Constitutive model for uniaxial time-dependent ratcheting of 6061-T6 aluminum alloy

Based on the experimental results of uniaxial time-dependent ratcheting of 6061-T6 aluminum alloy, a new time-dependent cyclic visco-plastic constitutive model is proposed by employing a new non-linear kinematic hardening rule in the framework of unified visco-plasticity. A static recovery term is introduced into the kinematic hardening rule to reflect the remarkable time-dependence of ratcheting, and a nonlinear isotropic hardening rule is also included in the proposed model to reflect the cyclic softening feature of the alloy. All the material parameters used in the proposed model are assumed to be temperature-dependent. Comparison of the experimental and simulated results shows that the proposed visco-plastic constitutive model can reasonably describe the uniaxial time-dependent ratcheting of 6061-T6 aluminum alloy presented at room and elevated temperatures.