A generalized visco-plasticity model and its algorithmic implementation

In this work we present a new rate-dependent model, which has the feature of being bounded by two plasticity models. After a brief review of the continuous equations for a material with inelastic behavior governed by a von Mises (J2) yield function, including both linear isotropic and kinematic hardening mechanisms, we introduce their discrete counterpart within the framework of a return mapping algorithm. Hence, we address the new material model, called generalized visco-plasticity, which includes as sub-cases classical visco-plasticity, classical plasticity and generalized plasticity. We discuss both the continuous and the discrete-time version for the case of a J2 associative model. Moreover, we present its algorithmic implementation in a return map setting as well as the form of the discrete consistent tangent tensor, which guarantees quadratic convergence in a Newton iterative technique. Finally, some numerical simulations are presented to illustrate the performance of the new material model.