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

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.