Dynamic Characteristic Analysis Of Dual-rotor System Under Different Supports

Aero-engine is a key component of a plane,its dynamic characteristics have great influence on the performance of the aircraft and the cause of the aircraft failure.Therefore,it has great significance to study the dynamic characteristics of aero-engine.However,it is difficult to accurately model the dual rotor aero-engine structure.Taking the dual rotor-bearing-casing aero-engine experimental apparatus as the reference,the casing and dual-rotor finite element model is established with truncated conical shell element method and Timoshenko beam theory separately,the whole aero-engine experimental apparatus finite element model has been got.Based on the finite element of the dual rotor-bearing-casing aero-engine experimental apparatus,this article simulate the casing response under different rotor position with fault,get the best position of response under the different rotor fault,then get the whole aero-engine model with different casing-rotor mass radio by changing the thickness of casing,researched the influence of different casing-rotor mass radio on the dynamic characteristics of dual-rotor aero-engine.As the material,the influence of different material of casing on the dynamic characteristics of dual-rotor aero-engine was studied.The research shows that with the casing-rotor mass ratio increased,the vibration amplitude of casing decreased first and then increased,from optimizing the vibration amplitude of whole aero-engine,there is an optimum mass ratio,when casing-rotor mass ratio is about 0.45,the vibration amplitude is minimum;different casing material has negligible effects on the critical speed,but it can influence thevibration amplitude of whole aero-engine,the vibration amplitude is minimum when alloy steel casing is used,and the vibration amplitude is maximum when aluminum alloy casing is used.Aircraft during maneuver flight,excessive motor load can lead to engine failure,the cause of the problem,however,is related to other factors.The influence of casing support stiffness,mount support stiffness and maneuver load on dynamics characteristic of aero-engine is studied in this article.The research shows that casing support stiffness and maneuver load have greater influence on aero-engine's rotor-stator radial rub-impact,and mount support stiffness has little influence on it;the vibration of observation point on the casing decreases with the decrease of the casing support stiffness,and it increases with the decrease of the mount support stiffness;the influence of maneuver load can be reflected by the vibration of observation point on the casing,but the influence degree can not be reflected by it.