Evaluation And Application Of The Overspeed Burst Prediction Method On Aero-engine Rotor

The burst speed of engine disk is an important content of modern aero-engine strength design.Among the main stress method,Hallinan method and local stress strain method are empirical methods.The prediction method based on the global plastic instability criterion is a method which is consistent with the law of burst.It's necessary to evaluate the prediction ability of each burst prediction method.So we can have a suitable prediction method that can be used to study the overspeed fracture characteristics of the typical engine multi-stage rotors from foreign countries.It's helpful to provide a reference for the design of the anti-fracture of domestic aviation engine rotors.In the overspeed test,the results are affected by the improper design of the connecting disk.It is necessary to study the design optimization method of the connecting disk which is used to make the overspeed test run smoothly and with good accuracy.Based on predecessor's work,numerical simulation and experiment method were used to study the fracture analysis of typical engine rotors and optimization of the connecting disk for overspeed test,theoretical analysis and numerical simulation.The main work content are as follow:An experiment was conducted on a GH4169 disk.By compared with the prediction results and experiment results,we find that the global plastic instability criterion can also predict the rupture mode and fracture location of the disk accurately.It is a method which is consistent with the law of burst.The average stress method can tell the right rupture mode of disks,but can't tell the accurate failure region.Hallinan method have acceptable engineering precision,but this method is only used to predict disk breaking in mode of circumference.Local stress-strain method has high precision.But this method can not predict the fracture mode of the disk in a accurate way.The prediction and analysis of the APU integral impeller rotor and foreign typical domestic turbofan engine rotor engine have been carried out based on the prediction method of fracture speed based on global instability criterion.The predicted burst speed of a type APU rotor was 145293 rpm and the burst speed margin is 181.6%.There is no obvious stress concentration area when the disc is near rupture,and the design is reasonable.The rotor fracture mode is caused by a crack in the center of the disc.The burst speed of CFM56-7b is 24150 rpm.The center of the disk of stage number 1 high pressure compressor is the dangerous zone.The burst speed of CFM56-7b LPT is 20364 rpm.The right drum of stage number 1 LPT is the dangerous zone.The LEAP-1b high pressure compressor has a burst speed of 23724 rpm.The center of the disk of stage number 4 high pressure compressor is the dangerous zone.The burst speed of LEAP-1b LPT is 10229 rpm.The dangerous zone of stage number 2 LPT is the center of the disk.The thesis has analyzed the influence of the design of transfer disk on deformation and fracture,the optimization method of transfer disk was also studied.The design and optimization on the transfer disk of several types of typical connections are carried out on the composite state befor and after the optimization.The effect of the optimized transfer disk on the test disc rupture speed was reduced effectively and the influence of the fracture area of the test disk is reduced significantly.