A New Approach to Compute the Non-Linear Whipping Response Using Hydro-Elastoplastic Coupling

In the last ten years, the importance of whipping on the extreme hull girder loads has received much attention, but its consequence on the hull girder’s collapse is still unclear. The most common practice is to consider the structural behavior as linear-elastic in the hydro-elastic coupling, and as non-linear elasto-plastic in the ultimate strength evaluation. In order to investigate the influence of the non-linear structural behavior on the hydro-structure interaction responses, a new hydro-elastoplastic model is proposed to compute the non-linear whipping response. The structural part is modeled as two beams connected by a non-linear hinge, which follows the collapse behavior of a ship’s hull girder. The hydrodynamic problem is solved using the three-dimensional boundary element method, and the exact coupling between the structural model and the hydrodynamic one is made by making use of the shape function approach. Finally, the fully-coupled hydro-elastoplastic problem is solved directly in time-domain by numerical integration.