Relevant bibliographies by topics / Elastohydrodynamic (EHD) lubrication

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'Elastohydrodynamic (EHD) lubrication'

Author: Grafiati
Published: 4 June 2021
Last updated: 5 February 2022

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Journal articles on the topic "Elastohydrodynamic (EHD) lubrication"

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Sadeghi, F., and Ping C. Sui. "Thermal Elastohydrodynamic Lubrication of Rough Surfaces." Journal of Tribology 112, no. 2 (April 1, 1990): 341–46. http://dx.doi.org/10.1115/1.2920262.

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A numerical solution to the problem of thermal and compressible elastohydrodynamic (EHD) lubrication of rolling/sliding rough surfaces was obtained by neglecting the transient effects. The technique involves the simultaneous solution of thermal Reynolds and modified elasticity equations using the Newton-Raphson technique, and the energy equation using the control volume finite element method. The effects of various loads, amplitude of asperity, and radius of curvature of asperity have been investigated. Results have been presented for moderate dimensionless load of W = 9.03 × 10−5 to heavy load of W = 2.3 × 10−4 at the speed of U* = 9.2 × 10−11. The results indicate that surface roughness significantly affect the pressure, temperature, and traction in EHD lubrication.
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Chang, L., and M. N. Webster. "A Study of Elastohydrodynamic Lubrication of Rough Surfaces." Journal of Tribology 113, no. 1 (January 1, 1991): 110–15. http://dx.doi.org/10.1115/1.2920574.

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This paper reports some results of rough-surface, elastohydrodynamically lubricated (EHD) contacts obtained using a previously developed transient EHD model. The surface roughness is modeled with sinusoidal functions of small wavelength compared to the contact zone. Results are presented showing how the operating conditions affect the film thickness, micro-deformation of the roughness, and the pressure perturbations due to motion and interaction of roughness within the contact. This preliminary work suggests that the entraining velocity and the slide-to-roll ratio are the most sensitive parameters influencing the lubrication process of rough-surface EHD contacts.
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Kaneta, M., H. Nishikawa, and K. Kameishi. "Observation of Wall Slip in Elastohydrodynamic Lubrication." Journal of Tribology 112, no. 3 (July 1, 1990): 447–52. http://dx.doi.org/10.1115/1.2920280.

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A new experimental technique using optical interferometry has been developed to obtain a direct indication of non-Newtonian response of an oil film under conditions of elastohydrodynamic (EHD) lubrication. A glass disk or a steel ball has been driven by a stepping motor so that crescent-shaped thick oil films with undulation in thickness along the direction of motion have been generated. The experiments have been carried out under pure rolling and pure sliding conditions. It has been found that the oil in an EHD contact behaves like a solid and slips at or near the contact surfaces.
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Kumar, A., P. K. Goenka, and J. F. Booker. "Modal Analysis of Elastohydrodynamic Lubrication: A Connecting Rod Application." Journal of Tribology 112, no. 3 (July 1, 1990): 524–31. http://dx.doi.org/10.1115/1.2920289.

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A method for performing transient elastohydrodynamic lubrication (EHD) analysis of journal bearings using the concept of modeshapes was developed earlier. This method was referred to as the modal EHD analysis method. In the present work, the method is applied to an engine bearing geometry and load. The numerical algorithm is found to be stable and robust, as long as the modeshapes are carefully chosen; some modeshapes do cause numerical instabilities. The results from the new method are compared to those from an available EHD analysis, DEHD. Modal EHD analysis results with only 8 modeshapes compared well with those from DEHD, both for film thickness and for pressure. The new method was found to take an order of magnitude less time than DEHD for analyzing the connecting-rod bearing.
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Chang, L., C. Cusano, and T. F. Conry. "Effects of Lubricant Rheology and Kinematic Conditions on Micro-Elastohydrodynamic Lubrication." Journal of Tribology 111, no. 2 (April 1, 1989): 344–51. http://dx.doi.org/10.1115/1.3261920.

