Damage Prediction in FRP Sandwich Structures for Marine Application under Dynamic Loading

FRP sandwich structures (FRPSSs) are increasingly popular in marine applications thanks to their high stiffness, lightweight, good buoyancy, and damage resistance. These structures are often subjected to damage foreign-object damage in the form of low-velocity impacts. In this study, an in situ acoustic emission methodology was employed to monitor seawater ingress into FRPSS samples with varying core configurations until saturation and subsequently samples were subjected to large-deflection impact bending tests. The obtained results indicated that the moisture uptake led to a reduction in impact bending capacity. Notably, there was a negligible change in energy-absorption performance after exposure. Post-exposure assessment of the damage morphology revealed extensive core shearing, delamination, core/face sheet debonding, and fibre breakage as major failure modes.