Experimental and numerical investigation into the effect of core density on the energy absorption of sandwich panels with Aluminum face sheets and Polyurethane foam core

Sandwich panels, due to high strength to weight ratio and energy absorption properties, are widely used in various industries including aerospace industries, marine and automotive industries. In this article several aluminum sandwich panels with polyurethane foam core with different densities were designed and tested using a shock tube facility. Some of blast tests were defined in order to determine the effects of foam density on transverse deflection of back face-sheet and energy absorption of sandwich structures. Also using the results of compression test performed on different foams, numerical simulation using Autodyn software were performed. There was a good agreement between experimental investigation and numerical results. Using experimental testes and parametric studies, it is shown that increasing foam density can lead to reducing the transverse deflection of back face-sheet of the sandwich panel, but the energy absorption of the panel also decreases. Also increasing the density of the foam, in addition to reducing the shape of the back face of the panel, lead to more uniform profile. On the other hand, the results show that by increasing the amount of explosives, the effect of increasing the core density on the amount of transverse posterior deformation grows. It can be concluded that if the sandwich panel is the main structure, it is advisable to use high-density foam, but if the panel is to be installed as a damping structure on another structure, a lower density foam should be used to reduce the pressure transferred to the back face of the panel.