A phenomenological model for microstructural evolution during plastic flow

A class of materials is considered that possesses local orthotropic symmetries. Constitutive models with microstructural evolution are developed within a conventional elastic–plastic multiplicative decomposition. In the current configuration, the orthotropic vectors evolve with the microstructural spin, which is the difference between the material and plastic spins. Representations for tensor-valued functions for orthotropic material behavior due to Zheng (1994) are extended to develop constitutive equations for the plastic parts of the rate of stretching and the spin. A key relation is established between components of the plastic part of the rate of stretching and the plastic spin. Comparisons with experiments are promising.