Space and velocity field models of debris cloud in hypervelocity impact of disk projectile on thin plate

In order to reconstruct the evolution process and characterize the fragments’ motion of the debris cloud, the space and velocity field models of debris cloud generated by a hypervelocity disk projectile impacting a thin plate are developed by using the shock wave theory in this study. To obtain the characteristic velocity of the debris cloud accurately, shock wave loading and isentropic unloading are considered. In particular, the effect of the isentropic unloading of rarefaction wave on particle velocity is considered based on the Bless model. The difference in particle velocity between shock wave loading and rarefaction wave isentropic unloading is calculated for oxygen-free high-conductivity copper (used as projectile material) and Al 6061-T6 (used as bumper material) considering different shock pressure values. To solve the characteristic velocity of the debris cloud, a modified isentropic unloading model is developed. Then, based on the self-similarity assumption and modified isentropic unloading model, the structural contour function of the debris cloud at a stable expansion stage is introduced to establish the space and velocity field models. Furthermore, numerical simulation using smooth particle hydrodynamics is conducted to verify and analyze the model results. The spray angle of the debris cloud and contour map of the velocity of particles in the cloud are obtained. Finally, the evolution process of the debris cloud is reconstructed, and the motion characteristics of the fragments in the cloud are quantitatively described.