Finite Element Analysis Of Dynamic Characteristics Of An Aeroengine Rotor System

The dynamic characteristics of aviation engine rotor system determine the reliability of operation and the integrity of the structure of an aircraft engine. So calculation and analysis of dynamic characteristics of aircraft engine rotor system are of great significance. In this paper, the dynamic characteristics of a simple dual-rotor model are calculated with the finite element method. Three types of finite element modeling methods are used for calculating and analyzing of the dual-rotor system and the feasibility of these methods is verified, so as to lay a foundation for reasonable modeling and calculating of the rotor system of an aircraft engine.An appropriate finite element model of engine rotor system is important for further studying the vibration of the engine. Four finite element modeling methods are used to calculate the critical speeds of the rotor system with cambered and twisting blades. Through the analysis of the results, it is found that the calculation results of the 3D model with blades simplified to mass element and the 3D model with cambered and twisting blades agree very well. This paper proposes that shaft and disk of the engine are created by 3D model, and the blades simplified by the mass element effectively take account of calculation accuracy and scale of the model.Taking the above mentioned into consideration, this paper proposes a modeling method for the rotor system of an aeroengine,then the model of the system is created reasonably. Before calculating the critical speeds, the stiffness of the support system of the engine is firstly calculated; then the critical speeds of the aeroengine dual-rotor system are calculated using APDL language programs and critical speeds and normal modes excited by the low-pressure rotor and the high-pressure rotor are obtained respectively by Campbell diagram method. The unbalance responses caused by imbalance of the low-pressure rotor and the high-pressure rotor are calculated by synchronization response method, from which the amplitude-frequency response curve of each disk is obtained. At the same time, critical speeds excited by the low-pressure rotor and the high-pressure rotor are obtained. Finally these two types of finite element method are used to mutually verify the critical speeds obtained.In this paper, the dynamic characteristics of the rotor system of an aircraft engine are calculated and analyzed using the finite element method. Analysis results show that the calculation method used in this paper works well and can be used to analyze similar aeroengines. The calculation results are reasonable, which have some reference value for analysis of aeroengine vibration.