A model of depth calculation for projectile penetration into dry sand and comparison with experiments

Abstract Dry sand can be viewed as a binary material composed of sand grains and pores. The dry sand's high compressibility needs to be considered in projectile penetration depth calculation. Current models for the sand's resistance to projectiles involve experimental data fitting and are valid in only a small range of circumstances. In this paper, the P-alpha equation of state and the Mohr-Coulomb Tresca-limit yield criterion are employed to describe the constitutive relations of the sand. A spherical cavity-expansion model including the compressibility of sand is established. Then a new sand penetration depth calculation method is obtained. Our results are compared with those from other models and experiments. It is found that the spherical cavity-expansion model based on the P-alpha equation of state can describe the dynamic response of sand well and is suitable for calculating the depth of penetration into sand by rigid projectiles with specific nose configurations.