Dynamic modeling of rotor-bearing-housing system with local defect on ball bearing using mass distribution and energy methods

The vibration response of ball bearing with local defect is closely associated with its lubrication condition. The previous bearing dynamic models were mainly established based on the idealised lubrication conditions, which may not uncover the influence of thermal effect of lubricant on vibration characteristics of defective bearing. This paper presented the influence of thermal effect on elastohydrodynamic lubrication (EHL) performances of ball bearing and the vibration characteristics of defective bearing under thermal EHL. Considering the point contact thermal EHL and the time-varying displacement excitation, a dynamic model of ball bearing with a localised defect on outer raceway was developed. The model was validated by the experimental results. Compared with isothermal EHL, the simulation results with thermal EHL reveal larger pressure and thinner film thickness in the ball-raceway contact interface. Meanwhile, the rotating speed and radial load have significant effects on the thermal EHL performance of ball bearing. The effects of three contact conditions (dry friction, isothermal and thermal EHL) on vibration amplitude of defective bearing in frequency domain are discussed. The results show that the lubricant could improve the vibration of defective bearing, whereas the addition of thermal effect of EHL could increase the vibration amplitude and deteriorate the lubricating performance. The model is beneficial to the bearing model optimisation and the rational selection of lubricants.

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“…The excitation function for time-varying displacement attributed to local defect can be written as equation (10):…”

Section: Time-varying Displacementmentioning

confidence: 99%

“…Patil et al 9 built a dynamic model with raceway defects including cage slip for bearing to study the contact forces and dynamic impacts during ball-defect interaction. Liu et al 10 integrated the rotor mass distribution method with a rotor-bearing-pedestal system model to research vibrations of the system with defective bearing.…”

Section: Introductionmentioning

confidence: 99%

Effect of thermal elastohydrodynamic lubrication on vibration characteristics of ball bearing with local defect

Wang

Yan

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part K:

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“…The numerical solutions and experimental observations of X-direction displacements at bearing-1 under idling and load conditions are depicted in Figure 7. The numerical solutions of the developed model are obtained via the fourth-order Runge-Kutta method 28 in Eq. (6) and, with the error tolerance being less than 10 − 5.…”

Section: Model Validationmentioning

confidence: 99%

Effect of the unbalanced magnetic pull force and oil-film force on nonlinearity of a dual-rotor bearing system

Zhao

Liao

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part K:

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Turbogenerator sets, the indispensible rotating machinery in thermal power plants, can be simplified into a dual-rotor bearing system. In this case, its nonlinear phenomenon largely results from the unbalanced magnetic pull (UMP) and the nonlinear oil film forces, which, however, are not well understood. In this study, a mathematical model for a dual-rotor bearing system is established, the effects of the UMP and the oil-film forces on its nonlinear phenomenon are investigated creatively. Of which, the UMP force is initially calculated by the integration of the air-magnetic energy, and the short journal bearing assumption is employed to derive the oil-film force. The fitness of the developed model is validated through the stability experiments of a 660 MW turbogenerator set. Results indicate that in the idling condition, nonlinear phenomenon of the system can be described as the period-1 and quasi-periodic motions as the rotational speed rises. At low speeds, the amplitude of oil whirl appears. With the rising rotational speed, the oil whirl turns into oil whip in the second quasi-periodic. Interestingly, the electromagnetic force can greatly alleviate the system amplitude and enhance its stability considering the UMP force. The nonlinear effect of air-gap distance of the system under load conditions is also investigated. The system is still in the quasi-periodic state with the increasing air-gap distance at low/high speed. But the system is still unstable owing to oil whirl/whip and UMP force, causing the system experiences multiple states and becomes more stable at the intermediate speed.

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“…Tian et al 25 proposed a vibration model of dual-rotor system with single-row bearings considering different defect sizes. Liu et al 26 proposed a vibration model of a rotor system with single-row bearings based on the energy method with the defect in the out ring.…”

Section: Introductionmentioning

confidence: 99%

A vibration model of a flexible rotor-bearing system considering the defect in a double-row cylindrical roller bearing

Liu,

Fancheng,

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part K:

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Vibration analysis of double-row cylindrical roller bearing systems is useful for controlling the vibrations of rotating transmission systems. However, most current works only formulated the rotor system with single-row cylindrical roller bearings. Moreover, the vibration characteristics of the rotor system with defective double-row cylindrical roller bearings are not clearly. To overcome this problem, a vibration model of a flexible rotor system with the defective double-row cylindrical roller bearing is proposed in this work. The effects of the speed and defect on the vibrations of flexible rotor systems are studied. The vibrations from flexible and rigid models are compared under different rotation speeds. Note that the vibration waveforms from rigid and flexible models are similar. The vibrations of different nodes are different under different speeds, which cannot be formulated by the previous rigid models. The vibration model can better represent the vibrations of rotor systems with and without the defect. Moreover, this paper can provide a comprehensive analytical method for vibrations and acoustics of flexible rotor systems with the double-row cylindrical roller bearings.

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Dynamic modeling of rotor-bearing-housing system with local defect on ball bearing using mass distribution and energy methods

Cited by 6 publications

References 32 publications

Effect of thermal elastohydrodynamic lubrication on vibration characteristics of ball bearing with local defect

Effect of thermal elastohydrodynamic lubrication on vibration characteristics of ball bearing with local defect

Effect of the unbalanced magnetic pull force and oil-film force on nonlinearity of a dual-rotor bearing system

A vibration model of a flexible rotor-bearing system considering the defect in a double-row cylindrical roller bearing

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