Sliding and damage criteria investigation of a micromechanical damage model for closed frictional microcracks

In this paper, a micromechanical damage model formulation for closed frictional microcracks considering the coupling between frictional sliding and damage evolution was reviewed. Then, the sliding criterion for closed microcracks was modified to consider the matrix containment of sliding on microcracks. Then, the adjusted model was programmed as a constitutive model to simulate the UCS test. On the other hand, some different forms of damage criteria have been proposed in phenomenological way in literature for micromechanical damage models. The effect of damage criterion on simulated sample behavior was studied with a variation of damage criterion input parameter. The exponential and tangential damage criteria are capable to control the hardening and softening behavior. Furthermore, the influence of matrix containment of sliding on microcracks faces on the simulated sample behavior was studied in this paper. According to the numerical results, the calculated strength of the simulated sample is sensitive to the matrix resistance parameter against sliding on microcracks. The simulation results are in agreement with the experimental data.