Springback Prediction Using the Split-Ring Test Based on a Combined Anisotropic Hardening Model

Abstract

Material model which could describe the Bauschinger effect is essential to accurately predict springback since strain path reverse is quite common in sheet metal forming. In this paper, a combined isotropic-kinematic hardening law which can capture the Bauschinger effect, transient behavior and permanent softening was used to model the hardening behavior. Also, the non-quadratic anisotropic yield function, Yld2000-2d, was chosen to describe the anisotropy. An inverse identificat- ion method was carried out to calibrate the material parameters by using uni-axial tension and Bauschinger simple shear tests. Experiments of cylindrical cup drawing and following split-ring tests were performed. Similar processes were carried out by numerical simulation, and springback predicted by present model was compared with experiments and that of vonMises model. The result shows that the current model significantly improves the accuracy of springback prediction.