Study of micro hydromechanical deep drawing of SUS304 circular cups by an ALE model

Transcription

1 University of Wollongong Reserch Online Fculty of Engineering nd Informtion Sciences - Ppers: Prt B Fculty of Engineering nd Informtion Sciences 2017 Study of micro hydromechnicl deep drwing of SUS304 circulr cups y n ALE model Ling Luo University of Wollongong, ll895@uowmil.edu.u Dongin Wei University of Wollongong, dwei@uow.edu.u Zhengyi Jing University of Wollongong, jing@uow.edu.u Cunlong Zhou Tiyun University of Science nd Technology, zcunlong@163.com Qingxue Hung Tiyun University of Science nd Technology See next pge for dditionl uthors Puliction Detils Luo, L., Wei, D., Jing, Z., Zhou, C., Hung, Q. & Hung, Z. (2017). Study of micro hydromechnicl deep drwing of SUS304 circulr cups y n ALE model. Procedi Engineering, Reserch Online is the open ccess institutionl repository for the University of Wollongong. For further informtion contct the UOW Lirry: reserch-pus@uow.edu.u

2 Study of micro hydromechnicl deep drwing of SUS304 circulr cups y n ALE model Astrct Accurte estimtion of hydrulic pressure on the lnk is importnt for micro hydromechnicl deep drwing simultion. An Aritrry Lgrnge Eulerin (ALE) simultion model tht considers strong fluid-solid interction (FSI) ws generted to ccurtely predict the hydrulic pressure on the lnk. The chngele pressure significntly ffects the drwn cup's qulity regrding wll thickness. Both the minimum nd the mximum wll thicknesses in the ALE model re significntly different from tht in conventionl model with simple pressure lod. The reltionship etween the mximum thickness nd the hydrulic pressure in the ALE model is similr to tht from the experimentl results while reverse to tht from the conventionl simultion model. The ALE model provides more precise hydrulic pressure on the lnk nd ccurte prediction of the drwn cups' qulity compred with the conventionl model. Disciplines Engineering Science nd Technology Studies Puliction Detils Luo, L., Wei, D., Jing, Z., Zhou, C., Hung, Q. & Hung, Z. (2017). Study of micro hydromechnicl deep drwing of SUS304 circulr cups y n ALE model. Procedi Engineering, Authors Ling Luo, Dongin Wei, Zhengyi Jing, Cunlong Zhou, Qingxue Hung, nd Zhicho Hung This journl rticle is ville t Reserch Online:

3 Aville online t ScienceDirect Procedi Engineering 207 (2017) Interntionl Conference on the Technology of Plsticity, ICTP 2017, Septemer 2017, Cmridge, United Kingdom Study of micro hydromechnicl deep drwing of SUS304 circulr cups y n ALE model Ling Luo, Dongin Wei,,Zhengyi Jing, *, Cunlong Zhou c,qingxue Hung c nd Zhicho Hung d School of Mechnicl, Mterils, Mechtronic nd Biomedicl Engineering, University of Wollongong, Wollongong, NSW 2522, Austrli School of Electricl, Mechnicl nd Mechtronic System, University of Technology, Sydney, NSW 2007, Austrli c School of Mterils Science nd Engineering, Tiyun University of Science nd Technology, Shnxi, , Chin d School of Mechnotronics & Vehicle Engineering, Est Chin Jiotong University, Jingxi, , Chin Astrct Accurte estimtion of hydrulic pressure on the lnk is importnt for micro hydromechnicl deep drwing simultion. An Aritrry Lgrnge Eulerin (ALE) simultion model tht considers strong fluid-solid interction (FSI) ws generted to ccurtely predict the hydrulic pressure on the lnk. The chngele pressure significntly ffects the drwn cup s qulity regrding wll thickness. Both the minimum nd the mximum wll thicknesses in the ALE model re significntly different from tht in conventionl model with simple pressure lod. The reltionship etween the mximum thickness nd the hydrulic pressure in the ALE model is similr to tht from the experimentl results while reverse to tht from the conventionl simultion model. The ALE model provides more precise hydrulic pressure on the lnk nd ccurte prediction of the drwn cups qulity compred with the conventionl model The Authors. Pulished y Elsevier Ltd. Peer-review under responsiility of the scientific committee of the Interntionl Conference on the Technology of Plsticity. Keywords: Micro hydromechnicl deep drwing, ALE, FSI, Hydrulic pressure, Cup qulity 1. Introduction Due to n ssistnce of hydrulic pressure, deep drwing process is improved regrding metl s formility, * Corresponding uthor. Tel.: ; fx: E-mil ddress: jing@uow.edu.u The Authors. Pulished y Elsevier Ltd. Peer-review under responsiility of the scientific committee of the Interntionl Conference on the Technology of Plsticity /j.proeng

