Impact Study of Composite Sandwich Panels with Different Types of Foam Cores toward Ballistic Impact Loading

This paper concerns the effect of foam types in sandwich structures under high velocity impact loading. The structure comprises composite facing made from glass fiber woven roving impregnated with epoxy resin and different polyurethane foam cores namely rigid, semi-rigid and flexible. To study their ballistic performance, smooth bore gas gun in velocity range of 150-242m/s and 2.7 g spherical-shaped steel projectile was utilized. Results demonstrated semi-rigid foam attained highest performance in terms of ballistic limit velocity and energy absorption in fully perforated specimens. Outstanding ballistic performance in semi-rigid foam core may be associated with high ability in this type of foam with respect to collapse mechanism involved in this type of core. By contrast, flexible foam indicated poor performance which arises from low shear strength inthis type of foam.