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Angular Speed

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Didier Rémond – One of the best experts on this subject based on the ideXlab platform.

  • Angular modeling of a rotating machine in non-stationary conditions: Application to monitoring bearing defects of wind turbines with instantaneous Angular Speed
    Mechanism and Machine Theory, 2019
    Co-Authors: Jose L. Gomez, Adeline Bourdon, Hugo Andre, Ilyes Khelf, Didier Rémond
    Abstract:

    Abstract This work has been developed within the framework of non-stationary rotating machinery surveillance with emphasis on the detection of rolling element bearing defects. The numerical models proposed in this paper are based on an “Angular” approach which introduces explicitly the machine’s free body rotation degrees of freedom allowing simulations in non-stationary operating conditions. In a previous work, a deep groove ball bearing model has been presented considering the rolling resistance phenomena, allowing to describe the Angular Speed variations due to the bearing dynamics, a phenomenon that has been detected experimentally. In this work, a classic gear mesh description together with the rolling element bearing defects model have been used to build a wind turbturbine virtual machine. The model is used as a device to test Instantaneous Angular Speed spectral indicators.

  • Modelling deep groove ball bearing localized defects inducing instantaneous Angular Speed variations
    Tribology International, 2016
    Co-Authors: Jose L. Gomez, Adeline Bourdon, Hugo Andre, Didier Rémond
    Abstract:

    Abstract Instantaneous Angular Speed (IAS) analysis has been presented as an advantageous tool for non-stationary machinery surveillance. The physical analysis indicates that the instantaneous rotating Speed variations are caused by torque perturbations. In a previous work, a method for introducing Angular periodic disturbances in rotating systems dynamic models was presented. This analysis was based on the introduction of a parametric perturbation applied to the system as an external torque. The current work introduces an original formulation to induce tangential forces to the shaft due to the bearing components dynamics by means of a Hertzian contact roller bearing model. The methodology takes into account rotational bearing races and rolling elements degrees of freedom, making the model suitable for non-stationary conditions.

  • Modelling Roller Bearing Dynamics Inducing Instantaneous Angular Speed Variations
    Proceedings of the 9th IFToMM International Conference on Rotor Dynamics, 2015
    Co-Authors: Jose L. Gomez, Adeline Bourdon, Hugo Andre, Didier Rémond
    Abstract:

    Modelling the dynamics of roller element bearings has been used to explain the interactions between localized faults and their impact on the measurable quantities representing the dynamic behavior of the system e.g. acceleration. Most part of the models describes the non-linear contact of roller bearing normal forces by means of Hertz Theory. Recently, analysis of the Instantaneous Angular Speed (IAS) has been proven to effectively detect bearing mechanical faults and it has shown to be an advantageous tool for non-stationary machinery surveillance. Mechanical analysis implies that rotating Speed variations are due to torque variations. However, the phenomena describing how dynamic interaction of bearing components induces tangential forces generating Angular periodic disturbances to the shaft Speed, have not been discussed at all. In this work an original formulation to induce tangential forces to the shaft due to the bearing components dynamics is presented. The roller bearing model is based on Hertzian contact, localized faults can be added and the analysis is suitable for simulation of non-stationary conditions.

Xiao Yang – One of the best experts on this subject based on the ideXlab platform.

  • Outliers Identification From Instantaneous Angular Speed Signal Generated by Zebra Tapes
    IEEE Access, 2019
    Co-Authors: Jiansheng Lin, Xiao Yang
    Abstract:

    Instantaneous Angular Speed (IAS) measurement using zebra tape has been presented as an advantageous tool for rotating machinery surveillance. Unfortunately, both butt joint and mounting imperfection of the zebra tape result in stripes with different widths, which cause the outliers appear in the acquired signal. This paper proposed a solution to accurately identify the outliers and define the Angular displacement values represented by outliers in the condition of periodic fluctuation of Speed. The procedure is based on K-means clustering method and Fourier series model. Specially, a series of algorithms take K-means clustering partitioning method as core, and is used for outliers identification; the Fourier series fitting model is used to analyze the Angular displacement values represented by outliers. Experimental study was performed on a test rig to validate the method under different measurement conditions. The result of error analysis shows the effectiveness of the algorithm.

Aleksandra Świetlicka – One of the best experts on this subject based on the ideXlab platform.

  • Effective estimation of Angular Speed of synchronous generator based on stator voltage measurement
    International Journal of Electrical Power & Energy Systems, 2018
    Co-Authors: Michał Lewandowski, Łukasz Majka, Aleksandra Świetlicka
    Abstract:

    Abstract Estimation of the parameters of the power generators are important part of a power system modeling and simulation. A reliable estimation of a synchronous generator parameters can be done using waveforms measured directly on the terminals of the machine. The waveforms are recorded during a carefully chosen disturbance tests of the generating unit. One of the quantities necessary to determine the generator parameters is the deviation of the generator Angular Speed. However, because of the safety reasons, it is very difficult to get access to the direct measurement of this quantity on a operating generating unit. Angular Speed estimation based on a generator stator voltage seems to be an alternative solution to the problem. The aim of the paper is to find a computationally efficient and accurate method of indirect Angular Speed estimation of a synchronous generator which is based on the recording of its stator voltage during a load rejection test. The algorithms evaluated in the paper are based on Prony’s estimator, zero-crossing detection, least-square data fitting and layer recurrent neural network. Paper contains literature survey, mathematical model of the considered generator, analysis of its stator voltage recorded in a power plant, description of the selected algorithms and results of the algorithms estimation using a signal with known frequency variation. Performed algorithms evaluation allows to choose the best solution in terms of accuracy and computational effort.

