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Date of Publication:2021-01-01

Journal:Zhendong yu Chongji/Journal of Vibration and Shock

Volume:40

Issue:12

Page Number:236-245

ISSN No.:1000-3835

Abstract:Based on the establishment of an unbalanced magnetic pull model considering both dynamic and static eccentricity, the corresponding dynamic equations of a coupled bending-torsional rotor-bearing system with rub-impact under electromagnetic excitation for hydraulic generating set were derived. A numerical analysis method was adopted to investigate the effect of mass eccentricity, excitation current, air gap dynamic and static eccentricity on nonlinear dynamic response of the system, compared with the previous similar model taking account into the single generalized air gap eccentricity. It is shown from the results that the bending-torsion coupling effect of the system is obviously increased with the augment of mass eccentricity. And the dynamic characteristics of the system are significantly influenced due to the existence of dynamic and static eccentricity, where the new dynamic phenomenon such as period-seven and period-ten appear. In addition, the impact on the dynamic response of the system is obviously different in terms of dynamic and static eccentricity. In comparison to static eccentricity, the dynamic fault, mainly inducing 1x frequency electromagnetic excitation component, is more likely to result in larger vibration, even full annular rubbing for the unit, which should be paid enough attention. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.

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