Hydroelastic study on the water impact of point absorbers made of composite materials

The water impact of a three-dimensional hemispherical point absorber made of composite materials at constant velocity is studied. The hydroelastic problem is assessed by the explicit finite element method with an Arbitrary Lagrangian Eulerian approach considering the deformation of the structure. The study starts with a comparison with results presented in the literature for a rigid body material and a sensitivity analysis of mesh size. The influence of the penalty factor, which models coupling between body and fluids, is assessed on both hydrodynamic and structural response for a sandwich composite material. The influence on both hydrodynamic and structural response of two different impact velocities is analysed with three different composite materials. According to the results, the penalty factor has a relative importance on both hydrodynamical and structural response while the impact velocity has a considerable effect on the structural response. The penalty factor values of 0.01, 0.1 and 0.5 cause around 22 % differences for strains and 16 % differences in case of stresses. Increasing the impact velocity from 4 m/s to 6.15 m/s increases the maximum principal strains and the Von Mises stress in the sandwich structure roughly by 2.