DFURVV DQJOHV RI DWWDFN DQG YDULRXV DGYDQFH UDWLRV LV SORWWHG LQ )LJ 7KH FRHIÂżFLHQW RI OLIW CL YDULDWLRQ DW ]HUR DQJOH RI DWWDFN IRU YDULRXV DGYDQFH UDWLRV ZDV VHHQ 6SHFLÂżFDOO\ CL varies from 478

1,4 1,2 Coefficient of Lift

WR PLOOLRQ ,W FDQ EH LQIHUUHG WKDW WKH YHORFLW\ YDULDWLRQ by itself is small enough to introduce any effect of Reynolds number on lift curve slope and stall angle of the aircraft. 7KHQ WKH PDSSLQJ RI WKUXVW DJDLQVW WKH DGYDQFH UDWLR ZDV FDUULHG RXW DQG WKH UHVXOW LV VKRZQ LQ )LJ ,W FDQ EH VHHQ that the static thrust of the aircraft is approximately 4 N. As the advance ratio is varied, the thrust eventually becomes negative. This means that such high advance ratios can only EH PDLQWDLQHG GXULQJ GLYH DQG QRW LQ VXVWDLQHG ÀLJKW 2YHUDOO WKH WKUXVW YDULHV ZLWK WKH DGYDQFH UDWLR LQ D SDUDEROLF IDVKLRQ ZKLFK LV LQ FORVH DJUHHPHQW WR 1XOO et al. 7KH SXUSRVH RI WKLV PDSSLQJ ZDV WR HYDOXDWH WKH G\QDPLF WKUXVW GDWD DV D IXQFWLRQ RI DGYDQFH UDWLR DQG DQJOH RI DWWDFN ,Q RUGHU WR JHW WUXH DHURG\QDPLF FRHI¿FLHQWV WKH G\QDPLF WKUXVW YDOXHV QHHG WR EH VXEWUDFWHG IURP OLIW DQG GUDJ GDWD DV VKRZQ LQ (T It should be noted that Dprop is negative and represents the propeller thrust.

1 0,8 J = 0.39 J = 0.56 J = 0.63 J = 0.73 J = 0.78 J = 0.82 Unpowered

0,6 0,4 0,2 0 0

2

4

6 8 10 Angle of Attack, degrees

12

14

)LJXUH &RHIÂżFLHQW RI OLIW EHKDYLRU ZLWK WKH YDULDWLRQ LQ DQJOH RI DWWDFN DQG DGYDQFH UDWLR

IRU XQSRZHUHG FDVH WR IRU KLJK DGYDQFH UDWLR 7KH ]HUR OLIW DQJOH RI DWWDFN EHFRPHV QHJDWLYH ZLWK WKH LQFUHDVH LQ DGYDQFH UDWLR 7KLV REVHUYDWLRQ LV FRQVLVWHQW ZLWK WKH LQYHVWLJDWLRQV FDUULHG RXW E\ :LWNRZVNL et al. D 7KH OLIW FXUYH VORSH VHHPV WR IROORZ OLQHDU WHQGHQF\ IRU DGYDQFH UDWLR YDU\LQJ IURP WR 7KH GHFUHDVH LQ OLIW FXUYH VORSH ZDV REVHUYHG ZLWK WKH LQFUHDVH LQ DGYDQFH UDWLR +RZHYHU WKH YDULDWLRQ ZDV YHU\ VPDOO OHVV WKDQ DQG WKXV FDQ EH QHJOHFWHG IRU VLPSOL¿FDWLRQ :LWNRZVNL et al. D KDYH REVHUYHG D GHFUHDVH LQ OLIW FXUYH VORSH RI ZLWK WKH LQFUHDVH in advance ratio. The investigations by Null et al. VKRZ WKDW WKH YDULDWLRQ RI OLIW VORSH GLPLQLVKHV EHWZHHQ SRZHUHG DQG XQSRZHUHG FDVHV DV WKH FDPEHU LV LQFUHDVHG 7KH DLUIRLO XVHG LQ WKLV H[SHULPHQW LV QRW FDPEHUHG EXW KDV D WKLFNQHVV WR FKRUG UDWLR RI 7KH VPDOO GLIIHUHQFH LQ WKH OLIW FXUYH slope variation in the current experiment might be caused by WKH WKLFNQHVV RI WKH DLUIRLO DQG QRW E\ WKH FDPEHU +RZHYHU FRQ¿UPDWLRQ RQ WKLV IDFW VWLOO QHHGV IXUWKHU LQYHVWLJDWLRQV 7KH FRHI¿FLHQW RI OLIW CL LV VKRZQ XS WR D ž DQJOH RI DWWDFN )LJ LQ RUGHU WKDW WKH CL behavior can be observed clearly DQG WKH VWDOO SDWWHUQ ZLOO EH GLVFXVVHG VHSDUDWHO\ 7KH SRZHU LQGXFHG ÀRZ DIIHFWV VLJQL¿FDQWO\ WKH VWDOO DQJOH RI DWWDFN ZKLFK LV JHQHUDOO\ GLIIHUHQW IRU ERWK ZLQJV 7KH ZLQJ IDFLQJ XSZDUG PRYLQJ EODGH VWDOOV VOLJKWO\ HDUOLHU ZKHUHDV WKH GRZQZDUG PRYLQJ EODGH VLGH H[SHULHQFH VOLJKWO\ GHOD\HG VWDOO 2YHUDOO WKH VWDOO DQJOH RI DWWDFN ZLOO EH GHOD\HG RQ ERWK VLGHV UHODWLYH WR XQSRZHUHG FDVH EHFDXVH WKH SURS VWUHDP HQHUJL]HV WKH ÀRZ DURXQG WKH DIIHFWHG SDUW RI WKH ZLQJ 7KH VWDOO DQJOH RI DWWDFN RYHU KHUH LV WDNHQ DV D FXPXODWLYH HIIHFW DQG UHFRUGHG DJDLQVW WKH ¿UVW GLS LQ WKH FRHI¿FLHQW RI OLIW FXUYH 7KH WUHQG IRU VWDOO DQJOH RI DWWDFN IRU VHYHUDO DGYDQFH UDWLRV LV VKRZQ LQ )LJ

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 475-480, Oct.-Dec., 2012

Propeller-induced Effects on the Aerodynamics of a Small Unmanned Aerial Vehicle

,W LV UHPDUNDEOH WKDW WKH VWDOO DQJOH RI DWWDFN LQ SRZHUHG VFHQDULRV FDQ EH H[SUHVVHG LQ LQYHUVH TXDGUDWLF UHODWLRQVKLS ZLWK DGYDQFH UDWLR (TXDWLRQ VKRZV WKH JHQHULF SRZHU ODZ PRGHO XVHG WR ¿W WKH VWDOO DQJOH RI DWWDFN EHKDYLRU ZLWK UHVSHFW to advance ratio: a stall,p =

a + a stall,up J2

(3)

ZKHUH IRU RXU FDVH a stall,p VWDOO DQJOH RI DWWDFN IRU SRZHUHG FDVH a stall,up VWDOO DQJOH RI DWWDFN IRU XQSRZHUHG FDVH a a stall,up = 9.6 and a(.): in degrees. 7KH FRHI¿FLHQW RI GHWHUPLQDWLRQ R2 YDOXH RI WKH SRZHU ODZ ¿W LV ZKLFK HQVXUHV LWV DGHTXDF\ )RU KLJK d/b YDOXHV ZKHUH PRVW DUHD RI WKH ZLQJ LV XQGHU SURS VWUHDP this relationship governs the overall shift in the stall behavior VSHFL¿F WR WKH FXUUHQW VFHQDULR )RU ORZ DGYDQFH UDWLRV WKH SURS VWUHDP ZLOO QRW OHW WKH DLUFUDIW VWDOO HYHQ DW YHU\ KLJK DQJOHV RI DWWDFN VLQFH WKH KLJK HQHUJ\ LV LPSDUWHG WR ORZ HQHUJ\ ÀRZ ¿HOG +RZHYHU DV WKH DGYDQFH UDWLR LV LQFUHDVHG WKH VWDOO DQJOH ZLOO DSSURDFK WKH XQSRZHUHG ZLQGPLOO FDVH 7KH GLIIHUHQFH EHWZHHQ WKH VHWWOLQJ VWDOO DQJOH RI DWWDFN IURP WKH TXDGUDWLF ¿W DQG H[SHULPHQWDO GDWD LV ZKLFK LV QHJOLJLEOH for practical purposes.

ÀLJKW 7KH SRZHUHG WHVW VKRZV IXQFWLRQDO LQGHSHQGHQFH RI WKH PDJQLWXGH RI OLIW FXUYH VORSH DJDLQVW DGYDQFH UDWLRV +RZHYHU VWDOO DQJOH RI DWWDFN KDV D VWURQJ IXQFWLRQDO GHSHQGHQFH against the advance ratio, and such dependence can be PRGHOHG DFFXUDWHO\ XVLQJ LQYHUVH TXDGUDWLF UHODWLRQVKLS 7KLV HPSLULFDO WUHQG RI WKH VWDOO EHKDYLRU ZLWK DGYDQFH UDWLR PLJKW EH XVHIXO LQ WKH DQDO\VLV DQG VLPXODWLRQ RI WKH UHVXOWLQJ ÀLJKW 0RUHRYHU WKH VWXG\ LQGLFDWHV WKH QHHG IRU D XQL¿HG WKHRU\ RQ WKH VWDOO DQJOH GHSHQGHQFH ZLWK d/b DQG DGYDQFH UDWLRV ZKLFK can be very useful during early aircraft design stage. REFERENCES %DUORZ - % et al. ³/RZ VSHHG ZLQG WXQQHO WHVWLQJ´ 0LFKLJDQ 8QLYHUVLW\ :LOH\ )UDQN $ et al. ³+RYHU 7UDQVLWLRQ DQG /HYHO )OLJKW &RQWURO 'HVLJQ IRU D 6LQJOH 3URSHOOHU ,QGRRU $LUSODQH´ ,Q AIAA Guidance, Navigation and Control Conference and Exhibit, South Carolina, USA. *UHHQ : ( DQG 2K 3 < ³$ 0$9 7KDW )OLHV /LNH DQ $LUSODQH DQG +RYHUV /LNH D +HOLFRSWHU´ ,Q ,((( ,QWHUQDWLRQDO &RQIHUHQFH RQ $GYDQFHG ,QWHOOLJHQW 0HFKDWURQLFV 0RQWHUH\ California. 0DTVRRG $ DQG *R 7 + ³2SWLPL]DWLRQ RI +RYHU WR &UXLVH 7UDQVLWLRQ 0DQHXYHU 8VLQJ 9DULDEOH ,QFLGHQFH :LQJ´ -RXUQDO RI $LUFUDIW 9RO 1R SS 1XOO : et al. ³(IIHFWV RI 3URSXOVLYH ,QGXFHG )ORZ RQ WKH $HURG\QDPLF RI 0LFUR $LU 9HKLFOHV´ ,Q UG $,$$ $SSOLHG $HURG\QDPLFV &RQIHUHQFH 7RURQWR 2QWDULR &DQDGD 5DOVWRQ - DQG +XOWEHUJ 5 ³)XOO (QYHORSH $HURG\QDPLFV 0RGHOLQJ RI D *HQHUDO $YLDWLRQ $LUFUDIW ZLWK 3URSHOOHU 6OLSVWUHDP (IIHFWV´ ,Q $,$$ 0RGHOLQJ DQG 6LPXODWLRQ 7HFKQRORJLHV &RQIHUHQFH 7RURQWR 2QWDULR &DQDGD

)LJXUH 6WDOO DQJOH RI DWWDFN YDULDWLRQ ZLWK DGYDQFH UDWLR

CONCLUSIONS 3URSHOOHU LQGXFHG ÀRZ ¿HOG KDV D VLJQL¿FDQW LPSDFW RQ WKH aerodynamic characteristics of small UAV/micro air vehicle 0$9 VSHFL¿FDOO\ IRU KLJK d/b values. The effects are more SURQRXQFHG DV WKH DGYDQFH UDWLR LV GHFUHDVHG KLJK SRZHU

6WRQH + ³$HURG\QDPLF 0RGHOOLQJ RI D :LQJ LQ 6OLSVWUHDP 7DLO 6LWWHU 8$9´ ,Q %LHQQLDO ,QWHUQDWLRQDO 3RZHUHG /LIW &RQIHUHQFH DQG ([KLELW :LOOLDPVEXUJ 9LUJLQLD Stone, H. et al. ³)OLJKW 7HVWLQJ RI WKH 7 :LQJ 7DLO 6LWWHU 8QPDQQHG $LU 9HKLFOH´ -RXUQDO RI $LUFUDIW 9RO 1R SS

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 475-480, Oct.-Dec., 2012

479

0DTVRRG $ et al.

7D\ORU ' - DQG 7KRPDV &RUG 0 9 2 ³6N\7RWH DQ XQPDQQHG SUHFLVLRQ FDUJR GHOLHYHU\ V\VWHP´ ,Q $,$$ ,&$6 International Air and Space Symposium and Exposition, The 1H[W < 'D\WRQ 2KLR

480

:LWNRZVNL ' 3 et al. D ³3URSHOOHU :LQJ ,QWHUDFWLRQ´ ,Q WK $HURVSDFH 6FLHQFHV 0HHWLQJ 5HQR 1HYDGD :LWNRZVNL ' 3 et al. E ³$HURG\QDPLF ,QWHUDFWLRQ %HWZHHQ 3URSHOOHUV DQG :LQJV´ -RXUQDO RI $LUFUDIW 9RO 1R SS

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 475-480, Oct.-Dec., 2012

GRL MDWP

EIIHFW RI DLHOHFWULF %DUULHU DLVFKDUJH RQ WKH $LUÀRZ $URXQG D C\OLQGHU $VKUDI EO DURXEL DDZVRQ TDGHX I]ROD (VFROD GH (QJHQKDULD GH 6mR &DUORV 8QLYHUVLW\ RI 6mR 3DXOR ¹ 6mR &DUORV 63 ¹ %UD]LO Abstract: Fluids in a dielectric barrier glow discharge at atmospheric pressure have attracted interest from communities of thermo and Àuid d\namics as well as control. 7his worN investigated the effects of a plasma actuator operating at . N9 and . N+] on the pressure distribution around a pol\vin\l chloride circular c\linder in low-velocit\ airÀow. 7he e[periment was repeated with the actuator at various angles. 7he results show an acceleration of the Àow demonstrated b\ a lower pressure coef¿cient at the actuator area. 7he Àow separation was also dela\ed b\ an angle of as much as ž. 7hese effects were shown to be greater when the actuator was positioned at an angle closer to the separation area. Keywords: *low discharge 'ielectric barrier discharge Flow control 3lasma actuator 6\nthetic plasma Met.

