Harmonic Response Analysis of a Dual-Rotor System with Mass Unbalance

Abstract

The finite element model of a dual-rotor system (coaxial structure) was established by Ansys entity model. The inner rotor is supported by three bearings while the outer rotor is supported by two bearings. The outer rotor connects the inner rotor by an intermediary bearing. The critical speed Characteristic of the dual-rotor system was calculated by selecting the inner rotor and outer rotor separately as the main excitation source. The harmonic response analysis of the dual-rotor system with mass unbalance were analyzed in order to study the influence of mass unbalance of the rotor system. The results indicate that the outer rotor with mass unbalance is more likely to cause resonance than the inner rotor with mass unbalance, but the resonance amplitude is relatively small. It is possible to reduce the harmonic resonance frequency in the dual-rotor system by improving the design of the outer rotor. Harmonic resonance amplitude gradually increases with the increase of excitation frequency.