Hypervelocity Impacts on Porous Metal: as a Capable Candidate for Debris Bumper Shield Material

Abstract

Porous materials absorb impact induced shock well. The pore crushing process results in the compaction of the target, and a considerable part of the impact energy is thought to be consumed in this process. In the case of the impact on gypsum targets, 31 to 62% of the impact energy was distributed into compaction. In this study, applicability of this effect of compaction to develop lightweight debris bumper shields is considered through impact experiments. Porous aluminum plates were employed as targets and solid aluminum spheres, 1.0 mm and 0.3 mm in diameter, were used as projectiles.Normal impacts at about 6 km/sec produced bulb shaped craters. Damaged depths in targets were at most 71% of the ones estimated from impact craterings on solid aluminum plates sharing the same mass per unit area with these porous aluminum plates. Little high speed ejecta was observed by a high-speed video camera.