INTRODUCTION The aerodynamic plasma actuator is a particular FRQ¿JXUDWLRQ RI WKH GLHOHFWULF JORZ GLVFKDUJH 7KH DFWXDWRU FRQVLVWV RI WZR WKLQ HOHFWURGHV DV\PPHWULFDOO\ LQVWDOOHG WKDW KDYH D VXSHULRU HOHFWURGH H[SRVHG WR WKH ÀXLG ÀRZ DQG DQ LQIHULRU RQH 7KH WZR HOHFWURGHV DUH VHSDUDWHG E\ D WKLQ VKHHW RI LQVXODWLQJ PDWHULDO L H WKH GLHOHFWULF DV VKRZQ LQ )LJ 7KH HOHFWURGHV RI WKH SODVPD DFWXDWRU DUH ORQJ DQG WKLQ LQVWDOOHG VSDQZLVH DORQJ WKH DHURG\QDPLF ERG\ :KHQ DSSO\LQJ DQ HOHFWULF SRWHQWLDO RI WR N9 DFURVV WKH HOHFWURGHV ZLWK D

)LJXUH ,OOXVWUDWLRQ RI WKH SODVPD DFWXDWRU ZLWK WKH LQGXFHG ÀRZ

5HFHLYHG

$FFHSWHG

DXWKRU IRU FRUUHVSRQGHQFH DVKUDI GURXEL#JPDLO FRP 'HSDUWDPHQWR GH 3yV *UDGXDomR HP (QJHQKDULD 0HFkQLFD 8QLYHUVLGDGH GH 6mR 3DXOR $YHQLGD 7UDEDOKDGRU 6mR &DUOHQVH Âą 3DUTXH $UQROG 6FKPLGW &(3 6mR &DUORV Âą 63 %UDVLO

IUHTXHQF\ RI WR N+] WKH DFWXDWRU LQGXFHV WKH IRUPDWLRQ RI JORZ GLVFKDUJH SODVPD RQ WKH VXUIDFH RI WKH ERG\ DORQJ WKH HOHFWURGH 7KH SODVPD SDUWLFOHV DUH DFFHOHUDWHG E\ WKH HOHFWULF ¿HOG RI WKH DFWXDWRU DQG WKHQ WKH\ FROOLGH ZLWK WKH QHXWUDO DLU SDUWLFOHV DURXQG LW 7KLV FDQ UHVXOW LQ DQ H[FKDQJH RI PRPHQWXP ZKLFK DOWHUV WKH ÀRZ DURXQG WKH ERG\ 7KH HIIHFW LV SHUFHLYHG DV D VPDOO MHW DORQJ WKH ERG\ PREVIOUS WORK ([SHULPHQWV IRXQG LQ OLWHUDWXUH DUH JHQHUDOO\ FDUULHG RXW RQ D ÀDW SODWH $ GLUHFW FXUUHQW '& FRURQD GLVFKDUJH ZDV XVHG IRU WKH ¿UVW WLPH E\ 0DOLN et al. RQ D ÀDW SODWH WR PDQLSXODWH WKH ERXQGDU\ OD\HUV UHVXOWLQJ LQ D GUDJ UHGXFWLRQ RI DERXW IRU VSHHGV XS WR P V ZLWK D N9 DSSOLHG YROWDJH 7KH HI¿FLHQF\ RI WKH DFWXDWRU ZRXOG PDLQO\ GHSHQG RQ WKH YROWDJH XVHG DFURVV WKH HOHFWURGHV )XUWKHUPRUH GUDJ UHGXFWLRQ GHFUHDVHG ZLWK LQFUHDVLQJ ÀRZ YHORFLW\ DQG ZLWK GHFUHDVH LQ WKH SRWHQWLDO GLIIHUHQFH EHWZHHQ HOHFWURGHV HO .KREDLU\ DQG &ORYHU ,Q ODWHU VWXGLHV JORZ GLVFKDUJH SODVPDV ZHUH XVHG WR FRQWURO WKH ÀRZ ERXQGDU\ OD\HU RQ ÀDW SODWHV DQG LW ZDV REVHUYHG WKDW DV\PPHWULFDO FRQ¿JXUDWLRQV RI WKH HOHFWURGHV SURGXFHG PRUH WKUXVW WKDQ V\PPHWULFDO RQHV ZKLOH DQ LQFUHDVH LQ GUDJ ZDV VHHQ 5RWK et al. 7KH HIIHFWV ZHUH DWWULEXWHG WR WKH FRPELQDWLRQ RI PDVV WUDQVSRUW DQG YRUWH[ LQGXFHG HOHFWURK\GURG\QDPLF (+' IRUFHV 6RPH DSSOLFDWLRQV RI WKH SODVPD DFWXDWRUV

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

481

'URXEL $ ( ,]ROD ' 7

KDYH EHHQ LQYHVWLJDWHG DQG LQFOXGH VHSDUDWLRQ FRQWURO RI ORZ 5H\QROG¶V ÀRZ *RNVHO et al. LPSURYHPHQW RI DLUIRLOV &RUNH et al. YLUWXDO ÀDSV DQG VODWV WR FRQWURO ÀRZ DLUIRLO &RUNH et al. FRQWURO RI ÀRZ VHSDUDWLRQ LQ ORZ SUHVVXUH WXUELQHV 5LYLU et al. DQG QRLVH UHGXFWLRQ JHDU 7KRPDV et al. :KLOH PRVW RI WKHVH DSSOLFDWLRQV DUH UHVWULFWHG WR LQFRPSUHVVLEOH ÀRZV DQ DSSOLFDWLRQ LQ KLJK VSHHG ÀRZV KDV EHHQ UHSRUWHG DV D[LV\PPHWULF MHW XVLQJ SODVPD 6DPLP\ et al. ,Q ODWHU H[SHULPHQWV SHUIRUPHG E\ (QORH et al. VHYHUDO ¿QGLQJV ZHUH SUHVHQWHG RQ WKH EHKDYLRU RI WKH SODVPD DFWXDWRUV %DVHG RQ YDULRXV PHDVXUHPHQWV RI SUHVVXUH YROWDJH DQG SODVPD HPLVVLRQ WKH DXWKRUV PDGH VHYHUDO LQWHUHVWLQJ FRQFOXVLRQV WKH LQSXW SRZHU 3 LQWR WKH SODVPD LV QRQOLQHDU ZLWK WKH YROWDJH GURS ǻ9 DQG WKH LQGXFHG VSHHG DQG WKUXVW DUH SURSRUWLRQDO WR WKH LQSXW SRZHU 7KH ¿QDO FRQFOXVLRQ LV WKDW WKH SODVPD LQGXFHV DQ HOHFWURVWDWLF IRUFH ZKLFK FDQ EH WUHDWHG DV D ERG\ IRUFH DV RSSRVHG WR D FRQWDFW IRUFH D ERG\ IRUFH RSHUDWHV WKURXJKRXW WKH ERG\ YROXPH DURXQG WKH ÀXLG SURSRUWLRQDO WR WKH QHW FKDUJH GHQVLW\ DQG VWUHQJWK RI WKH HOHFWULF ¿HOG ,W ZDV DOVR QRWHG WKDW WKH GLUHFWLRQ RI À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et al. PHDVXUHG WKH WKUXVW SURGXFHG GXULQJ WKH RQJRLQJ RSHUDWLRQ RI D SODVPD DFWXDWRU DQG H[DPLQHG WKH HIIHFWV RI LQGLYLGXDO YDULDEOHV WKH $& LQSXW YROWDJH DQG IUHTXHQF\ ,W ZDV FRQFOXGHG WKDW WKH DYHUDJH ERG\ IRUFH LV OLQHDUO\ SURSRUWLRQDO WR WKH LQSXW $& IUHTXHQF\ EHWZHHQ DQG N+] IRU FRQVWDQW LQSXW YROWDJH DQG QRQOLQHDUO\ SURSRUWLRQDO ZLWK WKH LQSXW YROWDJH IRU D FRQVWDQW IUHTXHQF\ )XUWKHUPRUH WKH DFWXDWRU µSXVKHV¶ ZLWK D UHODWLYHO\ KLJKHU PDJQLWXGH DQG µSXOOV¶ ZLWK D UHODWLYHO\ ORZHU PDJQLWXGH WKH ÀXLG LQ RSSRVLWH GLUHFWLRQV GXULQJ HDFK F\FOH 5RWK HW 'DL VWXGLHG WKH HIIHFWV RI FKDQJLQJ WKH GLHOHFWULF PDWHULDO HOHFWURGH JHRPHWU\ IUHTXHQF\ DQG 482

YROWDJH DSSOLHG WR WKH ÀRZ YHORFLW\ LQGXFHG E\ WKH DFWXDWRU 7KH\ REVHUYHG WKDW WKH FKRLFH RI GLHOHFWULF PDWHULDO DIIHFWV WKH SODVPD YROXPH WKH GLVWULEXWLRQ RI HOHFWULF ¿HOG OLQHV JRYHUQHG E\ WKH GLHOHFWULF FRQVWDQW DQG KHDW ORVV ZKLFK LQ WXUQ LV SURSRUWLRQDO WR WKH IUHTXHQF\ RI WKH DOWHUQDWLQJ FXUUHQW LQSXW DQG WKH DUHD HOHFWURGH ,Q JHQHUDO LW LV D PDWHULDO WKDW KDV EHHQ UHFRPPHQGHG WR FRPELQH WKH IROORZLQJ SURSHUWLHV JUHDWHU GLHOHFWULF FRQVWDQW DOXPLQXP IRU H[DPSOH JUHDWHU GLHOHFWULF VWUHQJWK H J .DSWRQ DQG D ORZHU WKHUPDO FRQGXFWLYLW\ IRU H[DPSOH TXDUW] SRO\WHWUDÀXRURHWK\OHQH ± DOVR NQRZQ DV 7HÀRQ ,I FRPSDUHG ZLWK TXDUW] SRO\WHWUDÀXRURHWK\OHQH ZKLFK KDV KLJK GLHOHFWULF FRQVWDQW KLJK GLHOHFWULF VWUHQJWK DQG ORZ WKHUPDO FRQGXFWLYLW\ ZDV XVHG WR JHQHUDWH D KLJKHU VSHHG DQG ORZHU ÀRZ LQGXFHG HQHUJ\ LQSXW ,W ZDV XVHG DV WKH GLHOHFWULF PDWHULDO IRU RWKHU VWXGLHV 7KH ZLGWK RI WKH HOHFWURGHV ZDV FKRVHQ WR KDYH WKH JUHDWHVW (+' HIIHFW 7KH KRUL]RQWDO VHSDUDWLRQ GLVWDQFH EHWZHHQ WKH HGJHV RI WKH XSSHU DQG ORZHU HOHFWURGHV KDV EHHQ IRXQG WR KDYH D VLJQL¿FDQW HIIHFW RQ WKH VSHHG RI WKH LQGXFHG ÀRZ DQG DQ RSWLPDO FRQ¿JXUDWLRQ ZDV IRXQG KDYLQJ D VHSDUDWLRQ RI WR PP ,W ZDV QRWHG WKDW E\ LQFUHDVLQJ WKH IUHTXHQF\ DQG NHHSLQJ WKH YROWDJH FRQVWDQW RU YLFH YHUVD LQGXFHG DQ LQFUHDVH LQ VSHHG ZKLFK EULHÀ\ VWDELOL]HG UHDFKLQJ D FHUWDLQ WKUHVKROG DQG GHFUHDVLQJ VRRQ DIWHU 9DQ'\NHQ et al. DOVR REVHUYHG WKDW D WKLFN GLHOHFWULF ZRXOG EH DEOH WR KDQGOH D KLJKHU LQSXW YROWDJH DQG WKLV KDV DQ LGHDO VSHFL¿F IUHTXHQF\ :KLOH PRVW RI WKH OLWHUDWXUH RQ ÀRZ FRQWURO WKURXJK WKH SODVPD LV HVVHQWLDOO\ H[SHULPHQWDO LQ QDWXUH VHYHUDO PHWKRGRORJLHV IRU WKH QXPHULFDO PRGHOLQJ RI WKH SODVPD DFWXDWRUV ZHUH LQYHVWLJDWHG 7KH PDMRULW\ RI FXUUHQW PRGHOV W\SLFDOO\ XVH (+' WHUP ERG\ IRUFH WR VLPXODWH WKH HIIHFW RI DQ DFWXDWRU RQ WKH H[WHUQDO ÀRZ PLASMA GENERATION 7KH JHQHUDWLRQ RI WKH SODVPD LV REWDLQHG ZLWK WZR HOHFWURGHV FRXSOHG WR RQH VXUIDFH RI WKH GLHOHFWULF PDWHULDO WKDW FRYHUV WKH DLUIRLO 7KH HOHFWURGHV DUH ¿[HG RQ XSSHU DQG ORZHU VLGHV )LJ ZKHUH DQ HOHFWULF ¿HOG LV DSSOLHG ZLWK D SRWHQWLDO DQG IUHTXHQF\ RI DERXW N9 DQG N+] UHVSHFWLYHO\ 6K\\ et al. SURSRVHG WKDW DV\PPHWU\ VKRXOG EH LQWURGXFHG WR WKH DUUDQJHPHQW RI WKH HOHFWURGHV DQG FRQVHTXHQWO\ WKDW GLVFKDUJH VWUXFWXUH SOD\V D VLJQL¿FDQW UROH LQ WKH JHQHUDWLRQ RI SODVPD )LJ 7KH SODVPD VWDWH LV D UHVXOW RI WKH DGGLWLRQ RI VXI¿FLHQW

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

(IIHFW RI 'LHOHFWULF %DUULHU 'LVFKDUJH RQ WKH $LUÀRZ $URXQG D &\OLQGHU

QHXWUDOV DW D PXFK ORZHU WHPSHUDWXUH QRUPDOO\ URRP WHPSHUDWXUH ZKHUHDV HOHFWURQV DUH PXFK µKRWWHU¶

)LJXUH (OHFWURGH FRQ¿JXUDWLRQ VKRZLQJ WKH LQGXFHG HOHFWULF ¿HOG OLQHV 6K\\ HW DO

)LJXUH 6FKHPDWLF VKRZLQJ WKH ODWHUDO DQG IURQW YLHZV RI WKH F\OLQGHU ZLWK GLPHQVLRQV DQG SRVLWLRQ RI WKH HOHFWURGHV 7KH ZKLWH VSDFHV UHSUHVHQW WKH SUHVVXUH WXEHV

