The technology of composite patches and their structural reliability inspection using infrared imaging

Nowadays, composite components and reinforcements are widely used in aircraft repair technology, since they present more efficient performance than conventional repairs. Composite patches (carbon or boron fibres) have been used for many years, mainly for research purposes, in aircraft maintenance. This move towards composites is mainly because of the increased mechanical performance, less corrosion and fatigue problems, allowing for longer service life of the aircraft. In this work, the technology and use of composite patching was described and reviewed. Furthermore, since the detection of structures integrity under patch, during the service life of aircraft, by non-destructive means is considered of great importance, infrared thermography was used for the detection of simulated artificially introduced damages—cracks, on the surface of Al 2024-T3 aircraft skin panels under composite patching or simulated delaminations between two plies of composite patches. Finally, real-time monitoring of damage during fatigue loading using thermography was also discussed and attempted in the laboratory on aircraft repaired panels.