Experimental study on penetration of non-circular cross-section long-rod projectiles into semi-infinite metal target

Abstract

To study the influences of the cross-sectional shapes on the final depths of penetration, a series of experiments were carried out on the penetration of long-rod projectiles with the same cross-sectional area different cross-sectional shapes into semi-infinite metal targets. The cross-sectional shapes were machined to be circular, square and cross, respectively. These experiments were divided into two groups. In one group of experiments, the long-rod projectiles with the aspect ratio of 8 and 93W alloy cores penetrated into armor-steel target plates. In another group of experiments, the long-rod projectiles with the aspect ratio of 15 and 45 steel cores penetrated into the 45 steel target plates. Depths of penetration under different impact velocities were experimentally obtained for different cross-sectional shapes, aspect ratios, and materials of projectiles and targets, respectively. Experimental results display that the penetration abilities of the three kinds of long-rod projectiles with non-circular cross-section are higher than that of the long-rod projectiles with circular cross-section under the same working conditions. And among the four kinds of long-rod projectiles, the penetration ability of the long-rod projectiles with cross section is the highest, followed by that of the long-rod projectiles with square section. With the increase of the impact velocity, the penetration gains of the cross and square cross-section long-rod projectiles to the circular cross-section ones increase. The cross-section shape of craters penetrated by the triangular cross-section long-rod projectiles takes on arc triangle, and the cross-section shape of craters penetrated by the long-rod projectiles with square and cross sections, respectively, takes on approximate circle. After penetration of the three kinds of non-circular cross-section long-rod projectiles, cracks at certain angles with the axial direction appear in the mushroomed heads of the projectile bodies, which leading to less resistance encountered by the projectiles in the process of penetration. The reason, why the penetration abilities of three kinds of non-circular cross-section long-rod projectiles are higher than that of the circular-section long-rod projectiles, is their structural self-sharpening in the process of penetration.