Simulation of dynamic response of granite: A numerical approach of shock-induced damage beneath impact craters

The mechanical response of rocks to dynamic loading is complex. It is not well understood because of the difficulty of defining an effective shear and tensile strength model. Recently AUTODYN-2D from Century Dynamics is used to simulate the shock-induced damage in granite targets impacted by projectiles at different velocities. The simulated results are compared with experiment data. Johnson-Holmquist shock damage constitutive model for brittle materials is applied to describe the damage and shear strain achieved in a confined volume of granite. A tensile crack softening model is coupled with the JH model to simulate the propagation of radial tensile cracks generated by the principal tensile stress perpendicular to the shock front. The tensile stress is assumed to be equal to the deviatoric stress at radii that experience less than the Hogoniot elastic limit stress. Instead of traditional grid-based methods, a smooth particle hydrodynamics is used to define damaged regions in brittle media. (C) 2006 Elsevier Ltd. All rights reserved.