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 Thermal Effects on Traction in Elastohydrodynamic Lubrication of Point Contacts by Use of Three dimensional Finite Element Models written by James Arthur Muenzenberger and published by . This book was released on 1985 with total page 310 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 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 Thermal Elastohydrodynamic Lubrication of Line Contacts written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical solution to the problem of thermal elastohydrodynamic lubrication of line contacts was obtained by using a finite difference formulation. The solution procedure consists of simultaneous solution of the thermal Reynolds equation, the elasticity equation, and the energy equation subject to appropriate boundary conditions. Pressure distribution, film shape, and temperature distribution were obtained for fully flooded conjunctions, a paraffinic lubricant, and various dimensionless speed parameters while the dimensionless load and materials parameters were held constant. Reduction in the minimum film thickness due to thermal effects (as a ratio of thermal to isothermal minimum film thickness) is given by a simple formula as a function of the thermal loading parameter Q: H(min)/H(min, I) = 10/10+ Q(0.4). Plots of pressure distribution, film shape, temperature distribution, and flow are shown for some representative cases. Ghosh, M. K. and Hamrock, B. J. Glenn Research Center NASA-TM-83424, E-1617, NAS 1.15:83424 RTOP 505-33-1B...
Download or read book The Elastohydrodynamic Lubration of Elliptical Contacts with Thermal Effects written by Alan Gary Blahey and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transient Processes in Tribology written by A A Lubrecht and published by Elsevier. This book was released on 2004-06-04 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers contained within this volume focus on the transient aspects of the preocesses in tribology highlighting the differences obtained with stationery conditions, be they experimental analytical or numerical.
Download or read book Friction in Mixed and Elastohydrodynamic Lubricated Contacts Including Thermal Effects written by Qiang Liu and published by . This book was released on 2002 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Applied Mechanics Reviews written by and published by . This book was released on 1974 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 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 Microasperity Model for Elastohydrodynamic Lubrication of a Spinning Ball on a Flat Surface written by Charles W. Allen and published by . This book was released on 1970 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A microasperity elastohydrodynamic (EHD) model was developed for a ball spinning without rolling on a f l a t surface. The theory was developed by using a sinusoidal surface model in conjunction with existing dry- contact deformation theory and point-contact elastohydrodynamic theory for the microasperities. The computed torques based on this model were compared with experimental torques using the NASA spinning torque apparatus. Fair agreement was obtained between theoretical and experimental results below 300 000 psi maximum Hertz stress. Based on the model presented herein microasperity EHD lubrication does not appear to be a primary force in maintaining separation between the opposing surfaces.
Download or read book Thermal Elastohydrodynamic Lubrication of Rolling sliding Contacts written by Farshid Sadeghi and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete numerical solution of thermal compressible elastohydrodynamic lubrication of rolling/sliding contacts has been obtained. The Newton-Raphson technique is used to solve the simultaneous system of Reynolds and elasticity equations. The control volume finite element modeling was employed to solve the energy equation and its boundary conditions. The effects of various loads, speeds, and slip conditions on the lubricant temperature, film thickness, and friction force have been investigated. The results indicate that the temperature effects are significant and cannot be neglected.
Download or read book Vehicle Tribology written by M. Godet and published by Elsevier. This book was released on 1991-07-03 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vehicle Tribology was chosen as the topic for the 17th Leeds-Lyon Symposium, as it was decided to be a timely opportunity to bring together experts of many disciplines connected with problems of emissions, particulates and energy efficiency associated with the automobile engine. The volume contains 55 papers divided into eighteen sessions.
