Experimental study of wave slamming of sandwich composites panels

Slamming of ship hull structures was simulated using sandwich composite panels that were repeatedly slammed on to a body of calm water with the main objective of understanding the damage accumulation mechanism and corresponding lifetime. Literature is abundant on ship hull slamming; however, it is limited to single slamming; while damage accumulation and progression under repeated slamming is largely absent. Therefore, an extensive experimental program was carried out to understand damage accumulation and failure in sandwich composites under repeated slamming as a function of deadrise angle and slamming energy. The two model material systems used consisted of polyester foam filled honeycomb sandwich composites and polyurethane foam core sandwich composites. Honeycomb core sandwich composites indicted a significant damage accumulation as a function of increasing slamming energy. Similarly, foam core sandwich composites revealed a gradual but substantial damage accumulation as a function of increasing slamming energy or decreasing deadrise angle. The modes of failure corresponded primarily to local facesheet yielding with evidence of core crushing for the honeycomb core sandwich composites. While, the modes of failure indicated mainly interface tearing, core shear and facesheet buckling in the case of foam core sandwich composites. Interestingly, the peak pressures and strains were observed to occur near the keel while the maximum damage was obtained near the chine at deadrise angles between 15° and 20°; as ship hull design is primarily based on peak pressures, this result is quite significant.