Download or read book A Study of Thermal and Rheological Effects in Elastohydrodynamic Contacts written by Hun June Kim and published by . This book was released on 1999 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rheological Effects on Friction in Elastohydrodynamic Lubrication written by Edward G. Trachman and published by . This book was released on 1973 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical and experimental investigation is presented of the friction in a rolling and sliding elastohydrodynamic lubricated contact. The rheological behavior of the lubricant is described in terms of two viscoelastic models. These models represent the separate effects of non-Newtonian behavior and the transient response of the fluid. A unified description of the non-Newtonian shear rate dependence of the viscosity is presented as a new hyperbolic liquid model. The transient response of viscosity, following the rapid pressure rise encountered in the contact, is described by a compressional viscoelastic model of the volume response of a liquid to an applied pressure step. The resulting momentum and energy equations are solved by an iterative numerical technique, and a friction coefficient is calculated. The experimental study was performed, with two synthetic paraffinic lubricants, to verify the friction predictions of the analysis. The values of friction coefficient from theory and experiment are in close agreement.
Download or read book High Pressure Rheology for Quantitative Elastohydrodynamics written by Scott S. Bair and published by Elsevier. This book was released on 2007-03-06 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational elastohydrodynamics, a part of tribology, has existed happily enough for about fifty years without the use of accurate models for the rheology of the liquids used as lubricants. For low molecular weight liquids, such as low viscosity mineral oils, it has been possible to calculate, with precision, the film thickness in a concentrated contact provided that the pressure and temperature are relatively low, even when the pressure variation of viscosity is not accurately modelled in detail. Other successes have been more qualitative in nature, using effective properties which come from the fitting of parameters used in calculations to experimental measurements of the contact behaviour, friction or film thickness. High Pressure Rheology for Quantitative Elastohydrodynamics is intended to provide a sufficiently accurate framework for the rheology of liquids at elevated pressure that it may be possible for computational elastohydrodynamics to discover the relationships between the behaviour of a lubricated concentrated contact and the measurable properties of the liquid lubricant. The required high-pressure measurement techniques are revealed in detail and data are presented for chemically well-defined liquids that may be used as quantitative reference materials.* Presents the property relations required for a quantitative calculation of the tribological behaviour of lubricated concentrated contacts.* Details of high-pressure experimental techniques.* Complete description of the pressure and temperature dependence of viscosity for high pressures.* Some little-known limitations on EHL modelling.
Download or read book Thermal and Thermoelastic Effects in Rolling Sliding Contacts written by T. A. Dow and published by . This book was released on 1984 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes a theoretical and experimental study of thermal and thermomechanical effects on frictionally and electrically heated rolling/sliding surfaces. A 2-D thermal analysis is used to predict the temperature distribution through the thickness of the lubricant film in an elastohydrodynamic (EHD) contact. The relative magnitude of shear and compressive heating as well as the losses due to conduction and convection are compared for pure rolling and slip conditions. Originator-supplied key words include: Tribology, Elastohydrodynamic lubrication, Electrical brush, Wear, Thermal effects, Thermomechanical effects, Lubricant rheology, and High current density monolithic electrical brushes.
Download or read book Thinning Films and Tribological Interfaces written by D. Dowson and published by Elsevier. This book was released on 2000-09-01 with total page 857 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of fully peer-reviewed papers were presented at the 26th Leeds-Lyon Tribology Symposium which was held in Leeds, UK, 14-17 September, 1999. The Leeds-Lyon Symposia on Tribology were launched in 1974, and the large number of references to original work published in the Proceedings over many years confirms the quality of the published papers. It also indicates that the volumes have served their purpose and become a recognised feature of the tribological literature. This year's title is 'Thinning Films and Tribological Interfaces', and the papers cover practical applications of tribological solutions in a wide range of situations. The evolution of a full peer review process has been evident for a number of years. An important feature of the Leeds-Lyon Symposia is the presentation of current research findings. This remains an essential feature of the meetings, but for the 26th Symposium authors were invited to submit their papers for review a few weeks in advance of the Symposium. This provided an opportunity to discuss recommendations for modifications with the authors.
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.
Download or read book Temperature Estimations in Elastohydrodynamic Contacts of Tribochemical Processes A Comparative Study Using Modeling by Mechanical Wear Process Mechanisms and Chemical Kinetic Modeling written by Raj Shah and published by . This book was released on 2018 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This article deals with the subject of thermal Elastohydrodynamic Lubrication (EHL) and how temperatures can be estimated in elastohydrodynamic contacts. An attempt has been made to explain why it is essential to study temperature effects in EHL, and the process of thermal EHL modeling has been elucidated by solving a simple thermal EHL model. The temperatures obtained from this simple model seem to agree well with published literature. A comprehensive literature review of the numerous studies in thermal EHL modeling with particular emphasis on recent developments in this field has been presented. The second part of this comprehensive study includes a comparison between temperatures in the EHL contact as obtained by mechanical models and a chemical model, which will be discussed. The contact temperature required to consume the lubricant by oxidation during a microsample wear test is determined by a chemical kinetic model. Finally, the discrepancy between the temperatures obtained by both the chemical kinetic model and the mechanical model is discussed, presenting various plausible explanations to account for the temperature difference.
