A Bulk Damage Model for Modeling Dynamic Fracture in Rock

The fracture response of rock, as a quasi-brittle material, is highly sensitive to its microstructural design. We present a statistical damage formulation to model dynamic rock fracture. The damage model is rate-dependent and the corresponding damage evolution is a dynamic equation which introduces a timescale to the problem. The introduced timescale preserves mesh objectivity of the method with much less computational efforts in comparison with other conventional non-local formulations. We define a statistical field for rock cohesion to involve microstructure effects in the proposed formulation. The statistical field is constructed through the e (KL) method. The damage model is coupled with the elastodynamic equation. The final system of coupled equations is discretized by an n (aSDG) method. Robustness of the proposed formulation is shown though dynamic fracture simulation of rock under uniaxial compressive load. The numerical investigation indicates the importance of load amplitude and microstructure randomness on failure response of rock.