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Modelisation De La Lubrification Sous Alimentee Dans Les Contacts Elastohydrodynamiques Elliptiques
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Book Synopsis Modélisation de la lubrification sous-alimentée dans les contacts élastohydrodynamiques elliptiques by : Bruno Damiens
Download or read book Modélisation de la lubrification sous-alimentée dans les contacts élastohydrodynamiques elliptiques written by Bruno Damiens and published by . This book was released on 2003 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dans les mécanismes lubrifiés, la durée de vie des surfaces en contact est fonction de l'épaisseur du film de lubrifiant qui sépare les solides. La sous-alimentation en lubrifiant affecte cette épaisseur de film et réduit la durée de vie des mécanismes. Une modélisation mathématique du problème à frontières libres est adoptée. Les techniques Multigrilles et Multi-Level Multi-Integral utilisées pour résoudre le système d'équations sont sommairement exposées. Le modèle fournit les champs de pression et d'épaisseur de film de lubrifiant dans le contact. Il permet de valider un modèle analytique développé afin de mettre en évidence et de quantifier le débit d'éjection de lubrifiant, dans la couche limite qui entoure le contact. La largeur de la couche limite régit le débit d'éjection et elle permet de déterminer la réponse du contact à la sous-alimentation. La largeur de la couche limite peut aussi être utilisée pour prédire la persistance d'une sous-alimentation locale dans un mécanisme.
Book Synopsis Grease Lubrication in Rolling Bearings by : Piet M. Lugt
Download or read book Grease Lubrication in Rolling Bearings written by Piet M. Lugt and published by John Wiley & Sons. This book was released on 2013-02-18 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal and dynamics properties. Later chapters cover the dynamics of greased bearings, including grease life, bearing life, reliability and testing. The final chapter covers lubrications systems – the systems that deliver grease to the components requiring lubrication. Grease Lubrication in Rolling Bearings: Describes the underlying physical and chemical properties of grease. Discusses the effect of load, speed, temperature, bearing geometry, bearing materials and grease type on bearing wear. Covers both bearing and grease performance, including thermo-mechanical ageing and testing methodologies. It is intended for researchers and engineers in the petro-chemical and bearing industry, industries related to this (e.g. wind turbine industry, automotive industry) and for application engineers. It will also be of interest for teaching in post-graduate courses.
Book Synopsis MODELISATION DES CONDITIONS D'ALIMENTATION DANS LES CONTACTS ELASTOHYDRODYNAMIQUES PONCTUELS by : FREDERIC.. CHEVALIER
Download or read book MODELISATION DES CONDITIONS D'ALIMENTATION DANS LES CONTACTS ELASTOHYDRODYNAMIQUES PONCTUELS written by FREDERIC.. CHEVALIER and published by . This book was released on 1996 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: EN LUBRIFICATION, DE NOMBREUX MECANISMES SONT AMENES A OPERER DANS DES CONDITIONS DE SOUS-ALIMENTATION EN LUBRIFIANT, CE QUI ENGENDRE UNE REDUCTION GLOBALE OU LOCALE DES EPAISSEURS DE FILM. UN MODELE EST DEVELOPPE AFIN D'ETUDIER L'INFLUENCE DES CONDITIONS D'ALIMENTATION SUR LE COMPORTEMENT DU CONTACT ELASTOHYDRODYNAMIQUE PONCTUEL. POUR APPROCHER LA REALITE PHYSIQUE, LE MODELE CONSIDERE DES DEBITS LOCAUX D'ALIMENTATION GENERES PAR LA DISTRIBUTION DU LUBRIFIANT ADHERANT AUX SURFACES A L'ENTREE DU CONTACT ET VEHICULEE PAR ELLES. LE PROBLEME EST ALORS RESOLU SUR DEUX ZONES COMPLEMENTAIRES A L'AIDE D'UNE EQUATION DE REYNOLDS MODIFIEE : UNE ZONE DE FILM COMPLET ET UNE ZONE DE FILM PARTIEL. LA POSITION DE LA FRONTIERE LIBRE, EN FORMATION ET EN RUPTURE DE FILM, RESULTE DE LA CONSERVATION DE LA MASSE ENTRE CES DEUX ZONES. LA SOLUTION NUMERIQUE EST OBTENUE A L'AIDE DES TECHNIQUES MULTIGRILLES. LORSQUE LE CONTACT EST ALIMENTE AVEC DES EPAISSEURS DE