摘要:A numerical approach to simulate the crack initiation and propagation process of the nonlinear fracture behavior of the quasi-brittle materials under tensile loading is presented. The nonlinear fracture of Mode I of quasi-brittle material is analyzed by considering the effects of microscopic softening rate and heterogeneity. The results show that the softening rate and the heterogeneity of quasi-brittle material affect the values of stress intensity factor KI. The softening index affects merely the size of the plastic zones while the heterogeneity causes the more sophisticated response of quasi-brittle materials.