Protective structure design of foam and gel filled metallic honeycomb sandwich panels subject to blast loading

Abstract

Honeycomb sandwich structures have been studied for a variety of applications, particularly as blast resistant structures because of their high strength to weight ratio. The current numerical study investigates the response of a circular core sandwich panel made of a stainless-steel alloy, AL-6XN, with hollow cores, foam filled cores, and gel filled cores under air blast load of 1–3 kg of Trinitrotoluene (TNT) at a distance of 100 mm.Furthermore, the circular core sandwich models filled with different proportions of foam and gel, distributed either along the height of the core or across its area are analyzed in order to determine the most effective blast-proof panel with minimum weight. Three hybrid foam-gel models are compared in this study: (a) gel filled in the top half of the core and foam in the bottom half, (b) gel filled in top three-quarter parts of the core and foam in the lower quarter part, and (c) fully gel filled cores in the central 25% of the core tubes and the remaining outer core tubes fully filled with foam. A comparative analysis for mass vs deflection is carried out for all the gel-filled, foam-filled and hybrid gel-foam models w.r.t. the hollow core model. The fully gel filled core sandwich panel showed minimum back plate deflection compared all the core filled models, but at the same its mass showed notable increase. Amongst the hybrid foam-gel panels, the model having central 25% of the core tubes fully filled with gel showed a good combination of reduced panel mass with superior blast resistance capacity.