Penetration of a coarse sand target by rigid projectiles

Abstract

This paper presents a theory for the normal rigid body penetration of particulate media. This theory consists of two separate force regimes divided by a critical velocity at which the transition between the two regimes takes place. Also included in this theory is sliding friction, separated into two different regimes, one for the nose and one for the shank. In order to verify this new penetration theory, a set of laboratory experiments was performed where 7075-T6 Aluminum projectiles were shot into coarse foundry sand. Utilizing the total penetration depth and impact velocity of each projectile in the test, along with known projectile geometry, analyses of the penetration events were completed. The results of these experiments and analyses, which confirm the required use of a friction coefficient on the shank, are reported.