Rheology and Elastohydrodynamic Lubrication
Rheology and Elastohydrodynamic Lubrication

Author: B.O. Jacobson

Publisher: Elsevier

Published: 1991-07-24

Total Pages: 399

ISBN-13: 0080875831

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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.

Elasto-Hydrodynamic Lubrication
Elasto-Hydrodynamic Lubrication

Author: D. Dowson

Publisher: Elsevier

Published: 2014-07-18

Total Pages: 254

ISBN-13: 1483181898

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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.

Finite Element Modeling of Elastohydrodynamic Lubrication Problems
Finite Element Modeling of Elastohydrodynamic Lubrication Problems

Author: Wassim Habchi

Publisher: John Wiley & Sons

Published: 2018-03-21

Total Pages: 464

ISBN-13: 1119225140

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Covers the latest developments in modeling elastohydrodynamic lubrication (EHL) problems using the finite element method (FEM) This comprehensive guide introduces readers to a powerful technology being used today in the modeling of elastohydrodynamic lubrication (EHL) problems. It provides a general framework based on the finite element method (FEM) for dealing with multi-physical problems of complex nature (such as the EHL problem) and is accompanied by a website hosting a user-friendly FEM software for the treatment of EHL problems, based on the methodology described in the book. Finite Element Modeling of Elastohydrodynamic Lubrication Problems begins with an introduction to both the EHL and FEM fields. It then covers Standard FEM modeling of EHL problems, before going over more advanced techniques that employ model order reduction to allow significant savings in computational overhead. Finally, the book looks at applications that show how the developed modeling framework could be used to accurately predict the performance of EHL contacts in terms of lubricant film thickness, pressure build-up and friction coefficients under different configurations. Finite Element Modeling of Elastohydrodynamic Lubrication Problems offers in-depth chapter coverage of Elastohydrodynamic Lubrication and its FEM Modeling, under Isothermal Newtonian and Generalized-Newtonian conditions with the inclusion of Thermal Effects; Standard FEM Modeling; Advanced FEM Modeling, including Model Order Reduction techniques; and Applications, including Pressure, Film Thickness and Friction Predictions, and Coated EHL. This book: Comprehensively covers the latest technology in modeling EHL problems Focuses on the FEM modeling of EHL problems Incorporates advanced techniques based on model order reduction Covers applications of the method to complex EHL problems Accompanied by a website hosting a user-friendly FEM-based EHL software Finite Element Modeling of Elastohydrodynamic Lubrication Problems is an ideal book for researchers and graduate students in the field of Tribology.

Elastohydrodynamic Lubrication for Line and Point Contacts
Elastohydrodynamic Lubrication for Line and Point Contacts

Author: Ilya I. Kudish

Publisher: CRC Press

Published: 2013-06-17

Total Pages: 714

ISBN-13: 1466583894

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Elastohydrodynamic Lubrication for Line and Point Contacts: Asymptotic and Numerical Approaches describes a coherent asymptotic approach to the analysis of lubrication problems for heavily loaded line and point contacts. This approach leads to unified asymptotic equations for line and point contacts as well as stable numerical algorithms for the solution of these elastohydrodynamic lubrication (EHL) problems. A Unique Approach to Analyzing Lubrication Problems for Heavily Loaded Line and Point Contacts The book presents a robust combination of asymptotic and numerical techniques to solve EHL problems for lightly and heavily loaded line and point contacts. It also proposes a reasonably simple and naturally based regularization approach that produces stable solutions in heavily loaded EHL contacts. The book offers a clear understanding of the processes taking place in heavily loaded line and point EHL contacts as well as of the proper solution structure for EHL problems. It outlines concrete ways to determine important design parameters such as lubrication film thickness and frictional stresses and forces. The book establishes a close link between EHL problems for heavily loaded point and line contacts. Fine Tune Your Methods for Solving Elastohydrodynamic Lubrication Problems In most cases, the equations in the book are derived from first principles. The author describes each of the asymptotic and numerical methods in detail, making it easier for readers to apply them to various problems. The problem solutions are presented in the form of simple analytical formulas, graphs, and tables. Almost all the chapters include exercises that highlight key points and skills. Suitable for engineering and applied mathematics students, this is also a unique resource for researchers and practitioners who want to fine tune their solution methods and design better numerical methods to tackle elastohydrodynamic lubrication problems.

Fundamentals of Fluid Film Lubrication
Fundamentals of Fluid Film Lubrication

Author: Bernard J. Hamrock

Publisher: CRC Press

Published: 2004-03-15

Total Pages: 747

ISBN-13: 1135537755

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Specifically focusing on fluid film, hydrodynamic, and elastohydrodynamic lubrication, this edition studies the most important principles of fluid film lubrication for the correct design of bearings, gears, and rolling operations, and for the prevention of friction and wear in engineering designs. It explains various theories, procedures, and equations for improved solutions to machining challenges. Providing more than 1120 display equations and an introductory section in each chapter, Fundamentals of Fluid Film Lubrication, Second Edition facilitates the analysis of any machine element that uses fluid film lubrication and strengthens understanding of critical design concepts.

High Pressure Rheology for Quantitative Elastohydrodynamics
High Pressure Rheology for Quantitative Elastohydrodynamics

Author: Scott S. Bair

Publisher: Elsevier

Published: 2007-03-06

Total Pages: 262

ISBN-13: 0080475302

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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.

Numerical Calculation of Elastohydrodynamic Lubrication
Numerical Calculation of Elastohydrodynamic Lubrication

Author: Ping Huang

Publisher: John Wiley & Sons

Published: 2015-05-05

Total Pages: 371

ISBN-13: 1118920988

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The book not only offers scientists and engineers a clear inter-disciplinary introduction and orientation to all major EHL problems and their solutions but, most importantly, it also provides numerical programs on specific application in engineering. • A one-stop reference providing equations and their solutions to all major elastohydrodynamic lubrication (EHL) problems, plus numerical programs on specific applications in engineering • offers engineers and scientists a clear inter-disciplinary introduction and a concise program for practical engineering applications to most important EHL problems and their solutions • brings together a number of case studies in one text, each being solved using solution methods which share common features and methods

Microasperity Model for Elastohydrodynamic Lubrication of a Spinning Ball on a Flat Surface
Microasperity Model for Elastohydrodynamic Lubrication of a Spinning Ball on a Flat Surface

Author: Charles W. Allen

Publisher:

Published: 1970

Total Pages: 28

ISBN-13:

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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.

Multi-Level Methods in Lubrication
Multi-Level Methods in Lubrication

Author: C.H. Venner

Publisher: Elsevier

Published: 2000-07-21

Total Pages: 401

ISBN-13: 008053709X

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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.