Abstract
Constitutive equations of elasto-plastic materials with saturating work-hardening are proposed. The equations consist of a stress rate-strain rate relation proposed by Tokuoka and two evolutional equations which govern the variations of a scalar and a tensor internal variable. They show that the isotropic and the translational work-hardening get saturated when the magnitude of work-hardening is considerably large. The stress-strain relations are formulated theoretically for the cases of uniaxial stress extension and of simple shear deformation. Seven material parameters including two elastic constants are determined to fit the stress-strain relations given by experiments. The obtained equations with determined parameters show a good agreement with the experimental data in the process of loading, unloading and reloading.
