A directional damage model Original Research Article

A directional damage model for initially isotropic metals and geomaterials is presented in this paper. The model is based on a space transformation using an analogy with the theory of finite strains. As a result, damage is defined by a second order damage tensor. The basic equations of the model are derived from the thermodynamics of irreversible processes. A return-mapping algorithm is developed for the numerical integration of the model. Applications examples presented show that the model is able to reproduce damage-induced anisotropy, with directional stiffness degradation and hardening, under general loading conditions.