LUBRIFIANT UNIFORMES, LES RESULTATS MONTRENT QUE LA REDUCTION DE L'EPAISSEUR CENTRALE DE FILM PEUT ETRE GENERALISEE A L'AIDE D'UNE RELATION SIMPLE INCORPORANT DEUX COMPORTEMENTS ASYMPTOTIQUES PHYSIQUES. UN SEUL PARAMETRE VARIE SUIVANT LES CONDITIONS DE FONCTIONNEMENT DU CONTACT. CE PARAMETRE PERMET EGALEMENT, EN PREMIERE APPROXIMATION, D'EVALUER LA REDUCTION PROGRESSIVE DES EPAISSEURS DE FILM EN FONCTION D'UN NOMBRE DE PASSAGES SUCCESSIFS, LORSQUE LES EFFETS DE REALIMENTATION SONT NEGLIGEABLES. LE CONTACT EST ENSUITE ETUDIE AVEC UNE DISTRIBUTION VARIABLE DU LUBRIFIANT SUR LES SURFACES. LES RESULTATS MONTRENT QUE CETTE DISTRIBUTION EST DIRECTEMENT RESPONSABLE DE LA VARIATION DES EPAISSEURS DE FILM A L'INTERIEUR DU CONTACT. UNE PARTIE DU CONTACT PEUT ETRE TRES SEVEREMENT SOUS-ALIMENTEE ALORS QU'UNE AUTRE PEUT ETRE SUR-ALIMENTEE. UNE BONNE CORRELATION, A LA FOIS QUALITATIVE ET QUANTITATIVE, EST OBTENUE AVEC LES RESULTATS EXPERIMENTAUX.
Download or read book Journal of Tribology written by and published by . This book was released on 2008 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Lubrification des contacts sous-alimentés by : Florian Bremond
Download or read book Lubrification des contacts sous-alimentés written by Florian Bremond and published by . This book was released on 2012 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: L’appauvrissement en lubrifiant d’un contact élasto-hydrodynamique peut menacer la pérennité du film interfacial séparant les surfaces, entraîner l’augmentation des forces de frottement et l’endommagement rapide du tribosystème. Industriellement, la volonté de réduire les quantités de lubrifiant embarquées et de limiter les opérations de maintenance favorisent la sous-alimentation. L’objectif de cette thèse est de contrôler l’alimentation d’un contact EHD sous-alimenté par une texturation de surface multi-échelle, afin d’assurer une lubrification minimale à l’interface. Une démarche scientifique s’appuyant sur la dissociation des échelles spatiales, temporelles ainsi que sur l’analyse des contributions des écoulements dans les différentes zones du contact a été mise en oeuvre. La compréhension de l’interaction laser/matière en irradiation ultra-brève a permis de générer des texturations nanométriques (ripples) et micrométriques (ondulations et réseaux de cavités) à l’aide d’un laser femtoseconde. La contribution de chaque échelle topographique sur la lubrification d’un contact a été étudiée. Lorsque les forces hydrodynamiques sont faibles (contact statique), l’alimentation d’un contact résulte d’une compétition entre une contribution capillaire et une contribution visqueuse. La macro géométrie des solides déformés ainsi que la viscosité pilotent au premier ordre la propagation du lubrifiant à l’extérieur de la zone haute pression. L’imbibition de la zone de Hertz n’est possible qu’avec l’introduction d’une surface nanotexturée et sa cinétique dépend de l’orientation et de l’amplitude des ripples. Pour des nombres capillaires élevés (contact dynamique), un critère de prédiction de l’apparition de la sous-alimentation a été établi. En présence de réseaux de cavités et sous l’action d’un cisaillement interfacial, les surfaces texturées possédant une capacité de rétention élevée réalimentent la zone de haute pression. Le volume piégé envahit alors le contact puis crée une surépaisseur de lubrifiant qui protège les solides de l’endommagement tout en limitant l’augmentation du frottement. Les texturations nanométriques (ripples) et micrométriques, anisotropes et périodiques, modifient l’équilibre entre les débits de réalimentation et les débits de fuite. Une orientation adaptée des motifs peut contenir le drainage du lubrifiant dans le contact et ainsi empêcher ou retarder l’apparition d’un régime de sous-alimentation totale. Au final, chaque échelle topographique contribue à la réalimentation d’un contact sousalimenté, soit en favorisant l’expansion des réservoirs latéraux, soit en apportant localement du lubrifiant, ou en maintenant un film fluide résiduel sur les surfaces.
