Optimization of Pulsed Eddy Current Sensor Parameters for Detection of Cracks around Rivet Sites in Multi-Layer Structure

Detection of the deeply embedded cracks around rivet sites in aircraft multi-layer structure is a difficulty and hotspot in the field of nondestructive testing. For the detection of this kind of defect, a kind of probe based on two exciting coil and TMR pick-up sensor has been designed in this paper. Two exciting coil were reversely-connected to produce a focused and intense magnetic field without the need of large current in the coil. A lot of experiments were done for selection of PEC sensor parameters to improve the detection sensitivity of the sensor. The experimental results showed that when the exciting coil winded as 180 turns, the spacing of two exciting coils was 20~30 millimeter, the angle between coil and horizontal was 60°~90°and the TMR sensor located above the crack, the detection sensitivity will reach maximum. This research provides reference for probe design in the cracks detection in aircraft multi-layer with PEC method.