Study on the damage patterns of ring-stiffened cylindrical shells under underwater explosion(UNDEX) loading

Structural damage caused by underwater explosions (UNDEX) is a critical research area in engineering and industrial applications. This study investigates the damage patterns of a typical ring-stiffened aluminum cylinder subjected to UNDEX through experiments and numerical simulations. A series of Φ9 m × 9 m explosion pond tests were conducted to validate numerical simulations and analyze structural responses under varying standoff distances (12/10.4/9.6/8.8 charge radii). An Arbitrary Lagrangian-Eulerian (ALE)-based method was employed to further explore the effects of charge weight (10/50/100/200/400/800 g) and standoff distance on structural failure. The results identified three failure modes—sagging deformation, wavelike deformation, and rupture—with sagging and rupture as the dominant modes. The coupling processes between the impact load and structural response for each mode were analyzed in detail. Based on these findings, a damage phase diagram was developed to illustrate the relationship between explosive mass, standoff distance, and damage modes, providing an intuitive representation of failure mechanisms. Additionally, dimensional analysis identified two key parameters—scaled distance and charge radius—that influence damage outcomes, with their relative influence weights quantified. This study provides critical insights into the failure mechanisms of ring-stiffened cylindrical shells under underwater explosions and offers valuable guidance for predicting damage and designing protective structures in engineering applications.