Book Synopsis Elasto-Hydrodynamic Lubrication by : D. Dowson
Download or read book Elasto-Hydrodynamic Lubrication written by D. Dowson and published by Elsevier. This book was released on 2014-07-18 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elasto-Hydrodynamic Lubrication deals with the mechanism of elasto-hydrodynamic lubrication, that is, the lubrication regime in operation over the small areas where machine components are in nominal point or line contact. The lubrication of rigid contacts is discussed, along with the effects of high pressure on the lubricant and bounding solids. The governing equations for the solution of elasto-hydrodynamic problems are presented. Comprised of 13 chapters, this volume begins with an overview of elasto-hydrodynamic lubrication and representation of contacts by cylinders, followed by a discussion on equations relevant to lubrication, including the Reynolds equation. The reader is then introduced to lubrication of rigid cylinders; the importance of film thickness in highly loaded rigid contacts; the elasticity of solids in contact; and the theory of elasto-hydrodynamic lubrication. Subsequent chapters focus on apparatus and measurements of film thickness and film shape; friction and viscosity; and lubrication of gears and roller bearings. This book will be of interest to tribologists.
Book Synopsis La lubrification des liaisons compliantes by : Dominique Guines
Download or read book La lubrification des liaisons compliantes written by Dominique Guines and published by . This book was released on 1994 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA LUBRIFICATION JOUE UN ROLE PREPONDERANT DANS LE BON FONCTIONNEMENT DE NOMBREUX MECANISMES. AFIN DE S'ASSURER DE L'EXISTENCE D'UN FILM D'HUILE ENTRE LES SURFACES EN MOUVEMENT RELATIF D'UN CONTACT LUBRIFIE, IL CONVIENT DE DEFINIR PRECISEMENT LES DEFORMATIONS DES STRUCTURES INTERVENANT DE PART ET D'AUTRE DU FILM LUBRIFIANT. EN EFFET, LORSQU'IL S'AGIT DE STRUCTURES TRES COMPLIANTES, TELLES QUE LES BIELLES DE MOTEURS THERMIQUES, LES DEFORMATIONS ELASTIQUES PEUVENT ETRE DU MEME ORDRE DE GRANDEUR QUE L'EPAISSEUR DU FILM D'HUILE ELLE-MEME. AFIN D'OBTENIR UNE MODELISATION PRECISE DES CONDITIONS REELLES DE FONCTIONNEMENT D'UN CONTACT LUBRIFIE, NOUS AVONS ETABLI UN PROGRAMME DE CALCUL BASE SUR UNE DESCRIPTION BIDIMENSIONNELLE DE L'ECOULEMENT DU FILM D'HUILE ET TRIDIMENSIONNELLE DES DEFORMATIONS DES SOLIDES. L'EQUATION DE REYNOLDS ECRITE EN REGIME TRANSITOIRE POUR LE FILM D'HUILE ET LES EQUATIONS DE L'ELASTICITE POUR LES DEFORMATIONS DES SOLIDES, SONT RESOLUES PAR LA METHODE NUMERIQUE DES ELEMENTS FINIS. LA FORTE NON-LINEARITE DU PROBLEME, CREE PAR LA PRESSION HYDRODYNAMIQUE QUI APPARAIT ALORS EXPLICITEMENT DANS L'EQUATION DEFINISSANT L'EPAISSEUR DU FILM ET PAR LES PHENOMENES DE RUPTURE ET DE REFORMATION DU FILM D'HUILE, EST RESOLUE PAR LA METHODE DE NEWTON-RAPHSON. ENFIN, UN ALGORITHME DECRIVANT CORRECTEMENT LA CONSERVATION DU DEBIT A TRAVERS L'ECOULEMENT UTILISE CONJOINTEMENT AVEC L'ALGORITHME DE MURTY, NOUS A PERMIS DE MODELISER LES CONDITIONS D'ALIMENTATION DU CONTACT EN LUBRIFIANT. UNE ETUDE COMPARATIVE DE NOS RESULTATS ET CEUX DE GOENKA NOUS ASSURE DE LA FIABILITE ET DE LA PRECISION DU PROGRAMME DEVELOPPE. UNE OPTIMISATION DE FORME DE BIELLE REALISEE DANS LE CADRE D'UNE COLLABORATION AVEC LA SOCIETE RENAULT, MONTRE TOUT L'INTERET DE LA MODELISATION ELASTOHYDRODYNAMIQUE DANS L'ANALYSE DU COMPORTEMENT DES CONTACTS LUBRIFIES
Book Synopsis Elastohydrodynamics by : Ramsey Gohar
Download or read book Elastohydrodynamics written by Ramsey Gohar and published by . This book was released on 1988 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Multi-Level Methods in Lubrication by : C.H. Venner
Download or read book Multi-Level Methods in Lubrication written by C.H. Venner and published by Elsevier. This book was released on 2000-07-21 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient numerical solution of realistic and, therefore, complex equation systems occupies many researchers in many disciplines. For various reasons, but mainly in order to approximate reality, a very large number of unknowns are needed. Using classical techniques, the solution of such a system of equations would take too long, and so sometimes MultiLevel techniques are used to accelerate convergence. Over the last one and a half decades, the authors have studied the problem of Elastohydrodynamic Lubrication, governed by a complex integro-differential equation. Their work has resulted in a very efficient and stable solver. In this book they describe the different intermediate problems analyzed and solved, and how those ingredients finally come together in the EHL solver. A number of these intermediate problems, such as Hydrodynamic Lubrication and Dry Contact, are useful in their own right. In the Appendix the full codes of the Poisson problem, the Hydrodynamic Lubrication problem, the dry contact solver and the EHL solver are given. These codes are all written in 'C' language, based on the 'ANSI-C' version.
