A dynamic material model for rock materials under conditions of high confining pressures and high strain rates

A dynamic material model is presented to characterize the mechanical behavior of rock materials under high confining pressures and high strain rates. The yield surface is defined based on the extended Drucker-Prager strength criterion and the Johnson-Cook material model. Two internal damage variables are introduced to represent, respectively, the tensile and compressive damage of rock materials. The proposed dynamic material model of rocks is incorporated into the nonlinear dynamic analysis code LS-DYNA through a user-defined material interface. Its reliability and accuracy are verified by the simulation of various basic experiments with different loading conditions. The present rock model is also applied to simulate the penetration of granite target plate by hard projectile. The typical damage and failure on the granite targets predicated by the proposed dynamic material model of rocks agree well with the experimental results. It demonstrates that the proposed model is capable of capturing the failure of rock materials. (C) 2015 Elsevier Ltd. All rights reserved.