Computational modeling of inelastic large ratcheting strains

A framework for phenomenological hyperelasto-plasticity with initial anisotropy, kinematic hardening as well as anisotropic damage is presented in Menzel et al. (2003a). In this contribution we exploit and extend this framework to include several back-stresses in order to capture the ratchetting response of polycrystalline metals subjected to cyclic stress with non-zero mid-value. The evolution equations for kinematic hardening resemble a linear combination of the multiple-Armstrong-Frederic and the Burlet-Cailletaud models, which are extended to the large strain setting. The capability of the model to capture various phenomenological characteristics, in particular multi-axial ratchetting, is illustrated by numerical examples. Comparisons with uni-axial and bi-axial experimental ratchetting results for carbon steel are given. Finally, the finite element analysis of a simplified railway turnout component subjected to cyclic loading is presented.