Simplified approach to dynamic responses of elastic wedges impacting with water

A simplified method is proposed to model the water impact of an elastic wedge, by combining a modal analysis for the structural deflection and an analytical model for the hydrodynamic pressure on a rigid body. The structural deflections are expressed by wet modes shapes of the beam, and are calculated using modal superposition and Duhamel integral method. The results from the simplified approach are compared with the calculations by using a fully coupled numerical method. The fully coupled simulation is based on an Arbitrary-Lagrangian-Eulerian formulation included in the commercial software LS-DYNA. The Lagrangian formulation is used to describe plane-strain deformations of the structure, and the Eulerian formulation is applied to analyze the changes of the fluid. The structural deflections of wedges with different deadrise angles from the simplified method are compared with published results of theoretical method and fully coupled BEM/FEM method, showing a very significant reduction of required computation time. The convergence of the modal shapes is also investigated. The deflections of flexible wedges with various deadrise angles, impact velocities, and edge boundary conditions are computed and discussed.