Modeling and validation of composite patch repair to cracked thick and thin metallic panels

Comparison between composite and metallic patches for repairing aircraft structures of aluminum alloy 7075 T6

“…Bonded patch repairs, however, require a stringent cleaning, preparation and curing procedure, but when properly designed, fabricated and used, they extend the life of cracked components with high structural efficiency at an economical cost. Mall and Conely [7] investigated the fatigue growth of repaired crack in thick and thin panels and they observed that there was significant bending as well as non-uniform crack growth between the un-patched and patched faces of the repaired thick panels due to the asymmetric repair. Fekih et al [8] tried to optimize the patch sizes using the design of experiment method.…”

Processing and Environmental Effects on Composite Repairs

“…Investigations, therefore, are going to determine the environmental effects of oil, fuel, paint striper, and absorbed moisture on the repaired laminates [14][15][16] and also to determine the differences between the properties of vacuum bag cured and autoclave cured laminates [4,5]. Geometric effects including laminate material thickness, stacking order, structural form, accessibility, and protrusion limitations are also being investigated [1,3,13,17].…”

Fatigue behavior of thick center cracked aluminum plates repaired by two-sided composite patching

“…An experimental investigation was also conducted by S. Mall and D.S. Conley [17] to characterize the fatigue crack growth behavior in pre-cracked aluminum specimens of two thicknesses (1 and 6.35 mm) with asymmetrically bonded patches. Repairs were found to provide four and ten times improvement in the fatigue life of thick and thin panels over the unrepaired cases, respectively.…”