An anisotropic finite strain elastoplastic model considering different plastic spin effects on the intermediate configuration

Large deformation anisotropic elastoplastic models have important application background and research value in engineering and materials fields. In this paper, a macroscopic phenomenological model of elastoplastic anisotropic deformation considering plastic spin is proposed. The model is based on the multiplication decomposition of deformation gradient. The free energy function is expressed as the isotropic function of the strain and the structural tensor on the intermediate configuration, which is a push-forward of initial configuration by using plastic deformation gradient. Advantageously, the non-equilibrium free energy function remains invariant under the superimposed rigid body rotation on the intermediate configuration, which is due to the non-uniqueness of the multiplicative decomposition of deformation gradient. However, the rate of superimposed rigid body rotation has effects on the model. The effects are discussed by considering three different spin assumptions. Numerical simulations show that the plastic spin has influence on the calculation results. Therefore, the plastic spin assumption should be carefully selected in the practical application of elastoplastic anisotropic model.