Table Of ContentS E C O N D E D I T I O N
Friction Science
and Technology
FROM CONCEPTS
to APPLICATIONS
CCRRCC__55440044XX__FFMM..iinndddd ii 99//1100//22000088 33::1100::4433 PPMM
CCRRCC__55440044XX__FFMM..iinndddd iiii 99//1100//22000088 33::1100::4444 PPMM
S E C O N D E D I T I O N
Friction Science
and Technology
FROM CONCEPTS
to APPLICATIONS
Peter J. Blau
Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
CCRRCC__55440044XX__FFMM..iinndddd iiiiii 99//1100//22000088 33::1100::4444 PPMM
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2009 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Printed in the United States of America on acid-free paper
10 9 8 7 6 5 4 3 2 1
International Standard Book Number-13: 978-1-4200-5404-0 (Hardcover)
This book contains information obtained from authentic and highly regarded sources. Reasonable
efforts have been made to publish reliable data and information, but the author and publisher can-
not assume responsibility for the validity of all materials or the consequences of their use. The
authors and publishers have attempted to trace the copyright holders of all material reproduced
in this publication and apologize to copyright holders if permission to publish in this form has not
been obtained. If any copyright material has not been acknowledged please write and let us know so
we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced,
transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or
hereafter invented, including photocopying, microfilming, and recording, or in any information
storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copy-
right.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222
Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that pro-
vides licenses and registration for a variety of users. For organizations that have been granted a
photocopy license by the CCC, a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and
are used only for identification and explanation without intent to infringe.
Library of Congress Cataloging-in-Publication Data
Blau, P. J.
Friction science and technology : from concepts to applications / Peter J. Blau.
-- 2nd ed.
p. cm.
Includes bibliographical references and index.
ISBN 978-1-4200-5404-0 (alk. paper)
1. Friction. I. Title.
TJ1075.B555 2008
621.8’9--dc22 2008018724
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
CCRRCC__55440044XX__FFMM..iinndddd iivv 99//1100//22000088 33::1100::4444 PPMM
Dedication
This book is dedicated to the memory of my parents: to my
father, a principled, hardworking man who valued ethics
and personal responsibility, and had a wonderful sense of
humor; and to my mother, a small woman with a big heart,
who opened my eyes to the richness of music and art.
One researcher had an addiction
To seeking the causes of friction;
He’d often confi de,
Whilst watching things slide,
That he suffered that mental affl iction.
CCRRCC__55440044XX__FFMM..iinndddd vv 99//1100//22000088 33::1100::4455 PPMM
CCRRCC__55440044XX__FFMM..iinndddd vvii 99//1100//22000088 33::1100::4455 PPMM
Contents
Foreword ...................................................................................................................xi
Preface ...................................................................................................................xiii
Chapter 1 Introduction ..........................................................................................1
1.1 World of Frictional Phenomena: Great and Small ............................................3
1.2 Historical Background ......................................................................................7
1.3 Traditional Introductions to Solid Friction .....................................................12
1.4 Approach of This Book ...................................................................................13
References ................................................................................................................14
Chapter 2 Introductory Mechanics Approaches to Solid Friction ......................17
2.1 Basic Defi nitions of Friction Quantities..........................................................17
2.2 Tipping and Onset of Slip ...............................................................................18
2.3 Introductory Friction Problems .......................................................................21
2.3.1 Case 1. Ladder against a Wall .............................................................22
2.3.2 Case 2. Speed of a Skier ......................................................................23
2.3.3 Case 3. Motorcycle Accident ...............................................................24
2.3.4 Case 4. Angle of Bank to Prevent Sliding of
an Automobile on a Curve under Wet or Dry Conditions ...................24
2.3.5 Case 5. Friction Coeffi cient Required to Avoid
Sliding on an Unbanked Curve in the Road ........................................25
2.4 Friction in Simple Machine Components .......................................................26
2.4.1 Wedge-Based Mechanisms..................................................................26
2.4.2 Pivots, Collars, and Disks....................................................................30
2.4.3 Belts and Ropes ...................................................................................31
2.4.4 Screws ..................................................................................................33
2.4.5 Shafts and Journal Bearings ................................................................35
2.5 Rolling Friction ...............................................................................................36
2.6 Friction in Gears .............................................................................................39
Further Reading .......................................................................................................41
References ................................................................................................................41
Chapter 3 Measuring Friction in the Laboratory ................................................43
3.1 Classifi cation of Tribometers ..........................................................................43
3.2 Specimen Preparation and Cleaning ...............................................................48
3.3 Design and Selection of Friction-Testing Methods .........................................52
3.3.1 Static Friction ......................................................................................56
3.3.2 Sliding Friction ....................................................................................61
3.3.3 Rolling Friction ...................................................................................64
vii
CCRRCC__55440044XX__FFMM..iinndddd vviiii 99//1100//22000088 33::1100::4455 PPMM
viii Contents
3.3.4 Tests of Flexible Surfaces ....................................................................65
3.3.5 Standards .............................................................................................69
3.4 Specialized Friction Tests for Basic and Applied Research ...........................73
3.4.1 Nanoscale Friction ...............................................................................73
3.4.2 Microscale Ball-on-Flat Tests .............................................................76
3.4.3 Friction of a Fiber within a Composite................................................78
3.4.4 Multidirectional Tribometers ..............................................................79
3.4.5 Friction of Impacting Spheres .............................................................79
