Modeling anisotropic hardening with a stochastic cellular automaton

The Bauschinger effect refers to an observed asymmetry in the forward and reverse loading curves of a metal or an alloy. It is characterized by the reduction of the absolute value of the yield stress in reverse loading, as compared to the maximum stress imposed on the initial, or forward, loading. The Bauschinger effect contributes to the phenomena known as kinematic or anisotropic hardening. Experimental investigations of dispersion hardened systems have shown that materials with strong, non-shearable particles exhibit a large degree of kinematic hardening. In the current work the use of a stochastic cellular automaton is investigated as a tool to model the anisotropic hardening of dispersion hardened alloy. A local rule is implemented that allows a redistribution of stresses from a cell to its neighbors. This response to loading takes place synchronously based on a probabilistic determination and conditions within each cell. Model results are generated for an alloy reinforced with non-shearable and shearable particles.