Experimental study on sandwich structures subjected to medium velocity impacts for aircraft armour applications
Résumé
Sandwich composites are well-established as lightweight materials for transport applications due to their good weight-specific bending stiffness. These structures present also good energy absorption capabilities; therefore they are good candidates as armour structures against shock waves or impacts. Studies on ballistic impacts (typically >250 m/s, 100 J) are mainly focusing on dry fabrics or compliant composites. Fibre material, woven pattern, ply number and friction properties as well as target dimensions and boundary conditions are identified as significant parameters. In naval applications, sandwich structures with metallic skins and metallic foam or honeycomb are typically used as against shock waves. Several studies on sandwich structures underline the role of the skins in energy absorption. This study focuses on armour solutions for the aircraft fuselage located near the engine. This zone is potentially subjected to engine debris or ice impacts. The selection criteria include impact resistance without perforation, minimal structure weight and back deformation. A preliminary investigation has been lead in order to evaluate the influence of the front skin on perforation resistance. The objectives are to identify efficient front skin – core combinations and to optimise the core properties.