Experimental investigation on the perforation behaviour of sandwich panels with hybrid composite face sheets and cellular aluminium core using quasi-static and instrumented inverse impact methods

With the rising demand for lightweight and high-performance shielding systems, sandwich panels made of thin rigid face sheets and cellular material cores have recently received much attention. The present study aims to investigate the perforation behaviour of lightweight sandwich panels made of fibre reinforced composite face sheets and aluminium foam core under quasi-static and dynamic testing conditions. A particular focus is made on the fibre hybridization effect on the overall panel behaviour. Impact perforation tests were conducted using an inverse perforation technique. Instead of conventional free-flying projectile impact tests, studied samples are fixed in a hollow projectile. Then, this assembly is accelerated toward an instrumented steel perforator replacing the incident bar of a split Hopkinson pressure bar. Consequently, this modified split Hopkinson pressure bar system can be used as both a perforator and a measuring device. Therefore, the piercing force-displacement curves, the energy absorption capability as well as the penetration and damage mechanisms of the tested panels was analysed and compared to quasi-static perforating tests. To better assess the testing results, quasi-static tensile and bending tests were carried out on the face sheets materials. Moreover, quasi-static and dynamic compression tests were performed on the aluminium foam core using conventional test methods and direct split Hopkinson pressure bar. Unlike the aluminium alloy face sheets, the experimental findings revealed that the sandwich panels with composite face sheets demonstrated higher rate sensitivity, better perforation resistance and specific energy absorption capability. Results have also shown that the hybridization of carbon and glass fabrics combined their best tension and bending properties as well as their higher dynamic strength, which has increased the sandwich panel's perforation resistance.