Finite element analysis of load characteristic of liquid-filled structure subjected to high velocity long-rod projectile penetration

To find effective protection for fluid-filled structures subjected to high-speed projectile penetration, we studied the characteristics of a structure bearing impact loads when undergoing high velocity rod projectile penetration using dynamic nonlinear finite element, and analyzed the process of the impact load, the load strength, the projectile initial velocity, and water scale, and their effects on the front and rear plates that bear the impact. Our results show that the initial penetrating effect (pit-opening) on the liquid-filled structure forms incident shock waves, which will have a high peak pressure but a short duration, and produce multiple reflections in the liquid. Along with the penetration process in the liquid, the cavitation will occur and result in a cavitation pressure load which will reach a small peak value with a long duration. Local high pressure load will be formed due to the rear plate hindering the liquid flow, and incident shock wave and local high pressure increase with the increase of the initial projectile velocity but decrease with the increase of the length of the waters. According to different characteristics of shock load borne by different parts of the structure, the front and rear plates are divided into three different areas, and a simplified model was established for each.