基于模态分析的某型飞机液压管路故障诊断

Fault Diagnosis Based on Modal Analysis for Certain Aircraft Hydraulic Pipe

针对某型飞机液压管路吸油模块与扩口式直角接头连接处螺纹损坏,接头脱出,导致液压系统漏油的故障,建立了管道有限元动力学模型,进行了管道模态仿真分析。发现故障管道出现了导致管道故障的危险模态,该阶模态频率范围正好在发动机的工作转速范围内,在发动机振动频率的激励下,激发该阶模态振动,引起管道共振,产生很大的作用力,导致连接螺纹损坏和接头脱出,从而形成故障。基于模态分析方法,对该管道进行了改进,有效地避免了该阶模态的出现。实际的飞机管路系统的改进效果表明了分析方法的正确性。

A finite element dynamic model of pipeline is established and a modal simulation of pipeline is carried out in view of screw thread damage at a connection of oil absorption module of hydraulic pipeline and a flared right angle joint and joint separation, which leads to oil leakage of hydraulic system. It is found that a dangerous mode of pipeline failure occurs in the fault pipeline, and the frequency range of this order mode is exactly within the range of engine working speed, which is excited by vibration frequency of engine and causes pipeline resonance. In this case, a large force will result in connection thread damage and pipeline failure. Based on the modal analysis method, the pipeline is improved to effectively avoid the appearance of the order mode. The improvement effect of the actual aircraft pipeline system shows the correctness of the analysis method.