Artículos de revistas: "Bearings (Machinery)"

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Vekteris, Vladas, Andrius Trumpa, Vytautas Turla, Vadim Mokšin, Gintas Viselga y Eugenijus Jurkonis. "Diagnosing faults in rolling-element bearings of rotor systems equipped with vibration dampers". Advances in Mechanical Engineering 12, n.º 4 (abril de 2020): 168781402091541. http://dx.doi.org/10.1177/1687814020915417.

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This article considers problems arising from conventional techniques used to diagnose faults in the rolling-element bearings of rotor-bearing systems, with dampers used in centrifugal milk processing machinery. Such machines include milk separators and related processing machinery. The article asserts that where the rotor-bearing system is equipped with vibration dampers, conventional fault diagnostic measurements produce inadequate results. Hence, for rotor-bearing systems of this type, this article suggests a different way to diagnose faults in bearings and monitor conditions.

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Goodwin, M. J., P. J. Ogrodnik, M. P. Roach, L. K. Lim y Y. Fang. "Steady Load-Carrying Capacity of Recessed Hydrodynamic Bearings". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 209, n.º 4 (diciembre de 1995): 255–62. http://dx.doi.org/10.1243/pime_proc_1995_209_436_02.

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Oil-film hydrodynamic bearings are one of the most common forms of bearing used in rotating machinery. Because of their effect on system unbalance response and stability, care has to be exercised in the design of machines running in hydrodynamic bearings—for example they cannot usually be used in machines operating at high rotational speeds when the steady load on the bearing is low. A novel form of hydrodynamic bearing which incorporates recesses in the bearing surface has been proposed by the authors which improves the dynamic characteristics; however, earlier work has not fully assessed the steady load characteristics of such bearings vis-à-vis conventional bearings for example. The aim of this paper is to present the results of experimental work on several designs of the proposed novel bearings, to assess the bearing's performance and to compare it with that of conventional bearings. The results of the work show that the steady load-carrying capacity is adversely affected by the inclusion of recesses in the bearing surface, but that this is only a marginal effect provided that the number of recesses and their geometry are selected with care.

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3

Dewrance, John. "MACHINERY BEARINGS". Journal of the American Society for Naval Engineers 9, n.º 1 (18 de marzo de 2009): 104–17. http://dx.doi.org/10.1111/j.1559-3584.1897.tb00708.x.

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Ramos, Leandro Ito, Douglas Jhon Ramos y Gregory Bregion Daniel. "Evaluation of textured journal bearings under dynamic operating conditions in rotating machinery". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, n.º 6 (5 de noviembre de 2019): 842–57. http://dx.doi.org/10.1177/1350650119887568.

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In order to obtain rotating machinery with improved energy efficiency, the approach of surface texturing journal bearings has been adopted to reduce the viscous dissipation in the lubricant. A possible reduction in shear viscous forces in the bearings of rotating machines could reduce the amount of heat released along its operation, resulting in a lower operating temperature that tends to improve journal bearings performance and the machine’s energetic efficiency. Thus, this work aims to investigate the texturing of journal bearings under dynamic loading conditions, considering the application in rotating systems. For this, computational simulations are performed through a rotating system model constructed by means of the finite element method in which the hydrodynamic journal bearings that support the rotor are modeled by Reynolds’ equation using the finite volume method and the full multigrid technique. The numerical results show that textured journal bearings can be applied to rotating machines, providing reductions in shear viscous forces. However, the magnitude of this reduction should be carefully evaluated, as the Reynolds cavitation model was applied to ensure a lower computational spent time and thus enable the simulations involved in this study. The novelty of this study is related to determining the appropriate distributions and geometric parameters of the textures for the journal bearing under dynamic load condition considering its equivalent static load condition what tends to drastically reduce computational time to perform this procedure, representing an important alternative for industrial application.

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Ravikumar, R. N., K. J. Rathanraj y V. Arun Kumar. "Experimental Studies on Air Foil Thrust Bearing Load Capabilities Considering the Effect of Foil Configuration". Applied Mechanics and Materials 813-814 (noviembre de 2015): 1007–11. http://dx.doi.org/10.4028/www.scientific.net/amm.813-814.1007.

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Abstract. Foil bearings are self-acting hydrodynamics bearings used to support lightly loaded high speed rotating machinery. The advantages that they offer to process fluid lubricated machines usingworking fluid as a lubricant (ambient air) physically non-contacting high speed operation. Foil bearings have been considered as an alternative to conventional bearings with the capacity to cater for high-speeds and hostile environment (high temperature). However, the lack of load carrying capacity at relatively lower speeds limits their applications in heavy turbo machinery and as such are highly suitable in lightly loaded, high speed turbo machinery like small gas turbines.This paper discusses the design and assessment of dynamic characteristics in terms of load carrying capabilities as a function of speed, gap between the bearing and the runner as well as shape of foils for an air foil thrust bearing. The effects of various bearing parameters like foil thickness, number of foils fixed circumferentially and along the axis of rotation and with foil geometry configuration. Characteristics of performance defined essentially in terms of load carrying capabilities and static stiffness have been used for evaluation. Experiments were conducted both for angular foils (with inner edge height less than outer edge height) and square foils by varying number of foils. The experimental results shows that the effect of foil configuration enhances the load carrying capabilities of air foil thrust bearing.

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Tulupov, Viktor D., Mikhail A. Sleptsov y Aleksandrs A. Briedis. "Ways to Improve the Reliability of Bearings in Traction Induction Machines". Vestnik MEI 2, n.º 2 (2021): 60–70. http://dx.doi.org/10.24160/1993-6982-2021-2-60-70.

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The problem of electric rolling stock traction machinery failures caused by electrical erosion of bearings is addressed. Damages inflicted to traction machinery bearings as a result of electric current flowing through them have been known since long ago. In recent time, however, damages of this kind have become more frequent, because frequency and voltage converters for control of three-phase inductor motors are widely used in the electric rolling stock. An overview of factors causing the occurrence of stray currents generated in frequency converter driven traction motors and sources of these currents is presented. Electric current flows through rolling bearings in the area of the contact between the rolling elements with inner and outer rings, thus causing damage to the bearing metal components' rolling surfaces and degrading the quality of lubricants. To study and analyze the currents through bearings, the stray capacitances existing in traction machines are determined, and their calculation methods are defined, the necessity of which is stemming from the fact that these capacitances influence the generation of parasitic currents. The stray capacitances in traction machines include the capacitance between the stator windings and the stator core pack, the capacitance between the stator windings and the rotor, the capacitance between the rotor and the stator core pack, and the capacitances of the bearings. From the electrical point of view, bearings may also be regarded as capacitances. As long as there is a continuous lubricant film between the inner ring and outer rings and the rolling elements, the bearings behave as capacitors. A difference of potentials across the bearing elements may lead to electrostatic discharges and, hence, to discharge currents through the bearings. One of possible ways to enhance the reliability of traction machine bearing units is to use insulated bearings. The change in the impedance of bearings with ceramic coating and hybrid rolling elements depending on the applied voltage frequency and operating temperature is calculated and analyzed. Conclusions regarding the expediency of using hybrid bearings having rings made of bearing steel and rolling elements made of bearing silicon nitride (Si3N4) are drawn.

