Experimental study on the expansion of metal cylinders by detonation

Abstract

Detonation-driven metal cylinder acceleration is an important issue in the design of warheads, and calculating the initial velocity of fragments is an important part of this problem. In most previous experiments, the final expansion velocity and fracture behavior of the cylindrical casing were the main focus. However, the expansion and acceleration process of a cylindrical casing driven by internal explosion loading has not been well studied. To study the whole acceleration process of cylindrical casings under internal explosive load, a high-speed framing camera and an arrayed Doppler Photonic System (DPS) are used in the experiments in this paper. Three cylindrical casings made of TU1 copper, 50SiMnVB steel and ANSI 1045 steel were tested in the experiments. The velocity oscillations of the cylindrical casings were clearly captured in the experiments and analyzed theoretically. The experimental results show that the acceleration process of the cylindrical casings can be divided into two distinct phases: initial acceleration under the load of shock waves, and further acceleration under the load of detonation products. It was concluded that the acceleration process under the load of shock waves is highly dependent on the material of the cylindrical casings. The copper casing had higher wave impedance, and achieved higher velocity than the steel casings during the acceleration process under the load of shock waves. Furthermore, comparison of the two steel casings shows that the plasticity of the casing affects its rupture radius significantly, while the impact of the cylindrical casing on the final velocity is negligible.