|
|
|
| NUMERICAL ANALYSIS ON THE FUNCTIONS OF STIR TOOL'S MECHANICAL LOADS DURING FRICTION STIR WELDING |
| YAN Dongyang1; SHI Qingyu1; WU Aiping1;Juergen Silvanus 2 |
1. Department of Mechanical Engineering; Tsinghua University; Beijing 100084
2. European Aeronautic Defence and Space Company (EADS) Innovation Works; Munich 81663; Germany |
|
Cite this article:
YAN Dongyang SHI Qingyu WU Aiping Juergen Silvanus . NUMERICAL ANALYSIS ON THE FUNCTIONS OF STIR TOOL'S MECHANICAL LOADS DURING FRICTION STIR WELDING. Acta Metall Sin, 2009, 45(8): 994-999.
|
|
|
Abstract Besides lower welding temperature and solid phase welding process, another significant difference between friction stir welding and conventional fusion welding (FSW) is that the forming of weld seam in FSW is effected by both thermal load and mechanical loads of stir tool. However, the definite functions of mechanical loads of stir tool in FSW process are not clearly described. With FSW experiments, only the material flow around stir tool can be observed, from which the results were obtained that the mechanical loads of stir tool gave birth to the plastic flow, a key factor of weld formation, of intenerated metal around the tool. In the simulation of FSW process, mechanical loads are always neglected in most analysis models, which can’t describe the unique characteristic of FSW. Although the mechanical loads have been considered in FSW simulation by some researchers, the loads are greatly simplified and the analysis is only localized in the asymmetric distribution of residual stress. In this paper, numerical simulation was applied to investigate the functions of mechanical loads during FSW process. Based on experiments of FSW aluminium alloy sheets, three simulation models were establised with different conditions of considering thermal load only, considering both thermal load and down force, and considering thermal load, down force and working torque synthetically. The results show that the down force significantly reduces residual stress and the torque leads to the unsymmetrical distribution of residual stress. On the other hand, mechanical loads absolutely change the residual distortion pattern from saddle state into anti–saddle state. Mechanical loads strengthen the mechanical restriction on sheet, forge and extrude the materials around tool, so the residual strain in weld zone is reduced, which leads to the eduction of residual stress. Furthermore, the mechanical loads change the correlaton of strain on top surface and bottom surface of sheet, which resultes in the change of distortion pattern.
|
|
Received: 23 December 2008
|
|
|
| Fund: Supported by National Natural Science Foundation of China (No.50875146) and High Technology Research and Development Program of China (No.2006AA04Z139) |
| [1] Thomas W M, Nicholas E D, Needham J C, Murch M G, Templesmith P, Dawes C J. Gr Br Pat Appl No. 9125978.8, 1991
[2] Mishra R S, Ma Z Y. Mater Sci Eng, 2005; R50: 1
[3] Colligan K. Weld J, 1999; 78: 229
[4] Li Y, Murr L E, McClure J C. Scr Mater, 1999; 40: 1041
[5] Sutton M A, Yang B, Renolds A P, Taylor R. Mater Sci Eng, 2002; A323: 160
[6] Xu S, Deng X, Reynolds A P, Seidel T U. Sci Technol Weld Join, 2001; 6: 191
[7] Khandkar M Z H, Khan J A, Reynolds A P, Sutton M A. J Mater Process Technol, 2006; 174: 195
[8] Zhu X K, Chao Y J. J Mater Process Technol, 2004; 146: 263
[9] Shi Q Y, Dickerson T L, Shercliff H R. Proc 4th Int Symp on Friction Stir Welding, Park City: TWI Center, 2003(CD-ROM)
[10] Li T, Shi Q Y, Li H K. Sci Technol Weld Join, 2007; 12: 664
[11] Zhang Z, Zhang H W. J Mater Process Technol. 2009; 209: 241
[12] Zhang Z, Zhang H W. Sci Technol Weld Join. 2007; 12:226
[13] Vijay S, Srdja Z, Kovacevic R. Int J Mach Tool Manuf, 2005; 45: 1577
[14] Buffa G, Fratini L, Pasta S, Shivpuri R. CIRP Annals–Manuf Technol. 2008; 57: 287
[15] Paun F, Azouzi A. Proceedings of the 8th International Conference on Numerical Methods in Industrial Forming Processes, 13–17 June 2004, Columbus, USA: Ohio State University. 2004: 1197
[16] Grimvall G. Thermophysical Properties of Materials: Non Metallic Solids. New York: Elsevier, 1999: 243
[17] Parrott J E, Stuckes A D. Thermal Conductivity of Solids, London: Pion, 1975: 156
[18] Zhang Z L, Silvanus J, Li H K, Shi Q Y. Sci Technol Weld Join, 2008; 13: 415
[19] Gallais C, Denquin A. Proc 5th Int Symp on Friction Stir Welding, France: TWI Center, 2004 (CD–ROM)
[20] Shi Q Y, Dickerson T L, Shercliff H R. In: David S A, DebRoy T, Lippold J C, Smartt H B, Vitek J M,eds., Proc 6th Int Conf on Trends n Welding Research, Pine Mountain: ASM International, 2003: 247
[21] Simar A, Beckers J L, Pardoen T, Meester B D. Sci Technol Weld Join, 2006; 11(2): 170
[22] Vuyst T, Dealvise L D. Proc 5th Int Symp on Friction Stir Welding, France: TWI Center, 2004 (CD–ROM)
[23] WC S. Numrical Analysis for Heat Transfer in elding Process. Harbin: Harbin Institute of Technology Press, 1990: 95
(武传松. 焊接热过程数值分析. 哈尔滨: 哈尔滨工业大学出版社, 1990: 95)
[24] Help Documentation of ABAQUS 6.5·ABAQUS Company, USA. 2004
[25] Yan D Y, Shi Q Y, Wu A P, Silvanus J, Liu Y, Zhang Z L. Acta Metall Sin. 2009; 45: 183
(鄢东洋, 史清宇, 吴爱萍, Juergen Silvanus, 刘园, 张增磊. 金属学报. 2009; 45: 183) |
| No Suggested Reading articles found! |
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
