Three-dimensional micromechanical model for quasi-brittle solids with residual strains under tension

Presented in this paper is a three-dimensional micromechanical model that e nables the simulation of microcrack-weakened quasi-brittle materials with p ermanent residual strains subjected to tension. The microcracking damage of such a material is described by the concept of domain of microcrack growth . It is thought that the occurrence of residual strains is attributable to two reasons, namely, the release of microscopic residual stresses due to mi crocracking and the microscopic plastic deformation along microcrack front edges. By introducing the analytical results of the two physical mechanisms into the constitutive relation, a micromechanical damage model is establis hed to describe the effective response of microcrack-weakened quasi-brittle materials such as ceramics and concrete under complex loading/unloading pa ths. The response of such a material is divided into four stages, namely, t he stages of linear elasticity, pre-peak nonlinearity, post-peak stress dro p, and strain softening before macroscopic fracture.