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Hou, Yu, Qi Zhao, Yu Guo, Xionghao Ren, Tianwei Lai y Shuangtao Chen. "Application of Gas Foil Bearings in China". Applied Sciences 11, n.º 13 (5 de julio de 2021): 6210. http://dx.doi.org/10.3390/app11136210.

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Gas foil bearing has been widely used in high-speed turbo machinery due to its oil-free, wide temperature range, low cost, high adaptability, high stability and environmental friendliness. In this paper, state-of-the-art investigations of gas foil bearings are reviewed, mainly on the development of the high-speed turbo machinery in China. After decades of development, progress has been achieved in the field of gas foil bearing in China. Small-scale applications of gas foil bearing have been realized in a variety of high-speed turbo machinery. The prospects and markets of high-speed turbo machinery are very broad. Various high-speed turbomachines with gas foil bearings have been developed. Due to the different application occasions, higher reliability requirements are imposed on the foil bearing technology. Therefore, its design principle, theory, and manufacturing technology should be adaptive to new application occasions before mass production. Thus, there are still a number of inherent challenges that must be addressed, for example, thermal management, rotor-dynamic stability and wear-resistant coatings.

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Deng, Linfeng, Aihua Zhang y Rongzhen Zhao. "Intelligent identification of incipient rolling bearing faults based on VMD and PCA-SVM". Advances in Mechanical Engineering 14, n.º 1 (enero de 2022): 168781402110729. http://dx.doi.org/10.1177/16878140211072990.

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Rolling bearings are the key components of rotating machinery. Incipient fault diagnosis of bearing plays an increasingly important role in guaranteeing normal and safe operation of rotating machinery. However, because of the high complexity of the fault feature extraction, the incipient faults of rolling bearings are difficult to diagnose. To solve this problem, this paper presents a new incipient fault intelligent identification method of rolling bearings based on variational mode decomposition (VMD), principal component analysis (PCA), and support vector machines (SVM). In the proposed method, the bearing vibration signals are decomposed by using VMD, and a series of intrinsic mode functions (IMFs) with different frequencies are obtained. Then, the energy and kurtosis values of each IMF are calculated to reveal the intrinsic characteristics of the vibration signals in different scales. Finally, all energy and kurtosis values of IMFs are processed via PCA and subsequently fed into SVM to achieve the bearing fault identification automatically. The effectiveness of this method is verified through the experimental bearing data. The verification results indicate that the proposed method can effectively extract the bearing fault features and accurately identify the bearing incipient faults, and outperform the two compared methods obviously in identification accuracy and computation time.

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Guo, Caiping. "Optimal Design of Sliding Bearings Based on Artificial Intelligence Algorithm and CFD Simulation". Wireless Communications and Mobile Computing 2022 (12 de abril de 2022): 1–11. http://dx.doi.org/10.1155/2022/5448332.

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Sliding bearings have a long history, simple manufacturing, and low cost. However, the function of sliding bearings is very large. As a key component of rotating machinery, thrust sliding bearing is directly related to the overall performance of the machine. The machines that can be seen in life, whether simple or complicated, have been used. However, with the development of science and technology and economy, all kinds of new things have been inoculated. One of the current issues is how sliding bearings can continue to keep machinery stable. CFD is the abbreviation of English computational fluid dynamics (computational fluid dynamics). It is developed with the development of computer technology and numerical computing technology. Simply put that CFD is equivalent to “virtually” doing experiments on the computer to simulate the actual fluid flow. The purpose of this article is to study the optimal design of sliding bearings by artificial intelligence algorithms and CFD simulation. This paper uses intelligent design methods to optimize the appearance, shape, and manufacturing process of sliding bearings and to carry the bearing capacity, friction coefficient and temperature rise of sliding bearings. Comprehensive research then establishes the objective function. The finite element algorithm, genetic algorithm, and matrix theory are used to calculate the stability of the sliding bearing under various conditions. The artificial intelligence algorithm is used to sort the calculated data. The CFD simulation is used to obtain the most reasonable result. Algorithm, as well as the appearance, shaft diameter, and material of the plain bearing, maintains stability under various conditions. The experimental data show that the classification using artificial intelligence algorithms and CFD simulation can significantly improve the performance of sliding bearings. It is found that the relationship between the sliding bearings is related to the speed, the diameter of the bearing, and other factors. Experimental data show that artificial intelligence algorithms and CFD simulation can provide reliable data references for the optimal design of sliding bearings, and the optimized sliding bearings can meet the stability under relevant conditions.

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Du, Fengming, Dawei Li, Xiaoxia Sa, Cong Li, Yang Yu, Chengdi Li, Jingsi Wang y Weiwei Wang. "Overview of Friction and Wear Performance of Sliding Bearings". Coatings 12, n.º 9 (5 de septiembre de 2022): 1303. http://dx.doi.org/10.3390/coatings12091303.

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Sliding bearings are critical components of the internal combustion engine. Friction and wear occur in the contact area between the shaft and the bearing. Significant wear can occur in poor working conditions or after a long service time, leading to the failure of the sliding bearing and affecting the reliability of the machinery. It is essential to investigate the wear performance of sliding bearings, understand their wear mechanism, predict their service life, and select wear-resistant materials and surface treatments. This paper reviews the current status and prospects of sliding bearing wear research, focusing on the classification of sliding bearing wear tests, wear testing machines, wear test research, wear prediction models, and future research prospects.

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Tóth, Dániel. "Investigation of Bearing Failures Using Vibration Analysis". Design of Machines and Structures 12, n.º 2 (2022): 126–32. http://dx.doi.org/10.32972/dms.2022.022.

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Bearings are important components of most machinery and their working conditions influence the operation of the entire machinery. Even if bearings are being used under excellent conditions, sooner or later material fatigue will occur. Besides other things poor operating environment contaminated or peculiarly moist areas and improper handling practices cause premature failures. This article focuses on vibration analysis methods for detecting bearing failures and presents a special lifetime test procedure.

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Manjunatha, G. y H. C. Chittappa. "Bearing Fault Classification using Empirical Mode Decomposition and Machine Learning Approach". Journal of Mines, Metals and Fuels 70, n.º 4 (20 de junio de 2022): 214. http://dx.doi.org/10.18311/jmmf/2022/30060.

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Industrial machinery often breakdowns due to faults in rolling bearing. Bearing diagnosis plays a vital role in condition monitoring of machinery. Operating conditions and working environment of bearings make them prone to single or multiple faults. In this research, signals from both healthy and faulty bearings are extracted and decomposed into empirical modes. By analyzing different empirical modes from 8 derived empirical modes for healthy and faulty bearings under different fault sizes, the first mode has the most information to classify bearing condition. From the first empirical mode eight features in time domain were calculated for various bearing conditions like healthy, rolling element fault, outer and inner race fault. The feature extraction of vibration signal based on Empirical Mode Decomposition (EMD) is extensively explored and applied in diagnosis of fault in rolling bearings. This paper presents mathematical analysis for selection of valid Intrinsic Mode Functions (IMFs) of EMD. These chosen features are trained and classified using different classifiers. Among them K-star classifier is most reliable to categorize the bearing defects.

