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Showing papers on "Bearing (mechanical) published in 2012"


Proceedings Article
18 Jun 2012
TL;DR: In this paper, the authors present an experimental platform called PRONOSTIA, which enables testing, verifying and validating methods related to bearing health assessment, diagnostic and prognostic, which are performed under constant and/or variable operating conditions.
Abstract: This paper deals with the presentation of an experimental platform called PRONOSTIA, which enables testing, verifying and validating methods related to bearing health assessment, diagnostic and prognostic. The choice of bearings is justified by the fact that most of failures of rotating machines are related to these components. Therefore, bearings can be considered as critical as their failure significantly decreases availability and security of machines. The main objective of PRONOSTIA is to provide real data related to accelerated degradation of bearings performed under constant and/or variable operating conditions, which are online controlled. The operating conditions are characterized by two sensors: a rotating speed sensor and a force sensor. In PRONOSTIA platform, the bearing's health monitoring is ensured by gathering online two types of signals: temperature and vibration (horizontal and vertical accelerometers). Furthermore, the data are recorded with a specific sampling frequency which allows catching all the frequency spectrum of the bearing during its whole degradation. Finally, the monitoring data provided by the sensors can be used for further processing in order to extract relevant features and continuously assess the health condition of the bearing. During the PHM conference, a "IEEE PHM 2012 Prognostic Challenge" is organized. For this purpose, a web link to the degradation data is provided to the competitors to allow them testing and verifying their prognostic methods. The results of each method can then be evaluated regarding its capability to accurately estimate the remaining useful life of the tested bearings.

537 citations


Journal ArticleDOI
TL;DR: In this article, the authors present the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems.
Abstract: This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN2. More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

385 citations


Journal ArticleDOI
TL;DR: In this article, data mining is applied to identify bearing faults in wind turbines, which leads to the prediction of faults 1.5 h before their occurrence. But the performance of the models is validated on different wind turbines with over 97% accuracy.

185 citations


Journal ArticleDOI
TL;DR: A hybrid two stage one-against-all Support Vector Machine (SVM) approach is proposed for the automated diagnosis of defective rolling element bearings, which can be performed using simulation data, describing the dynamic response of defectiverolling element bearings.

182 citations


Journal ArticleDOI
TL;DR: In this article, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters; the model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements.

154 citations


Journal ArticleDOI
TL;DR: This article employs bearing rigidity for mobile formations, which was developed for robot and sensor network localisation, so that bearings can be used for shape control in mobile formations.
Abstract: Distance measurements are not the only geometric quantities that can be used for multi-agent formation shape control. Bearing measurements can be used in conjunction with distances. This article employs bearing rigidity for mobile formations, which was developed for robot and sensor network localisation, so that bearings can be used for shape control in mobile formations. The first part of this article examines graph theoretical models for formation network analysis and control law design that are needed to maintain the shape of a formation in two-dimensional space, while the formation moves as a cohesive whole. Bearing-based shape control for a formation of mobile agents involves the design of distributed control laws that ensure the formation moves, so that bearing constraints maintain some desired values. The second part of this article focuses on the design of a distributed control scheme for nonholonomic agents to solve the bearing-based formation shape control problem. In particular, a control law u...

142 citations


Journal ArticleDOI
TL;DR: In this article, the potential use of laser surface texturing (LST) in hydrodynamic journal bearings is examined theoretically, and the effect of such a texture on load capacity and on the attitude angle of the journal bearing is investigated.
Abstract: The potential use of laser surface texturing (LST) in hydrodynamic journal bearings is examined theoretically. The regular surface texture has the form of micro-dimples with preselected diameter, depth, and area density. It can be applied to only a certain portion of the bearing perimeter (partial LST) or the full bearing perimeter (full LST). The effect of such a texture on load capacity and on the attitude angle of the journal bearing is investigated in the present work. The optimum parameters of the dimples and favorable LST mode for maximum load capacity have been found.

