航空发动机滑油供油管裂纹分析

飞行时航空发动机滑油压力告警，分解检查后发现滑油供油管与盖板钎焊缝焊角处存在一条裂纹，裂纹沿周向扩展，约占整个圆周的4/5，采用断口观察、金相组织分析、有限元计算分析、装配应力和振动应力测试等方法，分析了滑油供油管裂纹产生的原因。结果表明:滑油供油管裂纹性质为高周疲劳开裂，裂纹起始于外壁表面钎焊缝焊角部位，裂纹位置处装配应力为280 MPa，振动应力为21 MPa，较大的振动应力和装配应力共同作用导致滑油供油管裂纹。通过增加卡箍，改善校形，可避免类似故障。

Crack Analysis of Aero-engine Oil Supply Pipe

The lubricating oil system of an aero-engine alarmed during flying. Crack was found between the oil supply pipe and the cover plate after inspec-tion. The crack propagated along the circumference, accounting for about 4/5 of the whole circumference. The cause of crack was analyzed by fracture obser-vation, metallographic analysis, finite element analysis, and assembly stress and vibration stress testing. The results show that the crack of the oil pipe is high cycle fatigue crack. The crack initiated from the outer surface at the corner of the brazed weld. The assembly stress at the crack position is 280 MPa, and the vibration stress is 21 MPa.The larger vibration stress and assembly stress are the main causes for the crack. Clamp should be designed and the alignment should be improved to prevent such a failure.