随机振动下装配误差对液压导管疲劳寿命影响仿真分析

在军事实战化训练强度全面提高的背景下,战斗机液压导管频繁出现裂纹、漏油等严重威胁飞行安全的故障情况。针对后机身液压导管疲劳寿命与机体结构寿命不匹配的问题,重点以装配误差作为液压导管疲劳寿命主要影响因素开展仿真分析研究。从随机振动载荷疲劳寿命分析入手,运用数字建模方法绘制典型管路模型,结合Miner线性累计损伤理论,利用有限元分析软件设置疲劳计算程序对正常装配液压导管疲劳寿命进行仿真评估。根据管路不同装配误差情况调整模型设置,基于结构动力学理论,对不同装配误差下的液压导管进行疲劳寿命分析,得到当装配误差大于0.73mm,液压导管疲劳寿命将低于3 000飞行小时机体寿命的分析结果。研究成果为进一步开展航空液压导管装配理论研究提供了技术支撑和经验参考。

A Simulation Analysis of the Influence of Assembly Error on the Fatigue Life of Hydraulic Pipe under Random Vibration

With military training intensity being comprehensively improved, there are dangerous oil leakage, and cracks in hydraulic duct of fighter jet, these phenomena threaten to flight safety. Aimed to the problems thatthere are some mismatches between the fatigue life on the rear fuselage hydraulic conduit and the life of the body structure, this research is focused on one main influence factor, the assembly error. At the start of the fatigue life analysis of random vibration load, applying digital modeling methodology to develop the typical pipeline model, based on the Miner linear cumulative damage theory, the fatigue calculation program is developed by finite element analysis software to simulate and evaluate the fatigue life of normal assembly hydraulic conduit. Based on the influence of assembly stress on fatigue life, the pipeline model is adjusted to simulate different assembly errors, and the fatigue life of hydraulic ducts with different assembly errors is analyzed by using structural dynamics theory and fatigue calculation program. It follows that when the assembly error is greater than 0.73 mm, the fatigue life of the hydraulic duct will be lower than the airframe life of 3000 flight hours, i.e. seriously threatening flight safety. The research results provide technical support and experience reference for the further research on the theory of aero hydraulic pipe assembly.