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

• A new dynamic material model for rocks is proposed based on the extended Drucker–Prager strength criterion and the Johnson–Cook material model, in which the effect of strain rate on strength and the nonlinear hardening of confining pressure are taken into account.
• The tensile damage variable defined in terms of the volumetric strain can properly characterize the tensile failure of porous materials.
• The numerical simulations of uniaxial compressive test, uniaxial tensile test and standard Brazilian disc test based on the proposed rock material model were performed to verify the validity and accuracy of the new rock material model. And the comparison of the resulting numerical results with the experimental data shows that the new dynamic rock model is capable of capturing the damage and failure of rocks.

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.