Hypervelocity Penetration into Soil

AbstractThis paper is focused on the physics of hypervelocity soil penetration. The influence of the shape, material and structural integrity of various impactors on penetration depth was investigated in the range of speeds between 0.3 and 4.0km/s. Deviation of impactors from their initial trajectory, melting, erosion and spall has also been studied. Initially, with the increase in impact speed, the penetration depth increased. At a certain critical speed, the impactors reached their maximum penetration depth. With further increases in the impact speed the penetration depth declined. We developed refined analytical solutions to compute the maximum penetration depth achievable by a given impactor as well as its penetration depth in the region above the critical speed. These solutions accounted for the impactor weight, its length-to-diameter ratio and water content in soil. The results of these analytical predictions were compared with experimental data. Unexpected and rather damaging physical phenomena, including a fireball and unusual signals recorded by electronics, were observed in experiments involving hypervelocity impact against wet soil