Fracture Analysis And Structural Optimization Design Of Aero-engine Pipe

In this paper, in the field of aero-engine, the fracture fault phenomenon in the brazing round root zone of air tube,which material is 1Cr18Ni9 Ti steel, was chosen as the subject.From the viewpoint of reducing stress concentration and vibration,structure optimization method of the air tube was studied, the main contents are as follows:(1) Focus on the broken air duct,firstly, macro/micro morphology of the fracture failure of air pipe was observed, then the chemical composition of air tube was analyzed and strength check of the air tube was calculated. Bye this way the properties and the fracture causes of air duct was found. The results show that the fracture property of air pipe is fatigue fracture, and the fatigue propagation stress is small.(2) In order to solve the fatigue fracture fault of the engine air, an optimal scheme was put forward. By building UG model, and using ANSYS finite element analysis of vibration modal analysis of air duct and harmonic response calculation, the natural vibration frequency and the stress distribution maps, improved schemes for air duct was proposed and compared with each other. At last, after a comprehensive analysis of the simulation calculation,optimization structure of the air tube was determined, which shape is “?”.(3) The improved air tube was installed on engines, with the percussion method static frequency was obtained, in the test bench into action stress measurement, verified through the test data, the validity of the improved catheter in terms of avoiding fault was convinced.(4) The new structure air tube passed the all-life and accelerated life test evaluation,finally, the establishment of air duct optimization of batch production can be put into use in the engine.The result show that, the optimal air tube has the advantage of small maximum stress and steady stress level, the failure rate of fracture fault for the air tube was reduced, even eliminated after applied to the batch production engine, which provide strong protection for flight safety.