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Schweitzer, G. "Safety and Reliability Aspects for Active Magnetic Bearing Applications - A Survey". Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 219, n.º 6 (1 de septiembre de 2005): 383–92. http://dx.doi.org/10.1243/095965105x33491.

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The application of magnetic bearings for rotating machinery has become state of the art and spans from research prototypes to industrial series. Users are aware that beyond functionality the aspects of safety and related areas become increasingly important. This survey addresses the issues of safety and reliability, being a part of dependability. It gives a review on existing approaches, and it shows numerous examples of problems and solutions. Review topics are safety-oriented design methods, software tools, redundancy, robust control, and retainer bearings. Finally, the concept of smart machines is introduced as a way for further improving safety and dependability of machinery with active magnetic bearings.

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Koike, Hitonobu, Takashi Honda, Katsuyuki Kida, Edson Costa Santos, Justyna Rozwadowska, K. Houri, M. Uryu, Yuji Kashima y Kenji Kanemasu. "Influence of Radial Load on PEEK Plastic Bearings Life Cycle under Water Lubricated Conditions". Advanced Materials Research 217-218 (marzo de 2011): 1260–65. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.1260.

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Radial ball bearings made of metal, ceramics and plastics are commonly used as important components in industrial machinery. Usage of high performance engineering plastic polymers is increasing progressively as a replacement for metal components due to the latest markets demands. Poly-ether-ether-ketone (PEEK) is a promising material for precision-machined custom bearings, products that are expected to suit special market needs. In the present study, PEEK radial ball bearings were manufactured by lathe machining under different parameters and their rolling contact fatigue (RCF) resistance under water lubricated conditions was investigated. We observed the surface of the bearings prior and after testing by laser confocal microscope. The wear loss was measured by weighing the bearings before and after test. Cracks and/or flaking failures were identified on the bearing surface after testing. From the RCF tests results, we found that, at water lubricated conditions, crack initiation occurred later in the material that was machined at slower feed rate while at dry condition, the feed rate had little influence on the wear loss and cracking. Wear loss in the case of bearings tested under water was much less severe than that of bearings tested at dry conditions.

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WASILCZUK, Filip, Michał WASILCZUK y Michał WODTKE. "PROSPECTS OF DECREASING POWER LOSSES IN A HYDROSTATIC THRUST BEARING". Tribologia, n.º 4 (31 de agosto de 2017): 91–96. http://dx.doi.org/10.5604/01.3001.0010.6033.

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In numerous machines, axial load is carried by tilting pad thrust bearings known since the beginning of 20th century. These bearings are commonly bath lubricated, which is simple, does not require any additional pumps, and, due to this, such systems are highly reliable. In a contemporary technology, however, minimization of friction losses became an important goal of machinery improvement. Calculations based on elementary rules of fluid dynamics show that shearing losses in a specially designed hydrostatic bearing can be considerably smaller than the losses in a tilting pad hydrodynamic bearing. The aim of the research described in this paper was to check if the preliminary results can also be confirmed with the use of more advanced CFD calculations.

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Polyakov, Roman, Leonid Savin y Denis Shutin. "Reliability Improvement of Rotor Supports by Combining Rolling-Element Bearings and Fluid-Film Bearings". Applied Mechanics and Materials 630 (septiembre de 2014): 188–98. http://dx.doi.org/10.4028/www.scientific.net/amm.630.188.

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Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotation speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary performance characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. The aim of this work is to analyze the advantages and disadvantages of the hybrid bearings. Known real applications of hybrid bearings are discussed. Analysis shows that depending on the application different hybrid bearing types could improve dynamic characteristics and life time of the bearing unit, increase load capacity and DN limit of the rolling-element bearing.

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Ikeda, Kazunori, Toshio Hirano, Tatsuo Yamashita, Makoto Mikami y Hitoshi Sakakida. "An Experimental Study of Static and Dynamic Characteristics of a 580mm(22.8in.) Diameter Direct Lubrication Tilting Pad Journal Bearing". Journal of Tribology 128, n.º 1 (19 de agosto de 2005): 146–54. http://dx.doi.org/10.1115/1.2114929.

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Direct lubrication tilting pad journal bearings (DLTPJ bearings) have rarely been applied to large-scale rotating machinery, such as turbines or generators, whose journal diameters are more than 500mm. In this paper, static and dynamic characteristics of a 580mm(22.8in.) diameter DLTPJ bearing were studied experimentally using a full-scale bearing test rig. In the static test, distribution of metal temperature, oil film pressure, and bearing loss were measured in changing oil flow rate, with mean bearing pressure ranging up to 2.9MPa. The maximum metal temperature of the DLTPJ bearing was compared to that of a conventional flood lubrication bearing, and it was confirmed that the direct lubrication could increase load capacity. In the dynamic test, spring and damping coefficients of oil film were obtained by exciting the bearing casing that was floated by air bellows. These data will be used for analysis and design of steam turbine rotors and their bearing systems. Also, vibration of pads was investigated because metal failure on upper pads due to vibration has been found in some actual machines. In order to generate oil film pressure on the surface of upper pads, a Rayleigh-step was machined there, and it was confirmed that vibration was reduced by the Rayleigh-step.

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Imlach, J., B. J. Blair y P. E. Allaire. "Measured and Predicted Force and Stiffness Characteristics of Industrial Magnetic Bearings". Journal of Tribology 113, n.º 4 (1 de octubre de 1991): 784–88. http://dx.doi.org/10.1115/1.2920693.

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Closed-loop stiffness and load capacity (force) equations have been developed for industrial magnetic bearings. Two sets of magnetic bearings have been constructed using these equations as a design basis. These bearings have been installed in two canned motor pumps. The predicted force and stiffness values from the equations are compared to experimental measurements to determine their validity. When obvious sources of error were eliminated, agreement within 10 percent was obtained for development pump’s magnetic bearings. Agreement was generally better for this pump than for the demonstration pump. By employing these equations, along with easily measured current and displacement information from magnetic bearing equipped machinery, actual stiffness’ and bearing loadings can be determined for operating equipment. Thus, the range of information available from magnetic bearings is extended to include static and dynamic loadings as well as shaft orbits and critical speed and damping information (Humphris et al., 1989). This enhances their use as diagnostic and preventative maintenance tools which are built into machinery and can be used on line.

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Rai, Akhand y Sanjay H. Upadhyay. "Intelligent bearing performance degradation assessment and remaining useful life prediction based on self-organising map and support vector regression". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, n.º 6 (24 de marzo de 2017): 1118–32. http://dx.doi.org/10.1177/0954406217700180.

