当量加速腐蚀条件下飞机结构耐久性评估方法研究

Durability Evaluation on the Aircraft Structure in Equivalent Accelerated Corrosion

目的研究某型飞机机翼纵墙下缘条的结构细节模拟试件的耐久性。方法根据实测环境数据编制某沿海机场环境加速试验谱,开展不同当量腐蚀年限的加速腐蚀试验,然后进行耐久性试验,基于裂纹萌生寿命(TTCI)服从双参数威布尔分布和对数正态分布,建立表征腐蚀损伤下机翼纵墙结构细节原始疲劳质量(IFQ)的当量初始缺陷尺寸(EIFS)分布,并对机群机翼纵墙的经济寿命进行预测。结果铝合金材料在θ=40℃,pH=4.0,质量分数为5%的NaCl溶液盐雾环境中作用189.7 h,腐蚀损伤与该海洋大气环境腐蚀1 a相当。结论该关键结构在沿海机场环境条件下的耐久性能满足寿命指标要求。

Objective To research the durability of simulated sample for structural details of flanges under longitudinal wall of aircraft wing. Methods An acceleration test spectrum for coastal airport environment was drawn up according to environmental data measured to carry out accelerated corrosion test of different equivalent corrosion years. Then a durability test was carried out. An equivalent initial flaw size（EIFS） distribution was established to characterize the initial fatigue quality （IFQ） of critical details with corrosion damage, on the assumption of time-to-crack initiation（TTCI） followed double-parameter Weibull distribution and Logarithmic Normal distribution, which was used to predict the economic life of outer wings of aircraft fleet. Results The corrosion damage was equivalent to corrosion la in sea atmospheric environment after the aluminum alloy material reacted in 5% of NaCl salt-fog environment at θ=40 ℃ and pH=4.0. Conclusion The durability of the key structure meets the service life requirements in coastal airport environment.