Comparison of Kinematic Hardening vs Isotropic Hardening Plasticity Model for Low Cycle Fatigue Case

The study aims to analyze the behavior of pipe bends under constant cyclic loading case. Two advanced plasticity model were adopted in the study based on von mises yield surface. The first model adopts Armstrong-Frederick (AF) non-linear kinematic hardening model based on center and size of the yield surface. The size of the yield surface is assumed to be constant. The Isotropic hardening plasticity law is implemented using UMAT based on power hardening rule based on yield condition and plastic flow rule. From the results it was concluded that the A-F kinematic hardening law can accurately predict the cyclic response for joints as compared to the isotropic hardening rule.