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Rolling element bearings are critical components of rotating machines since the failure of rolling element bearings may cease the functioning of the entire equipment. The damages observed due to bearing failures are expeditious in nature and hence the need to develop an effective prognostic methodology becomes a requisite to prevent the sudden machinery breakdown. The performance degradation assessment and accurate determination of remaining useful life are the two key issues in prognostics of rolling element bearings. This paper proposes a degradation indicator based on self-organising map for the performance degradation assessment of bearings and later support vector regression is utilised to estimate the remaining useful life of bearings. The time-domain and frequency domain features extracted from the raw bearing vibration signals are supplied to the self-organising map classifier to achieve the degradation index termed as self-organising map-minimum quantisation error evolution in the paper. For estimating the remaining useful life of bearings, first the central trend of minimum quantisation error is extracted to achieve the feature vector defined as bearing health index in this work. The bearing health index is then used as input and the life percentage of the bearing is set to output in order to build the support vector regression prediction model for remaining useful life estimation of bearings. The proposed method is validated on the vibration signatures collected in a bearing test rig. The results show that the advocated method can efficiently track the evolution of deterioration and predict the remaining useful life of bearings.

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ŻYWICA, Grzegorz, Małgorzata BOGULICZ y Paweł BAGIŃSKI. "MODELLING AND ANALYSIS OF ROTATING SYSTEMS WITH GAS FOIL BEARINGS UNDER TRANSIENT OPERATING CONDITIONS". Tribologia 272, n.º 2 (30 de abril de 2018): 167–73. http://dx.doi.org/10.5604/01.3001.0010.6345.

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Gas foil bearings are on the cutting edge of bearing systems that spread worldwide. Although it is a common practice to apply such systems to high-speed fluid-flow machinery, their modelling and analysis still pose a number of problems. This article describes the methodology used to assess dynamic properties of a rotor-bearings system supported by foil bearings. Particularly close attention has been paid to the system operation in a transitional state during which a gaseous lubricating film is formed. The conception for the description of the rotor support characteristics was implemented in a computer program that is still under development. The approach that has been taken makes it possible to analyse the system properties throughout a whole range of rotational speeds. Another approach used in the past enabled for analyses of the dynamic performance of rotors, but only on the condition that bearing operation is correct (i.e. only fluid friction in bearing is present). The new model allows for much broader analyses of bearings operation, as confirmed by the obtained results. The article discusses exemplary results of analyses and shows a way one can assess the dynamic properties of rotating machinery equipped with foil bearings even when analysed under transient operating conditions.

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Patel, R. K. y V. K. Giri. "Condition monitoring of induction motor bearing based on bearing damage index". Archives of Electrical Engineering 66, n.º 1 (1 de marzo de 2017): 105–19. http://dx.doi.org/10.1515/aee-2017-0008.

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Abstract The rolling element bearings are used broadly in many machinery applications. It is used to support the load and preserve the clearance between stationary and rotating machinery elements. Unfortunately, rolling element bearings are exceedingly prone to premature failures. Vibration signal analysis has been widely used in the faults detection of rotating machinery and can be broadly classified as being a stationary or non-stationary signal. In the case of the faulty rolling element bearing the vibration signal is not strictly phase locked to the rotational speed of the shaft and become “transient” in nature. The purpose of this paper is to briefly discuss the identification of an Inner Raceway Fault (IRF) and an Outer Raceway Fault (ORF) with the different fault severity levels. The conventional statistical analysis was only able to detect the existence of a fault but unable to discriminate between IRF and ORF. In the present work, a detection technique named as bearing damage index (BDI) has been proposed. The proposed BDI technique uses wavelet packet node energy coefficient analysis method. The well-known combination of Hilbert transform (HT) and Fast Fourier Transform (FFT) has been carried out in order to identify the IRF and ORF faults. The results show that wavelet packet node energy coefficients are not only sensitive to detect the faults in bearing but at the same time they are able to detect the severity level of the fault. The proposed bearing damage index method for fault identification may be considered as an ‘index’ representing the health condition of rotating machines.

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Li, Xiaochuan, Faris Elasha, Suliman Shanbr y David Mba. "Remaining Useful Life Prediction of Rolling Element Bearings Using Supervised Machine Learning". Energies 12, n.º 14 (15 de julio de 2019): 2705. http://dx.doi.org/10.3390/en12142705.

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Components of rotating machines, such as shafts, bearings and gears are subject to performance degradation, which if left unattended could lead to failure or breakdown of the entire system. Analyzing condition monitoring data, implementing diagnostic techniques and using machinery prognostic algorithms will bring about accurate estimation of the remaining life and possible failures that may occur. This paper proposes a combination of two supervised machine learning techniques; namely, the regression model and multilayer artificial neural network model, to predict the remaining useful life of rolling element bearings. Root mean square and Kurtosis were analyzed to define the bearing failure stages. The proposed methodology was validated through two case studies involving vibration measurements of an operational wind turbine gearbox and a split cylindrical roller bearing in a test rig.

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Srinivasan, S., E. H. Maslen y L. E. Barrett. "Optimization of Bearing Locations for Rotor Systems With Magnetic Bearings". Journal of Engineering for Gas Turbines and Power 119, n.º 2 (1 de abril de 1997): 464–68. http://dx.doi.org/10.1115/1.2815597.

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This paper presents a method for quickly evaluating the effect of changes in bearing location on bearing design for stability of rotating machinery. This method is intended for use by rotating machinery designers to select the “best” bearing locations prior to the bearing design process. The purpose of the method is to improve the design process by separating the problem of determining the “best” bearing locations from that of determining the actual bearing design. The method is independent of the type of bearing employed. For each candidate bearing configuration, the method provides a scalar measure of the relative ability of bearings to meet stability specifications. Within certain limits, the stability specifications are defined by the designer. The scalar measure is used to rank the candidate bearing locations and thereby select the best one. The scalar measure is compared to a practical measure of magnetic bearing design such as the infinity norm of the controller for an example design of a multistage centrifugal compressor.

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Kirk, R. G. "Evaluation of AMB Turbomachinery Auxiliary Bearings". Journal of Vibration and Acoustics 121, n.º 2 (1 de abril de 1999): 156–61. http://dx.doi.org/10.1115/1.2893958.

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The use of active magnetic bearings (AMB) for turbomachinery has experienced substantial growth during the past two decades. The advantages for many applications make AMB’s a very attractive solution for potentially low loss and efficient support for both radial and thrust loads. New machinery must be shop tested prior to shipment to the field for installation on-line. For AMB turbomachinery, one additional test is the operation of the auxiliary drop or overload bearings. A major concern is ability of the selected auxiliary bearing to withstand the contact forces following an at speed rotor drop. The proper design of AMB machinery requires the calculation of the anticipated loading for the auxiliary bearings. Analytical techniques to predict the rotor transient response are reviewed. Results of transient response evaluation of a full-size compressor rotor are presented to illustrate some of the important parameters in the design for rotor drop.

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Lai, Tianwei, Yu Guo, Wei Wang, Yu Wang y Yu Hou. "Development and Application of Integrated Aerodynamic Protuberant Foil Journal and Thrust Bearing in Turboexpander". International Journal of Rotating Machinery 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/8430943.