139 citations


Journal ArticleDOI
TL;DR: This paper proposes a bearing-only formation controller requiring only bearing measurements, converging almost globally, and maintaining bounded inter-agent distances despite the lack of direct metric information, and introduces and thoroughly analyzes the concept and properties of bearing formations.
Abstract: In this paper we address the problem of controlling the motion of a group of unmanned aerial vehicles (UAVs) bound to keep a formation defined in terms of only relative angles (i.e. a bearing formation). This problem can naturally arise within the context of several multi-robot applications such as, e.g. exploration, coverage, and surveillance. First, we introduce and thoroughly analyze the concept and properties of bearing formations, and provide a class of minimally linear sets of bearings sufficient to uniquely define such formations. We then propose a bearing-only formation controller requiring only bearing measurements, converging almost globally, and maintaining bounded inter-agent distances despite the lack of direct metric information.The controller still leaves the possibility of imposing group motions tangent to the current bearing formation. These can be either autonomously chosen by the robots because of any additional task (e.g. exploration), or exploited by an assisting human co-operator. Fo...

126 citations


Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper developed a machine vision system for bearing defect inspection, which can inspect various types of defects on bearing covers, such as deformations, rusts, scratches and so on.

116 citations


Proceedings Article
15 Oct 2012
TL;DR: In this article, the multifractal detrended fluctuation analysis (MF-DFA) is applied to uncover the multifractality buried in nonstationary time series for exploring rolling bearing fault data.
Abstract: Vibrations of a defective rolling bearing often exhibit nonstationary and nonlinear characteristics which are submerged in strong noise and interference components. Thus, diagnostic feature extraction is always a challenge and has aroused wide concerns for a long time. In this paper, the multifractal detrended fluctuation analysis (MF-DFA) is applied to uncover the multifractality buried in nonstationary time series for exploring rolling bearing fault data. Subsequently, a new approach for fault diagnosis is proposed based on MF-DFA and Mahalanobis distance criterion. The multifractality of bearing data is estimated with the generalized the Hurst exponent and the multifractal spectrum. Five characteristic parameters which are sensitive to changes of bearing fault conditions are extracted from the spectrum for diagnosis of fault sizes. For benchmarking this new method, the empirical mode decomposition (EMD) method is also employed to analyze the same dataset. The results show that MF-DFA outperforms EMD in revealing the nature of rolling bearing fault data.

110 citations


Journal ArticleDOI
TL;DR: In this paper, a comparison between experiment and simulation results has been carried out on parallel thrust bearings in terms of cavitation zone morphology in a groove, friction coefficient, and bearing clearance.
Abstract: When a textured ring rotates relatively against the other texture-free ring in a parallel thrust bearing, cavitation of liquid lubricant may occur in the divergent zones of the dimples or grooves on the textured surface due to local pressure drops. The Reynolds and Jakobsson–Floberg–Olsson (JFO) models are two widely used cavitation models in hydrodynamic lubrication theory, where the former lacks mass conservation while the latter enforces it. In order to investigate the applicability of the two models to the hydrodynamic lubrication analysis of parallel thrust bearings with surface textures, comparison between experiment and simulation results has been carried out on parallel thrust bearings in terms of cavitation zone morphology in a groove, friction coefficient, and bearing clearance. The results have shown that the observed cavitation morphology in steady state is more similar to the prediction from the JFO model than that from the Reynolds model.

Journal ArticleDOI
TL;DR: In this paper, the authors presented the results of three-dimensional finite element analyses of bucket foundations in normally consolidated uniform clay under undrained conditions, and the bearing capacities were calculated and found to be largely dependent on the aspect ratio of the bucket foundation.

Journal ArticleDOI
TL;DR: Both torque and magnetic bearing forces are created inside this disk-shaped motor using a sophisticated control (proportional-integral-differential vector control) with superimposed drive and bearing currents fed to the concentrated combined stator coils.
Abstract: This paper presents a novel exterior rotor topology of a bearingless brushless synchronous motor with rated power of 300 W. Owing to the large possible magnetic gap and the absence of mechanical bearings, this motor is especially qualified for high-purity and low-shear applications (e.g., bioreactor mixing). Both torque and magnetic bearing forces are created inside this disk-shaped motor using a sophisticated control (proportional-integral-differential vector control) with superimposed drive and bearing currents fed to the concentrated combined stator coils. Optimal design is derived based on an electromagnetic analysis using the three-dimensional finite element method (3D-FEM), and the simulation results are verified with a prototype mixer setup.

