基于超声检测技术的铆钉缺陷信号特征研究

针对飞机进气道铆钉松动及断裂脱落打坏发动机等问题,该文通过使用D70超声波检测仪和频率为20 MHz、晶片尺寸为3.175 mm带延迟块的直探头以及用于调整探伤仪灵敏度的Ф4 mm、Ф4.5 mm、Ф5 mm铆钉人工缺陷对比试块,对比试块上人工缺陷位于铆钉头根部,用于验收的人工缺陷深度为0.6 mm,对多架次飞机进气道铆钉质量进行检测,得到不同状态铆钉的一系列超声波信号数据,总结裂纹缺陷回波与不同类型非缺陷回波的信号特征及其产生原因,有效实现进气道铆钉疲劳裂纹的检测,并及时更换有缺陷的铆钉,可以有效避免铆钉脱落打坏发动机的安全事故,最后为进气道铆钉超声检测提供参考,降低错探、误判的概率。

In order to solve the problems of rivet loosening and breaking off of aircraft intake port,this paper uses D70 ultrasonic detector and direct probe with frequency 20 MHz and chip size 3.175 mm with delay block andФ4 mm,Ф4.5 mm andФ5 mm rivets'artificial defect comparison test blocks which are used to adjust the sensitivity of flaw detector,the artificial defect on the test block is located at the root of rivet head,and the depth of artificial defect for acceptance is 0.6mm.The quality of rivets in the inlet of multi-sorties of aircraft is tested,a series of ultrasonic signal data of rivets in different states are obtained,and the signal characteristics and causes of crack defect echoes and different types of non-defect echoes are summarized.The fatigue crack detection of inlet rivets is effectively realized,and the defective rivets are replaced in time to avoid the safety accident of rivets falling off and damaging the engine.Finally,this paper provides a reference value for the ultrasonic detection of rivets in the inlet and reduces the probability of misdetection and misjudgment.