Vibration Characteristics of a Dual-Rotor System with Non-Concentricity

A finite element model of an aero-engine dual-rotor system with intermediate bearing supported by six bearings is set up. Three modes non-concentricity caused the assembly process are defined, namely parallel non-concentricity, front deflection angle and rear non-concentricity. The influence on vibration characteristics investigated in detail. results show that have a significant bending modals high-pressure rotor low-pressure rotor, but little local rotors. With increase magnitude natural frequencies decrease continuously, mode shapes may be interchanged, leading to emergence advance. Therefore, key parameters controlled In order prevent modal from appearing advance, it necessary control within 2 mm amount 0.18°.