Research On The Pulsed Eddy Current Nondestructive Technology

It is significant to detect corrosion in aircraft structure. Pulsed eddy current (PEC) technique is a new nondestructive testing (NDT) technique developed in recent years, which is current subject of widespread interest because of its key potential applications for detection and quantitative measurement of corrosion in multi-layer structures. The pulsed current technique has been researched in the paper:The status and the development home and abroad of the PEC technique are illustrated and the regular principle and theory foundation are discussed. The system of corrosion detection and analysis is designed and established. The sensors are designed and the detecting signal is analyzed and processed in time domain, frequency domain and wavelet. The noise is eliminated and the features including of peak amplitude and zero-crossing time are extracted to detect the corrosion.The two-dimensional sensor is designed and used to detect the corrosion quickly in multi-layer structure. The depth of corrosion can be measured by the Bx signal of two-dimensional sensor. The butterfly-shape graph consisted of two-dimensional signal can be used in practice to identify the corrosion effectively. Based on the analysis of low-frequency pulsed eddy current technique, the deeply corrosion can be identified effectively by applying excitation of low frequency. The PEC technique is improved and the columned hall sensor is designed and used to detect corrosion in the riveted structure.In the end, the conclusions of this paper are given and the suggestion for further research is provided.