ABSTRACT
Glass Reinforced Plastic (GRP) composites have been used in marine structures due to their excellent corrosion resistance, light weight, ease of reparability, ability to absorb noise and damp vibrations, design flexibility and ease of the manufacturing processes. It is estimated that composite boats are usually approximately 10% and 35% lighter than the same size aluminium and steel boats, respectively (Selvaraju 2011). Moreover, up to 65% weight reduction can be achieved for a naval craft by replacing steel with composite material (Heller 1967). However, the stiffness and the strength of composites in the through-thickness direction are very weak since no fibres exist in this direction. Thus, they are very susceptible to the impact damage, especially for out-of-plane impact events. During service operation, ships may experience various lowvelocity impact events, such as grounding, collision with floating object, other craft or dock. The impact damage may lead directly to the entire structural collapse. Moreover, the damage may grow with the ubiquitous cyclic loadings in the marine environment, and eventually lead to a catastrophic failure under normal loading. This should be paid attention since the damage may be internal and remain undetected.
