A modified Mroz model for springback prediction

Abstract

A new anisotropic material hardening model is introduced in this study for springback simulation. It is modified from the Mroz multi-yield surface hardening model and incorporated more realistic Bauschinger effect for cyclic loading and anisotropic yield surfaces for sheet metals. The model is targeted for sheet metal forming simulations where the accurate springback predictions are important, and where materials have more rapid hardening characteristics and ability to sustain higher stresses such as so-called advanced high-strength steels (AHSS). The constitutive integration algorithm is derived and it is numerically implemented in the commercial FEA code via a user-material subroutine. The new model is applied to a U-channel forming test with DP600 steel. Experiments are conducted and springback results are compared with numerical prediction to demonstrate the new model's effectiveness. © ASM International 2007.