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The effects of lubricant rheology and surface kinematic conditions on micro-elastohydrodynamic (EHD) lubrication are analyzed under isothermal line-contact conditions. Micro-EHD lubrication is modeled by introducing a surface irregularity in the form of an asperity or a furrow into the contact zone. Under simple sliding conditions, the pressure generated in the vicinity of the irregularity and the resulting surface deformation depend strongly on the lubricant rheology. The surface kinematic conditions have profound effects on micro-EHD lubrication. In general, a stationary surface irregularity produces a relatively strong downstream effect when it is in the inlet region of the contact, and a moving surface irregularity produces a relatively strong upstream effect after it enters the Hertzian central region. The simulated results agree qualitatively with previous experimental measurements and observations.
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Chang, L., T. F. Conry, and C. Cusano. "An Efficient, Robust, Multi-Level Computational Algorithm for Elastohydrodynamic Lubrication." Journal of Tribology 111, no. 2 (April 1, 1989): 193–99. http://dx.doi.org/10.1115/1.3261886.

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A new computational algorithm is developed for the numerical analysis of elastohydrodynamic (EHD) lubrication problems. This algorithm combines direct-iteration, Newton-Raphson, and multigrid methods into one working environment. Accurate solutions for a wide range of steady-state, line-contact problems are obtained with a relatively small number of numerical operations. The algorithm can be used to efficiently simulate transient processes in EHD lubrication. It can also be extended to solve point-contact problems with high computational and storage efficiency.
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Mokhtar, M. O. A., and A. A. Abdel Ghany. "Elastohydrodynamic Behavior of Elliptical Contacts Under Pure Rolling Situations." Journal of Tribology 109, no. 4 (October 1, 1987): 659–63. http://dx.doi.org/10.1115/1.3261531.

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This part is a complimentary work to a previously published work on EHD lubrication behavior under pure sliding and combined rolling and sliding situations. In order to cover all aspects of EHD lubrication, the experimental work has been herein extended to present the results attained when two disks describe a pure rolling motion. A wide range of loads and speeds has been applied to the contacting disks under EHD regimes. The recorded pressure values and distribution confirm the existence of a second peak (spike) near the exit of the contact zone also under pure rolling situation. The spike has a value higher than maximum Hertzian pressure. A local constriction of oil film profile to identify the minimum EHD film thickness at trailing (exit) end of the film is observed to be nearby the location of the pressure spike. The results, compared to theoretical predictions, concluded that under pure rolling conditions, any increase in the applied load results in a corresponding increase in the developed pressure while a noticeable reduction in the minimum film thickness is recorded with decreasing rolling speeds.
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Olson, E. G., and J. F. Booker. "EHD Analysis With Distributed Structural Inertia." Journal of Tribology 123, no. 3 (May 23, 1999): 462–68. http://dx.doi.org/10.1115/1.1332396.

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An elastohydrodynamic lubrication model is presented for the coupled problem of a hydrodynamic lubricating fluid in an elastic structure that includes distributed structural inertia. The problem is formulated and the governing equations solved with the finite element method for an illustrative journal bearing subject to dynamic loading. Inertia effects are demonstrated through comparisons with an existing quasi-static model. While it is true that structural inertia can be neglected without significant loss of accuracy for many journal bearing applications, the new model presented does capture effects of distributed structural inertia where such effects are important and exhibits improvements over existing methods with respect to numerical stability.
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Simon, V. "Thermo-EHD Analysis of Lubrication of Helical Gears." Journal of Mechanisms, Transmissions, and Automation in Design 110, no. 3 (September 1, 1988): 330–36. http://dx.doi.org/10.1115/1.3267466.

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The full thermal elastohydrodynamic analysis of lubrication of helical gears is presented. A numerical solution of the coupled Reynolds, elasticity, energy, and Laplace’s equations for the oil film shape, pressure and temperature distributions in the oil film, and temperature distribution in gear teeth is obtained. The effects of gear parameters and operating conditions on EHD performance characteristics is discussed. Based on the obtained results, by regression analysis, equations are derived to calculate the EHD load carrying capacity, maximum oil temperature, and power loss.
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Xing, Hui, Hui Zhang, Qili Wu, and Shu Lin Duan. "Full Shafting-Based Elastohydrodynamic Lubrication Simulation for Main Bearings of Marine Diesel Engine." Advanced Materials Research 479-481 (February 2012): 1119–23. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1119.

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To predict and analyze accurately the lubrication characteristics and its influencing factors of main bearing for large low-speed two-stroke marine diesel engine, based on EHD lubrication model of dynamically loaded bearing, coupling simulation between EHD and MBD for main bearing of marine diesel engine was carried out. Systemic models were established separately considering the independent crankshaft of diesel engine and the full shafting of propulsion power plant. Main bearing load, peak oil film pressure, oil film pressure distribution, MOFT and orbital path in one working cycle under rated working conditions were investigated, and simulation results were compared based on both models. The results show that, if the impact of full shafting was considered, the lubrication characteristics of No.8 main bearing changed significantly, the lubrication characteristics of other main bearings were similar as the simulation results of the independent crankshaft model.
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Dissertations / Theses on the topic "Elastohydrodynamic (EHD) lubrication"

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Košťál, David. "Studium utváření mazacích filmů za podmínek nedostatečného zásobování kontaktu mazivem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229431.

