Post on 26-Nov-2015
description
Introduction to theDesign and Behavior
of Bolted Joints
Non-Gasketed Joints
Fourth Edition
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page i 27.7.2007 9:35pm Compositor Name: VBalamugundan
MECHANICAL ENGINEERINGA Series of Textbooks and Reference Books
Founding EditorL. L. Faulkner
Columbus Division, Battelle Memorial Instituteand Department of Mechanical Engineering
The Ohio State UniversityColumbus, Ohio
1. Spring Designers Handbook, Harold Carlson2. Computer-Aided Graphics and Design, Daniel L. Ryan3. Lubrication Fundamentals, J. George Wills4. Solar Engineering for Domestic Buildings, William A. Himmelman5. Applied Engineering Mechanics: Statics and Dynamics, G. Boothroyd and C. Poli6. Centrifugal Pump Clinic, Igor J. Karassik7. Computer-Aided Kinetics for Machine Design, Daniel L. Ryan8. Plastics Products Design Handbook, Part A: Materials and Components; Part B:
Processes and Design for Processes, edited by Edward Miller9. Turbomachinery: Basic Theory and Applications, Earl Logan, Jr.10. Vibrations of Shells and Plates, Werner Soedel11. Flat and Corrugated Diaphragm Design Handbook, Mario Di Giovanni12. Practical Stress Analysis in Engineering Design, Alexander Blake13. An Introduction to the Design and Behavior of Bolted Joints, John H. Bickford14. Optimal Engineering Design: Principles and Applications, James N. Siddall15. Spring Manufacturing Handbook, Harold Carlson16. Industrial Noise Control: Fundamentals and Applications, edited by Lewis H. Bell17. Gears and Their Vibration: A Basic Approach to Understanding Gear Noise,
J. Derek Smith18. Chains for Power Transmission and Material Handling: Design and Applications
Handbook, American Chain Association19. Corrosion and Corrosion Protection Handbook, edited by Philip A. Schweitzer20. Gear Drive Systems: Design and Application, Peter Lynwander21. Controlling In-Plant Airborne Contaminants: Systems Design and Calculations,
John D. Constance22. CAD/CAM Systems Planning and Implementation, Charles S. Knox23. Probabilistic Engineering Design: Principles and Applications, James N. Siddall24. Traction Drives: Selection and Application, Frederick W. Heilich III
and Eugene E. Shube25. Finite Element Methods: An Introduction, Ronald L. Huston and Chris E. Passerello26. Mechanical Fastening of Plastics: An Engineering Handbook, Brayton Lincoln,
Kenneth J. Gomes, and James F. Braden27. Lubrication in Practice: Second Edition, edited by W. S. Robertson28. Principles of Automated Drafting, Daniel L. Ryan29. Practical Seal Design, edited by Leonard J. Martini30. Engineering Documentation for CAD/CAM Applications, Charles S. Knox31. Design Dimensioning with Computer Graphics Applications, Jerome C. Lange32. Mechanism Analysis: Simplified Graphical and Analytical Techniques,
Lyndon O. Barton
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page ii 27.7.2007 9:35pm Compositor Name: VBalamugundan
33. CAD/CAM Systems: Justification, Implementation, Productivity Measurement,Edward J. Preston, George W. Crawford, and Mark E. Coticchia
34. Steam Plant Calculations Manual, V. Ganapathy35. Design Assurance for Engineers and Managers, John A. Burgess36. Heat Transfer Fluids and Systems for Process and Energy Applications, Jasbir Singh37. Potential Flows: Computer Graphic Solutions, Robert H. Kirchhoff38. Computer-Aided Graphics and Design: Second Edition, Daniel L. Ryan39. Electronically Controlled Proportional Valves: Selection and Application,
