A Hydroelastic Method for the Analysis of Global Ship Response Due to Slamming Events

An important aspect of ship design is structural strength. To accurately assess the structural design, the loads experienced by the vessel during its lifetime must be properly understood. Hydroelasticity is the study of conditions where there is a coupled interaction between loads from a dense fluid, such as water, and the response of an elastic structure. Present methods for numerically predicting hydroelastic response either use potential flow models or computational-fluid dynamics (CFD) to model the fluid domain. The potential flow models cannot easily handle an overturning free surface as occurs in slamming, and thus the slamming problem is usually treated separately. The current hydroelastic method uses the accuracy and flexibility of CFD, focusing on efficiency while maintaining numerical stability.;The present fluid-structure interaction solver couples finite-volume CFD with a modal finite-element description of the structure. Predictions of vessel structural response in waves is achieved by combining the structural solver with a large-amplitude rigid-body motion solver. Under-relaxation and iteration are used for stability and accuracy. New stability limits are developed to guide relaxation selection. The solver is designed to be as efficient as possible, using inertial under-relaxation to reduce the number of iterations and an approximate boundary condition that removes the need for expensive mesh deformation.;Several problems are chosen to validate the present method. Constant velocity elastic wedge impact is used to validate the solver. Then, the role of hydroelasticity is examined for a wedge that enters and exits the water, highlighting that it is important to account for hydroelastic effects when the loading period is relatively small. The validation of the combined rigid-body and structural method is performed with Wigley hull seakeeping and segmented elastic box barge experiments, with the method performing exceptionally well vertical plane motions and bending. The method is demonstrated on the Joint High Speed Sealift (JHSS) segmented model data, a realistic ship geometry. The JHSS model is used to evaluate approximate methods used in industry and show cases when it is important to include hydroelastic effects for a ship in a seaway.