The flaw-detected coating and its applications in R&M of aircrafts

A monitoring method called ICM (Intelligent Coating Monitoring), which is based mainly on the intelligent coating sensors, has the capability to monitor crack initiation and growth in fatigue test coupons has been suggested in this study. The intelligent coating sensor is normally consisted of three layers: driving layer, sensing layer and protective layer where necessary. Fatigue tests with ICM for various materials demonstrate the capability to detect cracks with l<300μm, corresponding to the increment of the sensing layer's resistance at the level of 0.05Ω. Also, ICM resistance measurements correlate with crack length, permitting crack length monitoring. Numerous applications are under evaluation for ICM in difficult-to-access locations on commercial and military aircrafts. The motivation for the permanently flaw-detected coating monitoring is either (i) to replace an existing inspection that requires substantial disassembly and surface preparation (e.g. inside the fuel tank of an aircraft), or (ii) to take advantage of early detection and apply less invasive life-extension repairs, as well as reduce interruption of service when flaws are detected. Implementation of ICM is expected to improve fleet management practices and modify damage tolerance assumptions.