HQHUJ\ TXDQWLWLHV WR D JDV 7KH HQHUJ\ LV DGGHG WR GLVVRFLDWH WKH PROHFXOHV RI WKH JDV 7KLV LV D UHVXOW RI FROOLVLRQV EHWZHHQ SDUWLFOHV ZKRVH HQHUJ\ H[FHHGV WKH NLQHWLF PROHFXODU HQHUJ\ %DVHG RQ WKH DPRXQW RI LRQL]DWLRQ WKH SODVPD PD\ EH ZKROO\ RU SDUWLDOO\ LRQL]HG :HDNO\ LRQL]HG SODVPD FRQVLVWV SDUWO\ RI LRQV DQG HOHFWURQV DQG WKH JDV RI QHXWUDO SDUWLFOHV L H DWRPV DQG PROHFXOHV 2XU LQWHUHVW LV LQ SDUWLDOO\ LRQL]HG JDVHV 3ODVPD LV DOVR FODVVL¿HG EDVHG RQ WKH WHPSHUDWXUH UDQJHV /RZ WHPSHUDWXUH SODVPD FDQ EH FODVVL¿HG DV ȩ thermal plasmas have electrons and heavy particles at the VDPH WHPSHUDWXUH L H WKH\ DUH LQ WKHUPDO HTXLOLEULXP ZLWK HDFK RWKHU ȩ nonthermal plasmas on the other hand have the ions and

+LJK WHPSHUDWXUH SODVPDV DUH FKDUDFWHUL]HG E\ WKH NLQHWLF WHPSHUDWXUH RI HOHFWURQV RI 7e § 7 ! K ZKHUH 7e is the electron NLQHWLF WHPSHUDWXUH DQG 7 LV WKH RYHUDOO WHPSHUDWXUH RI WKH SODVPD /RZ WHPSHUDWXUH WKHUPDO SODVPDV DUH FKDUDFWHUL]HG E\ D YDOXH RI 7e § 7 ǜ K )LQDOO\ QRQWKHUPDO RQHV SRVVHVV ORZ WHPSHUDWXUHV RI 7 § K and 7e K 7KH HOHFWULF ¿HOG WKDW DFWV XSRQ WKH FKDUJHG SDUWLFOHV LQ SDUWLFXODU RQ WKH HOHFWURQV LV WKH PDLQ SRZHU VRXUFH WR WKH SODVPD 'XH WR WKH ORZHU PDVV RI HOHFWURQV RQO\ D VPDOO PRPHQWXP WUDQVIHU RFFXUV ZLWK WKH KHDYLHU SODVPD SDUWLFOHV DQG WKLV LV DFKLHYHG E\ HODVWLF FROOLVLRQV 7KHUHIRUH WKH HOHFWURQV UHDFK D PHDQ NLQHWLF HQHUJ\ OHYHO PXFK KLJKHU WKDQ WKDW RI QHXWUDO SDUWLFOHV DQG WKH PHGLXP EHFRPHV QRQWKHUPDO SODVPD $ VLJQL¿FDQW SRUWLRQ RI HOHFWURQV LV HQHUJHWLFDOO\ DEOH WR RYHUFRPH WKH WKUHVKROG DERYH ZKLFK LQHODVWLF FROOLVLRQV RFFXU +RZHYHU GXH WR WKHVH LQHODVWLF FROOLVLRQV WKH HOHFWURQV ORVH H[FHVV HQHUJ\ WKDW DOORZHG WKH LQHODVWLF FROOLVLRQV WKHUHIRUH WKH\ DUH WUDQVIHUUHG IURP D UHJLRQ RI KLJK NLQHWLF HQHUJ\ WR D ORZ HQHUJ\ RQH 7KXV WKH SRSXODWLRQ RI HOHFWURQV LQ WKH UHJLRQ RI LQHODVWLF FROOLVLRQV GHFUHDVHV VKDUSO\ ZLWK LQFUHDVLQJ SRZHU 7KLV LQWHUDFWLRQ EHWZHHQ WKH DFWLRQ RI WKH HOHFWULF ¿HOG DQG WKH SURFHVVHV RI HODVWLF DQG LQHODVWLF FROOLVLRQV FDXVHV WKH SODVPD WR UHDFK D VWDWH RI WKHUPRG\QDPLF HTXLOLEULXP 7KH HOHFWULF ¿HOG LV VWURQJHU LQ WKH UHJLRQ FORVHVW WR WKH LQQHU HGJH RI WKH WZR HOHFWURGHV ,WV HOHFWULF IRUFH GHFUHDVHV DV WKH GLVWDQFH RI WKLV UHJLRQ ,W LV ORJLFDO WKDW WKH SUREDELOLW\ RI SODVPD IRUPDWLRQ LV KLJKHU LQ WKH UHJLRQ RI VWURQJHU HOHFWULF ¿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ÀRZ UDWH LV OHVV WKDQ WKH IUHTXHQF\ RI GLVFKDUJH 7KLV FRQGLWLRQ PDLQWDLQV D FRQWLQXRXV GLVFKDUJH )UHTXHQFLHV KLJKHU WKDQ N+] DUH XVXDOO\ DEOH WR VXVWDLQ LW ZKLOH WKH SHULRGLFLW\ LV ORVW DW ORZHU IUHTXHQFLHV ,Q WKLV ZRUN WKH JORZ GLVFKDUJH FUHDWHG E\ WKH FRQ¿JXUDWLRQ DVVXPHV WKDW WKH FRQGLWLRQ RI TXDVL QHXWUDOLW\ LV PDLQWDLQHG DV LW LV D EDVLF SURSHUW\ LQ WHFKQRORJLFDO SODVPDV DQG ORZ HQHUJ\ '%'V

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

483

'URXEL $ ( ,]ROD ' 7

^ Pi - P3h

^ Pi - P3h ^ PT - P3h

METHODOLOGY

Cp =

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À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ÀRZ UHVXOWLQJ LQ D PRGL¿HG &S FXUYH WKDW LV FRPSDUHG ZLWK WKH LQLWLDO &S FXUYH ZLWK WKH DFWXDWRU RII 7KH SURFHVV LV UHSHDWHG ZLWK WKH DFWXDWRU SRVLWLRQHG DW WKH IROORZLQJ DQJOHV DQG

ZKHUH 37 – 3 LV WKH G\QDPLF SUHVVXUH 3ș LV WKH VWDWLF SUHVVXUH 37 WRWDO SUHVVXUH RI WKH IUHH VWUHDP 3 LV WKH IUHH VWUHDP VWDWLF SUHVVXUH

E[SHULPHQWDO FRQGLWLRQV ,Q WKH FKRVHQ FRQ¿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¿FLHQW &S LV GH¿QHG DV WKH GLIIHUHQFH LQ VWDWLF SUHVVXUH EHWZHHQ WKH ÀRZ RYHU WKH DLUIRLO DQG WKH IUHH ÀRZ LQ UHODWLRQ WR WKH G\QDPLF SUHVVXUH RI WKH IUHH VWUHDP ÀRZ DV LQ (T 484

1 tU 2 2 3

=

7KLV H[SUHVVLRQ RI &S FDQ EH ZULWWHQ DV (T Cp = 1 - `

v j2 v3

5HVXOWLQJ LQ D ÀRZ YHORFLW\ RI (T

V = V3 1 - C p

)RU D IUHH VWUHDP YHORFLW\ RI P V LQ WKH FDVH RI QR SODVPD WKHUH ZDV D Cp DW WKH SRLQW RI PD[LPXP DFWXDWLRQ ZKLFK FRUUHODWHG ZLWK D ÀRZ UDWH RI V = 3.92 1 + 1.5 = 6.2m/s :LWK WKH DFWXDWRU RQ ZH QRWLFHG D JUHDWHU QHJDWLYH Cp D KLJKHU YDOXH RI ZKHQ WKH DFWXDWRU LV SRVLWLRQHG DW 7KH ÀRZ VSHHG DFFHOHUDWLQJ WKH DFWXDWRU FDQ EH FDOFXODWHG E\ WKH VDPH HTXDWLRQ UHVXOWLQJ LQ V = 3.92 1 + 2.5 = 7.2m/s +HQFH ZH FDQ FRQFOXGH WKDW WKH DFWXDWRU ZDV DEOH WR DFFHOHUDWH WKH À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¿ODPHQWDU\ PXOWLSRLQW 3ODVPD FRQFHQWUDWLRQ ZLWK

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

(IIHFW RI 'LHOHFWULF %DUULHU 'LVFKDUJH RQ WKH $LUÀRZ $URXQG D &\OLQGHU

Actuator at 0°

1.5 1.0 0.5

Angle

0.0 0

30

60

90

120

150

180

210

240

270

300

330

360

-0.5

Cp

DQ LQFUHDVH LQ ERWK YROWDJH DQG IUHTXHQF\ 7KH WUDQVLWLRQ RI WKH GLVFKDUJH PRGH WR ¿ODPHQWDU\ GHSHQGV RQ WKH VSDFLQJ EHWZHHQ WKH HOHFWURGHV GLHOHFWULF WKLFNQHVV DQG GLHOHFWULF PDWHULDO 7KH ¿ODPHQWDU\ GLVFKDUJH RFFXUV ZKHQ ¿ODPHQWDU\ KRW VSRWV DSSHDU LQ WKH SODVPD ZKLFK DSSHDU WR EH EULJKWHU WKDQ RWKHU UHJLRQV RI WKH SODVPD GXH WR WKH LQFUHDVHG SODVPD IRUPDWLRQ LQ WKHVH UHJLRQV :KHQ WKH GLVFKDUJH ZDV ¿ODPHQWDU\ LQFUHDVLQJ WKH DFWXDWRU RSHUDWLRQ IUHTXHQF\ ZKLOH FRQVWDQW YROWDJH ZDV PDLQWDLQHG LW UHVXOWHG LQ DQ LQFUHDVHG QXPEHU RI KRW VSRWV LQ WKH SODVPD :LWK WKH DFWXDWRUV XVHG LQ WKLV VWXG\ WKH SUHVHQFH RI KRW VSRWV DOVR W\SLFDOO\ LQGLFDWHG WKDW WKH YROWDJH DSSOLHG WR WKH DFWXDWRU ZDV QHDU WKH PD[LPXP SHUPLWWHG E\ WKH GLHOHFWULF 7KHUHIRUH WKH LQFUHDVH LQ YROWDJH EH\RQG WKLV SRLQW UHVXOWHG LQ D IDLOXUH GXH WR DUFLQJ LQGXFHG EXUQV RI WKH GLHOHFWULF PDWHULDO )LJ

-1.0 -1.5 -2.0 -2.5

Off On

-3.0

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU SRVLWLRQHG DW

Actuator at 60° 1.0 0.5

Angle 0.0

Cp

0

30

60

90

120

150

180

210

240

270

300

330

360

-0.5 -1.0 -1.5

)LJXUH $ ¿ODPHQWDU\ GLVFKDUJH ZLWK YDULRXV KRW VSRWV DORQJ WKH HOHFWURGH

Off On

-2.0

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU SRVLWLRQHG DW

RESULTS AND DISCUSSION 7KH UHVXOWV SUHVHQWHG LQ WKLV VHFWLRQ DUH WKH DYHUDJH FXUYHV RI &S FDOFXODWHG DW HDFK DQJOH RI WKH DFWXDWRU 7KH HUURU LV FDOFXODWHG ZLWK DQ LQWHUYDO RI FRQ¿GHQFH RI DQG LV VKRZQ LQ EDUV DW YDULRXV SRLQWV RQ WKH FXUYHV 7KH SRVLWLRQ RI WKH DFWXDWRU UHODWLYH WR WKH F\OLQGHU LV SUHVHQWHG E\ D YHUWLFDO GRWWHG OLQH )LJ 3RVLWLRQLQJ WKH DFWXDWRU LQ WKH VWDJQDWLRQ SRLQW RI WKH F\OLQGHU GRHV QRW UHVXOW LQ D FRQVLGHUDEOH HIIHFW 7KH Cp curve LV DOPRVW LGHQWLFDO IRU WKH ÀRZ ZLWK DQG ZLWKRXW SODVPD ZLWK PLQRU GLIIHUHQFHV LQ WKH UHJLRQ RI WXUEXOHQFH 1RWLFH WKDW WKLV UHJLRQ LV YHU\ WXUEXOHQW DQG WKH SUHVVXUH JUDGLHQW YDULHV JUHDWO\ UHVXOWLQJ LQ ÀXFWXDWLRQV LQ WKH FXUYH RI Cp $OVR REVHUYH WKDW WKH HUURU YDOXH RI WKH WZR FXUYHV RYHUODS ZKLFK VKRZV VRPH FRQ¿GHQFH LQ WKH YDOXHV REWDLQHG LQ WKH H[SHULPHQW )LJ

3RVLWLRQHG DW WKH DFWXDWRU GHPRQVWUDWHV D VPDOO HIIHFW KRZHYHU LW LV FOHDU DQG LGHQWL¿HG $Q DFFHOHUDWLRQ RI WKH ÀRZ FDQ EH LQIHUUHG IURP WKH JUDSK ZLWK Cp UHDFKLQJ DQG WKHUH LV D JUHDWHU SUHVVXUH UHFRYHU\ 7KHUH ZDV DOVR D GHOD\ RI WKH SRLQW RI VHSDUDWLRQ WR DERXW )LJ $W WKH DFWXDWRU SURYLGHV D JUHDWHU HIIHFW 7KH DFFHOHUDWLRQ RI WKH ÀRZ UHVXOWV LQ D YDOXH RI IRU Cp 7KH VHSDUDWLRQ SRLQW LV DOVR VKLIWHG QHDUO\ WR WKH WUDLOLQJ HGJH RI WKH F\OLQGHU 7KLV HIIHFW LV QRW HQFRXQWHUHG RQ WKH RWKHU VLGH RI WKH F\OLQGHU ZKLFK GRHV QRW KDYH DQ DFWXDWRU KHUH WKH Cp FXUYH LV DOPRVW LGHQWLFDO ZLWK WKH DFWXDWRU WXUQHG RII 7KH DFWXDWRU VKRZV D JUHDWHU HIIHFW ZKHQ SRVLWLRQHG DW )LJ 7KHUHIRUH WKH DFFHOHUDWLRQ RI WKH ÀRZ FKDQJHV WKH SUHVVXUH FRHI¿FLHQW DW WKLV SRLQW WR Cp 7KH GLVSODFHPHQW RI WKH ÀRZ¶V VHSDUDWLRQ SRLQW VXUSDVVHV DQ DQJOH RI

