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Numerical investigation of rotor-bearing systems with fractional derivative material damping models

Überwimmer Gregor, Quinz Georg, Klanner Michael, Ellermann Katrin

Bulletin of the Polish Academy of Sciences. Technical Sciences

2023

Vol. 71, nr 6

art. no. e148610

The increasing demand for high-speed rotor-bearing systems results in the application of complex materials, which allow for a better control of the vibrational characteristics. This paper presents a model of a rotor including viscoelastic materials and valid up to high spin speeds. Regarding the destabilization of rotor-bearing systems, two main effects have to be investigated, which are strongly related to the associated internal and external damping of the rotor. For this reason, the internal material damping is modeled using fractional time derivatives, which can represent a large class of viscoelastic materials over a wide frequency range. In this paper, the Numerical Assembly Technique (NAT) is extended for the rotating viscoelastic Timoshenko beam with fractional derivative damping. An efficient and accurate simulation of the proposed rotor-bearing model is achieved. Several numerical examples are presented and the influence of internal damping on the rotor-bearing system is investigated and compared to classical damping models.

Stability analysis of rotor-bearing systems via Routh-Hurwitz criterion

El-Marhomy A. A. A. A.

Mechanics and Mechanical Engineering

2004

Vol. 7, nr 1

131-149

A method of analysis is developed for studying the whirl stability of rotor-bearing systems without the need to solve the governing differential equations of motion of such systems. A mathematical model comprised of an axially symmetric appendage at the mid span of a spinning shaft mounted on two dissimilar eight-coefficient bearings is used to illustrate the method. Sufficient conditions for asymptotic stability of both the translational and rotational modes of motion of the system have been derived. The system stability boundaries presented graphically in terms of the various system non-dimensionalized parameters afford a comprehensive demonstration of the effects of such parameters on system stability of motion.

Lateral-torsional vibration analysis of the rotor-shaftbearing system using various mechanical models

Kiciński J., Rządkowski R., Szolc T., Walczyk Z.

Vibrations in Physical Systems

2002

Vol. 20

180--181

On-line identification of squeeze-film dymanics of multi-mode rotor-bearing system

Yu Z., Meng L. T.

Computer Assisted Mechanics and Engineering Sciences

1998

Vol. 5, nr 3

253-266

This paper presents a practical algorithm for on-line parameter identification of squeeze-film bearing of multi-mode rotor-bearing system.The identification procedure is based on modeling each of the bearing pedestal by applying a multi-frequency excitation force on the rotor and frequency transfer function data are used. It suggested that accurate identification coefficients with reduced standard errors can be achieved without resource to full or reduced-order rotor system measurements. The approach can be applied to rotor-bearing system with any degree of complexity and other types of bearing. Simulation and experimental investigation show that the identification algorithm developed in the paper will considerably simplify the measurement and calculation task for testing work in laboratory and industral environment without any lost of identification accuracy. The experimental results of stiffness and damping characteristics of the squeeze-film bearings for different rotating speed are also presented.