Effect of kinematic hardening on localized necking in biaxially stretched sheets

Abstract

For elastic-plastic sheets under biaxial stretching localized necking is investigated assuming that the material follows a kinematic hardening rule. The investigation is mainly based on the plane stress approximation, but includes a few results obtained in the context of the three-dimensional theory. It is found that the forming limit curves predicted by kinematic hardening are in far better agreement with experimental results than the similar curves predicted by standard flow theory with isotropic hardening. For a high hardening material quite good agreement is obtained with predictions of deformation theory of plasticity, which may be considered as a simple model of a solid that develops a vertex on the yield surface.