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

485

'URXEL $ ( ,]ROD ' 7

Actuator at 70°

1.0 0.5

Angle 0.0

Cp

0

30

60

90

120

150

180

210

240

270

300

330

360

-0.5 -1.0

$W WKH DFFHOHUDWLRQ UHDFKHV WKH PD[LPXP DOORZHG E\ WKH DFWXDWRU )LJ 7KHUH ZDV D UHODWLYHO\ KLJK UHFRYHU\ RI Cp UHDFKLQJ 7KH VHSDUDWLRQ SRLQW PRYHV EDFN WR 7KHUH LV D ZRUWK QRWLQJ VPDOO GHFHOHUDWLRQ RQ WKH RWKHU VLGH RI WKH F\OLQGHU 7KH WXUEXOHQW UHJLRQ ZLWK WKH DFWXDWRU RQ VKRZV KLJKHU YDOXHV RI Cp WKDQ WKDW ZLWK WKH DFWXDWRU RII :H FDQ WKXV LQIHU WKDW WKH DFWXDWRU FDXVHG D GHFUHDVH LQ GUDJ E\ GLPLQLVKLQJ WKH ZDNH VL]H )LJ

-1.5

Actuator at 100°

1.5

Off On

-2.0

1.0

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU

0.5

SRVLWLRQHG DW

Angle

Cp

0.0 -30

0

30

60

90

120 150 180 210 240 270 300 330 360

-0.5

Actuator at 80°

1.5

-1.0

1.0

-1.5

0.5

Angle

0.0 0

30

60

90

120

150

180

210

240

270

300

330

360

-2.0

Off On

Cp

-0.5

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU

-1.0

SRVLWLRQHG DW

-1.5 -2.0

Off On

-2.5

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU SRVLWLRQHG DW

7KH DFWXDWRU FRQWLQXHV WR SUHVHQW DQ HIIHFW DIWHU +RZHYHU OHVV WKDQ WKDW RI WKH DFWXDWRU SODFHG DW ZDV DEOH WR DFFHOHUDWH WKH ÀRZ E\ SXOOLQJ WKH Cp YDOXH WR ,W LV LQWHUHVWLQJ WR QRWH WKDW WKH VHSDUDWLRQ SRLQW VKRZHG D VKLIW RI DERXW ZKHQ WKH DFWXDWRU ZDV SODFHG ULJKW DIWHU WKH VHSDUDWLRQ SRLQW )LJ

Actuator at 90°

1.5

1.0

1.0 0.5

0.5

Angle

Angle

0.0 0

30

60

90

120

150

180

210

240

270

300

330

0

Cp

Cp

0.0

360

-0.5

30

60

90

120

150

180

210

240

270

300

330

360

-0.5

-1.0

-1.0

-1.5

-1.5

-2.0 -2.5

Off On

-3.0

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU SRVLWLRQHG DW

486

Actuator at 110°

1.5

-2.0

Off On

)LJXUH Cp FXUYH ZLWK DFWXDWRU ERWK RQ DQG RII $FWXDWRU SRVLWLRQHG DW

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

(IIHFW RI 'LHOHFWULF %DUULHU 'LVFKDUJH RQ WKH $LUÀRZ $URXQG D &\OLQGHU

&RQWLQXLQJ WR WKH HIIHFW RI WKH DFWXDWRU GHFUHDVHV EXW VWLOO FDXVHV D VPDOO DFFHOHUDWLRQ VLPLODU WR ZKHQ WKH DFWXDWRU LV DW )LJ

Actuator at 120°

1.5 1.0 0.5

Angle Cp

0.0 0

30

60

90

120

150

180

210

240

270

300

330

360

-0.5 -1.0 -1.5

Off On

-2.0

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU SRVLWLRQHG DW

:LWK D ODUJHU DQJOH WKH DFWXDWRU FHDVHV WR KDYH DQ REVHUYHG HIIHFW 7KH Cp FXUYH ZLWK WKH DFWXDWRU RQ ZDV DOPRVW LGHQWLFDO ZLWK LW RII )LJ

Actuator at 180°

1.5

WR WKH ÀRZ 7KH DQJOHV ZLWK JUHDWHVW LQWHUDFWLRQ UHODWHG WR WKH ÀRZ DUH WKRVH FORVH WR WKH SRLQW RI VHSDUDWLRQ 7KH DFWXDWRU JUDGXDOO\ ORVHV DELOLW\ WR LQGXFH D FKDQJH LQ WKH ÀRZ WKH IXUWKHU LW LV SODFHG IURP WKH SRLQW RI VHSDUDWLRQ 7KH GHOD\ LQ WKH ÀRZ VHSDUDWLRQ LV DOVR D UHVXOW RI WKH KLJKHU VXFWLRQ LQGXFHG E\ WKH ORZ SUHVVXUH FUHDWHG E\ WKH DFWXDWRU ,W LV LPSRUWDQW WR QRWH WKDW DW DQJOHV VOLJKWO\ SDVW WKH VHSDUDWLRQ SRLQW WKH DFWXDWRU GHVSLWH LQGXFLQJ D UHODWLYHO\ ORZHU DFFHOHUDWLRQ FRXOG IXUWKHU GHOD\ WKH VHSDUDWLRQ E\ XS WR ,Q WKLV H[SHULPHQW WKH LQWHUDFWLRQ RI JORZ GLVFKDUJH SODVPD ZLWK DLUÀRZ ZDV GHPRQVWUDWHG DQG FRQ¿UPHG 7KH DFWXDWRU DFKLHYHG D FOHDU DFFHOHUDWLRQ RI WKH ÀRZ VKRZQ E\ D ORZHU Cp $OVR WKH DFWXDWRU LQGXFHG D GHOD\ LQ WKH VHSDUDWLRQ RI WKH ÀRZ E\ +RZHYHU LW VKRZHG D JUHDWHU HIIHFW ZKHQ ORFDWHG LQ WKH UHJLRQ RI VHSDUDWLRQ SUHVHQWLQJ GHFUHDVLQJ HI¿FLHQF\ ZLWK IXUWKHU SODFHPHQW IURP WKLV UHJLRQ 7KHVH UHVXOWV VKRZ D FDSDFLW\ WR JHQHUDWH PRUH OLIW DQG OHVV GUDJ PDNLQJ WKH DFWXDWRU D JRRG FRQWURO GHYLFH 7KLV PDNHV SODVPD DFWXDWRUV TXLWH DWWUDFWLYH LQ WKH DUHD RI DHURG\QDPLF UHVHDUFK :H FDQ FRQFOXGH IURP WKH GDWD REWDLQHG WKDW WKH SODVPD DFWXDWRU KDV D VXEVWDQWLDO DQG SRVLWLYH HIIHFW RQ WKH ÀRZ RYHU DQ DLUIRLO 7KLV SUHVHQWV PDQ\ RSSRUWXQLWLHV DQG VLWXDWLRQV LQ ZKLFK WKH DFWXDWRU FDQ EH XVHG LQ WKH IXWXUH DQG GHVHUYHV WR EH IXUWKHU UHVHDUFKHG REFERENCES

1.0

&RUNH / DQG 3RVW 0 ³2YHUYLHZ RI SODVPD ÀRZ FRQWURO FRQFHSWV RSWLPL]DWLRQ DQG DSSOLFDWLRQV´ UG $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

0.5

Angle

Cp

0.0 0

30

60

90

120

150

180

210

240

270

300

330

360

-0.5

&RUNH 7 & et al. ³3ODVPD ÀRZ FRQWURO RSWLPL]HG DLUIRLO´ WK $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

-1.0 -1.5

Off On

-2.0

)LJXUH Cp FXUYH ZLWK WKH DFWXDWRU ERWK RQ DQG RII $FWXDWRU

&RUNH 7 & et al. ³3ODVPD ÀDSV DQG VODWV DQ DSSOLFDWLRQ RI ZHDNO\ LRQL]HG SODVPD DFWXDWRUV´ QG $,$$ )ORZ &RQWURO &RQIHUHQFH S 3RUWODQG 25 $,$$

SRVLWLRQHG DW

$W WKH DFWXDWRU GLG QRW VKRZ DQ\ REVHUYDEOH HIIHFW

&RUNH 7 & et al. ³$SSOLFDWLRQ RI ZHDNO\ LRQL]HG SODVPDV DV ZLQJ ÀRZ FRQWURO GHYLFHV´ WK $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

CONCLUSIONS 7KH UHVXOWV VKRZ D WDQJLEOH HIIHFW RI XVLQJ WKH SODVPD DFWXDWRU 7KH DFWXDWRU LQGXFHG D UHPDUNDEOH DFFHOHUDWLRQ LQ WKH ÀRZ RYHU D F\OLQGHU YDU\LQJ ZLWK LWV DQJOH ZLWK UHVSHFW

(O .KDELU\ 6 DQG &ROYHU * ³'UDJ UHGXFWLRQ E\ GF FRURQD GLVFKDUJH DORQJ DQ HOHFWULFDOO\ FRQGXFWLYH ÀDW SODWH IRU VPDOO 5H\QROGV QXPEHU ÀRZ´ 3K\VLFV )OXLGV 9RO S

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

487

'URXEL $ ( ,]ROD ' 7

(QORH & / et al. ³3ODVPD VWUXFWXUH LQ WKH DHURG\QDPLF SODVPD DFWXDWRU´ QG $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

5RWK - 5 et al. ³(OHFWURK\GURG\QDPLF )ORZ &RQWURO ZLWK D *ORZ 'LVFKDUJH 6XUIDFH 3ODVPD´ $,$$ -RXUQDO 9RO 1R -XO\ SS

*RNVHO % et al. ³6WHDG\ DQG XQVWHDG\ SODVPD ZDOO MHWV IRU VHSDUDWLRQ DQG FLUFXODWLRQ FRQWURO´ UG $,$$ )ORZ &RQWURO &RQIHUHQFH 6DQ )UDQFLVFR &$ $,$$

5RWK - 5 DQG 'DL ; ³2SWLPL]DWLRQ RI WKH DHURG\QDPLF SODVPD DFWXDWRU DV DQ HOHFWURK\GURG\QDPLF HKG HOHFWULFDO GHYLFH´ WK $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$ 3DSHU

+XOWJUHQ / DQG $VKSLV ' ³'HPRQVWUDWLRQ RI VHSDUDWLRQ GHOD\ ZLWK JORZ GLVFKDUJH SODVPD DFWXDWRUV´ VW $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

6DPLP\ 0 et al. ³$FWLYH FRQWURO RI KLJK VSHHG MHWV XVLQJ ORFDOL]HG DUF ¿ODPHQW SODVPD DFWXDWRUV´ QG $,$$ )ORZ &RQWURO &RQIHUHQFH 3RUWODQG 25 $,$$

/LHEHUPDQ 0 $ DQG /LFKWHQEHUJ $ - ³3ULQFLSOHV RI 3ODVPD 'LVFKDUJHV DQG 0DWHULDOV 3URFHVVLQJ´ QG HG :LOH\ ,QWHUVFLHQFH SS

6K\\ : et al. ³0RGHOLQJ RI JORZ GLVFKDUJH LQGXFHG ÀXLG G\QDPLFV´ -RXUQDO RI $SSOLHG 3K\VLFV 9RO SS

0DOLN 0 et al. ³,RQ ZLQG GUDJ UHGXFWLRQ´ VW $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$ 3DSHU

7KRPDV ) 2 et al. ³3ODVPD DFWXDWRUV IRU ODQGLQJ JHDU QRLVH UHGXFWLRQ´ WK $,$$ &($6 $HURDFRXVWLFV &RQIHUHQFH 0RQWHUH\ &$ $,$$

3RUWHU & 2 et al. ³7HPSRUDO IRUFH PHDVXUHPHQWV RQ DQ DHURG\QDPLF SODVPD DFWXDWRU´ WK $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

9DQ'\NHQ 5 ' et al. ³3DUDPHWULF LQYHVWLJDWLRQV RI D VLQJOH GLHOHFWULF EDUULHU SODVPD DFWXDWRU´ QG $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW 5HQR 19 $,$$

5LYLU 5 et al. ³7XUELQH )ORZ &RQWURO 3ODVPD )ORZV´ VW $,$$ $HURVSDFH 6FLHQFHV 0HHWLQJ DQG ([KLELW S 5HQR 1HYDGD 86$ $,$$

488

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 481-488, Oct.-Dec., 2012

doi: 10.5028/jatm.2012. 04042712

Electronic Simulator of the PLATO Satellite Imaging System Rafael Corsi Ferrão*, Sergio Ribeiro Augusto, Tiago Sanches da Silva, Vanderlei Cunha Parro Instituto Mauá de Tecnologia – São Caetano do Sul/SP – Brazil Abstract: This paper described an architecture that is able to emulate the behavior of the imaging transfer system proposed for the PLATO satellite – PLAnetary transits and oscillations of stars. It was conceived to accurately represent Àight operation as to validate the satellite digital processing unit on its development phase. 'etails related to the PLATO mission, its architecture, and the implementation technical details are presented in this article. Keywords: SpaceWire, Remote Memory Access Protocol, PLAnetary Transits and Oscillations of stars, Ground support equipment, Hardware description languages.

INTRODUCTION

PLATO ARCHITECTURE

PLAnetary Transits and Oscillations of stars (PLATO) is a project from the Cosmic Vision program by the European Space Agency (ESA), which is currently in phase M3 (launch scheduled for 2022). A large-scale photometer composed of 34 cameras is used, whose objective is to detect and characterize extrasolar planets and their host stars by using the transit method (Catala and PLATO consortium, 2008). This multi-camera approach will jointly observe the same region of the sky. There is a front-end electronic system (FEE) associated with each camera, which is responsible for image digitization and for their sending to the digital processing unit (DPU) of the satellite. The satellite has 16 normal DPU (N-DPUs) for mining scienti¿c data from the images and two fast ones (F-DPUs) for interfacing with fast cameras. For the FEE and DPU communication, the SpaceWire and remote memory access protocols (RMAP) were selected (ESA, 2008), both of which were widely used in several space missions (Parkes and Ferrer, 2010). The project involves the creation of a dedicated device, which is capable of simulating the behavior of a normal FEE (NFEE) with the main objective of testing the proposed architecture for the PLATO satellite and of validating, in a near future, the DPU¶s Àight software. The system was implemented in VHSIC hardware description language (VHDL) and embedded into a ;ilinx ;C VL; 0 ¿eldprogrammable gate array (FPGA) (Xilinx, 2011).

