The influence of non-dissipative quantities in kinematic hardening plasticity

A kinematic hardening plasticity model valid for finite strains is presented. The model is based on the well-known multiplicative split of the deformation gradient into elastic and plastic parts. The basic ingredient in the formulation is the introduction of a locally defined configuration-a centre configuration-which is associated with a deformation gradient that is used to characterize the kinematic hardening behaviour. The non-dissipative quantities allowed in the model are found when the plastic and kinematic hardening evolution laws are split into two parts: a dissipative part, which is restricted by the dissipation inequality, and a non-dissipative part, which can be chosen without any thermodynamic considerations. To investigate the predictive capabilities of the proposed kinematic hardening formulation, necking of a bar is considered. Moreover, to show the influence of the non-dissipative quantities, the simple shear problem and torsion of a thin-walled cylinder are considered. The numerical examples reveal that the non-dissipative quantities can affect the response to a large extent and are consequently valuable and important ingredients in the formulation when representing real material behaviour.