Modeling Plastic Deformation of Mild Steel Under Nonproportional Deformation Path

Abstract

An elastic/viscoplastic theory that includes anisotropic strain hardening is used in the analysis of a nonproportional biaxial torsion-tension loading test. The theory is a combination of the formulation of Perzyna [5] and the anisotropic hardening model of Mróz [6], and is applied in modeling the behavior of mild steel in a nonproportional deformation test reported by Meguid and Malvern [2]. The results show that the theory predicts the material response well. Especially, the theory models adequately the noncoaxiality between the plastic strain rate and the deviatoric stress vectors following an abrupt change in the deformation path.