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The purpose of this thesis is to reveal production mechanisms of lubrication films between non-conformal surfaces in situations, when is not possible to designate lubrication regime as fully flooded elastohydrodynamic contact. Under certain conditions of lubrication volume, rolling speeds, temperatures, lubrication properties or loads could lubrication film decrease under values determined by fully flooded formulas. This regime is designated as starvation at it includes risk of increased wear. In this thesis the methodology and the new simulator of starving contact are described. Obtained film thickness results are compared with existing numerical models.
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Matoušek, Kamil. "Vliv povrchových rýh na mazání bodových kontaktů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231945.

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This diploma thesis deals with experimental study of the effect of surface grooves on distribution of lubricant film in elastohydrodynamic lubricated point contact. Lubricant film thickness was measured by ball-on-disc apparatus using an optical interferometry technique - thin film colorimetric interferometry. The effects of groove geometry, lubricant and operating conditions were studied in this diploma thesis. The effects of these variables are evaluated based on newly suggested parameter Rgi (groove influence ratio). Groove influence ratio is defined as an influenced film thickness influenced by groove divided by film thickness for smooth surfaces.
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Furtuna, Marian Dumitru. "Study of film formation in EHD contacts using a novel method based on electrical capacitance." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/5077.

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The elastohydrodynamic lubrication regime (EHD) is found in many machine elements, such as rolling element bearings, gears, cam/tappet, where a combination of hydrodynamic effect, elastic deformation of the surfaces and an increase of the lubricant’s viscosity with pressure create a continuous lubricant film which is capable of supporting pressures of the order of tens of thousands of atmospheres. One of the most important features of these films is their thickness, as this determines whether the bounding surfaces are completely separated, thus avoiding premature wear and failure of the contact. Consequently for many years scientists were interested in finding methods for measuring the lubricant film thickness in elastohydrodynamic conditions. One of the most versatile and widely used techniques for measuring lubricant film thickness in EHD contacts is the optical interferometry method. Apart from numerous advantages, this method has the limitation in the fact that one of the contacting surfaces must be transparent, usually glass or sapphire, thus it does not replicate real conditions found in machine elements contacts. On the other hand, the other group of methods used for studying the behaviour of elastohydrodynamic films includes a variety of electrical methods. Historically, these appeared before the optical methods, but gradually lost importance with the success of the later. Most capacitive, resistive, inductance methods developed so far use specially designed sensors for monitoring the lubricant film thickness. In the case of electrical techniques, both elements of the contact are metallic, which means that these can be used for measuring film thickness in real machine elements. One of the main disadvantages of electrical methods though, is the difficulty with which the calibration of various electrical quantities, against lubricant film thickness is obtained. This thesis describes the work carried out by the author on the application of a capacitive method for studying lubrication of elastohydrodynamic contacts. The novelty of the method used consists in the calibration of the capacitance of the contact with optical interferometry. This project started from the premises that a thicker Chromium layer will supply the phase change needed to precisely measure the lubricant film thickness by eliminating the fragile silica layer, and it has been shown that an increase in Cr thickness results in a increase in reflection of the glass–Cr interface making the resulting images hard to process. Modifications to the existing experimental rig were carried out in order to apply/collect an electrical signal from both the disc and the ball. Signal collection from the disc was quite straightforward and a graphite brush paired with a copper nut was used, as this is the oldest method of collecting/applying and electrical signal from a rotating element. Collecting an electrical signal from the ball presented quite a challenge as the ball is submerged in oil. A number of brushes was designed, made and tested and the one that provided the most stable results chosen. For calibration purposes a base oil and two additives were chosen, the additives were chosen in such a way that the improvement made to the lubrication process to be very different from one additive to the other. The chosen additives were a Viscosity Index Improver [VII] and an Organic Friction Modifier [OFM]. The VII is used by many researchers in order to obtain multigrade lubricants using the same base oil by varying its percentage in the mix. The OFM is used to provide protection between the two contacting bodies when EHD film fails and EHD lubrication is replaced by mixed lubrication by forming a boundary layer on the contacting surfaces. Optical measurements were carried out on the base oil and the two resulting lubricants from the additive mixes using the Ultra Thin Film Interferometry [UTFI] method. The measurements were used as a benchmark against which the capacitive measurements were calibrated. Tests were conducted in a number of controlled conditions for speed, temperature, load and sliding conditions. Results showed that the highest influence on the lubrication process was given by the speed, an increase in speed results in an increase in optically measured film thickness and a decrease in electrically measured film thickness. Phenomenon explained by a large amount of lubricant pushed into the contact. Another parameter that influenced the results quite significantly was temperature, a rise in temperature supplies a decrease in optically measured film thickness and an increase in capacitive measured film thickness which was explained by lubricant viscosity dropping with a rise in temperature. Three different sliding conditions were employed and a small drop in optically measured film thickness followed by a small rise in electrically measured film thickness was recorded due to a local increase in contact temperature when sliding was employed. The capacitive method developed in this project is precise enough to accurately measure lubricant film thickness down to 100nm; a model for thicknesses lower that 100nm was proposed Results from the optical and capacitive methods were compared and a good correlation was found, indicating that the developed capacitive method can be used as a tool for measuring metal on metal contacts without further calibration.
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Frýza, Josef. "Elastohydrodynamic Film Study under Impact Loading and Lateral Vibrations." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-371778.

