The Vibration Signatures of a Rotor System with the Effect of Bearing Radial Clearance

As the main support of the rotor system, the operation status of bearings is crucial for the stable operation of the rotor system. This paper focuses on the influence of bearings with different radial clearances on the vibration characteristics of a single rotor system under the condition of unbalance and misalignment. Firstly, a single rotor system dynamics model with double disks and double supports in unbalanced and misalignment is established based on Hertz contact theory and classical mechanics. Secondly, the Newmark-β method is used to solve the vibration response of the single rotor and obtain simulation signals under different radial clearances of the bearings. Then, the nonlinear phase coupling characteristics of the signal are extracted by combining the Bispectrum technique with bicoherence technique. Finally, it is found that the radial clearance of bearing leads to the appearance of characteristic frequency of variable flexibility bearing ( \(VC_{1}\) ). This frequency is coupled with the rotation frequency and its frequency doubling to produce a modulation frequency with a higher amplitude than the frequency itself, which is represented by a clear grid in the bicoherence diagram.