Pulsed Eddy Current Technique in Detection and Identification of Crack in Aircraft structure

It is difficult to detect crack in multilayer structure of an aging aircraft. Pulsed Eddy Current(PEC) is an effective method that has been demonstrated to be capable of quantifying flaw in multi-layer structure. Formula of PEC skin effect is theoretically analyzed. It is obtained that reducing frequency and increasing duty cycle of exciting signal are helpful for detection of deep crack. The detecting system of PEC and rectangular sensor are designed. Frequency and duty cycle of exciting signal have been optimized to detect crack in aircraft structure. Based on processing and analysis of detecting signal, the crack can be detected and identified effectively. It is predicted that PEC technique will play an important role in the field of aircraft nondestructive testing.