航空发动机液压管路裂纹故障分析

Crack Fault Analysis of Hydraulic pipe for an Aeroengine

针对某航空发动机试验过程中液压管路发生的裂纹故障,通过对管路故障件进行断口分析、设计复查等工作,确定管路裂纹产生的原因。结果表明:喷口油源泵出口压力及峰-峰值的控制超出正常工作范围,引起该管路在刚性连接位置的弯曲振动,在管路焊缝位置产生超限的循环应力,导致管路焊缝萌生裂纹并在较大振动应力和喷口油源泵出口脉动压力作用下发生裂纹故障。通过更换喷口油源泵控制附件,使脉动油压恢复正常范围,管路动应力符合限制值要求,有效避免此类故障再次发生。

In view of the crack fault of a hydraulic pipe during the test of an aeroengine,the cause of the pipe crack was determined by analyzing the fracture and checking the design of the fault parts of the pipe.The results show that the control of the outlet pressure and peak-peak value of nozzle oil source pump are out of the normal operation range,which cause the bending vibration of the pipe in the rigid connection position.The over-limit cyclic stress is produced in the weld position of the pipe,which leads to the crack initiation in the weld seam of the pipe and the crack failure under the action of the large vibration stress and the pulsation pressure at the outlet pressure of nozzle oil source pump.By replacing the control accessories of the nozzle oil source pump,the pulsation oil pressure can be restored to normal range,and the dynamic stress of the pipe meets the requirements of the limited value,which can effectively avoid the recurrence of such faults.