a model of one-surface cyclic plasticity and its application to springback prediction

this paper presents an elasto-plastic constitutive model based on one-surface plasticity, which can capture the bauschinger effect, transient behavior, permanent softening, and yield anisotropy. the combined isotropic–kinematic hardening law was used to model the hardening behavior, and the non-quadratic anisotropic yield function, yld2000-2d, was chosen to describe the anisotropy. this model is closely related to the anisotropic non-linear kinematic hardening model of chun et al. [2002. modeling the bauschinger effect for sheet metals, part i: theory. international journal of plasticity 18, 571–95.]. different with the model, the current model captures in particular permanent softening with a constant stress offset as well as the bauschinger effect and transient behavior under strain path reversal. inverse identification was carried out to fit the material parameters of hardening model by using uni-axial tension/compression data. springback predicted by the resulting material model was compared with experiments and with material models that do not account for permanent softening. the results show that the resulting material model has a good capability to predict springback.