Explosive Blast Response of Marine Sandwich Composites

Abstract

This chapter presents an experimental investigation on the explosive blast response of four types of sandwich composites commonly used in naval ships, including hull and topside structures. Air blast tests were performed using plastic explosive charges on square target sandwich plates made of carbon or glass fiber-polymer facesheets with either an end-grain balsa or closed-cell PVC foam core. The sandwich composites were dynamically loaded by air shock waves of increasing pressure and impulse generated by plastic explosive charges, and the deformation, damage and post-blast mechanical properties were determined. The amount of out-of-plane deformation and blast-induced damage for a given shock wave impulse depends on both the type of fiber reinforcement used in the facesheet laminates and the type of core material. For a given shock wave impulse, glass sandwich composites have higher resistance to deflection and blast-induced delamination cracking and tow rupture then carbon fiber sandwich composites. Also, the balsa core composites are more resistant to out-of-plane deformation then the PVC core composites at low blast impulses. Damage initiates in the balsa core composites as core cracking and splitting, and facesheet-core debonding, whereas damage in the PVC core composites initiated as front facesheet compressive failure. Blast-induced damage to the skins and core causes large reductions to the mechanical properties of the sandwich composites.