Fluid structure interaction analysis of a ship collision
Ship collisions are marine accidents in which, during the impact, a significant amount of the kinetic energy is used for the deformation and destruction of the colliding ships structural members. Depending on the collision scenario, a part of the impact energy is also used in the generation of the hydrodynamic effects, namely the drag force effects and the generation of waves. Classic approach to the analysis of ship collision problems is to account the hydrodynamic effects within the global motion or external dynamic analysis, while restraining the local deformation analysis to the internal mechanics analysis. Current state of the art collision analysis couples both the external dynamics and internal mechanics through the nonlinear FEM analysis of complex models. However, hydrodynamic effects are either neglected or taken into account in a simplified manner. This paper aims to address the modeling and analysis issues of a fluid structure interaction (FSI) type of ship collision analysis. A hybrid struck ship model, consisting of a structural model and a fluid model, is generated with a twofold purpose: to assure realistic collision simulation and, at the same time, to enable, as much as possible, the insight into the collision hydrodynamics. Fully coupled, long term FSI analysis is performed using LS Dyna commercial code and a discussion on the findings and results are presented.