Composite Patch Repair for Underwater Aluminum Structures

Abstract

Both experimental and numerical studies were conducted to investigate the effectiveness of composite patch repair on underwater structures, especially aluminum alloy structures. Physical samples were prepared using 5XXX aluminum plates with a premachined hole and E-glass woven fabric layers. The epoxy resin was selected such that it could be cured underwater. Test samples were prepared under different curing conditions such as dry curing and wet curing with different durations of in-water exposure. Strain gages were attached to all samples. The samples were tested for both tensile and four-point bending loads. Furthermore, numerical modeling and simulations were conducted, and the numerical models were validated against the experimental measurements. Then, the interface normal and shear stresses were determined from the numerical models so as to understand the delamination failure at the interface between the aluminum and composite patches. Underwater composite patching showed good interface strength and potential for successful usage in repairs.