Journal ArticleDOI
TL;DR: In this article, a non-linear, kinematic model for triple friction pendulum isolation bearings is presented, which incorporates coupled plasticity and circular restraining surfaces for all sliding surfaces, is capable of capturing bi-directional behavior and is able to track the movement of each internal component.
Abstract: SUMMARY This paper presents a non-linear, kinematic model for triple friction pendulum isolation bearings. The model, which incorporates coupled plasticity and circular restraining surfaces for all sliding surfaces, is capable of capturing bi-directional behavior and is able to explicitly track the movement of each internal component. The model is general so that no conditions regarding bearing properties, which effect the sequence of sliding stages, are required for the validity of the model. Controlled-displacement and seismic-input experiments were conducted using the shake table at the University of California, Berkeley to assess the fidelity of the proposed model under bi-directional motion. Comparison of the experimental data with the corresponding results of the kinematic model shows good agreement. Additionally, experiments showed that the performance of TFP bearings is reliable over many motions, and the behavior is repeatable even when initial slider offsets are present. Copyright © 2011 John Wiley & Sons, Ltd.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a new dynamic model of the planetary gear, in which the pressure angles and contact ratios change with time and the main difference from previous studies is that the present study regards the pressure angle and contact ratio as time-varying variables, while previous studies regarded them as constants.

Journal ArticleDOI
TL;DR: In this article, the adaptive spectral kurtosis (ASK) analysis of the vibration signal from a single sensor was proposed for fault detection of rolling element bearings, which can more effectively extract signatures of multiple bearing faults in the presence of strong background noise.

Journal ArticleDOI
TL;DR: In this article, the critical load capacity of elastomeric and lead-rubber bearing is calculated at a given lateral displacement that must be greater than a combination of axial forces imposed on the bearing.
Abstract: Elastomeric and lead-rubber bearings are two commonly used types of seismic isolation devices During seismic events, some of the bearings in an isolation system will be subjected to large axial compressive loads, caused by gravity plus overturning forces, accompanied by simultaneous large lateral displacements However, the critical load capacity of elastomeric bearings has been shown to reduce with increasing lateral displacement The design of isolation systems composed of these types of bearings therefore requires that stability at the maximum displacement be demonstrated The current procedure to assess the stability uses a ratio of areas, referred to as the overlapping area method, to determine the critical load capacity at a given lateral displacement that must be greater than a combination of axial forces imposed on the bearing Although the overlapping area method provides a simple means of calculating the critical load at a given lateral displacement, it lacks a rigorous theoretical basis and ha

Journal ArticleDOI
TL;DR: In this paper, the effect of internal clearance on radially loaded deepgroove ball and cylindrical roller bearing load distribution and fatigue life was determined for four clearance groups defined in the bearing standards.
Abstract: The effect of internal clearance on radially loaded deepgroove ball and cylindrical roller bearing load distribution and fatigue life was determined for four clearance groups defined in the bearing standards. The analysis was extended to negative clearance (interference) conditions to produce a curve of life factor versus internal clearance. Rolling-element loads can be optimized and bearing life maximized for a small negative operating clearance. Life declines gradually with positive clearance and rapidly with increasing negative clearance. Relationships were found between bearing life and internal clearance as a function of ball or roller diameter, adjusted for load. Results are presented as life factors for radially loaded bearings independent of bearing size or applied load. In addition, a modified Stribeck Equation is presented that relates the maximum rolling-element load to internal bearing clearance.

Journal ArticleDOI
TL;DR: In this paper, the effect of textured surfaces in hydrodynamic bearings is assessed using a mass-conserving numerical analysis that allows for arbitrary geometry and multiple regions of cavitation.

Journal ArticleDOI
TL;DR: In this paper, the authors deal with detection of local defects existing on races of deep groove ball bearing in the presence of external vibrations using envelope analysis and Duffing oscillator and confirm that the defect detection in envelope analysis mainly depends on the selection of centre frequency and bandwidth.

01 Jan 2012
TL;DR: In this article, a stator current spectral subtraction method was proposed to monitor induction machine bearings by means of Short Time Fourier Transform or Discrete Wavelet Transform and a diagnostic index based on the subtraction residue energy was proposed.
Abstract: Induction machines are widely used in industrial applications. Safety, reliability, efficiency and performance are major concerns that direct the research activities in the field of electrical machines. Even though the induction machine is very reliable, many failures can occur such as bearing faults, air-gap eccentricity and broken rotor bars. The challenge is therefore to detect them at an early stage in order to prevent breakdowns. In particular, stator current-based condition monitoring is an extensively investigated field for cost and maintenance savings. In this context, this paper deals with the assessment of a new stator current-based fault detection approach. Indeed, it is proposed to monitor induction machine bearings by means of stator current spectral subtraction, which is performed using Short Time Fourier Transform or Discrete Wavelet Transform. In addition, it is proposed a diagnostic index based on the subtraction residue energy. The proposed bearing faults condition monitoring approach is assessed using simulations, issued from a coupled electromagnetic circuits approach-based simulation tool, and experiments on a 0:75-kW induction machine test bed.