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Foil bearing provides compliant support and moderate Coulomb friction for rotor-bearing system, which is conducive to stability and reliability of high speed rotating machinery. In this paper, both hydrodynamic lubricated foil journal and foil thrust bearings are applied in a 150 m3·h−1 turboexpander for air separation. In the bearings, protuberant foil is chosen as the supporting subfoil due to its merits of easy fabrication and assembly. Static loading and deflection of the bearings are tested, respectively, before integration into the turboexpander. Afterwards, the loading and deflection curves of the journal and thrust bearings are polynomial fitted using least-square method. Then, performance tests are carried out on the rotor-bearing system, including transient speed-up, high speed, and speed-down processes. In the tests, the turboexpander supported by the hydrodynamic foil bearings operates smoothly with repeatability. Maximal rotor speed of the turboexpander reaches 52000 rpm with hydrodynamic lubricated protuberant foil bearings.

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26

Hu, Lei, Niao-qing Hu, Bin Fan, Feng-shou Gu y Xiang-yi Zhang. "Modeling the Relationship between Vibration Features and Condition Parameters Using Relevance Vector Machines for Health Monitoring of Rolling Element Bearings under Varying Operation Conditions". Mathematical Problems in Engineering 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/123730.

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Rotational speed and load usually change when rotating machinery works. Both this kind of changing operational conditions and machine fault could make the mechanical vibration characteristics change. Therefore, effective health monitoring method for rotating machinery must be able to adjust during the change of operational conditions. This paper presents an adaptive threshold model for the health monitoring of bearings under changing operational conditions. Relevance vector machines (RVMs) are used for regression of the relationships between the adaptive parameters of the threshold model and the statistical characteristics of vibration features. The adaptive threshold model is constructed based on these relationships. The health status of bearings can be indicated via detecting whether vibration features exceed the adaptive threshold. This method is validated on bearings running at changing speeds. The monitoring results show that this method is effective as long as the rotational speed is higher than a relative small value.

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27

Ciupitu, Liviu, Andrei Tudor, Doru Turcan y Daniel Sandor. "Vibration Diagnosis of Electric Motor’s Bearings". Advanced Materials Research 463-464 (febrero de 2012): 1725–28. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.1725.

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Recently technologies like vibration monitoring or acoustic measurement help the maintenance to improve the OEE (overall equipment effectiveness) factor. For example SKF company uses for fault detection vibration and temperature sensors and vibration signal processing techniques that differentiate between normal machinery process vibrations and abnormal vibrations caused by machinery faults. The fault can be eliminated or monitored until maintenance and repairs can be organized in a cost-effective way. The type of pattern with frosted or fluted features on the bearing inner or outer race it's often found on the electrical motors bearings due to electric discharge inside motor. This defect can decrease the asset life time from months to days and could lead to catastrophic defects.

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28

Zheng, Yuhuang. "Predicting Remaining Useful Life Based on Hilbert–Huang Entropy with Degradation Model". Journal of Electrical and Computer Engineering 2019 (3 de febrero de 2019): 1–11. http://dx.doi.org/10.1155/2019/3203959.

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Prognostics health management (PHM) of rotating machinery has become an important process for increasing reliability and reducing machine malfunctions in industry. Bearings are one of the most important equipment parts and are also one of the most common failure points. To assess the degradation of a machine, this paper presents a bearing remaining useful life (RUL) prediction method. The method relies on a novel health indicator and a linear degradation model to predict bearing RUL. The health indicator is extracted by using Hilbert–Huang entropy to process horizontal vibration signals obtained from bearings. We present a linear degradation model to estimate RUL using this health indicator. In the training phase, the degradation detection threshold and the failure threshold of this model are estimated by the distribution of 600 bootstrapped samples. These bootstrapped samples are taken from the six training sets. In the test phase, the health indicator and the model are used to estimate the bearing’s current health state and predict its RUL. This method is suitable for the degradation of bearings. The experimental results show that this method can effectively monitor bearing degradation and predict its RUL.

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29

Luo, Dong Song y Zheng Fan. "Wavelet Algorithm in Rotating Machinery Fault Feature Extraction". Advanced Materials Research 823 (octubre de 2013): 451–55. http://dx.doi.org/10.4028/www.scientific.net/amr.823.451.

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A method of Rotating Machinery fault feature extraction based on wavelet transform and Hilbert demodulation is been studied. On the basis of rotating machinery fault mechanism and spectral characteristics, wavelet transform is used to be decompose the vibration acceleration signals of bearing faults into different frequency bands, Which is then used to achieve accurate fault information by Hilbert demodulation. The result shows the method can effectively improve the frequency resolution and realize accurate extraction of fault feature, and it has certain practical value for industrial production of rotating machinery faults diagnosis when applied to the production industry. Key words: Rotating Machinery; bearings; Wavelet algorithm; Hilbert demodulation

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30

Qiang, Mingchen, Qi Zhao, Shaohang Yan, Xue Liu, Yu Hou y Tianwei Lai. "Performance Prediction of High-Speed Hydrogen Gas-Lubricated Herringbone Grooved Journal Bearing". Applied Sciences 12, n.º 13 (24 de junio de 2022): 6432. http://dx.doi.org/10.3390/app12136432.

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The liquefaction of hydrogen is considered to be a crucial process in the large-scale utilization of hydrogen energy. In hydrogen liquefaction, hydrogen turbo-expander is a key refrigerating machine for high liquefaction efficiency. Performance of the turbo-expander is directly affected by the hydrogen gas bearings. To obtain a deep understanding of the performance characteristics of hydrogen gas bearings, the static and dynamic characteristics of herringbone grooved journal bearings under hydrogen and other lubricating gases were numerically calculated and compared. The bearing load capacity and critical mass of hydrogen gas bearings were slightly lower than those of helium-, air- and nitrogen-lubricated bearings. To improve the performance of the hydrogen gas bearings used in high-speed turbo-machinery, the influence of working conditions was analyzed. It is found that the load capacity of hydrogen gas bearings can be improved by increasing the ambient pressure, reducing the gas film clearance, and raising the bearing eccentricity ratio. Meanwhile, the critical mass increases, and the bearing dynamic stability is enhanced.

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31

Polyakov, Roman, Leonid Savin y Alex Fetisov. "Analysis of the conditions for the occurrence of the effect of a minimum of friction in hybrid bearings based on the load separation principle". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, n.º 2 (21 de mayo de 2018): 271–80. http://dx.doi.org/10.1177/1350650118777143.

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Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotational speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary operating characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. A hybrid bearing, where a rolling-element bearing and a fluid-film bearing are positioned parallel to the vector of external load (PLEX), has the following advantages compared to a single bearing, whether rolling-element or fluid-film one: increase of life expectancy, load capacity increase, friction reduction, thermal regime enhancement, increase of stiffness, and damping properties. The present paper presents the results of theoretical and numerical research of friction characteristics of PLEX in mixed sliding and rolling friction, i.e. combination of viscous and rolling contact friction, regime. The conditions of minimum friction effect occurrence have been substantiated, and rational relations between characteristics of hybrid rolling-element bearings and fluid-film bearings needed for provision of such effect have been experimentally proven. Finally, the paper presents recommendations regarding design of such hybrid bearings for heavily loaded bearing nodes of rolling mills.

