Insightful working knowledge of friction, lubrication, and wear in machines
Applications of tribology are widespread in industries ranging from aerospace, marine and automotive to power, process, petrochemical and construction. With world-renowned expert co-authors from academia and industry, Applied Tribology: Lubrication and Bearing Design, 3rd Edition provides a balance of application and theory with numerous illustrative examples.
The book provides clear and up-to-date presentation of working principles of lubrication, friction and wear in vital mechanical components, such as bearings, seals and gears. The third edition has expanded coverage of friction and wear and contact mechanics with updated topics based on new developments in the field.
- Includes practical applications, homework problems and state-of-the-art references.
- Provides presentation of design procedure.
- Supplies clear and up-to-date information based on the authors’ widely referenced books and over 500 archival papers in this field.
Applied Tribology: Lubrication and Bearing Design, 3rd Edition provides a valuable and authoritative resource for mechanical engineering professionals working in a wide range of industries with machinery including turbines, compressors, motors, electrical appliances and electronic components. Senior and graduate students in mechanical engineering will also find it a useful text and reference.
About the Author
Dr. Michael M. Khonsari holds the Dow Chemical Endowed Chair and Professor of Mechanical Engineering at Louisiana State University (LSU), where he directs the Center for Rotating Machinery. Prior to joining LSU, he served as a faculty member at The Ohio State University, University of Pittsburgh, and Southern Illinois University, and was a research Faculty Fellow at NASA Lewis (now Glenn) Research Center, Wright-Patterson Air Force laboratories, and the U.S. Department of Energy. He is holder of several US patents, has authored over 270 archival papers, 50 book chapters and special publications, and three books on tribology, fatigue, and rotor dynamics. Professor Khonsari is the recipient of ASME Mayo Hersey, ASME Burt Newkirk Awards, and serves as the Editor-in-Chief of ASME Journal of Tribology. He is a fellow of the American Society of Mechanical Engineers (ASME), Society of Tribologist and Lubrication Engineers (STLE), and the American Association for the Advancement of Science (AAAS).
Dr. E. Richard Booser has been active in the field of tribology and lubrication for 70 years. He was employed by the General Electric Co. for 39 years in development work on bearings and lubricants for steam and gas turbines, electric motors and generators, aerospace and nuclear plant equipment, and a variety of related electrical products. He was the editor of three volumes of the Tribology Handbook series and a co-author of the 1957 book on Bearing Design and Application. He served as the President of the Society of Tribologists and Lubrication Engineers (STLE) in 1956 and has received the STLE National Award.
Read an Excerpt
1: Tribology-Friction, Wear, and LubricationTriboiogy is a relatively new term derived from the Greek word tribos for "rubbing:" It is now universally applied to the emerging science of friction, wear, and lubrication involved at moving contacts. In its broad scope, it involves mechanical, chemical, and material technology. Usual tasks in tribology are reduction of friction and wear to conserve energy, enabling faster and more precise motions, increased productivity, and reduced maintenance.
Tribology was formally identified as an important and unified technical field in a report issued by a committee of the British Ministry of State for Education and Science chaired by Peter Jost (1966). The report concluded that huge savings would be possible in the United Kingdom by fully utilizing improved design and lubrication procedures. The unified approach to this field filled an existing void, and the American Society of Mechanical Engineers (ASME) then adopted the term for its Tribology Division in 1983 and the American Society of Lubrication Engineers revised its name to the Society of Tribologists and Lubrication Engineers in 1985.
Fundamental interest in tribology now exists for lubricant formulation, industrial operations, aerospace and transportation equipment, material shaping and machining, computers and electronic devices, power generation, and almost all phases of life where motion is encountered. This text focuses primarily on tribology of bearings and a number of related applications. Fundamentals are applied in such a way as to allow application of the principles of tribology to a variety of other machine elements.
1.1 History of Tribology
Many of the advances in tribology and bearing technology evolved over years, decades, or even centuries to meet the needs of new machinery. The Industrial Revolution, with its increase in rotational speeds beyond those of the windmill and cart axle, brought full hydrodynamic lubrication into normal use. Theory and technical understanding commonly followed actual machinery applications. In many cases, this understanding of technical details played a vital role in continued improvements in bearing design, lubricants, and surface treatments for industrial machinery, aerospace units, transportation equipment, magnetic storage, and microelectromechanical devices.
A few historical stepping stones related to the primary subjects covered in this textbook will now be reviewed. Many of these events are covered in more detail in the references presented at the end of this chapter.
Notebooks of the famed engineer and artist Leonardo da Vinci revealed his postulation in 1508 of the concept of a characteristic coefficient of friction as the ratio of friction force to normal load. The French physicist Guillaume Amontons (1699) again established the significance of a coefficient of friction, which was independent of the apparent area of contact. The French physicist C. A. Coulomb (1785) further distinguished between static friction and kinetic friction, which was independent of velocity. Mechanisms for reduction of friction and wear with soft coatings and adherent molecular and lubricant surface layers were elucidated by Bowden and Tabor (1950).
