Numerical simulation and analytical study of ship-bridge collision based on fluid-structure interaction

Many ship-bridge collision studies underestimate the role of fluid dynamics, often relying on simplified models that assume a constant additional mass (CAM) for the ship. This approach neglects important factors such as ship profile and tonnage, leading to inaccuracies in collision predictions. To address this, a finite element model is developed using LS-DYNA, incorporating fluid dynamics in the ship-water-bridge interaction. This study examines the impact of fluid dynamics and key ship parameters—such as impact speed, draft depth, collision angle, and tonnage—on impact force, energy conversion, structural response, and ship damage. Comparisons between CAM and fluid-structure interaction (FSI) models show significant differences. For instance, higher impact velocity and draft depth increase ship damage, while the FSI model demonstrates that the fluid reduces structural damage through a “water cushion” effect. In collisions with large-tonnage, deep-draft ships, the CAM model underestimates peak collision force. These findings emphasize the importance of considering fluid effects in ship-bridge collision analyses and offer more accurate methods for future assessments.