High strain rate response of sandwich composites; Effect of core density and core-skin debond

Foam core sandwich composites with and without implanted delamination have been tested under high strain rate (HSR) loading in the thickness direction. Newly developed Hopkinson Bar technique has been implemented for this purpose. Three types of cores with various densities have been tested under compression at strain rates ranging from quasi-static to 1000 S-1. The compressive failure stress has been observed to be directly proportional to the core density, as well as to the strain rate. The strain rate sensitivity was moderate, and the sandwich composites mostly,failed by the collapse of the foam-cell. Delamination did not play a major role in the failure process and did not cause any significant decrease in load bearing capacity of foam core sandwich composites under dynamic loading in the thickness direction.