Damage in domains and interfaces: a coupled predictive theory

In this study, we propose a model coupling damage of domains and damage of interfaces. A predictive theory of continuum damage mechanics is developed within the framework of the principle of virtual power. Because damage results from microscopic motions, the power of these microscopic motions is included in the power of the internal forces. The power of the internal forces we choose depends on the damage velocity and on its gradient to take into account local interactions. An interaction between the domain damage and the damage along the interface is introduced. To overcome the insensitivity of the local interface model to elongation, nonlocal elongation has been considered as a source of damage. Representative numerical examples confirm that our proposed model can be used to describe various damage phenomena in agreement with experiments.