Hydrodynamic impact of sandwich structures with vibration isolation and structural damping properties

Foam filled hull structures show, especially for high speed crafts like RIB’s, new opportunities. These hull structures, sandwich structures with aluminium or fibre reinforced plastic face sheets and a flexible foam core, large compared to the face sheet thickness, have the advantage of low density, high strength, water penetration resistance, high corrosion resistance and promising vibration isolation and structural damping characteristics. Particular advantage is expected in case of dynamic loading in environmental severe conditions. Primary objective is to develop an analytical, 2D, mathematical model for the local structural response of a hydrodynamic impact loaded sandwich structure with vibration isolation and structural damping properties. The structural response is determined by solving semi-analytically a hydro-elastic coupled sandwich flexible core model and a hydrodynamic impact model in modal space, verified by results found in literature and FEM calculations. Beyond structural weight savings and increased buoyancy, an increased comfort level and less fatigue damage sensitivity compared to stiffened panel hull structures may be obtained.