The architecture proposed for the PLATO satellite (Larque and Plasson, 2011) has 34 independent telescopes, each made up of an optical unit and a camera. From the 34 cameras, 32 are normal ones (N-Cameras), meant for scienti¿c use and delivery of high-resolution photometry (81 Mpx/Camera, 1 px = 16 bits) at 25-second intervals. The two remaining cameras (F-Cameras) are used in the satellite’s control loop at 2.25-second intervals (41 Mpx/camera). The 32 scienti¿c-purpose N-Cameras were arranged in the satellite in four subgroups of eight cameras (Fig. 1). The two fast cameras work independently and have each a dedicated processing unit. The charge-coupled device (CCDs) used in the mission have two zones: the image zone, which is made up of detectors, and the memory zone, used for the storage of temporary images. The memory zone has two access points, thus enabling simultaneous readings in different areas. Each camera is equipped with its own four-CCD-wide matrix, each containing 4,520 lines by 4,535 pixels. A FEE is coupled to each camera and is responsible for controlling CCD operation and communicating with the DPU, sending images and status information (housekeeping). The FEE also propagates time information to the DPU, which uses these data for image processing. Image delivery occurs every 6.25 seconds, alternating the CCDs at every cycle. The process is handled using two SpaceWire links that operate each at 100 Mbps. Each link transfers half of a CCD’s image (right and left sides) simultaneously, increasing, thus, the system’s general data signaling rate to 200 Mbps. The RMAP was chosen for image transmission. This protocol allows writing and reading from a memory unit

Received: 08/05/12

Accepted: 06/09/12

*author for correspondence: rafael.corsi@maua.br Praça Mauá 1 – CEP: 09580 900 – São Caetano do Sul/SP – Brazil

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 489-494, Oct.-Dec., 2012

489

Ferrão, R.C. et al.

Figure 1. Optic bank.

through a SpaceWire node. Image transmission takes place in a manner which is transparent to both nodes, that is, without demanding processor intervention. Delivery is carried out by a RMAP command that encapsulates half of a CCD’s line. This command is sent without data veri¿cation or acknowledgement. Control commands sent from the DPU to the FEE, on the other hand, are provided with both of these capabilities. A total of 16 Normal-DPUs execute onboard of the satellite routines for mining scienti¿c data from the images stored in the memories. These routines run in parallel with image reception. Each N-DPU is responsible for data processing sent by two N-FEEs. The complete transfer of a quarter of an image (one CCD) must last at most 3.3 seconds, leaving enough spare time for the complete execution of the image data mining. Image transfer happens as depicted in Fig. 2.

care of two NFEE), sending new images at each sync signal. The objectives are to have a system capable of dynamically test the DPU’s embedded software and to validate the architecture proposed for the mission. The architecture shown in Fig. 3 has as its cornerstone two volatile memories used for temporary storage of the image to be transmitted. These memories work complementarily and are used as data buffers. Their operation may be described as follows: while a memory is being loaded with a new image that will be transferred, the other one is being read and its data sent by the simulator to the DPU. At the next sync signal, the

ARCHITECTURE PROPOSED FOR THE SIMULATOR The proposed platform (SimuCam) emulates a NFEE capable of testing half of a Normal-DPU (each NDPU takes 490

Figure 2.

One cycle of the Plato charge-coupled device transfer timing.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 489-494, Oct.-Dec., 2012

Electronic Simulator of the PLATO Satellite Imaging System

Figure 3.

Simulator architecture (SimuCam).

memories are switched, and a new picture is loaded into the memory that was recently read. Figure 4 illustrates the process. Image loading into memory is performed through a highspeed communication path (USB) between the workstation and the memory controller (Fig. 5), being the latter responsible for managing memory access and access to the simulator’s internal register. The SpW/RMAP block is responsible for the interface with the SpaceWire codec and for the creation and interpretation

Figure 4.

Data Àow in memory

of RMAP commands. Implemented according to the ECSSE-ST-50 standard (ESA, 2008), the block allows the DPU to read and modify the simulator’s internal registers, changing in this way its behavior during operation. It also creates and automatically sends RMAP writing commands containing the image that will be transferred, in addition to extra information in each command (information about the line and the CCD). Housekeeping data are sent separately, after the end of transmission of each CCD. The RMAP handling has two internal interfaces, read and write, which take care of generating and propagating RMAP packets, as well as of interpreting RMAP commands sent by the DPU. These interfaces run in parallel, allowing a writing command to be executed in local memory, while images are being transferred by the write block. If a write block interprets a command with acknowledgement or a read command, the answer is placed on a response queue (with a priority level inferior to that of the images). Only after the end of the image data transmission, the answers are dispatched. The read block is a Mealy state machine that interprets, reads or writes commands (with or without veri¿cation and/or answer). Communication to memory and to the codec is direct, making it entirely transparent to other blocks. The read block restrains the access to some data slots in memory, which can only be accessed by the DPU in some operation modes (Housekeeping, for example). Data concerned with the interpreted packets are recorded in the simulator’s register. The writing block is responsible for creating headers and for sending data to the DPU. At each new sync signal, the writing block reads from the simulator’s general register the initial con¿guration information of the SpaceWire link, DPU, and simulator. Using this information for image transmission,

Figure 5.

Memory allocation data.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 489-494, Oct.-Dec., 2012

491

Ferrão, R.C. et al.

the RMAP header con¿gurations are automatically changed at each new command, without the need for external control. Data sent to the DPU are previously loaded into an autonomous ¿rst in ¿rst out (FIFO) device (Haywood, 2004) by the data charge block, which addresses the memory controller by taking into account memory-image allocation. This charging procedure is necessary so that the memory controller can be shared with more than one RMAP writing block. Figure 6 illustrates the blocks interfaces of a single RMAP handling. The pattern generation block interprets addresses sent by data charge and creates patterns that are used for tests and validation. The simulator has an internal register bank that contains all of its con¿gurations. These registers are shared by all blocks, and the con¿gurations can be changed both by the USB interface and by the RMAP writing command sent by the DPU to the simulator. A TimeCode (ESA, 2008) is used for the propagation of time and is sent automatically whenever a sync signal is received, ensuring time propagation required by the application. The TimeCode points out to the DPU the beginning of a new transmission. Besides, it is also used to indicate the CCD (zero, one, two, three) being transferred. The sync block propagates or creates reference signals (6.25 and 25 seconds) used by all other blocks for synchronism and internal update.

The FEE control is a state machine that controls memory access to both the RMAP reading and loading blocks. It also oversees the memory exchange operation and takes care of arbitrating reading accesses, ensuring that both RMAP memories always have their internal buffers suf¿ciently full so that the image transmission does not remain idle, hence raising the system’s ef¿ciency. The control logic takes into consideration that the reading operation executed by the RMAP block is performed in bursts (of con¿gurable size), raising the ef¿ciency of the access to the system’s SDRAM memory. A codec provided by Commissariat à l’Énergie Atomique (CEA) was used for applications in Xilinx Virtex5 chips (Frédéric and CEA, 2008). It implements all protocol speci¿cations with low-chip resource usage. Furthermore, it supports a maximum transmission frequency of 320 Mbps and has a 32-byte reception FIFO. Several system and simulator characteristics can be modi¿ed, enabling the simulator to be as generic as possible. The following con¿gurations can be made: ȩ simulator parameters: they con¿gure the simulator’s operation and its operation mode. Among others, CCD reading direction (clockwise or counter-clockwise) can be selected. Likewise, error insertions into RMAP packets and internal and external synchronisms (and synchronism period) can be con¿gured ȩ housekeeping: related to SDRAM memory space allocation, data quantity, and RMAP protocol con¿gurations ȩ CCD description: it occupies itself with CCD physical information, such as size, pre-scan columns, semi-ring rows, analog to digital converter (ADC) speed and resolution, delays between lines, and RMAP protocol con¿gurations used for sending the image to the DPU. IMPLEMENTATION AND TESTS

Figure 6.

492

RMAP handling interfaces.

The GR-PCI-XC5V board from AeroÀex Gaisler (Gaisler, 2011) was used for the implementation of the simulator SimuCam. This board has a FPGA Virtex5 XC5VLX50 core from Xilinx, as well as FLASH, SRAM, and SDRAM memories. The hardware proposed for the application was described in VHDL in order to run operations in parallel, aiming at the global increase in performance of the simulator. All blocks having an interface between FIFOs were implemented using the concept of autonomous FIFO, dispensing data Àow control between blocks. The chip’s internal RAM was used as memory for the FIFOs.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 489-494, Oct.-Dec., 2012

Electronic Simulator of the PLATO Satellite Imaging System

All blocks within this project had their logic and functionality tested with test benches exclusively created for each block. A global system simulation was performed verifying system integrity and timing. Tests were carried out in the Paris Observatory, in Meudon jointly with LESIA (Laboratoire d’Études Spatiales et d’Instrumentation en Astrophysique), which is responsible for the speci¿cation of the satellite’s architecture. The test scenario can be seen in Fig. 7. The simulator was connected via two SpaceWire links to a GR-RASTA system (Gaisler, 2011) enclosing a LEON2 processor, left in charge of simulating a half normal DPU, and a Debug System Unit (DSU) to perform ¿rmware debugging. The tests involved sending data (patterns) from the simulator to LEON2’s memory zone, which was responsible for verifying data integrity. Timing imposed by the speci¿cation was tested with a SpaceWire link analyzer (STAR-Dundee, 2012). A Software Ground Support Equipment (SGSE) was developed to control the SimuCam. The sent patterns were prede¿ned and were generated inside the simulator with the pattern generation block (Fig. 6).

Table 1.

Comparative table between the real NFEE and the obtained timing from implemented SimuCam.

Con¿guration

NFEE

SimuCam

CCD width

4,510

4,510

Pixels

CCD height

4,510

4,510

Pixels

Smearing rows

10

10

Rows

Prescan per CCD output

25

25

Pixels

Pixel coding

16

16

Bits

ADC Speed

4

6.97

SpaceWire links

Unit

MHz

2

2

SpaceWire bit rates

100

100

Mbps

Full CCD total transfer time

3.3

2.93

seconds

4,576

4,576

Bytes

Instantaneous data rate for 1 link

80

100

Mbps

Averaged data rate over full CCD transfer

70.5

99.93

Mbps

Package size + 16 bytes RMAP header

Number

NFEE: normal front end electronic ADC: analog to digital converter.

Figure 7. Test bench.

CONCLUSIONS With the aid of the proposed system, it was possible to send an entire image from the SimuCam in only 2.93 seconds, better than the originally time proposed, i.e., 3.3 seconds (Table 1). The SpaceWire links attained a 99.93% utilization rate, being held idle for 240 ns for every half line sent (between RMAP commands) as shown in Fig. 8. The use of the platform at a higher speed of the SpaceWire link (200 Mbps) was also possible without incurring ef¿ciency loss in the link.

40 ns

20 ns

NCHAR

0 ns

40 ns

EOP

20 ns

20 ns

80 ns

60 ns

100 ns

20 ns

80 ns

140 ns

40 ns

40 ns

160 ns

20 ns

220 ns

60 ns

240 ns

20 ns

300 ns

60 ns

340 ns

40 ns

380 ns

40 ns

440 ns

60 ns

80 ns NULL

NULL 80 ns

Link Idle

NULL 80 ns NCHAR [FE] 80 ns NCHAR [01]

EOP – End of Package NCHAR – Normal character Figure 8.

Transfer analysis of the RMAP protocol with the least time between two lines using Stardundee’s SpaceWire analyzer.

The entire implementation of the architecture (SpaceWire codec RMAP handling memory controller USB handling FEE control, and internal register) used 45% (13314) of the

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 489-494, Oct.-Dec., 2012

493

Ferrão, R.C. et al.

FPGA’s lookup table (LUTs) and 22% (6,568) of its slice registers, enabling the implementation of two simulators in the same chip. The proposed architecture from the system is Àexible and suitable to be used again in other projects. Since it was developed with emphasis on recon¿gurability, this system allows the dynamic modi¿cation of its behavior through changes in several simulator values, such as CCD size, ADC rate, RMAP protocol con¿gurations, reading direction, among others.

Frédéric, P. and CEA, 2008, “Commissariat à l’Énergie Atomique et aux énergies alternatives”, IP SpaceWire Data Sheet. Gaisler, A., 2011, “AeroÀex Gaisler”, Retrieved in 21 Feb. 2011, from http://www.gaisler.com/cms/. Haywood, S., “Autonomous Cascadable Dual Port FIFO”, Retrieved in 2004, from http://www.spacewire.co.uk/ auto_¿fo.html.

ACKNOWLEDGEMENTS The authors thank the National Council for Scienti¿c and Technological Development – Brazil (CNPq) for the ¿nancial support, Mauá Institute of Technology (IMT) and LESIA for the collaboration opportunity. REFERENCES Catala, C. and PLATO consortium, 2008, “PLATO PLAnetary Transits and Oscillations of stars – A study of exoplanetary systems, proposal”, Vol. 1, Retrieved in 20 Feb. 2011, from http://www.lesia.obspm.fr/perso/claude-catala/ plato_web.html.

Larque, T. and Plasson, P., 2011, “DPU FEE interface requirement document”, PLATO DPS TS 138 THALES, Vol. 11. Parkes, S. and Ferrer, A., 2010, “SpaceWire-D: Deterministic Data Delivery with SpaceWire”, In: Proceedings of the 3rd International SpaceWire Conference, St. Petersburg. STAR-Dundee, 2011, “SpaceWire Link Analyser Mk2”, Retrieved in 20 Mar. 2012, from http://www.star-dundee.com/ products. Xilinx, 2011, “FPGA, CPLD, and EPP Solutions”, Retrieved in 1 Set. 2011, from www.xilinx.com/.

ESA Requirements and Standards Division, 2008, “SpaceWire links, nodes, routers and networks ECSS-E-ST-50-11C”.