Michael J. Tonyan, edited by Tobi Goldoftas40. Pressure Gauge Handbook, AMETEK, U.S. Gauge Division, edited by
Philip W. Harland41. Fabric Filtration for Combustion Sources: Fundamentals and Basic Technology,
R. P. Donovan42. Design of Mechanical Joints, Alexander Blake43. CAD/CAM Dictionary, Edward J. Preston, George W. Crawford, and Mark E. Coticchia44. Machinery Adhesives for Locking, Retaining, and Sealing, Girard S. Haviland45. Couplings and Joints: Design, Selection, and Application, Jon R. Mancuso46. Shaft Alignment Handbook, John Piotrowski47. BASIC Programs for Steam Plant Engineers: Boilers, Combustion, Fluid Flow,
and Heat Transfer, V. Ganapathy48. Solving Mechanical Design Problems with Computer Graphics, Jerome C. Lange49. Plastics Gearing: Selection and Application, Clifford E. Adams50. Clutches and Brakes: Design and Selection, William C. Orthwein51. Transducers in Mechanical and Electronic Design, Harry L. Trietley52. Metallurgical Applications of Shock-Wave and High-Strain-Rate Phenomena,
edited by Lawrence E. Murr, Karl P. Staudhammer, and Marc A. Meyers53. Magnesium Products Design, Robert S. Busk54. How to Integrate CAD/CAM Systems: Management and Technology,
William D. Engelke55. Cam Design and Manufacture: Second Edition; with cam design software for the IBM
PC and compatibles, disk included, Preben W. Jensen56. Solid-State AC Motor Controls: Selection and Application, Sylvester Campbell57. Fundamentals of Robotics, David D. Ardayfio58. Belt Selection and Application for Engineers, edited by Wallace D. Erickson59. Developing Three-Dimensional CAD Software with the IBM PC, C. Stan Wei60. Organizing Data for CIM Applications, Charles S. Knox, with contributions by
Thomas C. Boos, Ross S. Culverhouse, and Paul F. Muchnicki61. Computer-Aided Simulation in Railway Dynamics, by Rao V. Dukkipati
and Joseph R. Amyot62. Fiber-Reinforced Composites: Materials, Manufacturing, and Design, P. K. Mallick63. Photoelectric Sensors and Controls: Selection and Application, Scott M. Juds64. Finite Element Analysis with Personal Computers, Edward R. Champion, Jr.
and J. Michael Ensminger65. Ultrasonics: Fundamentals, Technology, Applications: Second Edition, Revised
and Expanded, Dale Ensminger66. Applied Finite Element Modeling: Practical Problem Solving for Engineers,
Jeffrey M. Steele67. Measurement and Instrumentation in Engineering: Principles and Basic Laboratory
Experiments, Francis S. Tse and Ivan E. Morse68. Centrifugal Pump Clinic: Second Edition, Revised and Expanded, Igor J. Karassik69. Practical Stress Analysis in Engineering Design: Second Edition, Revised and
Expanded, Alexander Blake70. An Introduction to the Design and Behavior of Bolted Joints: Second Edition,
Revised and Expanded, John H. Bickford71. High Vacuum Technology: A Practical Guide, Marsbed H. Hablanian
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page iii 27.7.2007 9:35pm Compositor Name: VBalamugundan
72. Pressure Sensors: Selection and Application, Duane Tandeske73. Zinc Handbook: Properties, Processing, and Use in Design, Frank Porter74. Thermal Fatigue of Metals, Andrzej Weronski and Tadeusz Hejwowski75. Classical and Modern Mechanisms for Engineers and Inventors, Preben W. Jensen76. Handbook of Electronic Package Design, edited by Michael Pecht77. Shock-Wave and High-Strain-Rate Phenomena in Materials, edited by Marc A.
