27. Micromechanical Models of Ductile Damage and Fracture

Two classes of micromechanics-based models of void enlargement are presented succinctly with their fundamental hypotheses and synopsis of derivation highlighted. The first class of models deals with conventional void growth, i.e., under conditions of generalized plastic flow within the elementary volume. The second class of models deals with void coalescence, i.e., an accelerated void growth process in which plastic flow is highly localized. The structure of constitutive relations pertaining to either class of models is the same but their implications are different. With this as basis, two kinds of integrated models are presented which can be implemented in a finite-element code and used in ductile fracture simulations, in particular for metal forming processes. This chapter also describes elements of material parameter identification and how to use the integrated models.