某航空发动机卡箍断裂故障分析

Fracture Failure Analysis of Clamp for an Aeroengine

针对某航空发动机在试车过程中风扇机匣安装边上用于固定管路的多处卡箍发生的断裂故障,通过对卡箍故障件进行断口分析和设计复查等,确定了卡箍断裂发生的原因:在设计状态下,卡箍上、下瓣之间装配夹角较大,在螺栓拧紧过程中,造成卡箍结构故障位置产生较大的初始局部应力,在较大的振动环境下导致综合应力增大,由于故障位置结构强度储备不足,从而发生高周疲劳断裂。通过对卡箍结构采取加装 2 mm 厚钢垫、降低静应力等改进措施优化设计,降低了其静应力,提高了其强度储备,有效避免此类故障再次发生。

In view of the fracture fault of multiple clamps on the side of fan casing installation used for fixed pipes during the test run of an aeroengine,the fracture surface analysis and design review of the fauit clamps parts were carried out,and the reason of clamps fracture was identified. In the design state,the angle between the upper and lower lobes of the clamps was large. In the process of tightening bolt,the fault position of clamp structure was caused by large initial local stress. Under the larger vibration environment,the comprehensive stress increases,and the high cycle fatigue fracture occured because the strength reserve of the fault location structure was insufficient. The optimum design of clamp structure was adopted by adding 2 mm thick steel cushion and reducing static stress. Then the static stress was reduced,the strength reserve was increased,and this kind of fault was prevented from happening again.