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Disertační práce se zabývá chováním a odezvou elastohydrodynamického (EHD) mazacího filmu za neustálených provozních podmínek. V úvodní části práce jsou shrnuty poznatky z oblasti EHD mazání; od jeho historie, přes základní mechanismy mazání a používané experimentální metody, až po nedávno publikované studie zaměřené na transientní podmínky. Hlavním cílem práce bylo experimentálně objasnit vliv provozních parametrů a reologických vlastností maziv na chování mazacího filmu v bodovém kontaktu při jeho nárazovém zatěžování a vystavení příčným vibracím. Za tímto účelem byla vyvinuta laboratorní zařízení umožňující měření rozložení mazacího filmu a tření za kontrolovaných nestacionárních podmínek. Experimenty odhalili zásadní roli přibližovacích a zatěžovacích rychlostí na formování stlačených mazacích filmů při nárazovém zatěžování. Výsledky byly srovnávány s nedávným teoretickým řešením. Bylo ukázáno na jeho nedostatky, jež byly následně odstraněny implementací empirických vztahů zohledňujících reologii maziv. V případě příčných vibrací byly nalezeny hranice selhání mazacího filmu a určeny vztahy popisující vliv příčných vibrací na centrální tloušťku filmu a její fluktuace jednotně pro všechny maziva. Závěrečná část práce poskytuje nový pohled na reologii maziv pomocí inovativního přístupu měření třecích reakcí maziva současně ve dvou směrech kontaktu za podmínek příčných vibrací. Tyto původní výsledky rozšiřují pochopení mechanizmů EHD mazání a mohou být použity k dokonalejším návrhům strojů, a vylepšit tak jejich účinnost, spolehlivost a životnost.
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Albahrani, Sayed Mohamed Baqer. "Photoluminescent CdSe/CdS/ZnS quantum dots for temperature and pressure sensing in elastohydrodynamic." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI016/document.

