Effects of gas pressure on the front wall damage of pressure vessel impacted by hypervelocity projectile

The typical damage of gas-filled pressure vessel impacted by hypervelocity projectile includes perforation and crack instability, which lead to gas leakage and explosion. The effect of gas pressure on front wall damage is still unclear so far. Experiments and numerical simulations are reported, in which spherical aluminum gas-filled pressure vessels with different inner pressures were impacted by spherical aluminum projectiles traveling at hypervelocity. A two-stage light gas gun was used to launch an aluminum alloy spherical projectile into the pressure vessel at hypervelocity. The size and cross-section morphology of the perforation with different inner pressures were obtained. According to the various purposes of numerical simulation, two kinds of two-dimensional axis symmetric pressure vessel models were established. The numerical model for type A is a whole model which behaves as the actual pressure vessel. The numerical model for type B included a vessel wall on which there was a stress with same value as inner pressure and non-pressure local gas. The numerical results of perforation diameter and morphology, shock wave propagation, and hoop tensile stress on the hole edge were obtained. The effects of gas on the morphology and diameter of holes in the front wall, as well as the hoop stress on the edge of hole were explored. The mechanism of shock wave in the gas affecting the crack instability in the front wall was discussed and supported by a description of the shock wave propagation. It is shown that the inner flanging morphology on the edge of hole is influenced by the gas pressure. It bends more lightly when the gas pressure is higher. It is shown that the influence of gas pressure on the hole diameter is positive, although it is less obvious than that of wall thickness and impact velocity. The hoop tensile stress is affected by not only the reflected shock wave from the back wall, but also the stress wave propagation in the vessel wall, which is in proportion to gas pressure. © 2021, Editorial Staff of EXPLOSION AND SHOCK WAVES. All right reserved.