Aluminium Block against Oblique Penetration of Tungsten Alloy Long Rod

Abstract

This paper studied ballistic performance of aluminium blocks subjected to oblique impact of tungsten long-rod projectiles. Penetration experiments of tungsten alloy long rods impacting 25.4mm thick blocks made of aluminium 7075-T651 were conducted at a nominal velocity of 1.25 km/s under NATO 60 degrees obliquity. A witness plate made of steel was placed behind the target with an air gap of 300mm. Flash X-ray radiography was applied to capture images of the projectiles before and after penetration. The test results showed the effect of the thick aluminium block to deflect the long rod projectile from its line of flight. Numerical simulation of the experiment was carried out by using the hydrocode LS-DYNA to explore defeat mechanisms of inclined aluminium blocks against tungsten long-rod projectiles. The inclined aluminium block created the upwards mushrooming and bending of the projectile’s nose during the whole process of penetration. The effect of trajectory deviation was insignificant during and immediate after the penetration; however, it became significant after some time of the penetration, resulting in a noticeable increase of the pitch angle of the residual projectile. Consequently, the residual projectile ricocheted from the surface of the witness plate with limited penetration.