飞机操纵系统钢索断裂原因分析

某型飞机在飞行减速收油门时,发动机操纵钢索突然发生断裂失效,导致发动机停车。通过断口宏微观观察、化学成分分析、极限拉力测试及钢丝表面痕迹观察,并结合理论分析和疲劳试验对飞机操纵系统钢索进行了综合分析,探讨了操纵钢索发生断裂的原因。结果表明：钢索的断裂是以弯曲应力为主要控制因素的疲劳断裂,钢索与滑轮及钢丝与钢丝间的磨损促使了疲劳裂纹的萌生。通过改进滑轮与钢索的直径设计及改善钢索与滑轮槽接触面的润滑条件,提高了操纵系统的疲劳寿命。

Failure Analysis of Control System Tightwire in Aircraft

The control system tightwire in an aircraft fractured during the deceleration of the engine. In order to find out the cause of the fracture, macro and micro observation of the fracture surface, chemical composition analysis, ultimate tension tests, surface trace observation and fatigue tests were carried out. The results show that the fracture of the tightwire is fatigue fracture mainly controlled by bending stress. The abrasion between the tightwire and pulley, as well as that between the steel wires, promoted the initiation of the fatigue cracks. The fatigue life of the control system can be enhanced by choosing the pulley of proper size and improving the lubricating condition between the tightwire and the pulley.