振动环境下机载吊舱结构连接螺栓疲劳寿命分析

Fatigue Life Analysis of Structural Connecting Bolts for Airborne Pods Under Vibration Environment

  • 摘要: 针对某机载吊舱在振动环境试验过程中出现连接螺栓断裂问题,该文首先建立了与试验条件一致的有限元模型,计算得到断裂位置在三个应力区间的最大等效应力值;随后,采用基于高斯分布的频域三区间法,结合Miner线性累积损伤理论,对螺栓疲劳寿命进行估算。结果表明,预测疲劳寿命为1.44 h,与试验中在横向振动30 min后发生断裂的现象基本吻合。基于分析结果,对吊舱舱体的薄弱部位进行了结构优化,优化后吊舱顺利通过振动试验,满足使用寿命指标要求。本研究为机载吊舱在复杂随机振动环境试验下的疲劳寿命预测提供了一种可行的工程化方法。

     

    Abstract: A connecting bolt fracture occurred in a certain type of airborne pod during vibration environmental testing. To address this issue, this paper first established a finite element model consistent with the test conditions, and calculated the maximum equivalent stress values at the fracture location in three stress intervals; subsequently, the frequency-domain three-interval method based on Gaussian distribution, combined with Miner’s linear cumulative damage theory, was adopted to estimate the fatigue life of the bolt. The results show that the predicted fatigue life is approximately 1.44 h, which is basically consistent with the phenomenon that the bolt fractured after 30 min of transverse vibration in the test. Based on the analysis results, structural optimization was carried out on the weak connection parts of the pod body. The optimized product successfully passed the vibration test and met the service life index requirements. This study provides a feasible engineering method for fatigue life prediction of airborne pods in complex random vibration environments.

     

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