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某型飞机主起落架车架前摇臂是决定主起落架翻修寿命的关键结构,在使用过程中多次出现疲劳裂纹,采用CAE对结构进行疲劳分析,分析结果显示结构疲劳寿命过低。据此提出基于疲劳寿命的改进优化,采用灵敏度分析方法,来确定各相关参量的敏感程度,找出主要的影响尺寸变量,并利用多目标优化找出最佳尺寸,依据优化结果建立模型对比分析。结果表明,在结构质量几乎不变的情况下,应力集中得到明显改善,疲劳寿命提高了49.7%,有效改善了前摇臂的疲劳寿命。
The main rocker arm of a main landing gear frame of a certain type of aircraft is the key structure that determines the life span of the main landing gear. Many fatigue cracks occur during use. The fatigue analysis of the structure is performed by CAE. The results show that the fatigue life of the structure is too low. Based on this, an improved optimization method based on fatigue life is proposed. Sensitivity analysis method is used to determine the sensitivity of each relevant parameter, and the main influential dimension variables are found out. The optimal size is found by multi-objective optimization. . The results show that under the condition of almost unchanged structure, the stress concentration is obviously improved, the fatigue life is increased by 49.7%, and the fatigue life of the front rocker arm is effectively improved.