Book Synopsis Tribology for Energy Conservation by : L. Flamand
Download or read book Tribology for Energy Conservation written by L. Flamand and published by Elsevier. This book was released on 1998-07-23 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 24th Leeds-Lyon Symposium was held in London from 4th-6th September 1997, where it was hosted by the Imperial College of Science, Technology and Medicine.The meeting addressed the topic of "Tribology for Energy Conservation" and attracted a wide range of stimulating papers and speakers. Some 150 delegates from nineteen countries attended and about sixty papers were presented in fifteen sessions. These covered the topics of lubricants, wear, friction reduction, hydrodynamics, elastohydrodynamic lubrication, surface roughness, manufacturing, component life (including condition monitoring), and automotive aspects.
Book Synopsis Lubrication at the Frontier: The Role of the Interface and Surface Layers in the Thin Film and Boundary Regime by : M. Priest
Download or read book Lubrication at the Frontier: The Role of the Interface and Surface Layers in the Thin Film and Boundary Regime written by M. Priest and published by Elsevier. This book was released on 1999-07-01 with total page 911 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 25th Leeds-Lyon Symposium on Tribology was held at the Institut des Sciences Appliquées de Lyon, from 8-11th September, 1998. Its central theme was, "Lubrication at the frontier: the role of the interface and surface layers in the thin film and boundary regime". This topic was chosen because it represents an important evolution of the research field.The Symposium opened with a keynote address entitled "Role of surface-anchored polymer chains in polymer friction" which described the processes taking place at the interface between "solid" and "liquid". The keynote address was followed by two invited lectures. Firstly, "Fuel efficient engine oils, additive interactions, boundary friction and wear" presented the industrial point of view on lubricant formulation and engine testing and its evolution. The second lecture was entitled "For establishment of a new EHL theory" and stressed the need to extend the current EHL theory.Beginning in 1974, The Leeds-Lyon Symposia have now covered a wide range of topics. The essential aim each year is to select a topic of current interest to tribologists and to contribute to further the advance of knowledge in selected fields.
Book Synopsis Contact Dynamics in the Field of Elastohydrodynamic Lubrication by : Ysbrand Hans Wijnant
Download or read book Contact Dynamics in the Field of Elastohydrodynamic Lubrication written by Ysbrand Hans Wijnant and published by . This book was released on 1998 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rheology and Elastohydrodynamic Lubrication by : B.O. Jacobson
Download or read book Rheology and Elastohydrodynamic Lubrication written by B.O. Jacobson and published by Elsevier. This book was released on 1991-07-24 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a thorough overview on recent developments in lubricant rheology, elastohydrodynamic lubrication and the effects of surface roughness and particulate contamination in the lubricant on the overall behaviour of a heavily loaded lubricated contact. One of the aims of the book is to make clear to the reader that a Newtonian model for the lubricant behaviour does not have enough degrees of freedom to be able to describe the friction - traction behaviour of heavily loaded lubricated contacts or the oil film build-up and collapse under surface asperities for rough surfaces. The book contains quite a lot of experimental data of lubricants at high pressures, both solidification pressures, compressibilities and shear strength increase coefficients, which make it possible to estimate the friction and power loss in heavily loaded lubricated contacts for different pressures, temperatures, sliding speeds, and lubricant types. This is the first time that data of this type has been included in a textbook and it is hoped that the questions highlighted will serve to initiate and guide future research in this field.
