Cohesive Zone Models and Fracture

Basic concepts on cohesive models and their usage in fracture are reviewed. These included potential based cohesive zone models and the concept of an anisotropic failure surface. Some new results are presented for history-dependent cohesive zone models. In particular, a class of cohesive zone models where damage is represented by a state variable which evolves according to loading history is studied. The connection between cohesive zone model and crack nucleation is explored.