飞机承力部件缺陷尖端的涡流检测定位方法

Eddy Current Detection and Tip Location of Defects in Aircraft Bearing Parts

涡流检测技术在航空铝合金的表面或近表面裂纹检测中具有较高的检测灵敏度,且速度快、无需耦合剂,但粘胶层会降低检测灵敏度。飞机在服役期间因应力集中萌生的疲劳裂纹,容易导致机体结构失效,故承力部件的完整性是保障飞机飞行安全的关键因素之一。针对承力部件虎口位置的疲劳裂纹,提出基于双线测长法缺陷尖端定位方法;设计虎口裂纹缺陷专用双拉线式涡流屏蔽探头,可自适应定位螺栓的安装误差。结果表明:利用自适应定位螺栓将测量装置固定于虎口,裂纹尖端双线测量装置可以有效定位裂纹;当激励频率为30~40 kHz时,研制的双拉线式涡流屏蔽探头能有效检出粘胶层下半径为7.0 mm、宽度为0.2 mm的扇形人工刻槽。

Eddy current testing technology applied for surface or near-surface cracks in aviation aluminum alloy is fast and does not require a coupling agent.Nevertheless,the detection sensitivity is low due to the negative influence of the adhesive layer.Fatigue cracks initiated by stress concentration during the service of the aircraft can easily lead to the structural failure in airframe.Therefore,the integrity of the bearing components is one of the key factors to ensure the flight safety of the aircraft.Aiming at the fatigue cracks of the bearing component,a method of defect tip location based on the double-line length measurement was proposed.A special double-line eddy current shielding probe for tiger-crack defects was designed,which can adaptively locate the installation error of bolts.The results show that the self-adaptive positioning bolt is used to fix the measuring device at the tiger mouth,and the double-line measuring device at the crack tip can effectively locate the crack.When the excitation frequency ranges from 30 to 40 kHz,the developed double-line eddy current shielding probe can sensitively detect 7.0 mm×0.2 mm(radius×width)fan-shaped artificial grooves under the adhesive layer.