FEM modeling technology and vibration analysis of flexible rotor system

The low-pressure spool in a high-bypass ratio turbofan engine has its unique characteristics. The slightness rotor and the large lumped mass in blade and disk are the structural characteristics while the dynamic coupling between bladed-disk and shaft is the mechanical characteristic. This paper studies on the modeling technology of a flexible rotor system based on the finite element method (FEM). The equivalent-disk method, an equivalent principle of finite element modeling, is put forward. The blades are equivalent to a disk which can not only retain the structural and mechanical characteristics but also control the scale of the model and convert the periodic geometry into axisymmetric geometry. The results show that the equivalent-disk method is helpful to improve the modeling techniques of rotor system and can be used in engineering.