Response of submerged metallic sandwich structures to underwater impulsive loads

The response of planar sandwich structures with metallic square-honeycomb cores under high-intensity water-based impulsive loading is analyzed through fully dynamic finite element simulations.The analyses concern overall structural response, damage and energy dissipation.The steel sandwich plates considered have different contact conditions with water -an air-backed configuration which simulates contact with water on only the load side and a water-backed configuration which simulates submerged conditions.The 3D finite element simulations account for the effects of fluid-structure interactions and the ductile failure of the sandwich structure material.Results show that the primary deformation mode is core-wall buckling in light-core structures and shear-rupture in face-sheets and core-webs in heavy-core structures.On a unit weight basis, sandwich structures with heavy cores perform poorly while those with light cores exhibit superior blast-resistance in terms of back-face deflection and total energy absorbed.Significant differences between the responses of air-backed and water-backed structures are observed.An analysis is carried out to develop structure-loading-performance relations to facilitate the design of structures tailored for specific loading conditions.