Deformation Process at Impact Face of Lead Projectile during Normal Impact on Target

When a cylindrical projectile is collided normally with a target at high velocity, plastic deformation and/or failure occur on both bodies. If the relative impact velocity between both bodies is not high, a sharrow crater appears on the impact face of the target and a mushrooming profile on the projectile after impact. However, when the relative velocity is very high and the deformation resistance of the projectile is much lower than that of the target, the deformation of the impact face of the projectile becomes large and the outer part of the face is separated from the target by bending moment. Therefore, it is considered that the deformation process at the impact face of projectile is complicated. In this study, a lead projectile of 11mm dia., which has lower deformation resistance than that of the target, was collided normally with a stainless or polycarbonate target, and the deformation process at the impact face of projectile was recorded by an image converter camera from the side and the front. Additionally, the process was also examined based on the profile of craters on both targets and the distribution of the ring cracks on the polycarbonate target. The following results were obtained. The region from the center to about 7mm dia. of the projectile during impact was loaded compressively, and the projectile material flowed radially in the region from about 7mm to 14mm dia. In the outer region from 14mm, the material of the projectile was bent and separated from the target. These results show that the impact face of the projectile during impact can be characterized by three different regions described above.