某飞机输油软管发生漏油现象，经检查为软管开裂所致。采用宏观观察、断口分析、红外光谱分析和热失重试验等方法，对软管开裂的原因进行了分析。结果表明：输油软管的开裂性质为疲劳开裂，裂纹起源于螺纹凹槽的根部；输油软管装配后产生应力老化，导致其疲劳性能下降，在振动和内部燃油压力等交变应力的作用下裂纹从凹槽根部的损伤位置起源，并最终发生疲劳开裂。

Oil leakage occurred in the oil transfer hose of an aircraft, which was checked to be caused by hose cracking. The causes of hose cracking were analyzed by means of macro observation, fracture analysis, infrared spectroscopy and thermogravimetric test. The results showed that the cracking of oil hose was fatigue cracking, and the crack originated from the root of thread groove. The stress aging of oil transfer hose after assembly led to the decline of its fatigue performance. Under the action of alternating stresses such as vibration and internal fuel pressure, the crack originated from the damage position at the root of the groove and finally fatigue cracking occurred.