Numerical implementation of tension–compression asymmetry in a gradient‐extended two‐surface damage–plasticity model

Based on the spectral decomposition of the strain tensor, the tension‐compression asymmetry (TCA) in a gradient‐extended two‐surface damage‐plasticity model is considered in this study. More specifically, the gradient extension is applied in the current model as a suitable damage regularization technique to prevent pathological mesh dependence issues. Furthermore, plasticity and damage are treated as distinct but strongly coupled dissipative mechanisms by using two different types of damage and yield criteria as well as the related loading/unloading conditions, respectively. Finally, a specific material parameter htc$h_{tc}$ is adopted to control the degree of TCA which results in a unique damage evolution in compression.