3.4.6 Pendulum-Based Devices ....................................................................79
3.4.7 Friction Measurement Using Precision Chains ...................................81
3.4.8 Piston Ring and Cylinder Bore Friction ..............................................82
3.4.9 Friction of Brake Linings ....................................................................85
3.4.10 Tire/Road Surface Testing ...................................................................93
3.4.11 Walkway Friction Testing ....................................................................94
3.4.12 Metalworking ......................................................................................96
3.4.13 Friction of Rock ...................................................................................97
3.4.14 Friction of Currency ............................................................................98
3.5 Friction Sensing and Recording ......................................................................99
3.6 Designing Friction Experiments ...................................................................105
Appendix ................................................................................................................109
References ..............................................................................................................112
Chapter 4 Fundamentals of Sliding Friction .....................................................119
4.1 Macrocontact, Microcontact, and Nanocontact ............................................126
4.2 Static Friction and Stick-Slip ........................................................................132
4.3 Sliding Friction .............................................................................................155
4.3.1 Models for Sliding Friction ...............................................................157
4.3.1.1 Plowing Models ...................................................................157
4.3.1.2 Adhesion, Junction Growth, and Shear Models ..................159
4.3.1.3 Plowing with Debris Generation ..........................................163
4.3.1.4 Plowing with Adhesion ........................................................164
4.3.1.5 Single-Layer Shear Models ..................................................164
4.3.1.6 Multiple-Layer Shear Models ..............................................165
4.3.1.7 Molecular Dynamics Models ...............................................166
4.3.1.8 Stimulus–Response Dynamical Friction Models ................167
4.3.1.9 Ultralow Friction and “Superlubricity” ...............................168
4.3.1.10 Selecting Friction Models ....................................................169
4.3.2 Phenomenological, Graphical, and Statistical Approaches ...............169
4.3.3 Friction Models That Include Wear ...................................................170
4.4 Frictional Heating .........................................................................................171
References ..............................................................................................................178
Chapter 5 Solid Friction of Materials ...............................................................183
5.1 Friction of Wood, Leather, and Stone ...........................................................183
5.2 Friction of Metals and Alloys .......................................................................184
CCRRCC__55440044XX__FFMM..iinndddd vviiiiii 99//1100//22000088 33::1100::4455 PPMM
Contents ix
5.3 Friction of Glasses and Ceramics .................................................................189
5.4 Friction of Polymers ......................................................................................192
5.5 Friction of Carbon Materials Including
Diamond ........................................................................................................200
5.6 Friction of Ice ................................................................................................204
5.7 Friction of Treated Surfaces ..........................................................................209
5.8 Friction of Particle Aggregates .....................................................................212
References ..............................................................................................................215
Chapter 6 Lubrication to Control Friction ........................................................221
6.1 Lubrication by Liquids and Greases .............................................................222
6.1.1 Liquid Lubrication .............................................................................222
6.1.2 Composition of Liquid Lubricants ....................................................232
6.1.2.1 Friction Polymers .................................................................242
6.1.2.2 Lubricating Characteristics of Ultrathin Layers ..................243
6.1.2.3 Ionic Liquid Lubricants .......................................................244
6.1.3 Grease Lubrication ............................................................................245
6.1.3.1 Liquid Crystal Lubricants ....................................................246
6.2 Lubrication by Solids ....................................................................................248
6.2.1 Role of Lamellar Crystal Structures ..................................................252
6.2.2 Simplifi ed Models for Solid Lubrication ...........................................253
6.2.3 Graphite and Molybdenum Disulfi de ................................................254
6.2.4 Solid Lubrication by Powders ............................................................257
6.3 Engineered Self-Lubricating Materials .........................................................260
References ..............................................................................................................263
Chapter 7 Effects of Tribosystem Variables on Friction ...................................269
7.1 Effects of Surface Finish ...............................................................................269
7.2 Effects of Load and Contact Pressure ...........................................................278
7.3 Effects of Sliding Velocity ............................................................................287
7.4 Effects of Type of Sliding Motion.................................................................293
7.5 Effects of Temperature ..................................................................................297
7.6 Effects of Surface Films and Chemical Environments.................................302
7.7 Stiffness and Vibration .................................................................................304
7.8 Combined Effects of Several Variables ........................................................309
References ..............................................................................................................310
Chapter 8 Running-In and Other Friction Transitions ......................................315
8.1 Understanding and Interpreting Friction Transitions ...................................315
8.2 Friction Transitions during Running-In ........................................................321
8.2.1 Analysis of Running-In Behavior ......................................................322
8.2.2 Modeling of Running-In ....................................................................330
8.2.3 Monitoring and Developing Running-In Procedures ........................335
CCRRCC__55440044XX__FFMM..iinndddd iixx 99//1100//22000088 33::1100::4455 PPMM