4 1040 Ling Luo et l. / Procedi Engineering 207 (2017) frictionl conditions nd the drwn cup s qulity [1 4]. Driven y growing requirement on micro-metl products, micro hydromechnicl deep drwing (MHDD) hs een developed to utilise potentil of the hydrulic pressure [5,6]. Existing knowledge out influences of the hydrulic pressure on conventionl hydromechnicl deep drwing, however, cnnot e directly pplied in the micro hydromechnicl deep drwing. Hydrulic pth is simplified due to difficulty in hydrulic pressure control in tiny fluid domin during short processing time. Hydrulic pressure grdient, tht drives fluid insted of the hydrulic pressure, significntly increses in the micro hydromechnicl deep drwing. Interction etween fluid nd solid (lnk) ecomes importnt nd considerly different from tht in conventionl hydromechnicl deep drwing process. Both frictionl conditions nd lnk deformtion re gretly ffected y fluid in micro-scle. Therefore, ccurte hydrulic pressure estimtion is importnt for investigtion of micro hydromechnicl deep drwing. It generlly simplifies hydrulic pressure in conventionl hydro deep drwing simultion [7,8] nd the simplified hydrulic pressure on the lnk is constnt, which is unsuitle for micro-scle due to strong fluid-solid coupling in tiny re. Inccurte pressure estimtion in micro hydromechnicl deep drwing will result in unprecise prediction. This study focuses on influences of the hydrulic pressure on micro hydromechnicl deep drwing nd the Aritrry Lgrnge Eulerin (ALE) method [9,10] with ility to simulte the fluid-solid interction ws selected for the MHDD simultion. Both n ALE model nd conventionl model with simple pressure lod on the lnk were employed in the simultion. Finlly, simultion results were discussed nd compred with experimentl results. Nomenclture p CCCC iiii=0,1,2,,6 E μμμμ γγγγ hydrulic pressure EOS coefficients internl energy per unit reference volume reltive density chnge mteril prmeter for ir 2. Simultion model 2.1. Conventionl model A conventionl model with simple pressure lod on lnk ws generted for comprison with the ALE model. The conventionl model hd the sme size with tht of the experimentl micro hydromechnicl deep drwing system. Fig. 1 shows the sketch of the micro hydromechnicl deep drwing system nd the conventionl simultion model. Only qurter of the drwing system ws modeled nd ll prts were of high-qulity qudrilterl shell elements. Only the lnk ws deformle nd ssigned the 3-Prmeter-Brlt mteril model while the other prts were rigid. The forming surfce-to-surfce contct lgorithm ws selected for contct/friction monitor in simultion. Mteril prmeters nd friction coefficient were otined from experiments. A constnt hydrulic pressure lod ws set norml to the lnk during whole drwing process. The shell thickness ws updted sed on the Lnkford coefficient. Punch Constnt drwing speed Blnk Holder Constnt gp Blnk p Die Fig. 1 () Sketch of micro hydromechnicl deep drwing system (unit: mm); nd () conventionl simultion model

