PENETRATION OF FINE FOUNDRY SAND BY RIGID PROJECTILES

摘要

In another paper, the authors presented an approach to penetration of a paniculate target. This theory is based on the friction that the particles of target material present to the entire penetrator surface, including its shank. The shank of the penetrator affords a very large surface area compared to that of the nose. Even modest friction acting on the shank can provide a fairly large retarding force. Normal pressure acting on the projectile is assumed to be velocity-squared dependant, as indicated by a number of methods, including cavity expansion modeling. Penetration of sand and soil has been considered by numerous investigators, e.g.. These investigations did not directly address the frictional component of the net resisting force acting on the penetrator. A series of laboratory scale penetrations tests were performed. Data from these tests was used to evaluate the parameters in the model. Fine foundry sand is a high-density medium (1960 kg/m~3) with a small amount of friction. This contrasts the target used by the authors in, which had a sizable amount of friction. Results from the theory are in excellent agreement with the experiments witfi velocities as high as 630 m/sec.