To monitor fatigue crack of aircraft metallic structure in real-time

a kind of eddy current array sensor based on flexible planar is proposed and a scheme for fatigue expansion crack monitoring is designed of aircraft metallic structure based on eddy current array sensor is put forward.The distribution rule of induced magnetic field and magnetic potential vector are obtained through establishing three dimensional finite element（FE） simulation model and the feasibility of the monitoring scheme is verified.By designing fatigue crack propagation experiment

quantitative capability of the sensor on monitoring is verified.The result of fatigue crack monitoring experiment of 2A12—T4 aluminum alloy under constant load indicates that the sensor can monitor the fatigue crack propagation efficiently with the precision of 1mm.The simulation result shows that the distribution of magnetic vector potential is symmetrical about the center of the exciting coil wire and the magnetic vector potential reaches maximum at the center of the exciting coil wire

and the normalized trans-impedance amplitude increases 10 % under the condition of fatigue crack.