A Rate-Dependent Elastoplastic Peridynamic Model for Rock and Its Numerical Implementation

Rocks exhibit complex mechanical behavior under impact loading, including strain-rate dependence, pressure sensitivity, tension-compression asymmetry, and nonlinear volumetric response, posing challenges for accurate prediction of their dynamic response and fracture behavior. This study presents a Holmquist-Johnson-Cook (HJC) elastoplastic model within the ordinary state-based peridynamic (OSB-PD) framework, accounting for distinct strain-rate effects in tension and compression. It incorporates pressure-dependent yielding, nonlinear volumetric response, and plastic damage evolution. The strain-rate strengthening factor is modified using a lower-bound constraint and a quintic smoothing function. A heterogeneous CPU-GPU parallel framework for fluid-solid interaction (FSI) simulations is developed by coupling the model with smoothed particle hydrodynamics (SPH). The model is validated using simulations of three-point bending, SHPB test, and single-hole rock blasting. The predicted crack patterns and stress responses show good agreement with previously reported results. In three-point bending, higher loading velocities intensify local compaction, reduce deviatoric plastic strain accumulation at the same displacement, and delay crack propagation. The displacement required for crack penetration increases from 0.104 to 0.29 mm. SHPB simulations capture irreversible volumetric compaction in compressed regions near crack tips and deviatoric plastic strain accumulation along crack paths. Single-hole rock blasting simulations reproduce near-borehole crushing, radial cracks, and localized annular damage, with early volumetric compaction followed by deviatoric plastic strain accumulation. Heterogeneous parallelization reduces runtime by approximately 53.1% relative to the CPU parallel scheme. The proposed model demonstrates significant potential for investigating the relationships among local compaction, plastic strain accumulation, and fracture evolution in rock under dynamic loading.