5 Ling Luo et l. / Procedi Engineering 207 (2017) ALE model The ALE model contined Lgrnge nd Eulerin modulus. The Lgrnge module ws the sme s the conventionl model without the hydrulic lod nd the Eulerin module represented fluid development nd counted fluid-solid interction. Fig. 2 shows the ALE model nd the Lgrnge nd Eulerin modulus respectively. Lgrnge module Eulerin module Fig. 2 () ALE model; nd () Lgrnge nd Eulerin modulus There were n inlet, n outlet nd fluid domin in the Eulerin module nd ll were meshed with high qulity hexgon elements with similr elementl edge size to the shell size of the lnk. The inlet nd fluid domin were initilly filled with pressured mechnicl oil while the outlet ws occupied y the ir under tmosphere pressure ( MP). The pressure genertion of liquid phse ws governed y liner polynomil eqution of stte (EOS) s shown in Eq. (1). The pressure updting of the ir ws controlled y γγγγ-lw EOS s shown in Eq. (2). All outer surfces of Eulerin prts were set wll oundry condition. pppp = CCCC 0 + CCCC 1 μμμμ + CCCC 2 μμμμ 2 + CCCC 3 μμμμ 3 + (CCCC 4 + CCCC 5 μμμμ + CCCC 6 μμμμ 2 )EEEE (1) PPPP = (γγγγ 1)(1 + μμμμ)eeee (2) The null mteril model nd one-point ALE multi-mteril elementl model were pplied to ll the Eulerin prts. Thus, the fluid development cn e clculted nd solid prts cn enter fluid domin intercting with the fluids. Four coupling points were ssigned long the edge of ech coupled element. Ten percent volume chnge of Eulerin coupling elements ws set s the dvection criterion, nd the second order ccurcy dvection method ws dopted. Compred with the influence of the oil, the impct of the ir with short ctivting time nd low hydrulic pressure ws ignorle nd thus ws not considered in the simultion. The ir domin ws still used for the oil development. Although the punch lso intercted with the oil in quite short time t the end of the drwing process, the interction etween the punch nd the fluid ws not of interest nd did not ffect the lnk-fluid interction significntly. Therefore, to ccelerte computtionl speed nd to increse roustness of the simultion progrm, only the interction etween the punch nd the oil ws considered in the ALE model. Additionlly, the time step in the simultion ws reduced to improve the computtionl stility. 3. Results & discussion SUS304 sheets with thickness of 50±2 µm were nneled t 975, 1050 nd 1100 for two minutes respectively, nd therefore, clled H975, H1050 nd H1100 sheets ccordingly. All the sheets were then drwn

6 1042 Ling Luo et l. / Procedi Engineering 207 (2017) under hydrulic pressures from 5 MP to 30 MP t n intervl of 5 MP. All the experimentl cses were modelled nd simulted in LS-DYNA. Fig. 3 displys the hydrulic pressure in fluid domin t four typicl drwing stges with n inlet pressure of 25 MP. Due to pre-ulging, the lnk deformed upwrds nd hydrulic pressure decresed. As the lnk ws grdully drwn through the die, the hydrulic pressure ws re-uilt nd incresed over the inlet pressure due to significnt oil domin compression. At the finl stge, the hydrulic pressure returned stle s oil domin compression compensted oil lekge. unit: MP unit: MP c unit: MP d unit: MP Fig. 3 Fluid pressure development t different drwing stges: () initil; () pre-ulging; (c) middle; nd (d) finl stge (inlet pressure: 25 MP) The hydrulic pressure developments on four specil points of the lnk were monitored, s shown in Fig. 4. For the points 1 nd 2, s they were locted under the punch, hydrulic pressure on these points were reltively stle nd remined slightly elow inlet pressure (15 MP). Regrding point 3 on the drwn cup wll re, hydrulic pressure reduced shrply when it entered die wll re nd seling ws filed. For the point 4, due to lck of effective seling, the hydrulic pressure ws low during the whole drwing process. Hydrulic Pressure / MP Drwing Time / s Fig. 4 () Four specil positons on the H1050 lnk; nd () their pressure development (inlet pressure: 15 MP)

