航空发动机引气管卡箍断裂失效分析

针对某发动机发生的引气管单联卡箍组件中的卡箍上半部断裂的故障，对断裂的卡箍上半部进行宏观侧表面检查、断口及材质分析，结果表明：卡箍上半部断口疲劳源区位于卡箍上半部与下半部接触侧的表面区域，在螺栓装配中引起卡箍上半部发生塑性变形而产生表面拉应力，并且在发动机振动载荷作用下产生微动磨损，从而破坏了卡箍上半部螺栓孔周围局部的表面完整性，降低了该部位的抗疲劳强度，是导致卡箍上半部产生疲劳萌生进而发生断裂故障的根本原因。在卡箍上、下半部之间加装垫片的改进建议已在新的结构设计中得到应用，垫片的加装消除了卡箍上半部在装配过程中由于变形而产生的表面拉应力，并且减轻了卡箍上、下半部之间的微动磨损，从而避免此类故障再次发生。

Fracture Failure Analysis of Aeroengine Suction Pipe Clamp

In view of the fracture failure of the clamp upper half in an engine suction pipe single union clamp,the macroscopic side surface inspection,fracture and material analysis were carried out on the fractured clamp upper half.The results show that the fracture fatigue source area of the clamp upper half is located in the surface area of the contact side between the upper half and the lower half of the clamp.During the bolt assembly,the plastic deformation of the clamp upper half is caused to produce surface tensile stress,and fretting wear is generated under the action of engine vibration load,which destroys the local surface integrity around the bolt hole of the clamp upper half and reduces the fatigue strength of this part.This is the root cause of fatigue initiation and fracture failure in the clamp upper half.The improvement suggestion of installing gaskets between the upper and lower halves of the clamp has been applied in the new structural design.The installation of gaskets eliminates the surface tensile stress caused by the deformation of the clamp upper half during assembly,and reduces the fretting wear between the upper and lower halves of the clamp,so as to avoid the recurrence of such faults.