Recent Developments In Wear Prevention, Friction And Lubrication

Recent Developments in Wear Prevention, Friction and Lubrication 2010 Editor George K. Nikas Research Associate, Tribology Group, Department of Mechanical Engineering Imperial College London, England Research Signpost, T.C. 37/661 (2), Fort P.O., Trivandrum-695 023 Kerala, India Published by Research Signpost 2010; Rights Reserved. Research Signpost T.C. 37/661(2), Fort P.O., Trivandrum-695 023, Kerala, India Editor George K. Nikas Managing Editor S. G. Pandalai Publication Manager A. Gayathri Research Signpost and the Editor assume no responsibility for the opinions and statements advanced by contributors ISBN: 978-81-308-0377-7 Preface The knowledge gained from studies on friction, lubrication and wear of contacting surfaces (three terms collectively known as tribology) is met in every branch of engineering. Tribology is a multidisciplinary science involving mechanical engineering, materials and lubrication science, physics, and chemistry. Tribological principles are normally used in characterising the mechanical behaviour of surfaces in relative motion. This involves a very large number of applications ranging in size from the nano-scale (molecular and nano-tribology) to the macro-scale (bearings, tyres, rock drills, etc.). Friction, lubrication and wear are inherent characteristics of the physical world regardless of scale. From the intermolecular forces holding a gecko’s feet on a vertical wall to the tractive forces at the contact patches of aircraft tyres; from the lubricating film at the rolling contact of a ball on a rolling-bearing raceway to the soft magma supporting tectonic plates of the earth; from the erosion of human teeth from toothpaste particles to the particle erosion of turbine blades; such diverse phenomena can be described and analysed in tribological terms. Every type of machinery includes parts affected by friction, lubrication, and wear. Therefore, the role of tribology in machine operation and reliability is a major one. As a result, the effect of tribology to modern world economy, even though unknown to the majority of the population, is crucial. Although the effect on the economy has been quantified and found to represent a significant proportion of the gross domestic product of economically advanced countries, the true effect pertaining to the development of technologically advanced products is far greater and not immediately obvious. There are several good books on tribology covering the fundamental theory and various applications. However, technology is progressing at an immense pace and engineering norms are quickly outdated. This book is based on the collective experience of some of the world’s top experts on friction, lubrication and wear. It presents recent developments in the field of tribology and its contributors are equally divided among theoreticians and experimentalists. Furthermore, some chapters contain new theory and results, which, in the editor’s experience, is at the frontier of research. The topics covered in the eight chapters of this book include thin-film lubrication from a theoretical perspective, a critical review of rolling-bearing lifeprediction models, a review of Laser Surface Texturing, a proposed unification of friction and wear via thermodynamic principles, the role of tribofilms in concentrated contacts from a materials-science perspective, transient phenomena in elastohydrodynamic lubrication from an experimental point of view, a theoretical assessment of the Stribeck curve in lubricated contacts, and, finally, a thorough presentation of modelling and adhesion problems of microelectromechanical systems (MEMS) and miniature devices. Chapter 1 by Professor Szeri is an in-depth discussion of the “thin-film” lubrication theory referring to hydrodynamic and elastohydrodynamic lubrication. Professor Szeri (University of Delaware, USA),