高速抛射体穿透沙层的实验研究
The dynamics associated with a long rod projectile, travelling at high velocity, penetrating aheterogeneous target has long been an active research area. Historically both analytic andnumeric models have assumed a continuous target medium in order to predict the performance ofthe penetrator-target system, even in cases where the target is composed of concrete, foam or agranular porous medium such as sand. Continuum models fail to capture the complicated grainlevel response within the heterogeneous target which can result in asymmetric loading of theprojectile leading to variations in projectile performance. In this work a series of experiments wereconducted in order to investigate the penetration dynamics of loose sand, specifically with a goalof building a better understanding of the grain level dynamics. High speed photography coupledwith a particle image velocimetry (PIV) technique were used to capture both the grain level andbulk response of the penetration event. Experiments were conducted over a velocity range of 30to 100 m/s using both cylindrical and spherical projectiles. The results indicate that variations inthe projectile size and shape effect cavity formation and that cavity formation occurs nearly 25times slower than the projectile velocity.