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.