Study on the dynamic response and dynamic buckling modes of cylindrical shells under deep-water explosions

This paper studies the deformation and dynamic buckling mechanisms of cylindrical shells subjected to explosive loads at varying water depths, through a combination of deep-water explosion experiments and numerical simulations. The underwater explosion experiments were conducted across different water depths, with high-speed photography used to capture the response process of the structure under the combined effects of dynamic loads (such as shock waves and bubble pulsations) and hydrostatic pressure loads. A deep-water explosion simulation model was established using LS-DYNA finite element software, and its accuracy was validated against experimental data. The results show that the response process of the cylindrical shells under dynamic-static coupled loads occurs in a sequence: initial hydrostatic pressure, shock wave-hydrostatic pressure coupling, water jet-hydrostatic pressure coupling, and finally hydrostatic pressure, each stage exhibiting distinct response characteristics. The dynamic-static coupled loads induced overall buckling of the structure at only 42.9% of the critical buckling pressure, resulting in significant deformation even at lower pressure conditions. Two modes of overall buckling were observed: mode 3 buckling at pressures slightly above the critical hydrostatic pressure, and mode 4 buckling under other conditions, consistent with the hydrostatic pressure buckling modes. The change in buckling mode is attributed to the relative relationship between the lateral and rear residual strength of the cylinder and the water pressure.