Improved Contact Bond Model of Discrete Element Method for Simulating Strain Rate Effect of Rock Materials

When the discrete element method (DEM) is used to simulate rock dynamic experiments with split Hopkinson pressure bar (SHPB), it is difficult to obtain the result that the numerical and experimental rock specimen will have the same rapid growth of dynamic compressive strength when strain rate increases. To solve this problem, an improved contact bond model of DEM considering the crack propagation velocity was proposed. Then this new contact bond model was used to simulate the rock dynamic experiments with SHPB under different loading rate. Compared with the simulation results of the original contact bond model, the simulation results of this new contact bond model are closer to the experimental results.