Coupling damage effects of simultaneous underwater explosions of double charge on multi-cabin structures

•Experiments on multi-cabin structures by simultaneous underwater explosions with double charges.•The relative positions of the charges affect the coupling of shock waves and bubbles.•Pre-cut holes change the mechanism of load transfer and structural damage.•The central region of the structure produces significant coupled damage features.•Pre-cut holes lead to structural tearing and severe internal damage. The damage mechanisms of ship structures subjected to underwater explosions are critical for marine engineering safety. Previous research has predominantly focused on the effects of single charges on simplified plates, often neglecting the coupling effects of multiple charges and the complex characteristics of ship structures. This study addresses these gaps by investigating the coupling damage effects of double-charge underwater explosions on complex multi-cabin structures under near-surface conditions using experimental and numerical methods. Our experimental and simulation results demonstrate that shock waves and bubbles couple in the central region, exacerbating structural damage. The relative position of charges alters coupling characteristics. Furthermore, the study highlights that pre-cut holes in the structure significantly influence load transmission and damage mechanisms, leading to tearing and severe internal damage. This research addresses a crucial knowledge gap, providing new insights and methodologies for enhancing blast-resistant design in ship engineering.