Chaboche's Viscoplasticity Model for Strain – Space Plasticity

To obtain reliable stress and strain fields using finite-element simulations, the applied constitutive equations, in general formulated in terms of evolution equations for the stresses and a set of state variables, that should be able to describe hardening properties as well as micro structural aspects with sufficient accuracy. The viscoplastic response of materials requires the time integration of system of non-linear first order differential equations. In viscoplasiticy, the constitutive equation might become very complicated to evaluate depending upon their degree of non-linearity. The constitutive model includes a yield criterion and multi-component formulations of non-linear isotropic and kinematic hardening. Both the types of the loading and the complexity of the constitutive laws ask a stable and efficient algorithm. The elasto-viscoplastic constitutive equations of the Chaboche model have been developed and modified many times. In this study Chaboche viscoplastic constitutive model is presented in strain-space. This model is further implemented in the framework of finite element. The performance of the new algorithm is compared to that is presented in existing literature results.