Research On Whole Body Vibration Of Aero-engine

The whole aero-engine vibration not only influences the working state of engine,accessories and instrument, but also brings engine structure huge vibration stress, so research on the whole body vibration of aero-engine is essential. According to the development of technology of the FEM software and computer, calculating the whole body vibration of aero-engine is becoming possible. In order to ensure aero-engine working safety and reliability, the finite element model of the whole aero-engine is built and used to analyse the whole body vibration, basing on its structural characteristic. The research work is carried out from analysis of the rotor critical speed and the vibration of casing to analysis of the whole body vibration, it is as follows:Firstly, in oreder to insure bilievable of the model of whole body aero-engine, the finite element calculation model of engine-casing is reasearched using some base theory, the static rigidity and dynamic rigidity of casing is analyzed with model. The calculating result of the critical speed of the rotor indicates that dynamic rigidity model is more reasonable than static rigidity model, owing to the caing natural modal appearing area of the working speed.Secondly, according to properties of the aero-engine structure, the characteristics of critical speeds are calculated separately adopting static rigidity and dynamic rigidity model of the low-pressure and the high-pressure rotor in the article.Thirdly, the critical speeds of the low-pressure and the high-pressure rotor are calculated with the transfer matrix method, and the calculating results are compared with the finite element model. It indicates the results of both methods are close; the errors within 10% and the calculating results reliabilities.Fourthly, the finite element model of the whole aero-engine is built and used to analyse the whole body vibration. The influence of the critical speed with the coupled effect between the dual-rotor is analyzed, and the influence with the different supporter's stiffness,the different speed ratio and bolt connection is researched in the article. It is found that, the calculating results of the critical speeds with the whole aero-engine model are reasonable, and close to reality.