Fracture Failure Analysis Of Aeroengine Compressor Blades

As the ‘heart’ of aero-engine,the blade is influenced by thermal stress as well as centrifugal load,aerodynamic load and vibration load.Because the working environment is bad,the probability of blade fracture failure is high,and when it happens,it will lead to the performance attenuation of engine,affect the normal work of engine,and even cause serious flight accident.Therefore,the study of aeroengine compressor blade fracture fault is an effective means to prevent the failure and ensure the stability and reliability of aeroengine blades.This article mainly has carried on the research from following aspects:(1)By means of macro-examination,micro-examination,metallographic analysis,chemical composition examination and mechanical property examination,it is found that the fracture failure character of compressor rotor blade is high cycle fatigue fracture;The main reason of fracture failure is that during the working process of the engine,the blade tip produces inter-granular microcracks,which leads to the decrease of local fatigue strength,local stress concentration,and finally in the Centrifugal Force,aerodynamic force,vibration stress under the combined action of blade fracture.(2)The stress distribution and displacement of the blade under the centrifugal force in the working speed range are calculated by ANSYS finite element software,at the same time,the aerodynamic force is calculated by CFX,and the stress variation of the blade under the aerodynamic force is analyzed.According to the calculation,the force of the air flow on the blade is mainly concentrated on the exhaust edge,and the maximum stress is located in the area near the exhaust edge,where the high cycle fatigue crack easily occurs.(3)Modal analysis: calculating the natural frequencies of each order and drawing the vibration patterns of each order of the blades under different rotating speeds,and determining the maximum displacement and the position of the blades under the resonance condition,the results show that the maximum displacement of the 3rd and 6th order main mode is consistent with the failure position of the blade.(4)The crack Propagation Direction of the blade is determined by the crack Propagation Analysis.Through calculation and comparison,the simulated crack growth path is basically consistent with the actual crack growth path.