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32

Xu, Dong, Yong Cheng Xu, Xun Chen, Yong Min Yang y Xing Lin Li. "A Series of New Nonlinear Dynamic Equations of Rolling Element Bearing Systems". Advanced Materials Research 118-120 (junio de 2010): 896–901. http://dx.doi.org/10.4028/www.scientific.net/amr.118-120.896.

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As one of the key parts of rotating machinery, rolling bearing is the primary fault source, therefore it is urgent to research failure mechanism and its evolution process. First, the number of laden rollers of rolling bearings in different states without radial clearance and preload is summed up, and then nonlinear analytical equations and an additional equation are proposed. To some extent it will be helpful for researching the fault evolution process of rolling element bearings combined with fatigue theories. Further they will conduce to analyze and predict the remaining life of ball bearings.

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33

Li, Peng, Min Wang, Xiao Li Qi, Jian You Feng, Xiao Hui Liu, Run Qiu Tang y Wen Ying Zhao. "Analysis of the Mechanical Properties of Slewing Bearings Using Finite Element Method". Applied Mechanics and Materials 224 (noviembre de 2012): 286–94. http://dx.doi.org/10.4028/www.scientific.net/amm.224.286.

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Slewing bearings are the basic structural components widely used in construction machinery industry. Their stress status and distribution have great influence on the service life. A finite element approach for a single-row slewing bearing is established based on the bilinear isotropic model. The stress status at different loading conditions is simulated with the bearing geometric and material parameters. The result shows that the numerical simulation is reasonable in comparison with the analytical result obtained by Hertz’s theory and provides reliable design guideline for slewing bearings.

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34

Morais, T. S., J. Der Hagopian, V. Steffen Jr. y J. Mahfoud. "Modeling and Identification of Electromagnetic Actuator for the Control of Rotating Machinery". Shock and Vibration 20, n.º 1 (2013): 171–79. http://dx.doi.org/10.1155/2013/473072.

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This work deals with the design and the assessment of electromagnetic actuators (EMAs) for the control of rotating machines. The system studied has a hybrid bearing that exhibits nonlinear behavior. The system is composed of a horizontal flexible shaft supported by two ball bearings at one end and a roller bearing that is located in a squirrel cage at the other end. Four identical EMAs supplied with constant current are utilized. The EMAs associated to the squirrel cage constitutes the hybrid bearing. The aim is to develop a strategy in order to define and to identify a reliable model necessary for the control of rotating machinery in the presence of localized non-linearity. The identification strategy consists in modeling the system with as many sub-models as needed that are identified separately. This enables obtaining a straightforward modeling of rotating machinery even in the case in which system components are frequency or time dependent. For the system studied, two sub-models were necessary. First the EMAs were modeled by using classical equations of electromagnetism and then identified experimentally. Then, a linear model of the shaft mounted on its bearings was defined by using the finite element method and was identified successfully. The model of the system was adjusted after assembling the different identified sub-models. The identification is carried out by using a pseudo-random search algorithm. The model of the system is then assessed for different configurations. The results obtained demonstrate the effectiveness of the developed strategy.

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35

Zhao, Qi, Mingchen Qiang, Yu Hou, Shuangtao Chen y Tianwei Lai. "Research Developments of Aerostatic Thrust Bearings: A Review". Applied Sciences 12, n.º 23 (22 de noviembre de 2022): 11887. http://dx.doi.org/10.3390/app122311887.

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In aerostatic thrust bearings (ATBs), a high-pressure gas film with a certain bearing capacity and stiffness is formed by passing high-pressure gas between the moving surface and the static surface. Aerostatic bearings have outstanding advantages in the following aspects: high precision, high speed, and long service life, etc. They are widely used in many fields, such as high-speed air spindles, precision machine tools, air-bearing guideways, turbine machinery, and high-speed drills. With the pursuit of higher efficiency and high-precision machining machinery, there is an increasing demand for high-performance ATBs. Much effort has been spent on the study of ATBs, such as improvements in load capacity and stiffness, and the enhancement of stability. Some significant progress has been achieved. In this paper, the research developments of ATBs are summarized from several aspects, such as theoretical models and experimental methods, static performance, dynamic performance, and applications. In addition, insights on the breakthrough and development trends of ATBs are put forward. It is hoped that this paper can provide some guidance for the design and application of ATBs.

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36

Liew, A., N. S. Feng y E. J. Hahn. "A non-linear transfer matrix technique for statically indeterminate rotor bearing systems". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 215, n.º 11 (1 de noviembre de 2001): 1343–55. http://dx.doi.org/10.1243/0954406011524720.

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Transfer matrix (TM) methods have long been used to obtain the vibration behaviour of linearized rotor bearing systems. Recently the technique has been enhanced to find the unbalance response of statically determinate systems with hydrodynamic bearing type non-linearities. This paper further extends the non-linear approach to statically indeterminate systems, enabling application to practical rotating machinery. The technique is illustrated on simple unbalanced rotor bearing systems with two and four bearings. It is shown that, in statically indeterminate systems, unbalance may affect not only the orbit size and shape but also the load distribution between the bearings.

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37

Qian, Xue Ming, Lan Duan y Chen Chen Yi. "Research on Expert System of Bearing Design". Applied Mechanics and Materials 556-562 (mayo de 2014): 1267–70. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.1267.

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In the design of machinery, Calculating and validating of bearings are exertive. Artificial Intelligence is the requirement of future design. This paper proposes a bearing expert system based on multiple reasoning, which highly improves the efficiency and quality of bearing design. The system and implementing method can be farther used in intelligent mechanical design.

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38

Sumate, Sathitbunanan y Wirote Ritthong. "Friction Tests of Ball Bearings with Comparison of Lubricants". Applied Mechanics and Materials 866 (junio de 2017): 375–78. http://dx.doi.org/10.4028/www.scientific.net/amm.866.375.

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The ball bearings are the rotating components which are widely spread to moving parts for all machinery operation in general industry. This paper presents the ball bearing resistance tool which has a proper size and can handle the maximum load of 300 kg by using an electric power. The ball bearing resistance tool was used to test the bearings No. 6011 cm. The series of tests was performed in the ball bearings lubricated; engine oil SAE 10W/40, auto transmission fluid Dexron, and hydraulic oil. The rotational speeds for testing were vary; 500, 600 and 700 rpm respectively. At each speed, there were various weight; 50, 70, 90,110,130,150, and 170 kg respectively. The results show that the hydraulic oil generated the smallest coefficients of friction and energy efficiency for ball bearing operation.

