Application of Gotoh's Orthotropic Yield Function for Modeling Advanced High-Strength Steel Sheets

Abstract

An accurate description of the directional dependence of uniaxial tensile yielding and plastic flow in advanced high-strength steel sheets may require either a nonassociated plasticity model with separate quadratic yield function and flow potential or an associated plasticity model with nonquadratic yield function. In this paper, Gotoh's fourth-order homogeneous polynomial yield function is applied to model two advanced high-strength steel sheets in an associated plasticity model. Both the parameter selection for calibrating Gotoh's yield function and its positivity and convexity verification are given in some detail. Similarities and differences between the associated plasticity model presented here and the nonassociated one appeared in the literature are discussed in terms of the directional dependence of yield stresses and plastic strain ratios under uniaxial tension and yield stresses under biaxial tension loading.