多层铆接结构铆钉孔周裂纹的脉冲涡流检测

飞机多层金属铆接结构中铆钉周边裂纹的检测是无损检测领域中的一个难点和热点。基于脉冲涡流检测技术，设计检测探头，并对探头的激励线圈匝数、检测频率、接收传感器距铆钉距离等参数进行优化，研制一种使探头能够围绕铆钉进行旋转检测的装置。检测探头参数和传感器与铆钉之间的距离参数的变化对检测灵敏度的影响较大。旋转装置检测时:激励匝数为180匝、检测频率为100 Hz、探头与铆钉距离4 mm时，对于长度为1、2 mm的铆钉孔周边裂纹检测效果较好；对于长度大于2 mm的铆钉孔周边裂纹，探头距离铆钉10 mm的时候检测灵敏度较高。利用旋转装置检测和纯手动检测的结果对比表明，旋转检测装置能够很好地抑制探头与铆钉之间的距离变化带来的对信号的干扰，减少伪缺陷并提高检测效率。

Pulsed Eddy Current Detection of Rivet Hole Cracks in Multi-layer Metal Riveting Structure

Detection of the cracks in the rivet in the aircraft multi-layer metal riveting structure has been a difficult task and hot spot in the field of nondestructive testing. Based on the pulsed eddy current technology, this study designs probes and optimizes detection parameters:number of turns of excitation coil, frequency, distance between receiving sensor and rivet. A rotation device is also designed to enable probe to rotate around the rivet. The parameters of the detection probe and the changes of distance between the sensor and the rivet have a greater impact on the detection sensitivity. When the rotating device was used for detection, the number of excitation turns was 180 and the detection frequency was 100 Hz, when the distance between the probe and the rivet was 4 mm, the crack around the rivet hole with a length of 1,2 mm is better detected; for the cracks with length greater than 2 mm around the Rivet holes, detection sensitivity is higher when the distance between the probe and the rivet is 10 mm. At the same time, the results of rotation device test show that compared with pure manual detection, signal interference caused by the change of distance between probe and rivet was well restrained, false defects was reduced and detection efficiency was improved.