环境对某型飞机典型结构部位疲劳寿命影响分析

Influences of Environment on Fatigue Life of a Typical Aircraft

目的研究环境对飞机典型结构部位疲劳寿命的影响。方法选取某型机机身连接壁板、机翼壁板、机翼内部大梁结构、平尾接头及垂尾接头的典型模拟件为研究对象,开展实验室加速腐蚀与随机载荷谱交替试验、载荷谱疲劳试验,分析环境对典型结构部位模拟件表面涂层损伤、疲劳断裂位置、疲劳源及中值寿命的影响,建立环境对结构部位疲劳寿命影响关系。结果采用载荷作用后结构部位模拟件疲劳中值寿命与加速腐蚀环境-疲劳寿命后试样的疲劳中值寿命比值,估算环境对结构部位模拟件疲劳寿命的影响,比值k=1.2~2.5,且比值k越大,说明环境对试样的疲劳寿命影响越大。结论采用载荷作用后结构部位模拟件疲劳中值寿命与加速环境-疲劳寿命后试样的疲劳中值寿命比值,可初步估算环境对结构部位模拟件疲劳寿命的影响,且试验结果表明,外部环境较内部环境对试样疲劳寿命的影响更大。

Objective To research the effects of environment on the fatigue life of typical structures of aircraft.Method Typical simulated parts of the fuselage connected with the wall plate,the wing wall,the structure of the girder inside the wing,the horizontal tail and vertical fin joint were selected as the research object to carry out laboratory accelerated corrosion and alternating test of random load spectrum and load spectrum fatigue test to analyze the influences of environment on the surface coating damage,fatigue fracture location,fatigue source and the median life of the simulated parts of typical structural components,and establish the influence relationship of environment on the fatigue life of structural components.Result The ratio between the fatigue life of the simulated part of the structure after loading and the accelerated corrosion environment-fatigue life of the sample after fatigue life was used to estimate the impact of the environment on the fatigue life of the simulated part of the structure.The ratio k=1.2-2.5 and the higher the ratio,the greater the impact of the environment on the fatigue life of the sample Conclusion The influence of environment on the fatigue life of structure parts can be preliminarily estimated by the ratio between the fatigue life of the simulated part of the structure after loading and the accelerated corrosion environment-fatigue life of the sample after fatigue life;and the test results show that the external environment has greater influences on the fatigue life of the sample compared with the internal environment.