机翼后梁接头裂纹故障分析

目的分析某型飞机机翼后梁接头裂纹形成的原因,避免类似问题的重复发生。方法通过对机翼后梁接头进行受力分析,在对机翼后梁接头结构装配关系进行分析的基础上,采用有限元方法对接头进行应力计算,并对裂纹断口进行宏观和微观分析,确定产生裂纹的原因。结果机翼后梁接头裂纹为应力腐蚀裂纹。结论机翼后梁接头材料为LD5,对应力腐蚀敏感,接头在装配过程中存在较大的装配拉应力,而接头表面的腐蚀防护又存在缺陷,在较严酷的服役环境作用下发生了应力腐蚀开裂。

Crack Failure Analysis of Wing Rear Spar Fitting

Objective In order to avoid the repeated occurrence of similar failures, the causes for the crack on the wing rear spar fitting of a certain type aircraft were analyzed. Methods Force analysis was conducted for the wing rear spar fitting, and based on the analysis of the structural assembly relationships of the wing rear spar fitting. FEM was used to calculate the stress on the fitting. Besides, macroscopic and microscopic analyses were performed for the crack fracture to determine the cause for the crack. Results The crack of aircraft wing rear spar fitting was caused by stress corrosion. Conclusion The material of the rear spar fitting LD5 was sensitive to stress corrosion. The fitting was subjected to relatively large assembly tension stress in the assembly process, and the corrosion preventive measure for the surface of the rear spar fitting was defective, therefore stress corrosion cracking occurred in the harsh servicing environment.