A micromechanics-based damage model for microcrack-weakened brittle solids

Abstract

Abstract In the present paper, a micromechanics-based, three-dimensional damage model for microcrack-weakened brittle solids is developed. In order to describe the evolutionary damage state and anisotropic properties of materials, the concept of domain of microcrack growth (DMG) is defined as the union of all possible orientations of propagated microcracks after a loading path. Based on modified mixed-mode growth criteria of microcrack, the evolution of DMG as well as the overall effective compliance tensor of damaged materials are formulated. Through a micromechanical analysis, the damage mechanisms and the complex constitutive behavior of materials are studied under complex loadings. The self-similar growth of open microcracks under tension, the mode-II growth and the kinking of closed microcracks under compression and the influences of these mechanisms on the mechanical properties of materials are all considered. It is explained that axial splitting may occur in a material only when the lateral normal stresses have positive or a small negative value. And the condition for axial splitting of a material is given. The evolutionary damage model is illustrated by two examples of uniaxial tension and uniaxial compression and the theoretical results are compared with experimental data and theoretical results obtained by others.