Material Damage to a Target Caused by an Impact with an Elongated Body

Abstract

Wave pattern analysis of the interaction of an elongated impactor with a target allowed us to establish a number of previously unknown features of the process. The entire length of the impactor can be divided into sections where the wave pattern repeats the initial phase of the impact, while the role of the target is played by the impactor material. Throughout the entire process of interaction of the two bodies, the mass velocity and the pressure behind the shock wave front moving along the side face have constant values equal to (0.25–0.32) of the initial value. The cycle itself is characterized by two stages. At the first stage, the convergence of the lateral unloading waves on the contact surface leads to the establishment of zero pressure, a layer of unloaded material is formed between the shock waves in the target and the impactor, while the impactor penetration stops. A needle-like crack along the symmetry axis appears as a result of focusing the unloading lateral waves. The second stage is characterized by shock wave attenuation. The incoming flow, the velocity of which is equal to the impact velocity, is braking at the attenuation wave front, which leads to an increase in pressure and the formation of compression impulses. The arrival of compression impulses on the target restores the interrupted process of the impactor penetration and creates new spall damage in the rings from around the needle-like spall, as a result of the unloading waves interference, the sources of which are the spall cracks formed earlier and the impactor side face.