Damage mechanism of double-layer cylindrical shell subjected to underwater explosion

In this paper, comprehensive underwater contact explosion experiments are carried out on flat plates, aiming to substantiate the experimentally observed damage characteristics. Furthermore, the radius size during the bubble pulsation process is validated. Subsequently, a study on the damage characteristics of underwater explosion loads on double-layered cylindrical shells is conducted. The coupling mechanism between underwater explosion loads and elastoplastic structures is explored. The influences of factors such as explosion distance, water depth, and the type of fluid medium between the double-layered shells on the structural damage modes and damage effects are analyzed. The research shows that within a certain range, variations in the explosion distance mainly affect the destructive effects of shock wave loads on the structure, while the large temporal and spatial scales of bubbles make them less affected by the explosion distance. Changes in water depth primarily affect the destructive effects of bubble loads on the structure. As the water depth increases, the pulsation period and radius of the bubble decrease, and the energy dissipation during bubble pulsation also decreases. Consequently, the pulsating pressure generated by the secondary expansion of the bubble and the intensity of the water jet load can be effectively increased. In deep-water environments, the structural deflection is mainly determined by the bubble load. The water layer between the double-layered shells can effectively reduce the damage effects of shock waves and bubble loads on the structure.