Crystal Plasticity Approach for Predicting the Bauschinger Effect in Dual-Phase Steels

Abstract

A multi-scale micro-mechanical model was proposed to predict the cyclic behavior of dual-phase steels. The approach proposed in this study incorporates a simplified dislocation density model into the crystal plasticity finite element method (CP-FEM). The back stress resulting from dislocation pileups was used to reproduce the transient hardening behavior during load reversal. The simulations conducted using representative volume elements for the dual-phase steels lead to the following conclusions: (1) the large Bauschinger effect (BE) and permanent softening in dual-phase steels originate primarily from the inhomogeneity due to the soft and hard phases; (2) the elastic incompatibility due to the grain orientation distribution generates some BE, but is not sufficient to explain the measured stress-strain curve; and (3) the inclusion of the back stress produced by the dislocation pileup can explain the strain hardening stagnation during reverse loading. (C) 2012 Elsevier B.V. All rights reserved.