Vibration And Transmission Characteristics Of An Aeroengine

Aero-engine is very important for aircraft operation process,which is closely related to the reliability,economy and other factors of aircraft.With the development of aero-engine technology,the requirements for aero-engine are higher and higher,such as thrust weight ratio,performance,thrust,stability and so on.As a common connecting part of aero-engine,bolt is the key factor to determine whether aeroengine can operate normally.Once the bolt fatigue failure occurs in the process of use,it will affect the normal operation of the engine,and even affect the service life of the engine.Therefore,it is very important to provide appropriate preload for bolts to ensure the stability and safety of bolt connection.Based on the theory of finite element modeling and the principle of mesh processing,three-dimensional models of fan casing,intermediate casing,highpressure compressor casing,combustor casing,low-pressure turbine casing and rear turbine casing are obtained.Three-dimensional software is used for solid modeling,and finite element software is used for mesh generation to obtain the finite element model of each casing.The three-dimensional model and finite element model of the whole aero-engine casing are obtained by assembling each casing.On the basis of modal analysis theory,the natural characteristics of aero-engine stator casings under free mode and bolt force are analyzed,and the influence law of bolt preload on the natural characteristics of stator casings is given.The natural frequency of aero-engine casing in free mode is calculated.The casing is hoisted and preloaded with bolts.The influence of bolt preload on the natural characteristics of aero-engine casing is given.Based on the finite element theory,the exciting force is applied to the whole aero-engine casing according to the actual working conditions.Firstly,the vibration response of the whole aero-engine casing when the bolt preload is evenly distributed is analyzed,and the whole aero-engine casing is analyzed and compared under two different speeds in the actual work.This paper analyzes the vibration response of the whole gearbox under the condition of non-uniform distribution of bolt preload,and obtains the vibration response of the whole gearbox under the condition of nonuniform bolt preload by analyzing the change of acceleration response of the gearbox node.According to the test program of aero-engine casing vibration transmission characteristics test,the whole engine casing is tested,and the monitoring points that meet the actual requirements are obtained.According to the test data,the natural frequency is compared with the simulation results to verify the rationality of the simulation.