494

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 489-494, Oct.-Dec., 2012

Thesis abstracts This section presents the abstract of most recent Master or PhD thesis related to aerospace technology and management

A Comprehensive Investigation of Retrodirective Cross-Eye Jamming

Ant Colony Optimization Applied to Laminated Composite Materials

Warren Paul du Plessis University of Pretoria Pretoria – South Africa wduplessis@ieee.org

Rubem Matimoto Koide Universidade Tecnológica Federal do Paranå Curitiba/PR – Brazil rubemkoide@hotmail.com

Thesis submitted for PhD degree in Electronic Engineering at the University of Pretoria, Pretoria, South Africa, in 2010.

Thesis submitted for Masters in Mechanical and Materials Engineering at Universidade TecnolĂłgica Federal do ParanĂĄ (UTFPR), Curitiba, ParanĂĄ, Brazil, in 2010.

Advisors: Professors J. Wimpie Odendaal and Johan Joubert Advisor: PhD Marco Antonio Luersen Keywords: Electronic countermeasures, Jamming, Monopulse radar, Tracking radar, Electronic warfare. Abstract: Cross-eye jamming is an electronic attack technique that induces an angular error in the radar being jammed. The PDLQ EHQHÂżW RI FURVV H\H MDPPLQJ LV WKDW LW LV HIIHFWLYH DJDLQVW monopulse tracking radars, which are largely immune to other forms of jamming. The objective of this research was to gain a complete understanding of cross-eye jamming so that systems WKDW PLJKW EH GHYHORSHG LQ IXWXUH FDQ EH SURSHUO\ VSHFLÂżHG The main contribution of this work is a comprehensive mathematical and experimental study of retrodirective cross-eye jamming. The mathematical analysis considers all aspects of an isolated, single-loop, retrodirective cross-eye jamming engagement, thereby avoiding the approximations inherent in other cross-eye jamming analyses. Laboratory experiments that accurately represent reality, by using the radar for both transmission and reception, and simulating a true retrodirective cross-eye jammer, were performed to validate the theoretical analysis. Lastly, the relationship between the angular error induced in the radar being jammed and the matching required from a cross-eye jammer system was explored. The most important conclusion of this work is that the traditional analyses of cross-eye jamming are inaccurate for the conditions under which cross-eye jammers operate. These inaccuracies mean that the traditional analyses are overly conservative, particularly at short ranges and for high cross-eye gains, suggesting that practical cross-eye jammers can be realized more easily than is generally believed.

Keywords: Ant colony optimization, Meta-heuristic, Laminated composite materials. Abstract: The ant colony algorithm is a heuristic that was formulated in the 1990s by Marco Dorigo. The idea was inspired by the behavior of real ants, related to their ability to ÂżQG WKH VKRUWHVW SDWK EHWZHHQ WKH QHVW DQG WKH IRRG 7KLV VHDUFK was running by exploiting the pheromone trails, a chemical substance deposited by the ants during their journeys. Due to this cooperative behavior and effective search, the ants build EHWWHU DOWHUQDWLYHV RQ WKH SDWK WR ÂżQG IRRG 7KLV EHKDYLRU ZDV then simulated in optimization algorithms, called ant colony optimization. Thus, this dissertation aimed at studying and applying the ant colony method to the optimization of laminated composite materials. This kind of material is made by stacking plies, in which each ply is composed by a matrix, usually SRO\PHULF UHLQIRUFHG E\ ÂżEHUV 8VXDOO\ LWV RSWLPL]DWLRQ LV related to the best settings of the orientation angles of the plies, DQG FRQVHTXHQWO\ WKH ÂżEHUV 7KH YDULDQW DQW FRORQ\ V\VWHP LV implemented and applied to laminated composite plate issues, such as the maximization of the strength, the minimization of the cost, and the maximization of the fundamental frequency. This last issue was also solved using an interface with the ÂżQLWH HOHPHQW SURJUDP $%$486 DOORZLQJ WKH RSWLPL]DWLRQ of problems without an analytical solution for the structural response. The numerical tests carried out indicate that the method is competitive compared to other techniques found in the literature for the optimization of composite laminates materials.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 495-496, Oct.-Dec., 2012

495

Classifying Low Probability of Intercept Radar Using Fuzzy ARTMAP Pieter Frederick Potgieter University of Pretoria Pretoria – South Africa pfpotgieter@ieee.org Dissertation submitted for Masters in Electronic Engineering at the University of Pretoria, Pretoria, South Africa, in 2011. Advisor: Professor Jan CornÊ Olivier Keywords: &ODVVL¿FDWLRQ 'HWHFWLRQ (OHFWURQLF ZDUIDUH Electronic support, Estimation, Fuzzy ARTMAP, Intercept receiver, Low probability of intercept, Parameters, Performance, Radar. Abstract: Electronic support operations concern themselves with the ability to search for, intercept, track, and classify threat emitters. Modern radar systems in turn aim at operating undetected by intercept receivers. These radar systems maintain low probability of intercept by using low power emissions, coded waveforms, wideband operation, narrow beam widths, and evasive scan patterns without compromising accuracy and resolution. The term low probability of intercept refers to the small chance or likelihood of intercept actually occurring. The complexity and degrees of freedom available to modern radar place a high demand on electronic support systems to provide detailed and accurate real-time information. Intercept alone LV QRW VXI¿FLHQW DQG WKLV VWXG\ IRFXVHG RQ WKH GHWHFWLRQ IHDWXUH H[WUDFWLRQ SDUDPHWHU HVWLPDWLRQ DQG FODVVL¿FDWLRQ (using Fuzzy ARTMAP) of the Pilot Mk3 low probability of intercept radar. Fuzzy ARTMAP is a cognitive neural method combining fuzzy logic and adaptive resonance theory to FUHDWH FDWHJRULHV RI FODVV SURWRW\SHV WR EH FODVVL¿HG )X]]\ ARTMAP systems are formed by self-organizing neural architectures that are able to rapidly learn and classify both

496

discreet and continuous input patterns. To evaluate the suitability of a given electronic support intercept receiver against a particular low probability of intercept radar, the ORZ SUREDELOLW\ RI LQWHUFHSW SHUIRUPDQFH IDFWRU LV GHÂżQHG by combining the radar range, intercept receiver range, and sensitivity equations. The radar wants to force an opposing intercept receiver into its range envelope. On the contrary, the intercept receiver would ideally want to operate outside WKH VSHFLÂżHG UDGDU GHWHFWLRQ UDQJH WR DYRLG EHLQJ GHWHFWHG E\ the radar. The maximum likelihood detector developed for this study was capable of detecting the Pilot Mk3 radar, as it allowed enough integration gain for detection beyond the radar maximum range. The accuracy of parameter estimation in an intercept receiver is of great importance, as it has a GLUHFW LPSDFW RQ WKH DFFXUDF\ RI WKH FODVVLÂżFDWLRQ VWDJH Among the various potentially useful radar parameters, antenna rotation rate, transmit frequency, frequency sweep, and sweep repetition frequency were used to classify the Pilot Mk3 radar. Estimation of these parameters resulted in very clear clustering of parameter data that distinguish the Pilot Mk3 radar. The estimated radar signal parameters are well separated to the point that there is no overlap of features. If the detector is able to detect an intercepted signal, it will be able to make accurate estimates of these parameters. The )X]]\ $570$3 FODVVLÂżHU LV FDSDEOH RI FODVVLI\LQJ WKH UDGDU modes of the Pilot Mk3 low probability of intercept radar. FRUUHFW FODVVLÂżFDWLRQ GHFLVLRQV DUH HDVLO\ DFKLHYHG IRU D YDULHW\ RI FODVVLÂżHU FRQÂżJXUDWLRQV &ODVVLÂżHU WUDLQLQJ LV TXLWH HIÂżFLHQW DV JRRG JHQHUDOLVDWLRQ EHWZHHQ LQSXW DQG output spaces is achieved from a training dataset comprising only 5% of the total dataset. If any radar has a low probability of intercept, there must be a consideration for the radar as well as the opposing intercept receiver. Calculating the low probability of intercept performance factor is a useful tool for such an evaluation. The claim that a particular radar has low probability of intercept against any intercept receiver is too broad to be insightful. This also holds for an intercept receiver claiming to have 100% probability of intercept against any radar.

J. Aerosp. Technol. Manag., SĂŁo JosĂŠ dos Campos, Vol.4, No 4, pp. 495-496, Oct.-Dec., 2012

AD HOC REFEREES Besides the participation of Editorial Board, the Journal of Aerospace Technology and Management had a collaboration of specialists as reviewers to evaluate the manuscripts. To them, the JATM thanks for the contribution in Vol. 4 (2012) Abel de Lima Nepomuceno - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Adilson Walter Chinatto Jr. - Universidade de Campinas - Campinas/SP - Brazil Adolfo Gomes Marto - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Adrián Roberto Wittwer - Universidad Nacional del Nordeste – Resistencia/ Argentina Alberto W. S. Mello Junior - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Alessandro Teixeira Neto - Escola de Engenharia de São Carlos - São Carlos/SP - Brazil Alex da Silva Sirqueira - Fundação Centro Universitário Est. Zona Oeste - Rio de Janeiro/RJ - Brazil Alexandre Nogueira Barbosa - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Amaury Caruzzo - Instituto Tecnológico de Aeronáutica - São José dos Campos/SP - Brazil Ana Cristina Figueiredo M. Costa - Universidade Fed. de Campina Grande - Campina Grande/PB - Brazil Anderson Zigiotto - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Andrea Fukue - Embraer - São José dos Campos/SP - Brazil Arcanjo Lenzi - Universidade Federal de Santa Catarina - Florianópolis - Brazil Argemiro Soares S. Sobrinho - Instituto Tecnológico de Aeronáutica - São José dos Campos/SP - Brazil Ariovaldo Felix Palmério - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Bernardo Barbosa da Silva - Universidade Federal de Pernambuco - Recife/PE - Brasil Carlos Alberto Gurgel Veras - Universidade de Brasília- Brasília/DF - Brazil Carlos Alberto Rocha Pimentel - Universidade Federal do ABC - Santo André/SP - Brazil Carlos R. Ilário da Silva - Embraer - São José dos Campos/SP - Brazil Cayo Prado Fernandes Francisco - Universidade Federal do ABC - Santo André/SP - Brazil Célio Costa Vaz - Orbital Engenharia - São José dos Campos/SP - Brazil Cesar J. Deschamps - Universidade Federal de Santa Catarina - Florianópolis - Brazil Cícero R. de Lima - Universidade Federal do ABC - Santo André/SP - Brazil Clovis Sansigolo - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Daniel Soares de Almeida - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Daniela Buske - Universidade Federal de Pelotas- Pelotas/RS - Brazil Dimitri Mavris - Georgia Institute of Technology - Atlanta/GE - USA Elcio Jeronimo de Oliveira - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 497-500, Oct.-Dec., 2012

497

Elizangela Camilo - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Evaldo Simões da Fonseca - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Fernando de Souza Costa - Instituto Nacional de Pesquisas Espaciais - Cachoeira Paulista/SP- Brasil Francisco K. Arakaki – Embraer - São José dos Campos/SP - Brazil Furio Damiani - Universidade Estadual de Campinas - Campinas/SP - Brazil Gustavo Bono - Universidade Federal de Pernambuco - Recife/PE - Brazil Gustavo Ripper - Inst. Nac. Metrologia, Normalização e Qualidade Ind.- Rio de Janeiro/RJ - Brazil Gustavo Trapp - Embraer - São José dos Campos/SP - Brazil Heidi Korzenowski - VALE Soluções em Energia - São José dos Campos/SP - Brazil Helcio Francisco Villa Nova -Universidade Federal do ABC - Santo André/SP - Brazil Heraldo Silva da Costa Mattos - Universidade Federal Fluminense - Niterói/RJ - Brazil Hilton Cleber Pietrobom - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Hossein Bonyan Khamseh - Shahid Beheshti University - Irã Humberto Araújo Machado - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Ijar M. Fonseca - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Jesuíno Takachi Tomita - Instituto Tecnológico de Aeronáutica - São José dos Campos/SP - Brazil Joana Ribeiro - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Joao Batista de Aguiar - Universidade Federal do ABC - Santo André/SP - Brazil João Batista P. Falcão Filho - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil João Marcelo Vedovoto - Universidade Federal de Uberlândia - Uberlândia/MG - Brazil Jonas Gentina - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Jorge Rady de Almeida Junior - Escola Politécnica da USP -São Paulo/SP - Brazil Jose Carlos Gois - Universidade de Coimbra/Coimbra - Portugal Jose Maria Fernandes Marlet - Embraer - São José dos Campos/SP - Brazil Katia Lucchesi - Universidade de Campinas - Campinas/SP - Brazil Leonel Fernando Perondi - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Leopoldo P.R. de Oliveira - Escola de Engenharia de São Carlos - São Carlos/SP - Brazil Ligia Maria Soto Urbina - Instituto Tecnológico de Aeronáutica - São José dos Campos/SP - Brazil Luciano Kiyoshi Araki - Universidade Federal do Paraná - Curitiba/PR - Brazil Luciene Dias Villar - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil

498

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 497-500, Oct.-Dec., 2012

Luis Cláudio Rezende - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Luiz Carlos Gadelha - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Luiz Carlos S. Goes - Instituto Tecnológico de Aeronáutica - São José dos Campos/SP - Brazil Marat Rafkov - Universidade Federal do ABC - Santo André/SP - Brazil Marcelo Araujo Silva - RM Soluções Engenharia - São Paulo/SP - Brazil Marcelo Curvo - Embraer - São José dos Campos/SP - Brazil Marcelo José Ruv Lemes - Embraer - São José dos Campos/SP - Brazil Marcio Teixera de Mendonça- Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Marco Antônio Ferraz - Embraer- São José dos Campos/SP - Brazil Marcos Massi- Instituto Tecnológico de Aeronáutica- São José dos Campos/SP - Brazil Maria Cecília Zanardi - Faculdade de Engenharia de Guaratinguetá - Guaratinguetá/SP - Brazil Maurício Vicente Donadon- Instituto Tecnológico de Aeronáutica- São José dos Campos/SP - Brazil Miriam Kasumi - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Nicelio José Lourenço - Instituto de Aeronáutica e Espaço- São José dos Campos/SP - Brazil Nilson C Cruz - Universidade Estadual Paulista - Sorocaba/SP - Brazil Odylio Denys de Aguiar - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Paulo César Pellanda - Instituto Militar de Engenharia - Rio de Janeiro/RJ - Brazil Paulo Gilberto de Paula Toro - Instituto de Estudos Avançados - São José dos Campos/SP - Brazil Paulo Roberto Bergamaschi - Universidade Federal de Goiás - Catalão/GO - Brazil Paulo Zavala - Universidade Estadual de Campinas - Campinas/SP - Brazil Pierre Kaufmann - Universidade Mackenzie - São Paulo/SP - Brazil Ricardo Elgul Samad - Instituto de Pesquisas Energéticas e Nucleares - São Paulo/SP - Brazil Robero Ramos - Universidade Federal do ABC - Santo André/SP - Brazil Roberto Gil Annes da Silva - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Roberto Lopes - Instituto Nacional de Pesquisa Espaciais - Cachoeira Paulista/SP - Brazil Roberto Mendes Finzi Neto- Universidade Federal de Uberlândia - Uberlândia/MG - Brazil Roberto Vasconcelos - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Rogéria Cristiane Gratão de Souza- Universidade Estadual Paulista - São José do Rio Preto/SP - Brazil Rogeria Eller- Instituto Tecnológico de Aeronáutica- São José dos Campos/SP - Brazil Rogério Mota- Faculdade de Engenharia de Guaratinguetá- Guaratinguetá/SP - Brazil

