Repeated Slamming of Sandwich Composite Panels on Water

Wave slamming was simulated by repeatedly slamming rectangular sandwich composite specimens mounted on a rigid wedge with constant deadrise angle onto the body of calm water at various energy levels. Under single slamming, peak pressures and strains on the specimens were consistently found near the keel, whereas the maximum damage was localized near the chine. Significant reduction in strength was observed resulting from a single slam even at a moderate slamming energy level that left no apparent/visible damage to the test panel. Similarly, a substantial reduction in strength was observed under repeated slamming at various energy levels. The results were corroborated with acoustic emission observations that indicated a substantial reduction in AE activity in slammed specimens. A methodology was developed for the quantitative assessment of remaining strength and damage accumulation in slammed specimens using AE technique. Face yielding and core crushing were found to be the dominant modes of failure.