Modeling the mechanical response and damage evolution in inelastic polycrystalline solids

In the current research an attempt is made to develop a model within the concepts of continuum mechanics. Advanced fracture mechanics is also utilized within the context of a highly rate dependent cohesive zone model to account for the development of internal boundaries during grain boundary fracture and/or sliding. Additionally, in order to account for dislocation generation and migration within the grains, it is assumed that the crystalline material can be characterized by a nonlinear viscoplastic mechanical constitutive theory. Due to the nonlinearities introduced by the crack growth and viscoplastic constitution, the model is implemented within a finite element framework. Thus far, other models have been unable to simultaneously predict multiple grain boundary crack growth and the interacting evolution of multiple grain boundary cracks. The current approach is shown to be capable of modeling multiple grain boundary crack growth in viscoplastic polycrystalline materials.