7 Ling Luo et l. / Procedi Engineering 207 (2017) All these hydrulic pressure developments were ignored in the conventionl model. Thus, the difference in hydrulic pressure will result in difference in drwing process nd drwn cups qulity. The mximum nd the minimum cup wll thickness were studied. Fig. 5 displys the mximum nd the minimum drwn cup wll thickness from the ALE nd the conventionl models. The minimum thickness occurred t the drwn cup corresponding to the punch fillet re nd the mximum thickness cn e found t the mouth of the drwn cup. The minimum wll thickness decresed with the hydrulic pressure in ll models, however, the minimum wll thickness predicted y the conventionl model reduced fster thn tht in the ALE model. The mximum wll thickness ws decresed in the ALE simultion while incresed in the conventionl simultion models. Their difference ecme lrge with n increse of the inlet pressure. Min. Wll Thickness / µm Norml H975 ALE H975 Norml H1050 ALE H1050 Norml H1100 ALE H Inlet Pressure / MP Mx. Wll Thickness / µm Norml H975 Norml H1100 ALE H Inlet Pressure / MP Norml H1050 ALE H975 ALE H1100 Fig. 5 () The minimum; nd () the mximum wll thicknesses of drwn cups The ALE simultion results were compred with the experimentl results. Fig. 6() displys drwn cup from H1050 sheet under inlet pressure of 20 MP nd Fig. 6() compres with the mximum cup wll thickness etween the ALE simultion nd experimentl results. A decresing trend of the mximum thickness with the hydrulic pressure ws oserved in oth ALE simultion nd the experiments. The mximum wll thickness in the ALE model, though ws not the sme, ws quite close to the experimentl results. By contrst, the mximum thickness development trend predicted y the conventionl simultion model (Fig. 5()) ws opposite to tht in the ALE simultion nd experimentl results. This indicted more precise hydrulic pressure estimtion in the ALE model thn tht in the conventionl simultion model. Exp. Wll Thickness / µm Exp. H975 Exp. H1050 Exp. H1100 ALE H975 ALE H1050 ALE H Inlet Pressure / MP ALE Wll Thickness / µm Fig. 6 () Drwn cup from H1050 sheet under 20 MP; nd () the mximum wll thickness from experiments nd ALE simultion results

8 1044 Ling Luo et l. / Procedi Engineering 207 (2017) Conclusions The developed ALE model cn ccurtely present the strong fluid-solid interction nd the hydrulic pressure on the lnk. The hydrulic pressure distriution nd its development cn e represented y the ALE model, which cnnot e considered in the conventionl model. Hydrulic pressure difference etween the ALE nd the conventionl models resulted in different drwn cup wll thickness. Although oth the conventionl nd the ALE models predicted the decresing minimum wll thickness trend with increse of the hydrulic pressure, the greter thinning is otined y the conventionl model thn tht of the ALE model. Regrding the mximum wll thickness, the conventionl model predicted reverse trend to tht in the ALE model nd the experimentl results. The ALE model provides more precise pressure distriution on the lnk thn tht of the conventionl simultion model for the MHDD simultion. Acknowledgements The first uthor gretly thnks for the finncil support from the Chin Scholrship Council (CSC ) nd the interntionl postgrdute tuition wrd (IPTA) offered y the University of Wollongong. This work ws lso supported y Austrlin Reserch Council (ARC) Future Fellowship project (FT ), nd the Stte Key Lortory of Rolling nd Automtion, Northestern University Open Reserch Fund (Contrct No.: ). References [1] R. Zfr, L. Lihui, Z. Rongjing, Int. J. Adv. Mnuf. Technol. (2015) [2] M. Jnkhsh, M. Rihi, F. Djvnroodi, Int. J. Adv. Des. Mnuf. Technol. 6 (2013) 1 7. [3] S. Yun, Z. He, G. Liu, Mter. Trns. 53 (2012) [4] T.F. Hung, H.Y. Hsien, Y.J. Chen, Key Eng. Mter. 626 (2014) [5] H. Sto, K. Mne, D. Wei, Z. Jing, D. Kondo, Fc. Eng. Inf. Sci. - Pp. (2015) [6] I. Irthie, G. Green, S. Hshim, A. Krim, Int. J. Mch. Tools Mnuf. 76 (2014) [7] S. Bgherzdeh, M.J. Mirni, M.B. Drini, J. Mnuf. Process. 18 (2015) [8] C. Wng, B. Guo, D. Shn, M. Zhng, X. Bi, Int. J. Adv. Mnuf. Technol. 71 (2014) [9] S. Wng, B.C. Khoo, G.R. Liu, G.X. Xu, Comput. Fluids 71 (2013) [10] S. Tnk, K. Kshiym, Int. J. Comput. Fluid Dyn. 20 (2006)