Journal ArticleDOI
TL;DR: A two-phase algorithm, where the wheel acceleration is controlled in closed-loop and the longitudinal force measurement is used to fire phase switching, which can handle changes in vehicle velocity and tire-road friction without extra logic or adaptation of the controller parameters.
Abstract: The anti-lock braking system (ABS) is the most important active safety system for passenger cars. Thanks to tire force measurement, provided for example by the new SKF load sensing hub bearing units, hybrid ABS algorithms can be made simpler and more robust than when only using wheel acceleration measurement. A two-phase algorithm is presented, where the wheel acceleration is controlled in closed-loop and the longitudinal force measurement is used to fire phase switching. Load transfer is accounted for using the vertical force measurement. Realistic simulations show that this simple algorithm can handle changes in vehicle velocity and tire-road friction without extra logic or adaptation of the controller parameters. Stability analysis provides tuning indications. Finally, the algorithm is validated on a tire-in-the-loop experimental facility.

Journal ArticleDOI
TL;DR: In this article, the authors show that precipitate shearing, dissolution, cell and nanocrystal formation as well as matrix/inclusion debonding may take place throughout bearing life and such microstructural features have a negative effect on bearing hardness, strength, ductility and toughness, usually preceding failure.
Abstract: For over a century, rolling contact fatigue in bearings has been recognised as a key feature limiting bearing life. The phenomenon is manifested through dark etching regions, 30 and 80° white etching bands as well as white etching areas, the latter often forming intricate defects commonly referred to as butterflies. Their presence depends on testing conditions, such as contact pressure, temperature, number of revolutions and steel cleanliness. Microstructural inspection demonstrates that precipitate shearing, dissolution, cell and nanocrystal formation as well as matrix/inclusion debonding may take place throughout bearing life. Such microstructural features have a negative effect on bearing hardness, strength, ductility and toughness, usually preceding failure. The present review shows how such phenomena are interconnected, highlighting the need for integral characterisation and modelling across the scales. This will aid in the conception of new heat treatments, steel grades and microstructures f...

Journal ArticleDOI
TL;DR: In this paper, the role of bearing preloads on the modal characteristics of a shaft-bearing assembly with a double row angular contact ball bearing is investigated, and an analytical model is developed to comparatively evaluate the effects of axial bearing preloading on the vibratory responses of alternate double row configurations.

Journal ArticleDOI
TL;DR: In this article, the design and development of a magnetic bearing system which consists of passive magnetic axial/tilting bearing and active two-axial radial magnetic bearing (RMB) used in magnetically suspended wheel (MSW) or magnetically suspend control moment gyroscope (MSCMG) for agile satellite application is presented.
Abstract: In this paper, the design and development of a magnetic bearing system which consists of passive magnetic axial/tilting bearing and active two-axial radial magnetic bearing (RMB) used in magnetically suspended wheel (MSW) or magnetically suspended control moment gyroscope (MSCMG) for agile satellite application is presented. The passive axial/tilting magnetic bearing supplies an axial position stiffness to stabilize the rotor in the axial direction and a tilting stiffness to restrain the rotor when subjected to gyroscopic torque. The active two-axis radial magnetic bearing with bias permanent magnet stabilizes the rotor on the axes perpendicular to the rotation axis. Considering the complex distribution of flux density the system performance cannot be accurately analyzed by the conventional magnetic circuit method because of the high coupling between force and moment produced by the axial magnetic axial/tilting bearing and RMB. To analyze the coupling problem of the force, moment, position stiffness, and tilting stiffness between the passive magnetic axial/tilting bearing and RMB, an integral design and analysis method based on three-dimensional finite-element method is presented. An example is given and analysis results prove that the high coupling occurs on the radial direction and the light occurs on the axial and tilting directions orthogonal to the spin axis. Then the linearized model is given in this paper.

