Nonlinear Vibration and Stability Analysis of Flexible Rotor Supported on SFD by IHB Method

Abstract

In this paper, the nonlinear vibration of a flexible rotor supported on squeeze-film dampers (SFDs) with centering springs is analyzed using the incremental harmonic balance (IHB) method, and bifurcation phenomena appeared in the resonance region are investigated. Complex nonlinear phenomena occur in this system due to the interaction of the fluid-film forces and the unbalance forces of the rotor in the SFD. Systems with these complex nonlinearities cannot be solved using the classical IHB methods. To overcome this problem, the classical IHB method and the alternating frequency/time (AFT) method are combined. The processing of linear matrices is performed in the same way as the classical IHB method, and only the processing of nonlinear force matrix caused by fluid–structure interaction is modified (application of transformation matrix). To prove the validity of the proposed method, the results calculated using the proposed method are compared with the results calculated using the Runge–Kutta method and the results presented in reference. Then, frequency response curves according to changes in bearing parameter [Formula: see text], gravity parameter [Formula: see text], stiffness ratio [Formula: see text], mass ratio [Formula: see text], and unbalance parameter [Formula: see text] are constructed. Stability and bifurcation analyses of the calculated solution are performed using the Floquet theory. The proposed method can be effectively applied to the nonlinear vibration analysis of rotor systems supported on fluid-film bearings.

Nonlinear Dynamic Responses of a Rotor-Bearing System with Eccentric Squeeze Film Dampers

“…The results show that the response characteristics of the rotor at different positions are different. Ri et al [8] proposed an IHB method for analyzing the dynamic response of a flexible rotor-elastic support system with SFD, compared the calculation results of this method with the calculation results of the Runge-Kutta method and literature results, and finally analyzed the stability of the rotor system with SFD based on this method. Chen et al [9] combined the harmonic balance method and Runge-Kutta method to analyze the dynamic characteristics of the SFD-rotor system with dualfrequency excitation.…”