........ published in NEWSLETTER # 46
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........ published in NEWSLETTER # 46
FUNDAMENTALS OF FRICTION: MACROSCOPIC AND MICROSCOPIC PROCESSES
by Dr. I. Singer, Naval Research Laboratory, Washington/DC (U.S.A.)
In August 1991, leading experts in two hitherto separate fields met in the Harz Mountains of Germany to grapple with the meaning of friction. Classical tribologists presented models of macroscopic friction behavior and concepts of surface contact, adhesion, deformation and fracture that have evolved over the past half century. Surface scientists filled in gaps in understanding with recent findings of surface-mechanical behavior (including friction) at the microscopic scale. The latter group included theorists, molecular dynamicists, and developers of surface proximity probes (surface force apparatus, single asperity probes and atomic force/spanning tunneling microscopy) who now have the tools to carry out fundamental studies of sliding interfaces at the atomic level.
Unlike previous tribology conference proceedings, this book (NATO ASI SERIES E220) is devoted to a single topic: FRICTION. It begins with the foundations (and problems) of contact mechanics and friction, laid out in tutorial elegance by many of the developers (Tabor, Johnson, Greenwood, ...). Next, deformation and fracture behavior of materials in frictional contact is presented. Then on to interfacial processes, from macroscopic properties to microscopic models. Lubrication by solids, tribochemical films and fluids (bulk and molecular films) is introduced next, from classical flow properties to the physical and chemical reorganization of atoms and molecules under normal and shear stresses. The physics and chemistry of interfaces preface an array of visually exciting molecular dynamic simulations of solids and liquids in sliding contact. Friction at the atomic level and related AFM/STM studies round out the microscopic aspects of friction. The last topical section provides a modern engineering perspective of friction: how friction affects machines and how it is affected by machine interactions (vibrations and other instabilities). Edited discussions follow most of the chapters. Finally, the Appendix provides an Epilogue detailing issues for future friction research, replete with commentaries transcribed from meeting recordings, a summary of the principal formulae in contact mechanics (Johnson), and an extensively cross-referenced Subject Index.
In addition to being comprehensive, the book offers a synthesis of fundamental issues of friction in an erudite and pleasant manner. It is filled with historical commentary and sketches pertaining to discoveries in tribology. Readers will see how the classical and more modern surface disciplines are being integrated. Tribologists will gain new insights into friction processes, while proximity-probe scientist will recognize the challenges (and rewards) of solving tribological problems.
Reference books: E56, E57, E220