2 MATERIAL MODELS FOR CYCLIC PLASTICITY - NONLINEAR KINEMATIC HARDENING AND GENERALIZED PLASTICITY

We present a comparative study between a nonlinear kinematic hardening model and a generalized plasticity model. The two models are reviewed and discussed from both continuous and discrete time points of view. The integration of the discrete models based on a return map algorithm is also addressed. The form of the elastoplastic tangent tensors consistent with both the continuous and the discrete versions is discussed; in particular, the latter guarantees quadratic convergence for a Newton method, frequently adopted in an incremental solution scheme. Finally, numerical examples for uniaxial and multiaxial cyclic loading conditions are presented.