Experimental and numerical investigation on performance of sandwich panels using aluminum faces and polyurethane foam core with variable density against explosive loading

Sandwich panels, due to high strength to weight ratio and energy absorption properties, are widely used in various fields including aerospace, marine and automotive industries. This study has explored the blast resistance of sandwich structures with aluminum face-sheets and variable density polyurethane foam core (graded). In this article, several aluminum sandwich panels with polyurethane foam core having different densities is designed and have been tested. Using a blast shock tube facility, the effects of graded changes of core foam density and foam layers sequence with different densities on transverse deflection of back face-sheet are studied. Also using the compression test results performed on the foam, numerical simulations are performed using Autodyn software. The results show that there is a good agreement between numerical and experimental results with a maximum error of 13%. Experimental and numerical investigations indicate that deformation of back face-sheet of the sandwich panel with graded foam core, when the foam layer with higher density is placed in the blast side, is less than a single layer sandwich panel and equivalent mass. So it is better to use it as the main structure. Also, in case the foam layer with less density is placed in the blast side, the energy absorption of the panel increases and so the use of this panel is suggested as a protective structure.