Damage characteristics of a reinforced cylindrical shell under underwater dual-charge explosion during navigation

There is a dynamic coupling relationship between the bubble period of underwater explosion and the velocity of underwater vehicles. The interaction characteristics between bubbles and structures vary under different matching relationships of these two factors. The arbitrary Lagrangian–Eulerian numerical method is primarily employed in this study to investigate the damage characteristics of a typical hull structure under the impact of synchronized underwater explosion loads from dual charges. The study primarily analyzes the variations in bubble and load-induced damage under different relative velocity conditions. The results indicate that relative velocity is a crucial factor in studying underwater explosion-induced structural damage. The primary effect is that the relative velocity influences the symmetry of the coalesced bubble, weakening the jet load and causing the point of action of the jet load to shift toward the rear. Therefore, the damage area of the structure increases under the navigation state, but the maximum deflection decreases. The sensitivity of shock wave load and jet load to changes in relative velocity differs. When the relative velocity (vs) exceeds 0.6, the deflection caused by the shock wave load remains almost unchanged, while the deflection caused by the jet load continues to decrease. Therefore, when the relative velocity is low, the jet load plays a dominant role in the shell damage process. However, when vs exceeds 1.8, the situation reverses, and the shock wave load becomes the primary factor. To ensure damage efficiency, the bubble period induced by charge explosion should be regulated to match the structural velocity.