Damage tolerance and repair of GFRP warships

The United Kingdom has operated glass-fiber-reinforced plastic (GFRP) minesweeper vessels since the early 1970s. Under typical operating conditions they may sustain minor impact damage, leading to delaminations within the hull shell and debonding of the stiffener frames. Such damage is costly to repair, and hence there has been a move towards cost reduction through better understanding of the structural behavior of typical defects under the loading conditions present within the structure. This approach, using damage tolerance techniques, has led to a relaxation in the requirement for repair, and consequently the number of repairs has been substantially reduced. In addition, advance techniques have been developed using resin infusion technology for the re-attachment of debonded stiffener frames. The structural element tests used to validate the damage tolerance philosophy will be examined and the resin-infusion repair method explained using a case study detailing its first successful application.