Numerical simulation of cyclic behavior of ductile metals with a coupled damage–viscoplasticity model

In this paper, the evolution of ductile damage and the failure is investigated in the cyclic loading of ductile metals based on the rate-dependent elasto-viscoplastic damage model with the linear and nonlinear isotropic-kinematic hardening rules. The constitutive model is derived by introducing the damage variable, based on the plastic strain behavior, in both the elasto-plasticity and visco-plasticity frameworks. The cyclic behavior is modeled by using the visco-plasticity model since the rate-dependent behavior is observed experimentally for various metal alloys. In order to obtain a more realistic response in the compression zone, the crack closure effect is employed in the stress–strain constitutive relations. Finally, four different cases are studied numerically to assess the overall framework of the proposed constitutive model, including the fatigue behavior and lifetime assessment of AISI316L alloy, and the results are compared with available experimental data.