Hong-liang Dai – One of the best experts on this subject based on the ideXlab platform.

  • thermo elastic analysis of a functionally graded rotating hollow circular disk with variable thickness and Angular Speed
    Applied Mathematical Modelling, 2016
    Co-Authors: Ting Dai, Hong-liang Dai
    Abstract:

    Abstract In this paper, the displacement and stress fields in a functionally graded material (FGM) hollow circular disk, rotating with an Angular acceleration under a changing temperature field, are achieved by using a semi-analytical approach. The material properties are assumed to vary along the radial coordinate and related to the volume fraction of each material. The modulus of elasticity and the coefficient of thermal expansion are supposed to be temperature-dependent, while the Poisson’s ratio is assumed to be constant. In numerical examples, effects of the functionally graded index, the geometric shape, the Angular Speed and the temperature boundary conditions to the displacement and stresses are considered. The results of this study may be useful for other investigations of rotating FGM circular disks with variable thickness.

  • Investigation of mechanical behavior for a rotating FGM circular disk with a variable Angular Speed
    Journal of Mechanical Science and Technology, 2015
    Co-Authors: Ting Dai, Hong-liang Dai
    Abstract:

    In this paper, the displacement and stress distribution in a rotating FGM (Functionally graded material) circular disk with a variable Angular Speed are studied. The modulus of elasticity and mass density of the circular disk are assumed to vary along its radius and relate to the volume fraction of the materials, while the Poisson’s ratio remains to be a constant. The motion equations of the FGM rotating circular disk are simplified into boundary value problems of ordinary differential equation, which are solved by Runge-Kutta method, and the whole problem is solved by utilizing shooting method. Numerical results show that the functionally graded index, Angular Speeds and geometric shape all have significant effect on the mechanical behaviors of the rotating FGM circular disk. The results of this study may be useful for other investigations of a rotating FGM circular disk.

Hugo Andre – One of the best experts on this subject based on the ideXlab platform.

  • High Frequency Demodulation Technique for Instantaneous Angular Speed Estimation
    , 2019
    Co-Authors: Frédéric Bonnardot, Hugo Andre, Khalid Lizoul, Saad Errafik, Francois Guillet
    Abstract:

    Many vibration monitoring methods use an accelerometer sensor in order to diagnose the systems. Instantaneous Angular Speed (IAS) has appeared to provide a new source of information on the rotating machine and it is commonly used to diagnose faults such as bearings faults [1], gearboxes [2], … Classically, IAS use an optical encoder as a Speed sensor. This sensor is available in many rotating machines (especially for Speed and position control). It provides a square / sine wave with a frequency proportional to the rotation Speed. Thus, this signal is frequency modulated by the system Speed variations. There are two major methods for recording IAS signal: timer / counter technics [3], and ADC- based methods [4]. The latter is limited by the capability of the ADC-board to collect the data (sampling frequency) which could restrict the use of higher encoder resolution and introduces spatial aliasing. In this study, we are interested in IAS estimation using a super-heterodyne like demodulation technique. The idea is to be able to acquire the Speed signal with relatively higher resolution without using a higher sampling frequency. The IAS signal is first analogously shifted in frequency domain in order to be acquired at a lower sampling rate. Then, the sampled signal is further treated to get IAS. A first part recalls the classic IAS estimation methods and their limits. In a second part, a new technique is introduced for IAS estimation. The spectral components of the method are compared to the spectrum of the IAS signal estimated by elapsed time technique. At the end, the effect of noise is shortly discussed.

  • Angular modeling of a rotating machine in non-stationary conditions: Application to monitoring bearing defects of wind turbines with instantaneous Angular Speed
    Mechanism and Machine Theory, 2019
    Co-Authors: Jose L. Gomez, Adeline Bourdon, Hugo Andre, Ilyes Khelf, Didier Rémond
    Abstract:

    Abstract This work has been developed within the framework of non-stationary rotating machinery surveillance with emphasis on the detection of rolling element bearing defects. The numerical models proposed in this paper are based on an “Angular” approach which introduces explicitly the machine’s free body rotation degrees of freedom allowing simulations in non-stationary operating conditions. In a previous work, a deep groove ball bearing model has been presented considering the rolling resistance phenomena, allowing to describe the Angular Speed variations due to the bearing dynamics, a phenomenon that has been detected experimentally. In this work, a classic gear mesh description together with the rolling element bearing defects model have been used to build a wind turbine virtual machine. The model is used as a device to test Instantaneous Angular Speed spectral indicators.

  • Modelling deep groove ball bearing localized defects inducing instantaneous Angular Speed variations
    Tribology International, 2016
    Co-Authors: Jose L. Gomez, Adeline Bourdon, Hugo Andre, Didier Rémond
    Abstract:

    Abstract Instantaneous Angular Speed (IAS) analysis has been presented as an advantageous tool for non-stationary machinery surveillance. The physical analysis indicates that the instantaneous rotating Speed variations are caused by torque perturbations. In a previous work, a method for introducing Angular periodic disturbances in rotating systems dynamic models was presented. This analysis was based on the introduction of a parametric perturbation applied to the system as an external torque. The current work introduces an original formulation to induce tangential forces to the shaft due to the bearing components dynamics by means of a Hertzian contact roller bearing model. The methodology takes into account rotational bearing races and rolling elements degrees of freedom, making the model suitable for non-stationary conditions.