This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Bifurcation in Binder Wrap Forming
Annotation ability available
Sector:
Language:
English
Abstract
Binder wrap forming for automobile body panels can be evaluated by finite element analysis. Sometimes, however, numerical instabilities occur in the implicit nonlinear solution process. While this instability may be an artifact of the numerical model, it may also signal the onset of a real physical phenomenon, such as bifurcation.
This paper presents a numerical experiment to examine bifurcation in binder wrap forming, using an experimental decklid die. Numerical instability occurred early in the deformation process. Two stable solutions for the binder wrap surface were obtained, demonstrating that the instability resulted from bifurcation. One of the deformation modes is saddle like, and the other is cylindrical. In practice, the blank will deform to one of the above modes under the clamping actions generated by the closing of the binders. If the deformation takes the other mode, substantially different strains will result in the subsequent punch forming.
Authors
Citation
Chen, K. and Baran, D., "Bifurcation in Binder Wrap Forming," SAE Technical Paper 930514, 1993, https://doi.org/10.4271/930514.Also In
References
- Chen, K. K. 1984 ‘A numerical method for computing the sheet shape in the blank holding stage of a draw die,’ ASME Paper 84-WA/DE-6
- Chen, K. K. 1986 ‘An iteration method for binder wrap calculations,’ Proceedings of the NUMIFORM '86 Conference Balkema
- Chen, K. K. Waugh, T. G. 1990 ‘Application of a binder wrap calculation model to layout of autobody sheet steel stamping dies,’ SAE Paper No. 900278 SAE SP-625 SAE Transactions
- Tang, S. C. 1985 ‘Verification and application of a binder wrap analysis,’ Computer modeling of sheet metal forming process Wang N. M. Tang S. C. The Metallurgy Society USA 193 208
- Tang, S. C. Wu, J. H. 1991 ‘Pre-bent effect on binder wrap of a trunk deck-lid,’ SAE Paper No. 910515 SAE SP-865
- Stevenson, R. 1988 ‘Development in the design and analysis of sheet metal stamping dies,’ Product and process design Chryssolouris G. Komanduri R. ASME Book H00412 173 179
- Wang, N. M. Somaratna, N. 1989 ‘Numerical simulation of industrial sheet forming processes,’ NUMIFORM'89 Thompson E. G. et al. Balkema 75 84