机翼连接耳片微动疲劳裂纹萌生机制

 对歼击机机翼全尺寸模拟疲劳试验的耳片断口进行了观察和分析,从断裂处存在磨痕和磨屑的形貌及耳片受力变形状态,证明耳片属于微动疲劳断裂。本文提出铝合金耳片和钢衬套接触时,微动疲劳裂纹萌生过程的模型。

A MECHANISM OF FRETTING FATIGUE FAILURE IN THE JOINING LUG OF A WING STRUCTURE

The fatigue test for a full scale fighter wing was carried out under simulated condition in order to examine its fatigue strengrlh. In the test, the aluminium alloy lug, which joins the wing and the fuselage, failed at the boundary of lug hole parallel to the fuselage. The fracture surface was observed by optical and scanning electron microscopes. There were widespread scars and extruded debris in the lug mated with a steel bushing. In the area of initial crack, wear was particularly obvious and serious and the crack origin caused by wear scars was observable directly. According to the condition of the stress and strain suffered by the lug, it is clear that fretting occured between the lug hole and the bush lug surface. The lug fracture, therefore, belongs to fretting fatigue fracture. A model illustrating the mechanism of the crack origin in fretting fatigue in the joining lug has been presented.