Dynamic Characteristics and Experimental Research of a Two‐Span Rotor‐Bearing System with Rub‐Impact Fault

Zhu, Rui; Wang, Guang-chao; Han, Qingpeng; Zhao, Anlei; Ren, Jianxing; Xia, Xin

doi:10.1155/2019/6309809

Cited by 7 publications

(6 citation statements)

References 19 publications

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“…However, in a fluid medium, the peak values are minimal and somewhere masked by the fluid properties. The comparison on the reproduced time history, orbit, and the full spectrum features of the rotating shaft measured by the experiment precisely at the contact point of one side of the screw impact and the simulation showed qualitatively the same trend as the previously reported papers [10][11][12]. The experimental results allow a deeper understanding of the underlying internal mechanisms of the fluid coupling to be achieved.…”

Section: ) and 10(d))supporting

confidence: 82%

“…However, there are some strong interference components, e.g., the multiple embraced part shown by a yellow line around the main frequency peak in Figures 8(c) and 8(d) which is excited by the frictional impact. Figures 8(a)-8(d) show that the rotor vibrations are periodic motions with sub-and superharmonics, which become quasiperiodic and regarded as chaos by some researchers, as stated in references [11,12].…”

Section: Resultsmentioning

confidence: 98%

“…Presently, a few researchers are still devoted to investigate experimentally the dynamic stability of the rotor filled with liquid. Zhu et al [11] made the experimental analysis on the dynamic characteristics of an overhung rigid centrifuge rotor partially filled with fluid. The research chiefly focused on the influences of viscous fluid-fill ratio on rotor whirl frequency, the range of the unstable region, and the rotor unbalance.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influences of Hydrodynamic Forces on the Identification of the Rotor-Stator-Rubbing Fault in a Rotating Machinery

Tchomeni

Sozinando

Alugongo

2020

International Journal of Rotating Machinery

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Mechanical failures of a complex machine such as rotor widely used in severe conditions often require specialized knowledge, technical expertise, and imagination to prevent its rupture. In this paper, a model for analyzing excitation of a coupled lateral-torsional vibrations of a shaft system in an inviscid fluid is proposed. The model considers the recurrent contact of the vibrating shaft to a fixed stator. The simplified mathematical model of the rotor-stator system is established based on the energy principle. The dynamic characteristics of the fluid-rotor system are studied, and the features of rub-impact are extracted numerically and validated experimentally under the effects of the unbalance and the hydrodynamic forces. The main contribution of this article is in extraction and identification of the rub features in an inviscid medium which proved to be complex by the obstruction of the fluid and required the use of appropriate signal processing tools. The results through a synchrosqueezing wavelet transform indicated that the exciting fluid force could significantly attenuate the instability and amplitude of rubbing rotor. The experimental results demonstrated that for half the first critical speed, the subharmonic 1 / 2 × Ω and the irregular orbit patterns provide good indices for rub detection in an inviscid fluid of the rotating shafts. Finally, it is revealed that the instantaneous frequency extraction based on wavelet synchrosqueezing is a useful tool to identify the weak and hidden peak harmonics localised in the time-frequency maps of the fluid-rotor system.

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Section: ) and 10(d))supporting

confidence: 82%

Section: Resultsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influences of Hydrodynamic Forces on the Identification of the Rotor-Stator-Rubbing Fault in a Rotating Machinery

Tchomeni

Sozinando

Alugongo

2020

International Journal of Rotating Machinery

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“…They considered the influence of Hertz contact force, number of rollers, bearing radial clearance and other factors on the rotor system. After years of development, the research on rub impact dynamics of rotor system has successfully moved from single vibration to bending torsional coupling vibration [5].Wang [6] also takes into account the strong nonlinear characteristics of rolling bearings. The difference is that he mainly analyzes the rotor system under heavy load and high speed.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamics analysis of rotor system

Sun

Zhang

Zhou

2023

J. Phys.: Conf. Ser.

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In order to get the motion of the disc core and bearing in the rotor system, the nonlinear dynamic model was established. The influence of the disc core and bearing under the action of different rotor speeds and different bearing clearances is analyzed by numerical calculation. The results show that the change of rotor speed will not have a great impact on the disc center, will affect the movement cycle and amplitude, which will have a slight impact on the bearing. The increase of clearance will change the overall movement of the disc center, especially in the initial stage of the system, which will have a greater impact on the bearing.

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“…Zhu et al develops a dynamic model of a two-span rotor-bearing system with rubbing faults, and numerical simulation is carried out. Rotors running under normal condition, local slight rubbing, and severe rubbing throughout the entire cycle are simulated [19]. Dynamic trajectories and frequency spectrum diagrams are used to analyze the features of the rotor-bearing system with rub-impact faults under various parameters, and vibration characteristics of rub impact are obtained.…”

Section: Introductionmentioning

confidence: 99%

Variation and Modal Characteristic of Tangential Threshing Cylinder Undergoing Threshing Dynamics

Tang

Wang

Zhang

et al. 2020

Mathematical Problems in Engineering

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During the rice-threshing process, straws always attached to a threshing cylinder and induced vibration and modal variation. In this paper, the constraint and threshing modals of the threshing cylinder were tested under idling and load conditions, and the causes of vibration and modal variation were explained. Based on the constraint and modal of the threshing cylinder, the vibration amplitudes and frequencies undergoing rice threshing were tested and analyzed. Results showed that mass of straws decreased gradually with the separation of rice grains and straws. And there was a nonuniform change in the circumferential resistance of the threshing cylinder. The fluctuating torque, speed, and frequencies during threshing process would cause vibration of the threshing cylinder. During rice-threshing process, the other natural frequencies were greater than the excitation frequency. With the accumulation of a large amount of straws, the threshing modal frequencies of the tangential threshing cylinder increased. The threshing bars caused vibration of the tangential threshing cylinder in the left and right direction mainly at two frequencies. At idling state of no-load, the vibration frequency 42.97 Hz of the tangential threshing cylinder in X direction was close to the constraint modal frequency 41.58 Hz. The eccentric load caused the excitation frequency to increase during the rice-threshing process. The vibration frequency was also closely related to the threshing modal. The tangential threshing cylinder with low vibration characteristics could be designed by using the eccentric vibration characteristics during the threshing process.

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Dynamic Characteristics and Experimental Research of a Two‐Span Rotor‐Bearing System with Rub‐Impact Fault

Cited by 7 publications

References 19 publications

Influences of Hydrodynamic Forces on the Identification of the Rotor-Stator-Rubbing Fault in a Rotating Machinery

Influences of Hydrodynamic Forces on the Identification of the Rotor-Stator-Rubbing Fault in a Rotating Machinery

Nonlinear dynamics analysis of rotor system

Variation and Modal Characteristic of Tangential Threshing Cylinder Undergoing Threshing Dynamics

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