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39

Pilyushina, Galina, Pavel Pyrikov, Evgeny Pamfilov, Aleksey Danilyuk y Vladimir Kapustin. "Improving the Performance of Wood-Metal Slide Bearings for Forestry Machinery". Lesnoy Zhurnal (Forestry Journal), n.º 2 (4 de abril de 2021): 156–68. http://dx.doi.org/10.37482/0536-1036-2021-2-156-168.

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The performance of slide bearings in forestry machines and equipment is largely determined by the load-carrying capacity and antifriction qualities that depend on the bearing capacity of the sleeve (insert) material, the design rigidity and the nature of the forces during operation. As a result, the bearing materials undergo cyclic changes in the state of the sleeve material, as well as the elements that provide reinforcing, heat-conducting and anti-wear functions. The paper shows the results of research on the stress-strain behavior of anisotropic composite materials in the structures of wood-metal slide bearings. A method for ensuring vibration stability is proposed. It is based on maintaining the damping properties of the support that change in the course of wearing. The functionality of the developed program, which is used to solve the contact and thermal issues in the design of slide bearings, is described. A wood-metal material for making bearing sleeves and inserts from laminated compositions was created and studied. The compositions include a vibration-absorbing and fine-fractional component in a vibration-weighted state and a layered structure heterogeneous in thickness of the sleeve, characterized by a variable elastic modulus, that provides damping properties. The proposed design of a slide bearing using this material is focused on its use mainly in the conditions of shock-cyclic loading, which is typical for operation of most forestry machines and equipment.

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40

Cheng, Li, Xintao Xia y Liang Ye. "Chaotic prediction of vibration performance degradation trend of rolling element bearing based on Weibull distribution". Science Progress 103, n.º 1 (2 de diciembre de 2019): 003685041989219. http://dx.doi.org/10.1177/0036850419892194.

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Rolling element bearings are used in all rotating machinery, and the degradation performance of rolling element bearings directly affects the performance of the machine. Therefore, high reliability prediction of the performance degradation trend of rolling element bearings has become an urgent research problem. However, the degradation characteristics of the rolling element bearings vibration time series are difficult to extract, and the mechanism of performance degradation is very complicated. The accurate physical model is difficult to establish. In view of the above reasons, based on the vibration performance data of rolling element bearings, a model of bearing performance degradation trend parameter based on wavelet denoising and Weibull distribution is established. Then, the phase space reconstruction of the series of bearing performance degradation trend parameter is carried out, and the prognosis is obtained by the improved adding weighted first-order local prediction method. The experimental results show that the bearing vibration performance degradation parameter can accurately depict the degradation trend of the bearing, and the reliability level is 91.55%; and the prediction of bearing performance degradation trend parameter is satisfactory: the mean relative error is only 0.0053% and the maximum relative error is less than 0.03%.

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41

Iordanoff, I., P. Stefan, R. Boudet y D. Poirier. "Dynamic Analysis of a Thrust Bearing—Effect of Misalignment and Load". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 209, n.º 3 (septiembre de 1995): 189–94. http://dx.doi.org/10.1243/pime_proc_1995_209_424_02.

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The ABG SEMCA, specialists in air-conditioning machinery, has considered the concept of small turbines with high rotation speeds (50 000–80 000 r/min). Air radial and thrust bearings are particularly well adapted for this kind of turbine. The load on the thrust bearing can be directed on one way or en the other. Therefore two thrust bearings are needed in order to support a bidirectional load However, some problems of stability have been found in the non-loading thrust bearing. This paper deals with a dynamic analysis of a thrust bearing and outlines the bad effects of misalignment on the unloaded thrust bearing and the importance of the sector angle on stability.

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42

Sun, Qiao, Ping Chen, Dajun Zhang y Fengfeng Xi. "Pattern Recognition for Automatic Machinery Fault Diagnosis". Journal of Vibration and Acoustics 126, n.º 2 (1 de abril de 2004): 307–16. http://dx.doi.org/10.1115/1.1687391.

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We present a generic methodology for machinery fault diagnosis through pattern recognition techniques. The proposed method has the advantage of dealing with complicated signatures, such as those present in the vibration signals of rolling element bearings with and without defects. The signature varies with the location and severity of bearing defects, load and speed of the shaft, and different bearing housing structures. More specifically, the proposed technique contains effective feature extraction, good learning ability, reliable feature fusion, and a simple classification algorithm. Examples with experimental testing data were used to illustrate the idea and effectiveness of the proposed method.

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43

Darwis, Sutawanir, Nusar Hajarisman, Suliadi, Achmad Widodo y Rejeki Wulan Islamiyati. "Exploring Pattern Recognition for Bearing Fault Diagnosis". STATISTIKA Journal of Theoretical Statistics and Its Applications 22, n.º 2 (30 de diciembre de 2022): 175–82. http://dx.doi.org/10.29313/statistika.v22i2.1128.

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Traditional bearing sensory diagnostic include touching and hearing rely on personal experience, and for more complex system are unable to meet the needs of equipment fault diagnosis. The research on bearing fault diagnosis is developing significantly. Bearings are used in rotating machinery and most machinery failures are caused by bearing failures. The fault diagnosis of bearings is an important research area. The core of bearing fault diagnosis is the pattern recognition of fault features. The key of pattern recognition is to develop a reasonable classifier. Intelligent pattern recognition has been developed such as principal components, support vector machine, neural network. In this study, a bearing fault diagnosis based on exploring pattern recognition is proposed. The key to pattern recognition is to design a significant classifier. A number of features from bearing vibration of normal and fault bearing are extracted and processed using principal components of correlation matrix. Plot of principal components shows the visualization of normal and fault bearing and the classifier is chosen subjectively. The principal components exploration will be confirmed using least squares support vector machine. The parameter of support vector machine estimated using heuristic optimization particle swarm optimization. The proposed method can be applied in the detection of faults of bearing

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44

Medeiros, Everton C., Airton Nabarrete, Marcela A. Cruchaga, Willy R. P. Mendonca y Mauro H. Mathias. "Numerical and Experimental Evaluation of Hydrodynamic Bearings Applied to a Jeffcott Test Bench". International Journal of Acoustics and Vibration 26, n.º 1 (30 de marzo de 2021): 64–69. http://dx.doi.org/10.20855/ijav.2020.25.11732.

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Merging analytical and numerical models with experimental results improve the behaviour predictions of mechanical elements applied to rotor machinery, such as the bearings. This work aims to present the design of a hydrodynamic bearing prototype, a comparison and validation between the numerical and experimental results of critical speeds, and the differences of behaviour when the bush geometries and lubrication are changed. The bush geometries and the fluid film properties are analysed by measuring the dynamic behaviour of a rotor supported by these bearings. The experimental evaluation is based on measuring the Jeffcott test bench supported in a pair of bearings, showing the anisotropic behaviour caused by the stiffness difference in horizontal and vertical directions. It also presents an optimization of bushings for isotropic conditions when they were changed for different geometries (elliptical, offset halves) and different materials with boundary lubrication. This detailed study shows how the dynamic behaviour of rotating machinery can be predicted using numerical models and its validation by a test rig. Results also show how the vibration occurs if the bushes geometries are modified or its lubrication condition is changed.

