连接梁断裂失效分析

Analysis of machine beam fracture fault

为探究某型航空发动机收扩喷口作动筒活塞杆端连接梁的断裂原因,结合断口,对装配过程、服役状态进行分析。结果表明:故障连接梁材质未见异常,其断裂模式为过载断裂。同时,发现与梁连接的作动筒外加螺母保险锁紧不佳,发生周向松动,导致衬筒内壁与活塞出现异常偏磨。综合分析表明:故障件活塞与衬筒发生异常偏磨引起活塞杆运动卡滞,故障组件外放喷口时活塞杆无法收缩,与之相连的梁中部因受到异常大的应力而发生断裂。

In order to investigate the cause of beam fracture in the piston rod end connection of a certain type of aircraft engine's intake and expansion nozzle actuator,combined with the fracture surface,assembly process,and service status,an analysis was conducted.The results showed that the material of the faulty beam was not abnormal,and its fracture mode was overload fracture.At the same time,it was found that the external nut safety lock of the actuator connected to the beam was not tight enough,causing circumferential loosening,resulting in abnormal eccentric wear between the inner wall of the lining cylinder and the piston.The comprehensive analysis results show that the abnormal eccentric wear between the faulty piston and liner causes the piston rod to move and become stuck.When the faulty component is discharged from the nozzle,the piston rod cannot contract,and the middle part of the beam connected to it is subjected to abnormal large stress,resulting in fracture.