| The broad focus of this dissertation is on developing continuum models of in-elastic response of crystalline materials that include the influence of microstructure, material symmetry, and dissipation of energy accompanying the changes in the microstructure. A framework has been developed, built on the idea of natural configurations of a material, that has provisions for explicit treatment of material microstructure (slip planes, dislocations, interfaces, etc.). It is demonstrated that the developed framework is applicable to plasticity due to slip and martensitic phase transformations. However, a specific constitutive model based on the aforementioned framework is developed for modeling the inelastic behavior of silicon. A full finite strain finite element formulation is developed and implemented to analyze inelastic behavior of single crystals. It is anticipated that the present research on silicon will aid studies in crack tip plasticity during fracture, brittle-ductile transition, dislocation structure and phase transformations under an indenter in micro/nanoindentation, and eventually the role of defects and plastic deformation in electrical behavior of semiconductors and optical behavior in solar energy applications. |