Download or read book Elastohydrodynamics 96 written by C. Taylor and published by Elsevier. This book was released on 1997-07-22 with total page 773 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume represents the latest issue of a collection of Proceedings each dealing with a different topic in Tribology. This volume contains the Proceedings from the 23rd Leeds-Lyon Symposium which addressed the topic of Elastohydrodynamics and was attended by many international experts in the field.The Keynote Address was presented by Professor Stathis Ioannides on the subject of "Tribology in Rolling Element Bearings" and was followed by fifteen other sessions covering a wide variety of general areas from "Experimental" to "Lubricant Properties". In addition, nine other invited technical papers were presented to support the sessions.
Download or read book Thermal and Non Newtonian Effects in Elastohydrodynamic Lubrication of Rolling sliding Contacts written by Moosa Zand and published by . This book was released on 1990 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Effects in Elastohydrodynamic Spinning Circular Contacts written by Thomas Doki-Thonon and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to the study of spinning contacts located in bearing between the roller-end and the ring flange. The main direction of the lubricant flow may change when the contact is subjected to skew. This complex kinematics influences the contact behaviour. A dual experimental-numerical approach is proposed to study this problem. The Tribogyr test-rig allows the experimentation of the contact at the 1:1 scale. A film thickness measurement method, based on white light interferometry, was developed on Tribogyr. This method allows the measurement of film thickness between 0 and 800 nm with an accuracy of a few nanometres. The measurement of forces in the main flow direction shows similarities with classical rolling-sliding contacts. However, the friction coefficient is globally lower as soon as spin is involved. Transverse forces are of the same order of magnitude as the longitudinal forces. This is due to transverse shearing caused by the spin. A numerical model has been developed for the simulation of these spinning contacts. The finite element model, which is based on a fully-coupled solving strategy, takes into account the temperature calculation and the lubricant non-Newtonian rheology. Its validation with Tribogyr experimental results in terms of film thickness and friction has been conducted. Spin and skew effects induce high shear-thinning and thermal-thinning of the lubricant that lead to a decrease of the film thickness. Under high spinning condition, the lubricant exiting the contact may be re-injected to the contact inlet. Consequently, the heat transfers between the lubricant and the solids in contact are modified. In contact subjected to high skew, a local increase (dimple) of the film thickness may occur. Important skew may also lead to starvation conditions. Many experimental campaigns, coupled with an intensive use of the numerical model, allowed to understand the physical phenomena involved as well as to predict the efficiency, in terms of power losses, of the spinning contacts.
Download or read book Modeling and Analysis of Elastohydrodynamic Lubrication of Line Contacts Considering Thermal and Non Newtonian Effects written by Hsing-Sen Hsiao and published by . This book was released on 1992 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Elastohydrodynamic Lubrication of Line Contacts written by and published by . This book was released on 1983 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CRC Handbook of Lubrication written by Robert W. Bruce and published by CRC Press. This book was released on 2010-12-12 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook covers the general area of lubrication and tribology in all its facets: friction, wear lubricants (liquid, solid, and gas), greases, lubrication principles, applications to various mechanisms, design principles of devices incorporating lubrication, maintenance, lubrication scheduling, and standardized tests; as well as environmental problems and conservation. The information contained in these two volumes will aid in achieving effective lubrication for control of friction and wear, and is another step to improve understanding of the complex factors involved in tribology. Both metric and English units are provided throughout both volumes.
Download or read book Rheological Effects in Elastohydrodynamic Lubrication written by Hannu Tapani Iivonen and published by . This book was released on 1988 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Lubrication and Tribology written by Robert W. Bruce and published by CRC Press. This book was released on 2012-07-06 with total page 1173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the best-selling first edition, the growing price and environmental cost of energy have increased the significance of tribology. Handbook of Lubrication and Tribology, Volume II: Theory and Design, Second Edition demonstrates how the principles of tribology can address cost savings, energy conservation, and environmental protection. This second edition provides a thorough treatment of established knowledge and practices, along with detailed references for further study. Written by the foremost experts in the field, the book is divided into four sections. The first reviews the basic principles of tribology, wear mechanisms, and modes of lubrication. The second section covers the full range of lubricants/coolants, including mineral oil, synthetic fluids, and water-based fluids. In the third section, the contributors describe many wear- and friction-reducing materials and treatments, which are currently the fastest growing areas of tribology, with announcements of new coatings, better performance, and new vendors being made every month. The final section presents components, equipment, and designs commonly found in tribological systems. It also examines specific industrial areas and their processes. Sponsored by the Society of Tribologists and Lubrication Engineers, this handbook incorporates up-to-date, peer-reviewed information for tackling tribological problems and improving lubricants and tribological systems. The book shows how the proper use of generally accepted tribological practices can save money, conserve energy, and protect the environment.
Download or read book Investigation of Some Temperature related Phenomena in Elastohydrodynamic Contacts Including Surface Roughness Effects written by Holavanahally Seshachar Nagaraj and published by . This book was released on 1977 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interface Dynamics written by D. Berthe and published by Elsevier. This book was released on 1988-09-01 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many tribologists are today not only explicitly concerned with interface action but also with interface composition. This proceedings volume presents a timely review on topics ranging from interface dynamics to interface elimination, covering all factors such as contact stress fields, interface rheology, and boundary slip, that control the passage from formation to elimination. The volume contains 45 papers divided into 13 sessions, that were presented at the symposium.