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 497-500, Oct.-Dec., 2012

499

Sonia A. Goulart de Oliveira - Universidade Federal de Uberlândia- Uberlândia/MG - Brazil Tony Springer - NASA Headquarters - Washington DC - USA Valdemir Carrara - Instituto Nacional de Pesquisa Espaciais - São José dos Campos/SP - Brazil Vinicius André R.Henriques - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil Wesley Gois - Universidade Federal do ABC - Santo André/SP - Brazil William W. Vaughan - National Space Science and Technology Center- Huntsville/AL - USA Wilson F. N. Santos - Instituto Nacional de Pesquisa Espaciais - Cachoeira Paulista/SP - Brazil Wilson Shimote - Instituto de Aeronáutica e Espaço - São José dos Campos/SP - Brazil

500

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 497-500, Oct.-Dec., 2012

INSTRUCTIONS TO AUTHORS (Revised in March, 2012)

SCOPE AND EDITORIAL POLICY 7KH -RXUQDO RI $HURVSDFH 7HFKQRORJ\ DQG 0DQDJHPHQW -$70 LV WKH RI¿FLDO SXEOLFDWLRQ RI WKH Departamento de Ciência e Tecnologia Aeroespacial (DCTA), in São José dos Campos, São Paulo State, Brazil. The journal is quarterly SXEOLVKHG 0DUFK -XQH 6HSWHPEHU DQG 'HFHPEHU DQG LV GHYRWHG WR UHVHDUFK DQG PDQDJHPHQW RQ GLIIHUHQW DVSHFWV RI DHURVSDFH WHFKQRORJLHV 7KH DXWKRUV DUH VROHO\ UHVSRQVLEOH IRU WKH FRQWHQWV RI WKHLU FRQWULEXWLRQ ,W LV DVVXPHG WKDW WKH\ KDYH WKH QHFHVVDU\ DXWKRULW\ IRU SXEOLFDWLRQ :KHQ VXEPLWWLQJ WKH FRQWULEXWLRQ DXWKRUV VKRXOG FODVVLI\ LW DFFRUGLQJ WR WKH DUHD selected from the following topics:

$FRXVWLFV $HURG\QDPLFV $HURVSDFH &LUFXLWU\ $HURVSDFH 0HWHRURORJ\ $HURVSDFH 6\VWHPV $LU DQG 6SDFH 'HIHQVH 6\VWHPV $SSOLHG &RPSXWDWLRQ $VWURG\QDPLFV &HUDPLF 0DWHULDOV &RPSRVLWHV (OHWURPDJQHWLF &RPSDWLELOLW\ (QHUJHWLF 0DWHULDOV )OXLG '\QDPLFV DQG 7XUEXOHQFH

*XLGDQFH 1DYLJDWLRQ DQG &RQWURO 0DQDJHPHQW 6\VWHPV 0HWDOOLF 0DWHULDOV 3KRWRQLFV 3RO\PHULF 0DWHULDOV 3URFHVVLQJ RI $HURVSDFH 0DWHULDOV 3URSXOVLRQ DQG &RPEXVWLRQ 5DGDUV DQG 7UDFNLQJ 6\VWHPV 5RERWLFV DQG $XWRPDWLRQ 6WUXFWXUHV 6\QWKHVLV DQG &KDUDFWHUL]DWLRQ RI $HURVSDFH 0DWHULDOV 7KHUPDO 6FLHQFHV 9LEUDWLRQ DQG 6WUXFWXUDO '\QDPLFV

PAPER SUBMISSION 7KH PDQXVFULSW VKRXOG EH GLJLWDOL]HG XVLQJ D 0LFURVRIW :RUG GRF VRIWZDUH SURJUDP DQG VXEPLWWHG HOHFWURQLFDOO\ LQ (QJOLVK 6HH WKH LQVWUXFWLRQV DW ZZZ MDWP FRP EU SDSHU VXEPLVVLRQ ,I WKHUH LV DQ\ FRQÀLFW RI LQWHUHVW UHJDUGLQJ WKH HYDOXDWLRQ of the manuscript, the author must send a declaration indicating the reasons so that the review process occurs fairly. $IWHU VXEPLWWLQJ WKH PDQXVFULSW WKH FRUUHVSRQGLQJ DXWKRU ZLOO UHFHLYH DQ H PDLO ZLWK WKH 7HUP RI &RS\ULJKW 7UDQVIHU LQ ZKLFK WKH DXWKRU DJUHHV WR WUDQVIHU FRS\ULJKWV WR WKH '&7$ LQ FDVH RI DFFHSWDQFH IRU SXEOLFDWLRQ WKXV EHLQJ IRUELGGHQ DQ\ PHDQV RI UHSURGXFWLRQ SULQWHG RU HOHFWURQLF ZLWKRXW SUHYLRXV DXWKRUL]DWLRQ RI WKH (GLWRU LQ &KLHI ,I WKH UHSURGXFWLRQ LV allowed, it is mandatory to mention the JATM. The author also declares that the manuscript is an original paper, its content is not EHLQJ FRQVLGHUHG IRU SXEOLFDWLRQ LQ RWKHU SHULRGLFDOV DQG WKDW DOO FR DXWKRUV SDUWLFLSDWHG VDWLVIDFWRULO\ LQ WKH SDSHU HODERUDWLRQ DV WR PDNH SXEOLF WKH UHVSRQVLELOLW\ IRU LWV FRQWHQW 7KH GHFODUDWLRQ PXVW EH SULQWHG VLJQHG E\ WKH PDLQ DXWKRU DQG VHQW EDFN E\ PDLOLQJ WR WKH IROORZLQJ DGGUHVV Instituto de Aeronáutica e Espaço $771 +HOHQD 3UDGR 3UDoD 0DUHFKDO (GXDUGR *RPHV ± 9LOD GDV $FiFLDV ± &(3 ± 6mR -RVp GRV &DPSRV 63 %UD]LO 3DSHUV DOUHDG\ SUHVHQWHG DW FRQIHUHQFHV ZLOO EH DFFHSWHG LI WKH\ ZHUH QRW SXEOLVKHG LQ FRPSOHWH IRUP LQ WKH $QQDOV RI WKH FRQIHUHQFH RU LI WKH\ DUH H[WHQGHG ZLWK DGGLWLRQDO UHVXOWV RU QHZ ¿QGLQJV 7KHVH DUWLFOHV ZLOO EH HYDOXDWHG DV WKH RWKHUV $UWLFOHV IURP JXHVW DXWKRUV ZLOO EH SXEOLVKHG DIWHU DSSURYDO RI RQH VSHFLDOLVW DVVRFLDWH HGLWRU 7KH -$70 GRHV QRW SXEOLVK WUDQVODWHG articles from other journals.

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 501-504, Oct.-Dec., 2012

501

PEER REVIEW 0DQXVFULSWV ZLOO EH UHYLHZHG E\ DW OHDVW WZR H[SHUW FRQVXOWDQWV PHPEHUV RI WKH (GLWRULDO &RPPLWWHH RU H[WHUQDO HYDOXDWRUV DG KRF UHIHUHHV LQ GRXEOH EOLQG SHHU UHYLHZ PRGH HQVXULQJ FRPSOHWH DQRQ\PLW\ ,Q FDVH RI GLVDJUHHPHQW RQ WKH UHVXOWV RI WKH HYDOXDWLRQ WKH PDQXVFULSW ZLOO EH IRUZDUGHG WR D WKLUG UHYLHZHU DQG LW ZLOO EH DFFHSWHG IRU SXEOLFDWLRQ RQO\ LI WZR DSSURYDOV DUH UHFHLYHG 7KH HYDOXDWRUV FDQ DFFHSW WKH PDQXVFULSW LQ WKH IRUP LW ZDV VXEPLWWHG WKH\ FDQ UHMHFW LW RU UHTXHVW UHYLVLRQV 7KH PDQXVFULSW WKDW UHTXLUHV UHYLVLRQ ZLOO EH VHQW WR WKH DXWKRU WKDW LV VXSSRVHG WR VXEPLW D QHZ YHUVLRQ DQG LQ WKH FDVH WKH DXWKRU GRHV QRW DJUHH ZLWK WKH VXJJHVWLRQV LW LV QHFHVVDU\ WR VHQG D ³OHWWHU WR HGLWRU´ H[SODLQLQJ WKH UHDVRQV 7KH (GLWRU LQ &KLHI ZLOO approve after verifying in the new version the adherence to the reviewers’ suggestions or will send to another evaluation round LI WKH FKDQJHV KDYH QRW EHHQ VXI¿FLHQWO\ DGGUHVVHG $FFHSWHG PDQXVFULSWV FDQ EH HGLWHG WR FRPSO\ ZLWK WKH IRUPDW RI WKH MRXUQDO UHPRYH UHGXQGDQFLHV DQG LPSURYH FODULW\ DQG XQGHUVWDQGLQJ ZLWKRXW DOWHULQJ PHDQLQJ $XWKRUV DUH DOVR VWURQJO\ DGYLVHG WR XVH DEEUHYLDWLRQV VSDULQJO\ ZKHQHYHU SRVVLEOH WR DYRLG MDUJRQ DQG LPSURYH WKH UHDGDELOLW\ RI WKH PDQXVFULSW $OO DEEUHYLDWLRQV PXVW EH GH¿QHG WKH ¿UVW WLPH WKDW WKH\ DUH XVHG 7KH HGLWHG WH[W ZLOO EH SUHVHQWHG WR DXWKRUV IRU DSSURYDO

MANUSCRIPT CATEGORIES Editorial: $Q\ UHVHDUFKHU PD\ ZULWH WKH HGLWRULDO RQ WKH LQYLWDWLRQ RI WKH (GLWRU LQ &KLHI (GLWRULDOV VKRXOG FRYHU EURDG DVSHFWV RI $HURVSDFH 7HFKQRORJ\ 6XFK PDQXVFULSWV DUH QRW VXEPLWWHG WR SHHU UHYLHZ Review articles: 7KHVH VKRXOG FRYHU VXEMHFWV WKDW DUH UHOHYDQW WR WKH VFRSH RI WKH MRXUQDO $XWKRUV VKRXOG EHDU LQ PLQG WKDW WKH\ DUH H[SHFWHG WR KDYH H[SHUWLVH LQ WKH UHYLHZHG ¿HOG 7KH DUWLFOH PD\ EH RI DQ\ OHQJWK UHTXLUHG IRU WKH FRQFLVH SUHVHQWDWLRQ RI WKH VXEMHFW Original papers: 7KHVH DUWLFOHV VKRXOG UHSRUW UHVXOWV RI WKH VFLHQWL¿F UHVHDUFK 7KH DUWLFOH PD\ EH RI DQ\ OHQJWK UHTXLUHG IRU WKH FRQFLVH SUHVHQWDWLRQ DQG GLVFXVVLRQ RI WKH GDWD EXW VXFFLQFW SDSHUV DUH IDYRUHG LQ WHUPV RI LPSDFW DV ZHOO DV LQ UHDGDELOLW\ Communications: They should report previous results of ongoing research and should not exceed eight pages. Thesis abstracts: 7KH MRXUQDO ZHOFRPHV UHFHQW 0DVWHUV DQG 3K' WKHVLV DEVWUDFWV IRU SXEOLFDWLRQ 6XFK FRQWULEXWLRQ ZLOO QRW EH VXEPLWWHG WR SHHU UHYLHZ

MANUSCRIPT STRUCTURE :KHQHYHU LV SRVVLEOH DUWLFOHV VKRXOG LQFOXGH WKH IROORZLQJ VXEVHFWLRQV KRZHYHU DUWLFOHV IURP VRPH DUHDV VKRXOG IROORZ WKHLU usual format. Title and names of authors: 7KH WLWOH VKRXOG QRW FRQWDLQ DEEUHYLDWLRQV $OO DXWKRUV VKRXOG EH LGHQWL¿HG ZLWK IXOO QDPH H PDLO LQVWLWXWLRQ WR ZKLFK WKH\ DUH UHODWHG FLW\ VWDWH DQG FRXQWU\ 2QH RI WKHP VKRXOG EH LQGLFDWHG DV WKH DXWKRU IRU FRUUHVSRQGHQFH DQG KLV KHU IXOO DGGUHVV LV UHTXLUHG Abstract: 7KH\ DUH OLPLWHG WR ZRUGV DQG VWUXFWXUHG LQWR REMHFWLYHV PHWKRGV UHVXOWV DQG FRQFOXVLRQV &LWDWLRQV RU DEEUHYLDWLRQV H[FHSW LQWHUQDWLRQDOO\ UHFRJQL]HG DEEUHYLDWLRQV VXFK DV ZHLJKWV PHDVXUHV DQG SK\VLFDO RU FKHPLFDO RQHV DUH not permitted.

