Dynamic modeling and analysis of the rotor-bearing-disc coupling system with misalignment

The disc coupling has been widely used in aviation, ship and other fields, which often introduces the intermediate shaft to achieve large misalignment and ensure sufficient flexibility. However, there is no published and accurate theoretical dynamic model of this kind of coupling, and study to analyze the rotor system connected by the disc coupling with the intermediate shaft, especially with misalignment. Therefore, dynamic modeling and analysis of the rotor-bearing-disc coupling system with misalignment are carried out in this paper, and the dynamic model of the disc coupling with the intermediate shaft is established, emphatically. For the shafting connected by this kind of coupling, shaft misalignment can be unified as the combination of the angular misalignment between the drive shaft and the intermediate shaft, which simplifies the analysis of misalignment of the system with this kind of coupling. The accuracy of the established dynamic model is verified by the comparison of the critical speed between the finite element software and the dynamic model. The dynamic characteristics analysis reveals that: misalignment leads to the irregularity of the axis trajectory, the phenomenon of 1/4, 1/3, 1/2 subharmonic resonance, and the occurrence of the high-order harmonic components in the frequency-domain response, which can be used as the identification signal of misalignment. And it is effective to monitor the axis trajectory of the intermediate shaft for the rotor system connected by this kind of coupling.