Journal ArticleDOI
TL;DR: In this article, the influence of different forms of surface texture on finite journal bearing has been investigated in the form of negative texture (micro cavities) at different locations of bearing surface.
Abstract: Many researchers have adopted various techniques for improving the performance characteristics of journal bearing. Apart from other parameters, incorporation of different forms of surface texture (sinusoidal, dimple, spherical etc.) on bearing or shaft also helps to increase the load carrying capacity and reduce the friction coefficient etc. in the journal bearing. Present study investigates the influence of different forms of surface texture on finite journal bearing which has been considered in the form of negative texture (micro cavities) at different locations of bearing surface. The Governing equations are solved numerically through finite difference approach for analysis of texture effects on bearing characteristics. It has been observed that the presence of micro cavities at different locations of bearing surface help in enhancing the bearing performance. It has also been found that the negative half wave texture enhances the bearing performance more in comparison to full wave texture on bearing surface.

Journal ArticleDOI
Ali Rezaei1, Wim Van Paepegem1, Patrick De Baets1, Wouter Ost1, Joris Degrieck1 
30 Aug 2012-Wear
TL;DR: In this article, an adaptive wear modeling method was employed to study the wear progress in radial sliding bearings contacting with a rotary shaft, and the wear coefficients were obtained from flat-on-flat experiments and were applied as pressure and velocity dependent parameters in the wear processor.

Journal ArticleDOI
TL;DR: Experimental results show that the bearing fault features extracted using both traditional vibration analysis methods and the proposed method give clear bearing heath degradation trend for the dataset collected under normal operating conditions, however, for the data collected under abnormal operating conditions it fails to show the bearing health degradation trend.
Abstract: Over the past years, investigation on condition-based maintenance (CBM) technique on bearing has been conducted. Bearing diagnostics and prognostics are the important aspects in CBM. A key to the success of using vibration data for bearing fault diagnostics and bearing lifecycle prognostics is a quantified relationship between bearing damage and bearing fault features. To establish such a quantitative relationship, effective signal processing techniques to extract bearing fault features from vibration signals are needed. This paper describes a newly developed fault feature extraction method for bearing prognostics. The effectiveness of the method is demonstrated with two real bearing run-to-failure test datasets: one collected under normal operating conditions and another one under abnormal operating conditions. Experimental results show that the bearing fault features extracted using both traditional vibration analysis methods and the proposed method give clear bearing heath degradation trend for the dataset collected under normal operating conditions. However, for the data collected under abnormal operating conditions, bearing fault features obtained using traditional vibration analysis methods fail to show the bearing health degradation trend while the fault features extracted using the proposed method give consistent bearing degradation trends.

Journal ArticleDOI
TL;DR: In this paper, the influence of internal rotor material damping and fluid film forces on the modal behavior of a flexible rotor-shaft system was studied, and it was shown that correct estimation of internal friction, in general, and the journal bearing coefficients at the rotor spin-speed are essential to accurately predict the rotor dynamic behaviour.

Journal ArticleDOI
12 Oct 2012-Sensors
TL;DR: This paper proposes a spectral regression (SR)-based approach for fault feature extraction from original features including time, frequency and time-frequency domain features of bearing accelerometer sensor signals and demonstrates that the proposed feature extraction scheme has an advantage over other similar approaches.
Abstract: Bearings are not only the most important element but also a common source of failures in rotary machinery. Bearing fault prognosis technology has been receiving more and more attention recently, in particular because it plays an increasingly important role in avoiding the occurrence of accidents. Therein, fault feature extraction (FFE) of bearing accelerometer sensor signals is essential to highlight representative features of bearing conditions for machinery fault diagnosis and prognosis. This paper proposes a spectral regression (SR)-based approach for fault feature extraction from original features including time, frequency and time-frequency domain features of bearing accelerometer sensor signals. SR is a novel regression framework for efficient regularized subspace learning and feature extraction technology, and it uses the least squares method to obtain the best projection direction, rather than computing the density matrix of features, so it also has the advantage in dimensionality reduction. The effectiveness of the SR-based method is validated experimentally by applying the acquired vibration signals data to bearings. The experimental results indicate that SR can reduce the computation cost and preserve more structure information about different bearing faults and severities, and it is demonstrated that the proposed feature extraction scheme has an advantage over other similar approaches.