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La température et la pression sont deux paramètres particulièrement importants pour l’optimisation des performances du régime de lubrification élastohydrodynamique (EHL). A ce jour, différentes méthodes expérimentales ont été développées, avec plus ou moins du succès, pour la mesure de ces deux paramètres. Ce travail présente, en continuité de ces approches, des investigations visant à développer une nouvelle technique in situ permettant de mesurer localement ces deux grandeurs dans les contacts élastohydrodynamiques (EHD). Cette technique exploite la sensibilité en photoluminescence (PL) des boîtes quantiques (ou en anglais « quantum dots (QDs)) de CdSe/CdS/ZnS aux variations de température et de pression. A cet égard, des calibrations ont été réalisées afin d’évaluer la sensibilité de ces QDs aux deux paramètres. De plus, la versatilité de ces QDs comme nanosondes a été examinée en testant deux lubrifiants différents : le squalane et un mélange de squalane et de cyclopentane. Des mesures ont été également effectuées sous conditions dynamiques afin d’étudier (i) l’influence de la présence des QDs sur la rhéologie du lubrifiant et (ii) l’influence du taux de cisaillement sur la PL des QDs. Bien que ces différents tests aient prouvé le potentiel des QDs de CdSe/CdS/ZnS, ils ont révélé l’existence d’autres paramètres qui peuvent, tout comme la température et la pression, en modifier la réponse. L’étude a été menée afin d’approfondir la compréhension des mécanismes responsables de tels effets. Plus important encore, une méthodologie a été définie pour minimiser ces effets indésirables, et pour in fine, permettre l’usage de ces QDs en tant que nanosondes fiables
Temperature and pressure are two relevant parameters for the optimization of lubrication performance in the elastohydrodynamic lubrication (EHL) regime. To date, various experimental methods have been developed to measure these two parameters with more or less success. In a continuation of these efforts, some investigations are presented in the current work in view of developing a new in situ technique allowing for local measurements of these two parameters throughout elastohydrodynamic (EHD) contacts. This technique exploits the photoluminescence (PL) sensitivity of CdSe/CdS/ZnS quantum dots (QDs) to changes in temperature and pressure. In this respect, calibrations have been carried out in order to establish the sensitivity of these QDs to the two parameters. Moreover, the versatility of these QDs for sensing applications have been examined by testing two different lubricants, namely squalane and a mixture of squalane and cyclopentane. Some measurements were also conducted under dynamic conditions, in order to study (i) the influence of the QDs presence on the lubricant rheology and (ii) the influence of shear rate on the PL of QDs. Although these different tests demonstrated the potential of CdSe/CdS/ZnS QDs, they revealed the existence of other parameters that affect, in addition to temperature and pressure, their response. A comprehensive study was thus conducted in order to elucidate the mechanisms behind these findings. More importantly, a methodology was defined in order to minimize these undesired influences and, in fine, enable these QDs to be used as reliable nanosensors
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Omasta, Milan. "Studium utváření elastohydrodynamických mazacích filmů u hypoidních převodů." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-234175.

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This PhD thesis deals with elastohydrodynamic lubrication (EHL) under the conditions that occur between mated hypoid gear teeth. The aim is to describe experimentally the behaviour of lubricating film and mechanisms of its formation. The focus is mainly placed on clarifying the influence of direction and magnitude of sliding velocity in circular and elliptical contacts. Generally, it is still assumed that the direction of sliding velocity has no effect on the resulting lubricant film. In this study optical interferometry is used to determine distribution of lubricant film thickness. This work includes new and original results which clarify the studied problem. It was found that the direction of sliding velocity affects shape of the film at high speeds. This relates to the effect on heat flow through the contact. The results have an impact on the development of general EHL theory and provide knowledge applicable in film thickness prediction in the design of real tribological nodes.
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Ficza, Ildikó. "Effects of Non-Newtonian Lubricants on Surface Roughness in Point Contacts." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-234243.

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Tato dizertační práce je zaměřena na studium deformace nerovnosti uvnitř elastohydrodynamicky mazaného (EHD) kruhového kontaktu. Práce se zabývá studiem přechodu příčné nerovnosti přes kontaktní oblast, která je modelována pomocí numerických metod. Model dále uvažuje nenewtonské chování maziva. Použitý matematický model se skládá z parciální diferenciální rovnice druhého řádu pro řešení tlaku a integro-diferenciální rovnice pro řešení elastických deformací. Pro řešení tohoto modelu je použitá takzvaná multigrid (vícesíťová) metoda. Práce obsahuje popis matematického modelu EHD kontaktu a aplikované numeriké metody. Výsledky simulací jsou porovnány s experimentálně stanovenýma hodnotama tloušťky mazacího filmu. Deformace nerovnosti uvnitř kontaktní oblasti je studována pro různé provozní podmínky (střední rychlost, poměr proklzu) a různá vlastnosti maziva.
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Aitken, M. B. "Elastohydrodynamic lubrication of big end bearings under steady and cyclic loads." Thesis, University of Canterbury. Mechanical Engineering, 1989. http://hdl.handle.net/10092/6012.