502

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 501-504, Oct.-Dec., 2012

Keywords: 7KUHH WR VL[ LWHPV WKDW VKRXOG EH EDVHG RQ 1$6$ 7KHVDXUXV YROXPH ± $FFHVV 9RFDEXODU\ Introduction: ,W VKRXOG VHW WKH SXUSRVH RI WKH VWXG\ SURYLGLQJ D EULHI VXPPDU\ QRW D UHYLHZ RI SUHYLRXV UHOHYDQW VWXGLHV DQG VWDWLQJ WKH QHZ DGYDQFHV LQ WKH FXUUHQW LQYHVWLJDWLRQ 7KH LQWURGXFWLRQ VKRXOG QRW LQFOXGH GDWD RU FRQFOXVLRQV IURP WKH ZRUN EHLQJ UHSRUWHG $ ¿QDO VHQWHQFH VXPPDUL]LQJ WKH QRYHO ¿QGLQJ WR EH SUHVHQWHG LV SHUPLVVLEOH Methodology: 7KH DXWKRUV DUH IUHH WR XVH DQ\ VWUXFWXUH LQ WKLV VHFWLRQ WR ¿W WKH REMHFWLYHV RI WKH ZRUN WKH\ FRXOG DOVR UHQDPH LW H J 1XPHULFDO DQDO\VLV &DVH VWXG\ DQG VR RQ DQG LQ VRPH FDVHV LW PD\ EH DGYLVDEOH WR RPLW LW &OHDU DQG VXI¿FLHQW LQIRUPDWLRQ WR SHUPLW WKH VWXG\ WR EH UHSHDWHG E\ RWKHUV VKRXOG EH EULHÀ\ JLYHQ 6WDQGDUG WHFKQLTXHV QHHG RQO\ WR EH UHIHUHQFHG 3UHYLRXVO\ SXEOLVKHG PHWKRGV PD\ EH EULHÀ\ GHVFULEHG IROORZLQJ WKH UHIHUHQFH Results: 7KLV VHFWLRQ VKRXOG EH D FRQFLVH DFFRXQW RI WKH QHZ LQIRUPDWLRQ WKDW ZDV GLVFRYHUHG ZLWK WKH OHDVW SHUVRQDO MXGJPHQW 'R QRW UHSHDW LQ WH[W DOO WKH GDWD LQ WKH WDEOHV DQG LOOXVWUDWLRQV EXW EULHÀ\ GHVFULEH ZKDW WKHVH GDWD FRPSULVH Discussion: 7KH GLVFXVVLRQ VKRXOG LQFOXGH WKH VLJQL¿FDQFH RI WKH QHZ LQIRUPDWLRQ DQG UHOHYDQFH RI WKH QHZ ¿QGLQJV LQ OLJKW RI H[LVWLQJ NQRZOHGJH 2QO\ XQDYRLGDEOH FLWDWLRQV VKRXOG EH LQFOXGHG &LWDWLRQV WR UHYLHZ DUWLFOHV DUH QRW HQFRXUDJHG LQ WKLV VHFWLRQ ,Q VRPH FDVHV LW PD\ EH DGYLVDEOH WR PHUJH ZLWK WKH SUHYLRXV VHFWLRQ ³5HVXOWV DQG 'LVFXVVLRQ´ Acknowledgements: 7KLV VHFWLRQ VKRXOG EH VKRUW FRQFLVH DQG UHVWULFWHG WR DFNQRZOHGJHPHQWV WKDW DUH QHFHVVDU\ 7KH ¿QDQFLDO VXSSRUW UHFHLYHG IRU WKH HODERUDWLRQ RI WKH PDQXVFULSW PXVW EH GHFODUHG LQ WKLV LWHP References: $FFHSWDEOH UHIHUHQFHV LQFOXGH MRXUQDO DUWLFOHV QXPEHUHG SDSHUV ERRNV DQG VXEPLWWHG DUWLFOHV LI WKH MRXUQDO LV LGHQWL¿HG 5HIHUHQFHV PXVW EH UHVWULFWHG WR GLUHFWO\ UHOHYDQW SXEOLVKHG ZRUNV SDSHUV RU DEVWUDFWV WKDW KDYH EHHQ DFFHSWHG IRU SXEOLFDWLRQ 5HIHUHQFHV IURP SULYDWH FRPPXQLFDWLRQV GLVVHUWDWLRQV WKHVLV SXEOLVKHG FRQIHUHQFH SURFHHGLQJV DQG SUHSULQWV IURP FRQIHUHQFHV VKRXOG EH DYRLGHG 6HOI FLWDWLRQ VKRXOG EH OLPLWHG WR D PLQLPXP $XWKRUV DUH UHVSRQVLEOH IRU WKH DFFXUDF\ and completeness of their references. References in text: 7KH UHIHUHQFHV VKRXOG EH PHQWLRQHG LQ WKH WH[W E\ JLYLQJ WKH ODVW QDPH RI WKH DXWKRU V DQG WKH \HDU RI SXEOLFDWLRQ (LWKHU XVH ³5HFHQW ZRUN 6PLWK DQG )DULDV ´ RU ³5HFHQWO\ 6PLWK DQG )DULDV ´ :LWK WKUHH RU PRUH names, use the form “Smith et al ´ ,I WZR RU PRUH UHIHUHQFHV KDYH WKH VDPH LGHQWL¿FDWLRQ GLVWLQJXLVK WKHP E\ DSSHQGLQJ ³D´ ³E´ HWF WR WKH \HDU RI SXEOLFDWLRQ 6WDQGDUGV VKRXOG EH FLWHG LQ WH[W E\ WKH DFURQ\P RI HQWLW\ IROORZHG E\ WKH QXPEHU DQG they do not need to appear in the reference list. Reference list: 5HIHUHQFHV VKRXOG EH OLVWHG LQ DOSKDEHWLFDO RUGHU DFFRUGLQJ WR WKH ODVW QDPH RI WKH ¿UVW DXWKRU DW WKH HQG RI WKH DUWLFOH 2QO\ FLWDWLRQV WKDW DSSHDU LQ WKH WH[W VKRXOG EH UHIHUHQFHG 8QSXEOLVKHG SDSHUV XQOHVV DFFHSWHG IRU SXEOLFDWLRQ VKRXOG QRW EH FLWHG :RUN WKDW LV DFFHSWHG IRU SXEOLFDWLRQ VKRXOG EH UHIHUUHG WR DV ³,Q SUHVV´ ,W LV UHFRPPHQGHG WKDW HDFK UHIHUHQFH FRQWDLQV WKH GLJLWDO REMHFW LGHQWL¿HU QXPEHU '2, 5HIHUHQFHV UHWULHYHG IURP WKH ,QWHUQHW VKRXOG EH FLWHG E\ WKH ODVW QDPH RI WKH DXWKRU V DQG WKH \HDU RI SXEOLFDWLRQ RU Q G LI QRW DYDLODEOH IROORZHG E\ WKH GDWH RI DFFHVV 6RPH H[DPSOHV RI UHIHUHQFHV are as the following ones: $OYHV 0 % DQG 0RUDLV $ 0 ) ³7KH PDQDJHPHQW RI NQRZOHGJH DQG WHFKQRORJLHV LQ D 6SDFH 3URJUDP´ -RXUQDO RI $HURVSDFH 7HFKQRORJ\ DQG 0DQDJHPHQW 9RO 1R SS GRL MDWP %RUGDOR 6 1 HW DO ³7KH 'HYHORSPHQW RI =RQDO 0RGHOV IRU 7XUEXOHQFH´ 3URFHHGLQJV RI WKH WK %UD]LOLDQ &RQJUHVV RI 0HFKDQLFDO (QJLQHHULQJ 9RO 5LR GH -DQHLUR %UD]LO SS

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 501-504, Oct.-Dec., 2012

503

&RLPEUD $ / ³/HVVRQV RI &RQWLQXXP 0HFKDQLFV´ (G (GJDUG %O FKHU 6mR 3DXOR %UD]LO S &ODUN - $ ³3ULYDWH &RPPXQLFDWLRQ´ 8QLYHUVLW\ RI 0LFKLJDQ $QQ +DUERU (0%5$3$ ³3ROLWLFV RI 5 '´ 5HWULHYHG LQ 0D\ IURP KWWS ZZZ HPEUDSD EU SXEOLFDFRHV LQVWLWXFLRQDLV SRO3' SGI 6LOYD / + 0 ³1HZ ,QWHJUDO )RUPXODWLRQ IRU 3UREOHPV LQ 0HFKDQLFV´ ,Q 3RUWXJXHVH 3K ' 7KHVLV )HGHUDO 8QLYHUVLW\ RI 6DQWD &DWDULQD )ORULDQySROLV 6 & %UD]LO S 6SDUURZ ( 0 D ³)RUFHG &RQYHFWLRQ +HDW 7UDQVIHU LQ D 'XFW +DYLQJ 6SDQZLVH 3HULRGLF 5HFWDQJXODU 3URWXEHUDQFHV´ 1XPHULFDO +HDW 7UDQVIHU 9RO SS 6SDUURZ ( 0 E ³)OXLG WR )OXLG &RQMXJDWH +HDW 7UDQVIHU IRU D 9HUWLFDO 3LSH ,QWHUQDO DQG ([WHUQDO 1DWXUDO &RQYHFWLRQ´ $60( -RXUQDO RI +HDW 7UDQVIHU 9RO SS

Tables: 7DEOHV VKRXOG EH FRQVWUXFWHG XVLQJ WKH WDEOH IHDWXUH LQ WKH ZRUG SURFHVVRU RU XVLQJ D VSUHDGVKHHW SURJUDP VXFK DV 0LFURVRIW ([FHO 7KH\ VKRXOG EH QXPEHUHG LQ RUGHU RI DSSHDUDQFH LQ WKH WH[W XVLQJ $UDELF QXPHUDOV (DFK WDEOH VKRXOG KDYH D WLWOH DQG DQ H[SODQDWRU\ OHJHQG LI QHFHVVDU\ $OO WDEOHV PXVW EH UHIHUHQFHG DQG PHQWLRQHG LQ WKH WH[W DV ³7DEOH´ DQG VXFFLQFWO\ GHVFULEHG LQ WKH WH[W 8QGHU QR FLUFXPVWDQFHV VKRXOG D WDEOH UHSHDW GDWD WKDW DUH SUHVHQWHG LQ DQ LOOXVWUDWLRQ 6WDWLVWLFDO PHDVXUHV RI YDULDWLRQ L H VWDQGDUG GHYLDWLRQ RU VWDQGDUG HUURU VKRXOG EH LGHQWL¿HG DQG GHFLPDO SODFHV LQ WDEXODU GDWD VKRXOG EH UHVWULFWHG WR WKRVH ZLWK PDWKHPDWLFDO DQG VWDWLVWLFDO VLJQL¿FDQFH $XWKRUV VKRXOG WDNH QRWLFH RI WKH OLPLWDWLRQV VHW E\ WKH VL]H DQG OD\RXW RI WKH MRXUQDO 7KHUHIRUH ODUJH WDEOHV VKRXOG EH DYRLGHG Figures: $OO LOOXVWUDWLRQV OLQH JUDSKV FKDUWV VFKHPHV SKRWRJUDSKV DQG JUDSKV VKRXOG EH UHIHUUHG DV ³)LJXUH´ DQG VXEPLWWHG ZLWK JRRG GH¿QLWLRQ 1XPEHU ¿JXUHV FRQVHFXWLYHO\ XVLQJ $UDELF QXPHUDOV LQ RUGHU RI DSSHDUDQFH 5HIHUHQFHV VKRXOG EH PDGH LQ WKH WH[W WR HDFK ¿JXUH XVLQJ WKH DEEUHYLDWHG IRUP ³)LJ ´ H[FHSW LI WKH\ DUH PHQWLRQHG LQ WKH EHJLQQLQJ RI WKH VHQWHQFHV &DSWLRQV VKRXOG EH GHVFULSWLYH DQG VKRXOG DOORZ WKH H[DPLQDWLRQ RI WKH ¿JXUHV ZLWKRXW UHIHUHQFH WR WH[W 7KH VL]H RI WKH ¿JXUHV LQFOXGLQJ IUDPH VKRXOG EH FP RQH FROXPQ RU FP WZR FROXPQV ZLGH ZLWK PD[LPDO KHLJKW VPDOOHU WKDQ FP Equations: 7\SH WKHP RQ LQGLYLGXDO OLQHV LGHQWLI\LQJ WKHP E\ $UDELF QXPHUDOV HQFORVHG LQ SDUHQWKHVLV 5HIHUHQFHV VKRXOG EH PDGH LQ WKH WH[W WR HDFK HTXDWLRQ XVLQJ WKH DEEUHYLDWHG IRUP ³(T ´ H[FHSW LQ WKH EHJLQQLQJ RI WKH VHQWHQFHV ZKHUH WKH IRUP ³(TXDWLRQ´ VKRXOG EH XVHG

504

J. Aerosp. Technol. Manag., São José dos Campos, Vol.4, No 4, pp. 501-504, Oct.-Dec., 2012

Correspondence All correspondence should be sent to: JOURNAL OF AEROSPACE TECHNOLOGY AND MANAGEMENT Instituto de Aeronåutica e Espaço Praça Mal. Eduardo Gomes, 50- Vila das Acåcias CEP 12228-901 São JosÊ dos Campos/São Paulo/Brazil

Contact Phone: (55) 12-3947- 6493/5122 E-mail: editor@jatm.com.br Web: http://www.jatm.com.br

Published by: Departamento de Ciência e Tecnologia Aeroespacial Distributed by: Instituto de Aeronåutica e Espaço Proofreading and standardization: Zeppelini Editorial Editing: TL Publicidade e Assessoria Ltda 3ULQWLQJ ,QJUDIRWR 3URGXo}HV *Ui¿FDV Cover: Created by Gus Morais-based on the original by Paulo R. Porphirio Moreira Edition: 750 São JosÊ dos Campos, SP, Brazil ISSN 1984-9648

Historical Note: JATM was created in 2009 after the iniciative of the diretor of Instituto de Aeronåutica e Espaço (IAE), Brigadeiro Engenheiro Francisco Carlos Melo Pantoja. In order to reach the goal of becoming a journal that could represent NQRZOHGJH LQ VFLHQFH DQG DHURVSDFH WHFKQRORJ\ -$70 VHDUFKHG IRU SDUWQHUVKLSV ZLWK RWKHUV LQVWLWXWLRQV LQ WKH VDPH ¿HOG from the beginning. From September 2011, it has been edited by the Departamento de Ciência e Tecnologia Aeroespacial '&7$ DQG LW DOVR VWDUWHG WR EH ¿QDQFLDOO\ VXSSRUWHG E\ )XQGDomR &RQUDGR :HVVHO

The copyright on all published material belongs to Departamento de CiĂŞncia e Tecnologia Aeroespacial (DCTA)

Journal of Aerospace Technology and Management www.jatm.com.br

Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.