Damage-plastic model for numerical simulation of rock fracture in dynamic loading

This paper presents an explicit FE-procedure for numerical simulation of rock under dynamic loading. The continuum approach is chosen for modeling the brittle fracture of rock. Within this framework a damage-plastic model formulated in the effective principal stress space is presented. The plasticity part of the model uses the modified Mohr-Coulomb yield criterion to indicate plastic flow. In the damage part, the asymmetric behavior of rock under loading is accounted for by using separate damage variables in tension and compression. In tension the orthotropic damage approach is chosen whereas in compression the isotropic damage model is employed. The exponential damage evolution law in compression is dependent on the confining pressure in a novel manner via the degradation index concept. The equations of motion are solved with an explicit time integrator in the time domain. The model is calibrated for Tennessee marble, and the dynamic indentation problem is simulated in order to demonstrate the performance of the model.