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Lubrication of the big-end bearing is re-examined under elastohydrodynamic assumptions. All current models were found to be in someway deficient, motivating the development of a new consistent schema. Uniform axial film-thickness assumptions and parabolic axial pressure profiles are combined with curved-beam and planar Finite Element housings to produce a single dimensional EHL model. Body-forces due to con-rod motion were found to be a necessary part of the elasticity implementation. The role of discretisation and surface displacement interpolation errors are investigated under steady load conditions. Under dynamic load, ring, housing and previous experimental works are compared. Increased dynamic journal action from housing distorsion was found to lead to film collapses not present in equivalent rigid bearing analyses; these collapses are likened to vapour cavitation. Correlation of dynamic film-thickness measurements with the elastic solutions are generally improved over rigid predictions. With regard to minimum film thickness, inertial 'ring' solutions gave similar values to housing solutions with and without gas loading; this facilitates non-dimensionalisation. Two separate minimum-film regime were subsequently identified: one in the con-rod neck and a second, at higher load, in the cap. The first condition sees thicker minimum films than the rigid bearing; the second, thinner films with an increased sensitivity to load. Non-dimensionalisation of this transition along with bearing flexibility and load enabled new tribological measures to be developed; the influence of elastic geometry on minimum film thickness is sufficiently well portrayed to make these useful design tools.
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Moraru, Laurentiu Eugen. "Numerical Predictions and Measurements in the Lubrication of Aeronautical Engine and Transmission Components." University of Toledo / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1125769629.

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Hegedus, Phil. "Evaluation and Prediction of Elastohydrodynamic Lubrication Film Thickness Under Conditions of Severe Sliding and Zero Entrainment." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1513786919757098.

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Book chapters on the topic "Elastohydrodynamic (EHD) lubrication"

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Zhu, Dong. "Elastohydrodynamic Lubrication (EHL)." In Encyclopedia of Tribology, 874–89. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_624.

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Zhu, Dong, and Q. Jane Wang. "EHL History (Elastohydrodynamic Lubrication)." In Encyclopedia of Tribology, 832–47. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_625.

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Wang, Q. Jane, and Dong Zhu. "Lubrication in Counterformal Contacts—Elastohydrodynamic Lubrication (EHL)." In Interfacial Mechanics, 183–250. First edition. | Boca Raton, FL : CRC Press/Taylor & Francis Group, 2019.: CRC Press, 2019. http://dx.doi.org/10.1201/9780429131011-7.

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Kudish, Ilya I. "Numerical Stability and Precision in Elastohydrodynamic Lubrication (EHL)." In Encyclopedia of Tribology, 2454–64. Boston, MA: Springer US, 2013. http://dx.doi.org/10.1007/978-0-387-92897-5_651.

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"Elastohydrodynamic Lubrication (EHL)." In Finite Element Modelling of Elastohydrodynamic Lubrication Problems, 1–58. Chichester, UK: John Wiley & Sons Ltd, 2018. http://dx.doi.org/10.1002/9781119225133.ch1.

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"Elastohydrodynamic Lubrication (EHL)." In Fundamentals of Tribology, 217–63. WORLD SCIENTIFIC (EUROPE), 2018. http://dx.doi.org/10.1142/9781786345189_0010.

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"ELASTOHYDRODYNAMIC LUBRICATION (EHL)." In Fundamentals of Tribology, 185–216. IMPERIAL COLLEGE PRESS, 2008. http://dx.doi.org/10.1142/9781848161856_0010.

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"Numerical calculation method and program for thermal EHL." In Numerical Calculation of Elastohydrodynamic Lubrication, 173–216. Singapore: John Wiley & Sons Singapore Pte Ltd., 2015. http://dx.doi.org/10.1002/9781118920978.ch10.

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"Numerical calculation method and program for grease EHL." In Numerical Calculation of Elastohydrodynamic Lubrication, 217–78. Singapore: John Wiley & Sons Singapore Pte Ltd., 2015. http://dx.doi.org/10.1002/9781118920978.ch11.

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"Numerical calculation method and program for micropolar fluid EHL." In Numerical Calculation of Elastohydrodynamic Lubrication, 329–43. Singapore: John Wiley & Sons Singapore Pte Ltd., 2015. http://dx.doi.org/10.1002/9781118920978.ch15.

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Conference papers on the topic "Elastohydrodynamic (EHD) lubrication"

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Simon, Vilmos V. "Influence of Lubricant and Operating Parameters on EHD Lubrication in Hypoid Gears." In World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63118.

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The influence of lubricant characteristics and operating parameters on the elastohydrodynamic lubrication in hypoid gears is investigated. The full thermal elastohydrodynamic analysis of lubrication is applied, based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. Using a computer algorithm, the influence of oil viscosity, pressure-viscosity and temperature-viscosity exponents, supplied oil temperature, speed and minimum oil film thickness on maximum oil film pressure and temperature, EHD load carrying capacity, and power losses in the oil film is investigated. The obtained results are presented and discussed.
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Fatu, Aurelian, and Dominique Bonneau. "EHD Lubrication of Multi-Body Common-Pin Conrod Big End Bearings System." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44260.

