腐蚀环境对飞机梁结构连接件疲劳寿命和裂纹扩展的影响

Influences of Corrosion Environments on Fatigue Life and Crack Propagation of Aircraft Beam Structure Connectors

借助腐蚀环境谱与疲劳载荷谱交替作用来模拟沿海飞机停放飞行停放过程。以飞机梁结构连接件的下壁板为主要研究对象,采用标记载荷法和详细目视检测法监测其裂纹的扩展状况,并采用GE5显微镜观测断口形貌。分析了腐蚀环境对梁结构连接件疲劳寿命与裂纹扩展的影响。试验结果表明:在形成穿透裂纹的初始阶段,试验件受到表面的防护漆以及连接处的密封胶保护,腐蚀环境在该阶段对梁结构连接件的疲劳寿命影响不明显,与非腐蚀试验相比,该阶段的寿命仅缩短了5.5%;在穿透裂纹的扩展阶段,腐蚀环境加速了穿透裂纹的扩展过程,同时还加剧了穿透裂纹扩展过程的分散性,与非腐蚀试验相比,穿透裂纹的扩展寿命缩短了23.1%。

The coastal aircraft’s parking-flight-parking processes were modeled by the alternating effects of the corrosion environment spectrum and the fatigue load spectrum, taking the lower wall panels of the aircraft beam structure connectors as the main research object. The propagation of the cracks was monitored by the marked load method and the detailed visual inspection method, and the fracture morphology was observed with a GE5 microscope. The influences of the corrosion environments on the fatigue life and crack propagation of the aircraft beam structure connectors were analyzed. The testing results show that the specimens are protected by the protective paints on the surfaces and the sealant at the joints during the initial formation stages of the penetrated cracks, the corrosion environments have no obvious effects on the fatigue life of the beam structure connectors during this stage. Compared with the non-corrosion tests, the life of this period is reduced by 5.5%. The corrosion environment accelerates the propagation processes of penetrated cracks during the propagation stages of penetration cracks. Meanwhile, the dispersion of the crack propagation processes was exacerbated. Compared with the non-corrosion tests, the propagation life of penetrated cracks is reduced by 23.1%.