Investigation of Porosity Evolution and Orthotropic Axes on Anisotropic Materials.

摘要

Advancement of porosities that happens in shear deformation of anisotropic materials is investigated by Dr. Kweon. As the hydrostatic stress in shear deformation is zero, in the solid mechanics' researches it is proved several times that porosity will not be expanded in shear deformation. Dr. Kweon showed that this statement can be wrong in large deformation of simple shear. He proposed anisotropic ductile fracture model to show that hydrostatic stress becomes nonzero and porosities are increased in the simple shear deformation of anisotropic materials. This study investigates the effect of the evolution of anisotropy which means the rotation of the orthotropic axes onto the porosity changes. Hill coefficient shows that how orthotropic materials indicate different ductile fracture manners in shear deformation. Also the effect of void aspect ratio on change of porosity is investigated. It has been found that the interaction among porosity, the matrix anisotropy and void aspect ratio play a crucial role in the ductile damage of porous materials.