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This paper describes a model for the analysis of elastohydrodynamic (EHD) lubrication of a multi-body common-pin connecting-rod (conrod) big end bearing system. Two conrod and three thrust bearings are fully coupled in order to simulate real behavior of the system. An extended Reynolds equation including mass conservation and oil film history is solved in the big end conrod bearings. The HD behavior of the thrust bearings is simulated by a cylindrical coordinate Reynolds equation. By comparisons with classical single rod analysis results show the pertinancy of simulating twin moving conrods.
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Simon, Vilmos V. "Influence of Misalignments on EHD Lubrication in Hypoid Gears." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-34014.

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The thermal elastohydrodynamic analysis of lubrication is applied to investigate the influence of misalignments of the meshing members on EHD lubrication in hypoid gears. The calculation is based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The full thermal EHD lubrication analysis is applied, therefore, the oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. The real shape of the gap existing between the contacting tooth surfaces is treated, based on gear teeth geometry defined by the gear processing method and including the misalignments of mating members. By using the corresponding computer program, the influence of pinion’s running offset and axial adjustment errors, and angular position error of pinion axis on maximum oil film pressure and temperature, EHD load carrying capacity, and on power losses in the oil film is investigated. The obtained results are presented and discussed.
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Otsu, Takefumi, Yuichiro Nagata, Joichi Sugimura, and Romeo Glovnea. "Cavitation Phenomena in Pure-Sliding Grease EHL Films." In STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41119.

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Grease lubricants are widely used in many machine elements which work in elastohydrodynamic (EHD) lubrication regime. They have advantages over lubricating oils, but are prone to starvation, especially when operating at large speeds. At the same time the complex nature of lubricating grease is little understood and only little knowledge about its chemistry and physics is accessible, which makes the prediction of grease film behavior difficult. In the present paper the relation between lubricating grease composition and operating parameters on one hand and the cavitation length on the other, was evaluated.
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Simon, Vilmos. "Influence of Position Errors on EHD Lubrication in Spiral Bevel Gears." In STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41048.

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The thermal elastohydrodynamic analysis of lubrication is applied to investigate the influence of misalignments of the meshing members on lubrication in spiral bevel gears. The calculation is based on the simultaneous solution of the Reynolds, elasticity, energy, and Laplace’s equations. The full thermal EHD lubrication analysis is applied, therefore, the oil viscosity variation with respect to pressure and temperature and the density variation with respect to pressure are included. By using the corresponding computer program, the influence of pinion’s running offset and axial adjustment errors, and angular position error of pinion axis on maximum oil film pressure and temperature, EHD load carrying capacity, and on power losses in the oil film is investigated. On the basis of the obtained results it can be concluded that the EHD load carrying capacity and the friction factor are very sensitive to misalignments of the mating members in the spiral bevel gear pair, the friction factor is reduced by the increase of EHD load carrying capacity and vise versa, and the maximum inlet oil temperature is almost insensitive to the misalignments.
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Varela, Alejandro Cerda, and Ilmar Ferreira Santos. "Stability Analysis of an Industrial Gas Compressor Supported by Tilting-Pad Bearings Under Different Lubrication Regimes." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46450.

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This work is aimed at theoretically study the dynamic behavior of a rotor-tilting pad journal bearing system under different lubrication regimes, namely thermohydrodynamic (THD), elastohydrodynamic (EHD) and hybrid lubrication regime. The rotor modeled corresponds to an industrial compressor. Special emphasis is put on analyzing the stability map of the rotor when the different lubrication regimes are included into the TPJB modeling. Results show that, for the studied rotor, the inclusion of a THD model is more relevant when compared to an EHD model, as it implies a reduction on the instability onset speed for the rotor. Also, results show the feasibility of extending the stable operating range of the rotor by implementing a hybrid lubrication regime.
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Malik, M. Afzaal, Badar Rashid, Syed Adnan Qasim, and Shahab Khushnood. "Modeling and Simulation of Elastohydrodynamic Lubrication of Piston Skirts Considering Elastic Deformation in the Initial Engine Start-Up." In ASME/STLE 2004 International Joint Tribology Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/trib2004-64101.

