油箱积水环境对油箱结构疲劳安全寿命的影响研究

目的 摸索飞机服役条件下油箱积水环境对油箱结构疲劳寿命的影响,评估基于常规疲劳寿命除以理论分散系数确定的安全寿命是否可以保证服役环境下的飞行安全.方法 首先通过试验确定加速腐蚀试验中飞机油箱积水介质浓度,并结合飞机使用特点,确定战斗机机翼梁结构腐蚀-腐蚀疲劳试验环境-载荷谱.以此环境-载荷谱为基础,试验模拟油箱结构在地面停放和空中飞行所经历的腐蚀和腐蚀疲劳过程.采用结构和载荷谱分离的可靠性分析方法,研究腐蚀-腐蚀疲劳作用下结构的疲劳寿命.结果 对常温疲劳试验结果与腐蚀-腐蚀疲劳试验结果的对比分析,表明腐蚀环境虽然降低了结构疲劳品质,导致疲劳中值寿命降低,但对结构寿命分散基本无影响.结论 严重谱下疲劳分散系数可保证油箱结构的安全.

Influence of Tank Water Environment on the Fatigue Safety Life of Tank Structure

In order to explore the influence of tank water on fatigue safe life of aircraft in service, and to evaluate whether the safety life determined by the conventional fatigue life divided by the fatigue dispersion coefficient can guarantee the flight safety in service environment, an experimental study was carried out. The corrosion medium concentration is determined by the test. Combined with the use characteristics of the aircraft, the load-environment spectrum is also determined. On the basis of this, the pre-corrosion and corrosion-fatigue process of the tank structure on the ground and in the air are simulated. The safe life of the structure under the corrosion-corrosion fatigue was studied using the reliability analysis on fatigue life with separated structural and load spectrum scatters. The results show that the corrosion environment results in reduced median life, as that fatigue quality of the structure was reduced, but the corrosion environment has no effect on the dispersion of the structure life; the fatigue scatter factor of severe spectrum can ensure the safety of tank structure.