Book Synopsis Lubricating Grease Manufacturing Technology by : Yu.L. Ishchuk
Download or read book Lubricating Grease Manufacturing Technology written by Yu.L. Ishchuk and published by New Age International. This book was released on 2005 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lubricating Grease (Or Grease, To Use A Short Name), Leaving Aside Synthetic Grease For The Moment, Is Arguably Amongst The Highest Value Added Petroleum Products. Lubricating Greases Play Very Crucial Role In The Performance Of Automobiles, Industrial Machinery And Appliances Which Almost Every One Of Us Use, Rely Upon Or Work With Everyday. Lubricating Greases Account For About 5% Of The Global Consumption Of The Lubricants, Which In Turn Account For About 1% Of All Petroleum Products. Thus, In Volume Terms, Lubricating Greases Constitute A Relatively Small, Specialized Industry. Nonetheless, The Importance Of Lubricating Greases Can Not Be Overemphasized. The World Would Quite Literally Grind To A Halt Without Lubricating Greases.There Are Not Many Books On Lubricating Greases. Even The Very Few Books That Are Available In English Language, Largely Encapsulate The Work And Knowledge Developed In North America And West Europe. Significant Scientific And Technological Advancements Were Achieved In The Erstwhile East Bloc Countries During The Second Half Of The 20Th Century. However, It Is Only Over The Last Two Decades That Those Outside The Erstwhile East Bloc Have Been Getting Glimpses Of The Prolific Work Done By Scientists And Technologists In That Part Of The World. This Book Endeavours To Further This Process In A Small Way.
Book Synopsis Tribology Data Handbook by : E. Richard Booser
Download or read book Tribology Data Handbook written by E. Richard Booser and published by CRC Press. This book was released on 1997-09-26 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook is a useful aid for anyone working to achieve more effective lubrication, better control of friction and wear, and a better understanding of the complex field of tribology. Developed in cooperation with the Society of Tribologists and Lubrication Engineers and containing contributions from 74 experts in the field, the Tribology Data Handbook covers properties of materials, lubricant viscosities, and design, friction and wear formulae. The broad scope of this handbook includes military, industrial and automotive lubricant specifications; evolving areas of friction and wear; performance and design considerations for machine elements, computer storage units, and metal working; and more. Important guidelines for the monitoring, maintenance, and failure assessment of lubrication in automotive, industrial, and aircraft equipment are also included. Current environmental and toxicological concerns complete this one-stop reference. With hundreds of figures, tables, and equations, as well as essential background information explaining the information presented, this is the only source you need to find virtually any tribology information.
Book Synopsis Lubricant Additives by : Leslie R. Rudnick
Download or read book Lubricant Additives written by Leslie R. Rudnick and published by CRC Press. This book was released on 2017-07-12 with total page 1432 pages. Available in PDF, EPUB and Kindle. Book excerpt: This indispensable book describes lubricant additives, their synthesis, chemistry, and mode of action. All important areas of application are covered, detailing which lubricants are needed for a particular application. Laboratory and field performance data for each application is provided and the design of cost-effective, environmentally friendly technologies is fully explored. This edition includes new chapters on chlorohydrocarbons, foaming chemistry and physics, antifoams for nonaqueous lubricants, hydrogenated styrene–diene viscosity modifiers, alkylated aromatics, and the impact of REACh and GHS on the lubricant industry.
Book Synopsis Lubricants and Special Fluids by : V. Stepina
Download or read book Lubricants and Special Fluids written by V. Stepina and published by Elsevier. This book was released on 1992-12-04 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: The constitution, properties, production and applications of lubricants and related fluids of all states of aggregation are reviewed in this volume. Special attention is devoted to synthetic lubricants and to additives for lubricants. Standards of quality are listed, together with systems of classification and the most important specifications and methods of testing the properties of lubricants and their performance in service. Future trends in lubricants are also discussed. Non-conventional lubricants and additives are examined in detail. The relationship between constitution and properties of lubricants, e.g., the viscosity -temperature -pressure relationship, the behaviour in ageing, the biodegradability, synergisms and antagonisms in the blends of lubricants, of additives and lubricant-additive are analyzed. Guidelines for the selection of lubricants and fluids in the design, service and maintenance of machines and machine parts are also given. The work will be of interest to all those involved in the research and development of petrochemical and machinery industries, as well as lecturers and students specializing in this field.
