Shock resistance of elastomer-strengthened metallic corrugated core sandwich panels

How polyurea coating affects the shock resistance of fully-clamped metallic corrugated core sandwich panels against high-velocity aluminum foam projectile impact is systematically elucidated via a mixed experimental and numerical investigation. Dynamic deformation process, deformation/failure modes, and permanent deflections of polyurea-coated sandwich panels are testified at various projectile momentum and compared with those of non-coated sandwich panels. A high-fidelity finite element (FE) model considering both rate-dependent compressive and tensile behaviors of polyurea elastomer is established and employed to simulate the dynamic response of polyurea-coated sandwich panels, interrogate the underlying enhancement mechanisms, and estimate the effects of projectile momentum and coating thickness/area/position upon permanent mid-span deflection and energy absorption. Reasonable agreement is realized between FE predictions and measurements. The presence of polyurea coating helps curtail permanent deflection in the central region and avoid shear failure around the clamping area. The benefit of polyurea coating on mitigating impact deformation remains stable as the projectile momentum is varied over a broad range, and the use of thicker, larger, and impact-side coating is preferred. The observed performance improvement is attributed mainly to enhanced plastic bending moment and membrane force in the polyurea-coated sandwich panel. The results of this study open up a new avenue to enhance the shock resistance of metallic sandwich structures subjected to impulsive loading.