This subject has proven to be quite complex, and generalizations are still elusive. Hundreds of empirical equations have been generated for specific materials and conditions. The most useful one appears to be that of Archard (1953), which enables a generalized dimensionless wear coefficients k = W H/LN to relate wear volume W to sliding distance L, normal load N, and indentation hardness H of the wearing material (see Chapter 4).
For many centuries wood, stone, leather, iron, and copper were common bearing materials. Almost all engineering materials have now been employed in the continuing search for the best bearing material (see Chapter 4). In an early consideration of improved materials, Robert Hooke (1684) suggested steel shafts and bell-metal bushes as preferable to wood shod with iron for wheel bearings (Bhushan, 1999). High-lead and high-tin alloys patented in the United States in 1839 by Isaac Babbitt are unsurpassed for a wide range of industrial, automotive, and railway applications. An early German study of railway journal bearings by F. A. von Pauli (1849) established a composition similar to that of Babbitt (91 % tin, 6% copper, and 3% zinc) as the best of 13 bearing metals (Cameron, 1966).
Suitably hard, fatigue-resistant rolling element bearing materials were achieved with modification of tool steel in Europe about 1900. This led to the development of AISI 52100 steel and its derivatives, which have since been used for all types of commercial and automotive rolling bearings.
Porous metal bearings were introduced in the 1920s. Plastics and composites involving polymers compounded with a wide variety of solid filler materials have found wide use, gaining their greatest impetus with the invention of nylon and polytetrafluoroethylene (PTFE) during World War II. The search continues, with ceramics among the materials being developed for high-temperature capability in aircraft engines and for high-speed rolling element bearings.
Tallow was used to lubricate chariot wheels before 1400 B.c. Although vegetable oils and greases were used later, significant advances in the development of lubricants occurred only after the founding of the modern petroleum industry with the opening of the Drake well in Titusville, Pennsylvania, in 1859. Lubricant production reached 9500 m3/yr (2,500,000 gal/yr) in the following 20 years; worldwide production now exceeds 1000 times that volume at 3 billion gal/yr. Petroleum lubricants still constitute well over 95% of total oil and grease production volume.
Polymerized olefins were the first synthetic oils to be produced. This occurred in 1929 in an effort to improve on properties of petroleum oils. Interest in ester lubricants dates from 1937 in Germany, and their production and use expanded rapidly during and following World War II to meet military needs and for use in the newly developed jet aircraft engines. A broad range of other synthetic lubricants came into production during that same period for wide-temperature use, fire resistance, and other uses geared to a range of unique properties (see Chapter 2). Current production of synthetics approaches 100 million gal/yr, with nearly half being polyalphaolefin synthetic hydrocarbons.
Development of chemical additives to upgrade the properties and extend the lives of lubricating oils began about 1920. Commercial use has proceeded since about 1930 in step with increasing demands in automobiles, jet engines and other aerospace units, and high-speed and high-pressure hydraulic equipment (see Chapter 2).
Air, water, gasoline, solvents, refrigerant gases, air, and various fluids being processed in individual machines began to find use as "lubricants" on a broadening scale in fluid-film bearings in the second half of the 1900s as improved designs and mating materials were developed on a customized basis.
The first studies of a shaft and bearing running under full hydrodynamic conditions were performed by F. A. von Pauli in 1849 and by G. A. Him in 1854 (see Cameron, 1966). In 1883 the celebrated Russian Nikilay Petroff concluded that friction in fluidfilm bearings was a hydrodynamic phenomenon. His resulting power loss equation has continued to provide a foundation in this field...
Table of Contents
Series Preface ix
Part I General Considerations 1
1 Tribology – Friction, Wear, and Lubrication 3
2 Lubricants and Lubrication 23
3 Surface Texture and Interactions 63
4 Bearing Materials 89
Part II Fluid-Film Bearings 113
5 Fundamentals of Viscous Flow 115
6 Reynolds Equation and Applications 143
7 Thrust Bearings 173
8 Journal Bearings 201
9 Squeeze-Film Bearings 263
10 Hydrostatic Bearings 299
11 Gas Bearings 321
12 Dry and Starved Bearings 361
Part III Rolling Element Bearings 389
13 Selecting Bearing Type and Size 391
14 Principles and Operating Limits 425
15 Friction, Wear and Lubrication 459
Part IV Seals and Monitoring
16 Seal Fundamentals 487
17 Condition Monitoring and Failure Analysis 531
Appendix A Unit Conversion Factors 551
Appendix B Viscosity Conversions 555