Dynamical Behavior Analysis of Rubbing Rotor System under Asymmetric Oil Film Force

Tang, Youfu; Feng, Lin; Zou, Qian

doi:10.1155/2019/1253646

Cited by 4 publications

(4 citation statements)

References 25 publications

(27 reference statements)

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“…Therefore, we use the correlation method to find out the final value of c K . In the correlation method, two vectors are formed, + = (6) Where d=1, 2, 3, …9 is the significant digit. Most of the data sets that follow Benford's Law are naturally occurring such as set of numbers in a newspaper or length of rivers in a country.…”

Section: The 0-1 Test For Chaosmentioning

confidence: 99%

Composite Test inclusive of Benford’s Law, Noise reduction and 0-1 Test for effective detection of Chaos in Rotor-Stator Rub

Srivastava

Tiwari

Singh

2021

Preprint

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Segregating noise from chaos in a dynamical system has been one of the most challenging work for the researchers across the globe due to their seemingly similar statistical properties. Even the most used tools such as 0-1 test and Lyapunov exponents fail to distinguish chaos from regular dynamics when signal is mixed with noise. This paper addresses the issue of segregating the dynamics in a rotor-stator rub system when the vibrations are subjected to different levels of noise. First, the limitation of 0-1 test in segregating chaotic signal from regular signal mixed with noise has been established. Second, the underexplored Benford’s Law and its application to the vibratory dynamical rotor-stator rub system has been introduced for the first time. Using the Benford’s Law Compliance Test (BLCT), successful segregation of not only noise from chaos but also very low Signal to Noise Ratio (SNR) signals which are mainly stochastic has been achieved. The Euclidean Distance concept has been used to explore the scale-invariant probability distribution of systems that comply with Benford’s Law to separate chaos from noise. Moreover, for moderate bands of noise in signals, we have shown that the Schreiber’s Nonlinear Noise Reduction technique works effectively in reducing the noise without damaging the dynamic properties of the system. Combining these individual layers (0-1 Test, BLCT and Noise reduction) on a rotor system, a Decision Tree based method to effectively segregate regular dynamics from chaotic dynamics in noisy environment has been proposed.

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Section: The 0-1 Test For Chaosmentioning

confidence: 99%

Composite Test inclusive of Benford’s Law, Noise reduction and 0-1 Test for effective detection of Chaos in Rotor-Stator Rub

Srivastava

Tiwari

Singh

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The developed simulation method involving the UMP model is simple, but still accurate (Kim et al, 2020).Tang et al established a dynamic model of a frictional rotor system under asymmetric oil film forces. Based on the nonlinear rotor dynamics theory, the dynamic behavior of rotor with different parameters is analyzed, and the corresponding chaotic characteristics are extracted (Tang et al, 2019). From the existing studies, the influence of UMP or OFF on the dynamic characteristics of the system is simply considered in most studies.…”

Section: Introductionmentioning

confidence: 99%

Dynamic analysis of grinding electric spindle bearing-rotor system under eccentric action

Sheng

Sun

et al. 2023

JAMDSM

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To study the influence of eccentricity on the dynamic characteristics of grinding electric spindle, firstly, the nonlinear oil film force (NOFF) expression of sliding bearing is established based on the boundary condition of adhesion pressure. Then, the expression of the unbalanced magnetic pull (UMP) under the eccentricity of the air gap is derived. Finally, the bearing-rotor dynamics equation of the grinding electric spindle considering the NOFF and UMP is established, and the dimensionless processing is carried out. The nonlinear dynamics study of the bearing-rotor system under the influence of geometric eccentricity and mass eccentricity is carried out through the shaft center trajectory and the shaft center vibration spectrum. The research results can provide reference for the optimal design of grinding electric spindle.

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“…A novel dynamic model of the rubbing rotor system was developed by Tang et al. Based on the nonlinear rotor dynamic theory, its dynamic behavior with different parameters was analyzed [18]. Zhu et al develops a dynamic model of a two-span rotor-bearing system with rubbing faults, and numerical simulation is carried out.…”

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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Dynamical Behavior Analysis of Rubbing Rotor System under Asymmetric Oil Film Force

Cited by 4 publications

References 25 publications

Composite Test inclusive of Benford’s Law, Noise reduction and 0-1 Test for effective detection of Chaos in Rotor-Stator Rub

Composite Test inclusive of Benford’s Law, Noise reduction and 0-1 Test for effective detection of Chaos in Rotor-Stator Rub

Dynamic analysis of grinding electric spindle bearing-rotor system under eccentric action

Variation and Modal Characteristic of Tangential Threshing Cylinder Undergoing Threshing Dynamics

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