Dynamic responses of kerosene-filled riveted tanks subjected to hydrodynamic ram caused by ballistic impacts

The hydrodynamic ram (HRAM) is a hydrodynamic pressure phenomenon that occurs when high-speed projectiles impact a liquid-filled tank. During combat missions, aircraft are prone to HRAMs caused by projectile impacts, which can damage the structural integrity of riveted tanks, posing a threat to flight safety. In this study, kerosene-filled riveted tanks were chosen as the research object. The dynamic response histories of the rear panel were observed using the three-dimensional digital image correlation (3D-DIC) technique. Additionally, numerical simulations of the projectile's impact on the tank were performed using the fluid–structure interaction finite element method. The simulation results had a good fit with the experimental results. The spatial and temporal distribution of the HRAM and the effect of the projectile impact velocity on the deformation of the tank structure were further analyzed. The impulse exerted by the drag wave on the rear panel was greater than that of the pioneer wave. However, the drag wave's region was limited to a radius of 6 cm around the exit point with the impact velocity range of the projectile of 955 m·s−1–1607 m·s−1 in both the experiments and simulations. When the impact velocity of the projectile reached 955 m·s−1, radial plastic hinge lines appeared on the rear panel along the diagonal direction. When the impact velocity increased to 1607 m·s−1, radial plastic hinge lines along the diagonal direction, and traveling plastic hinges at the root of the central cross-shaped cracks appeared on the rear panel, accompanied by a petal-shaped hole. Based on the spatial distribution of the impulse on the rear panel, a dimensional relationship was established between the hole size and the impulse on the rear panel. The petal model for describing petal-shaped cracks was proposed based on the law of conservation of energy, which could predict the hole size in the case of projectile impact at high velocity. The research results are of great significance for the study of the damage of riveted tanks with HRAMs and provide support for the vulnerability analysis of aircraft tanks.