Electric potential detection for structural surface crack using coating sensors

For the structures enduring cyclic loading during their operation, the fatigue crack will likely occur on the structural surface and continually spread, and this will endanger key structures safety. It is very necessary and important to effectively discover and monitor surface crack in aero-structures. This study presents an approach to detect crack length and location by measuring a set of the electric potential difference or resistance values between any two points on the structural surface. In experiments, nickel–phosphorus coating is covered on the structural surface as sensors. The results show that it is feasible to detect crack damage in the structural surface using the proposed technology and coating sensors.