脉冲涡流技术对飞机结构内层裂纹缺陷的检测识别

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

如何检测老龄化飞机多层结构中的裂纹缺陷一直是无损检测领域的一个难点。脉冲涡流技术是一种可以对多层结构中缺陷进行有效检测的电磁无损检测技术。理论推导了脉冲涡流渗透深度的公式,得出适当的减小脉冲激励频率与增加占空比有利于检测深层缺陷。设计了实验系统与矩形传感器,对激励信号的频率与占空比进行了优化设计。对多层结构中的内层缺陷进行了实验,并对微弱的检测信号进行了必要的数据处理。实验结果证明脉冲涡流检测技术可以对内层裂纹缺陷进行有效的检测。脉冲涡流技术将会在航空无损检测领域发挥重大的作用。

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.