Repairing impact damaged fiber reinforced composite pipes by external wrapping with composite patches

Repairs made with composite patches on impact damaged fiber reinforced composite pipes offer distinct advantages over traditional repairs in addition to reduced cost. In this study, effects of number of patch layers on the burst pressure of low velocity impact damaged tubes that have been repaired with composite patches were investigated. The tubes were pressurized up to 32 bar prior to impact. The pre-stressed glass fiber reinforced plastic tubes were damaged by applying low velocity impacts at different energy levels (5, 10 and 15 J). The damaged areas of the affected tubes were repaired with 2, 4 and 6 layers of glass/epoxy fabrics. The repaired tubes were then failed catastrophically by being subjected to monotonic internal burst tests based on ASTM D 1599-99 standards. Changes in the tubes' burst pressures were recorded and the resulting damages on the tubes were studied. It was found that, for all the energy levels employed in this study, a six-layered patch repairing is suitable for the retrofitting of impact damaged tubes.