Implosion of composite cylinders due to underwater impulsive loads

Abstract The implosion of composite cylindrical shells in underwater blasts is a process in which a structure collapses inward onto itself and releases energy via outwardly radiating pressure pulses. Relevant issues include incident loading, elastic buckling, plasticity, damage, and release of impulsive waves. Research is still in an early stage. So far, experimental studies have primarily focused on the structural response of composite tubes including the load threshold for buckling and material damage and the release of impulsive waves from the collapse site. The latter is of concern as it is a source of potential damage for surrounding assets. Computational simulations have tracked and complemented the development of experiments, focusing on the effects on structural response of material, layup, and loading. It has been shown that filament-wound glass-fiber composite structures offer superior resistance to damage and yield lower postcollapse energy release compared with carbon-fiber composite structures. One focus has been on the development of quantitative relations between structural response in terms of deflection, energy dissipation, and intensity of released pressure pulses and input conditions in terms of initial incoming load intensity, internal air pressure, fiber orientation, and structural design attributes. The overarching objective is to establish criteria and load-structure-performance relations for the design of structures with enhanced, tailored, and adaptive performance offerings. This chapter reviews the progress in experimental investigations and presents recent computational studies on the response of composite cylindrical structures during an implosion event.