Phenomenological Damage Models of Anisotropic Structural Materials

Damage in metals is mainly the process of the initiation and growth of voids. A formulation for anisotropic damage is established in the framework of the principle of strain equivalence, principle of increment complementary energy equivalence and principle of elastic energy equivalence. This paper presents the development of an anisotropic damage theory. This work is focused on the development of evolution anisotropic damage models which is based on a Young’s modulus/Poisson’s ratio change of the initial isotropic material. Anisotropic damage account is as important as accounting of the loading history and the type of stress state. Therefore, validation of the existing damage accumulation models with anisotropy account and the development of new ones is an important and promising direction in the solid mechanics. Today more widely for engineering applications the phenomenological approach, which is based on the continuum damage mechanics (СDM) and the thermodynamics of irreversible processes are used. The main idea of all damage models consists in replacing the conventional stress with the effective stress in the constitutive equation.