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The presence of Elasto-hydrodynamic Lubrication (EHL) film between opposing piston and liner surfaces prevents possible solid-to-solid contact and wear. This enhances engine life manifold as compared to when the EHL film is non-existent in the initial engine startup or breaks down during normal engine operation. Forced dry sliding of piston during engine cranking followed by partial lubrication in the initial engine startup leads to adhesive wear. This research investigates the possibility of an EHL film on such an occasion by considering elastic deformation of opposing piston skirt and liner surfaces due to Elasto-hydrodynamic (EHD) pressures. The geometry of piston skirts is defined and governing equations are applied to determine hydrodynamic pressures. The EHL film thickness profile generated by inverse solution technique and its expression is defined by incorporating contact geometry and EHD pressures in the piezoviscous regime. A computer code is developed and used to simulate the performance parameters and their behavior during initial engine startup. Due to critical factors such as engine speed, redial clearance between piston skirts and liner and lubricant viscosity, a time dependent 2-D EHL film profile is generated. The simulated results indicate that, despite piston eccentricities due to secondary oscillatory motion, EHL film established between the opposing piston skirts and liner surfaces prevented possible solid-to-solid contact in the entire duration of 720-degree crankshaft rotation, which corresponds to four piston strokes.
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Ma, Ming-Tang, Bernhard Loibnegger, and Paul Herster. "Advanced Elastohydrodynamic Analysis of Journal Bearings in IC Engines With a Multi-Body System Approach." In ASME 2006 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ices2006-1349.

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This paper presents a rigorous analysis of the elastohydrodynamic (EHD) lubrication of journal bearings in internal combustion (IC) engines. The approach treats a set of radial slider (plain journal) bearings as a system or a subsystem. Thus, they can be simulated simultaneously, and hence the system effect is included. The analysis considers both the elasticity and dynamics of the connected parts such as the cylinder block (or main bearing walls), crankshaft and conrod. Both local vibration and global motion of these elastic parts are modelled by a multi-body system (MBS) approach. Hence, the EHD behaviour of engine bearings is simulated in a realistic manner.
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Boedo, S., and J. F. Booker. "Modal and Nodal EHD Analysis for Gas Journal Bearings." In ASME/STLE 2004 International Joint Tribology Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/trib2004-64140.

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This paper presents a novel finite element elastohydrodynamic lubrication analysis appropriate for gas journal bearings under dynamic conditions. The method employs gas pressure as a state variable, and structural sleeve deformation is represented by a linear combination of pre-selected mode shapes obtained from a related eigenvalue problem. The method takes into account temporal variation of journal position and velocity, and second-order slip flow boundary effects are included at no additional computational cost. The formulation is subsequently applied to a particular example (flexible large-aspect ratio, high-speed, MEMS-scale journal microbearing), where it is shown that a judicious choice of structural sleeve elasticity can significantly improve bearing performance (as measured by pressure distribution and load capacity) when compared with results obtained using rigid bearing surfaces.
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Qasim, Syed Adnan, M. Afzaal Malik, Usman F. Chaudhri, and Riaz A. Mufti. "Non-Newtonian Elastohydrodynamic Lubrication Fluid Flow Modeling of Piston Skirts Considering Low Speed Effects in Initial Engine Start Up." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38439.

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Elastohydrodynamic lubrication (EHL) is critically essential to minimize engine wear at low engine start up speeds. During the normal engine operations at medium to high speeds, non-Newtonian characteristics of multigrade engine lubricants enhance engine life by preventing adhesive wear. By incorporating viscoelastic effects of a non-Newtonian lubricant and focusing on different low engine start up speeds, this study models EHL fluid flow in the initial engine start up conditions. A 2-D non-Newtonian piston skirts lubrication model and analysis at the time of engine start up is presented based on the upper convected Maxwell viscoelastic model. The analysis of a non-Newtonian lubricant between piston and cylinder liner by using characteristic lubricant relaxation times in all order of magnitude analysis is done by using a perturbation method. The EHL film profile is predicted by solving the two-dimensional Reynolds equation using the inverse solution technique and the finite difference computational method in the fully flooded lubrication conditions. At different low engine start up speeds, the effect of viscoelasticity on lubricant velocity and pressure fields is examined and the influence of film thickness on lubricant characteristics is investigated. Numerical simulations show that piston eccentricities, EHD pressures and film thickness profiles are functions of low range of engine start up speeds. This study suggests that the initial engine start up speed at low range can be optimized as viscoelasticity produces a beneficial effect on piston skirt lubrication in the initial engine start up.
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