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45

Ghoneam, S. M., M. A. Asy, A. G. Embaby y E. A. Elhadhody. "DYNAMIC ANALYSIS OF ROTOR SYSTEM WITH ACTIVE MAGNETIC BEARINGS USING FINITE ELEMENT METHOD". International Journal of Engineering Applied Sciences and Technology 7, n.º 1 (1 de mayo de 2022): 09–16. http://dx.doi.org/10.33564/ijeast.2022.v07i01.002.

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The rotor is a key element of rotating machinery that can be used in different of mechanical devices such as gas turbines, industrial compressors, motors, and aero engines. The dynamic analysis of a rotor system with active magnetic bearings is presented in this paper. This system consists of a flexible shaft with a rigid disk and flexible bearings. An sys Workbench is used to study a 3D simulation of a finite element model. Correct estimation of the rotor's natural frequencies and mode shapes is required for rotating machinery safety procedures. In order to compute the natural frequencies and mode shapes of this system, in the first case it is assumed a free-free system in which no bearings are used, and the natural frequencies and mode shapes are calculated without rigid body modes. In the second case, the natural frequencies and mode shapes are determined with bearing stiffness. The natural frequencies are also evaluated using finite elements based on matlab code. A comparison between the two methods was carried out.

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46

Guijosa, J. M. M. y Z. C. Feng. "Stability analysis of a rigid rotor on tilting-pad journal bearings". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 214, n.º 3 (1 de marzo de 2000): 243–51. http://dx.doi.org/10.1243/1350650001543142.

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Tilting-pad journal bearings are used in many rotating machinery applications. They are known to have superior performance in comparison with fixed geometry cylindrical bearings. Previous analysis by other investigators on the rotor stability has shown that the pad inertia is the main limiting factor on the bearing performance. In this paper, that analysis is extended to examine the bifurcation types that are associated with the loss of stability in order to gain insight into whether the linear stable regions are robust under finite perturbations. The effect of pad friction force on the rotor stability is also examined. Furthermore, the analysis is extended to bearings with four pads.

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47

Wang, Hua Qing, Yong Wei Guo, Jian Feng Yang, Liu Yang Song, Jia Pan, Peng Chen y Hong Fang Yuan. "Fault Diagnosis Based on Acoustic Emission Signal for Low Speed Rolling Element Bearing". Advanced Materials Research 199-200 (febrero de 2011): 1020–23. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.1020.

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The fault of a bearing may cause the breakdown of a rotating machine, leading to serious consequences. A rolling element bearing is an important part of, and is widely used in rotating machinery. Therefore, fault diagnosis of rolling bearings is important for guaranteeing production efficiency and plant safety. Although many studies have been carried out with the goal of achieving fault diagnosis of a bearing, most of these works were studied for rotating machinery with a high rotating speed rather than with a low rotating speed. Fault diagnosis for bearings under a low rotating speed, is more difficult than under a high rotating speed. Because bearing faults signal is very weak under a low rotating speed. This work acquires vibration and acoustic emission signals from the rolling bearing under low speed respectively, and analyzes the both kinds of signals in time domain and frequency domain for diagnosing the typical bearing faults contrastively. This paper also discussed the advantages using the acoustic emission signal for fault diagnosis of rolling speed bearing. From the results of analysis and experiment we can find the effectiveness of acoustic emission signal is better than vibration signal for fault diagnosis of a bearing under the low speed.

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48

Wang, Xiaofeng, Xiuyan Liu, Jinlong Wang, Xiaoyun Xiong, Suhuan Bi y Zhaopeng Deng. "Improved Variational Mode Decomposition and One-Dimensional CNN Network with Parametric Rectified Linear Unit (PReLU) Approach for Rolling Bearing Fault Diagnosis". Applied Sciences 12, n.º 18 (17 de septiembre de 2022): 9324. http://dx.doi.org/10.3390/app12189324.

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As a critical component of rotating machinery, rolling bearings are essential for the safe and efficient operation of machinery. Sudden faults of rolling bearings can lead to unscheduled downtime and substantial economic costs. Therefore, diagnosing and identifying the equipment status is essential for ensuring the operation and decreasing the additional maintenance costs of the machines. However, extracting the features from the early bearing fault signals is challenging under background noise interference. With the purpose of solving the above problem, we propose an integrated rolling bearing fault diagnosis model based on the improved grey wolf optimized variational modal decomposition (IGVMD) and an improved 1DCNN with a parametric rectified linear unit (PReLU). Firstly, an improved grey wolf optimizer (IGWO) with the fitness function, the minimum envelope entropy, is designed for adaptively searching the optimal parameter values of the VMD model. The performance of the basic grey wolf optimizer (GWO) algorithm by introducing three improvement strategies, the non-linear convergence factor adjustment strategy, the grey wolf adaptive position update strategy, and the Levy flight strategy in the IGWO algorithm, is improved. Then, an improved 1DCNN model with the PReLU activation function is proposed, which extracts the bearing fault features, and a grid search to optimize the model parameters of the 1DCNN is introduced. Finally, the effectiveness of the proposed model is demonstrated well by employing two experimental datasets. The preliminary comparative results of the average identification accuracy in the proposed method in two datasets are 99.98% and 99.50%, respectively, suggesting that this proposed method has a relatively higher recognition accuracy and application values.

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49

Heshmat, Hooshang. "Operation of Foil Bearings Beyond the Bending Critical Mode". Journal of Tribology 122, n.º 1 (27 de julio de 1999): 192–98. http://dx.doi.org/10.1115/1.555342.

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A series of experiments were conducted to determine a foil bearings ability to operate in the region of the bending mode of a flexible rotor. Three different bearings, spaced at three different positions along the shaft, were tested in order to make super-bending-critical operation possible. This was achieved with a proper bearing design located at an optimum position with respect to the bending nodes. After proper trim balancing the bearings passed the 34,100 rpm first bending critical and went on to operate up to 85,000 rpm, 2.5 times the bending critical. Throughout, the amplitudes of vibration remained small. The documented ability of these bearings to operate in the domain of a flexible rotor’s bending mode makes these bearings a prime candidate for the high-speed machinery of modern technology. [S0742-4787(00)02401-2]

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50

Gray, Kerrie, Takahiro Matsueda, Taisei Nishiyama, Soji Matsubayashi y Katsuyuki Kida. "Weibull Distribution to Evaluate the Reliability of PEEK Thrust Bearings under Rolling Contact Fatigue in Water". Solid State Phenomena 331 (29 de abril de 2022): 191–95. http://dx.doi.org/10.4028/p-8r8z28.

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Bearings are important in moving machinery. Today machines are used in varied fields, including environments where metals are not ideal materials. Industrial polymers are a possible alternative due to their mechanical properties, and the thermoplastic polymer Polyether ether ketone (PEEK) is suitable in many varied conditions. The failure mechanisms of PEEK are not fully understood, so the purpose of this study is to continue examining the relationship between load and rotation speed in rolling contact fatigue of PEEK thrust bearings in water conditions, to evaluate fatigue strength and life.

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