A new constitutive model for HCP metals

This paper develops a new constitutive model for HCP metals subjected to high strain, high strain rate and high temperature based on the theory of thermally activated dislocation motion in crystal materials. The constitutive parameters of the material are determined by a new efficient method composed of a global genetic algorithm and a local penalty-function algorithm, which guarantees that the constitutive parameters are a globally optimal solution in their theoretically allowed ranges. The application of the model to Ti6Al4V alloy shows that in the high strain rate regime, the model prediction is much more accurate than those by the Johnson–Cook and Zerilli–Armstrong models.