Strain Space Formulation of the Armstrong-Frederick Family of Plasticity Models

Abstract

Strain space based plasticity models have certain advantages in theoretical development and numerical implementation. Previous efforts have been made to formulate cyclic plasticity models in strain space using the idea of multiple-yield surface theory. Recently, however, Armstrong-Frederick type plasticity models have received increasingly more attention because of their enhanced performance in predicting ratchetting behavior. In this paper, the strain space formulation of the Armstrong-Frederick family of cyclic plasticity models is established, and several representative strain controlled loading paths are used to compare the results from the proposed formulation and previous experimental data. The excellent agreement suggests the proposed strain space formulation is very promising in strain controlled cyclic plasticity such as finite element analysis, strain gage rosette applications, and multiaxial notch analysis using pseudo-stress or pseudo-strain approaches.