Meyers, Lawrence E. Murr, and Karl P. Staudhammer78. Industrial Refrigeration: Principles, Design and Applications, P. C. Koelet79. Applied Combustion, Eugene L. Keating80. Engine Oils and Automotive Lubrication, edited by Wilfried J. Bartz81. Mechanism Analysis: Simplified and Graphical Techniques, Second Edition,
Revised and Expanded, Lyndon O. Barton82. Fundamental Fluid Mechanics for the Practicing Engineer, James W. Murdock83. Fiber-Reinforced Composites: Materials, Manufacturing, and Design, Second Edition,
Revised and Expanded, P. K. Mallick84. Numerical Methods for Engineering Applications, Edward R. Champion, Jr.85. Turbomachinery: Basic Theory and Applications, Second Edition, Revised
and Expanded, Earl Logan, Jr.86. Vibrations of Shells and Plates: Second Edition, Revised and Expanded,
Werner Soedel87. Steam Plant Calculations Manual: Second Edition, Revised and Expanded,
V. Ganapathy88. Industrial Noise Control: Fundamentals and Applications, Second Edition,
Revised and Expanded, Lewis H. Bell and Douglas H. Bell89. Finite Elements: Their Design and Performance, Richard H. MacNeal90. Mechanical Properties of Polymers and Composites: Second Edition,
Revised and Expanded, Lawrence E. Nielsen and Robert F. Landel91. Mechanical Wear Prediction and Prevention, Raymond G. Bayer92. Mechanical Power Transmission Components, edited by David W. South
and Jon R. Mancuso93. Handbook of Turbomachinery, edited by Earl Logan, Jr.94. Engineering Documentation Control Practices and Procedures, Ray E. Monahan95. Refractory Linings Thermomechanical Design and Applications, Charles A. Schacht96. Geometric Dimensioning and Tolerancing: Applications and Techniques for Use
in Design, Manufacturing, and Inspection, James D. Meadows97. An Introduction to the Design and Behavior of Bolted Joints: Third Edition,
Revised and Expanded, John H. Bickford98. Shaft Alignment Handbook: Second Edition, Revised and Expanded, John Piotrowski99. Computer-Aided Design of Polymer-Matrix Composite Structures, edited by
Suong Van Hoa100. Friction Science and Technology, Peter J. Blau101. Introduction to Plastics and Composites: Mechanical Properties and Engineering
Applications, Edward Miller102. Practical Fracture Mechanics in Design, Alexander Blake103. Pump Characteristics and Applications, Michael W. Volk104. Optical Principles and Technology for Engineers, James E. Stewart105. Optimizing the Shape of Mechanical Elements and Structures, A. A. Seireg
and Jorge Rodriguez106. Kinematics and Dynamics of Machinery, Vladimr Stejskal and Michael Valsek107. Shaft Seals for Dynamic Applications, Les Horve108. Reliability-Based Mechanical Design, edited by Thomas A. Cruse109. Mechanical Fastening, Joining, and Assembly, James A. Speck110. Turbomachinery Fluid Dynamics and Heat Transfer, edited by Chunill Hah111. High-Vacuum Technology: A Practical Guide, Second Edition, Revised and Expanded,
Marsbed H. Hablanian
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page iv 27.7.2007 9:35pm Compositor Name: VBalamugundan
112. Geometric Dimensioning and Tolerancing: Workbook and Answerbook,James D. Meadows
113. Handbook of Materials Selection for Engineering Applications, edited by G. T. Murray114. Handbook of Thermoplastic Piping System Design, Thomas Sixsmith
and Reinhard Hanselka115. Practical Guide to Finite Elements: A Solid Mechanics Approach, Steven M. Lepi116. Applied Computational Fluid Dynamics, edited by Vijay K. Garg117. Fluid Sealing Technology, Heinz K. Muller and Bernard S. Nau118. Friction and Lubrication in Mechanical Design, A. A. Seireg119. Influence Functions and Matrices, Yuri A. Melnikov120. Mechanical Analysis of Electronic Packaging Systems, Stephen A. McKeown121. Couplings and Joints: Design, Selection, and Application, Second Edition,
Revised and Expanded, Jon R. Mancuso122. Thermodynamics: Processes and Applications, Earl Logan, Jr.123. Gear Noise and Vibration, J. Derek Smith124. Practical Fluid Mechanics for Engineering Applications, John J. Bloomer125. Handbook of Hydraulic Fluid Technology, edited by George E. Totten126. Heat Exchanger Design Handbook, T. Kuppan127. Designing for Product Sound Quality, Richard H. Lyon128. Probability Applications in Mechanical Design, Franklin E. Fisher and Joy R. Fisher129. Nickel Alloys, edited by Ulrich Heubner130. Rotating Machinery Vibration: Problem Analysis and Troubleshooting,
Maurice L. Adams, Jr.131. Formulas for Dynamic Analysis, Ronald L. Huston and C. Q. Liu132. Handbook of Machinery Dynamics, Lynn L. Faulkner and Earl Logan, Jr.133. Rapid Prototyping Technology: Selection and Application, Kenneth G. Cooper134. Reciprocating Machinery Dynamics: Design and Analysis, Abdulla S. Rangwala135. Maintenance Excellence: Optimizing Equipment Life-Cycle Decisions, edited by
John D. Campbell and Andrew K. S. Jardine136. Practical Guide to Industrial Boiler Systems, Ralph L. Vandagriff137. Lubrication Fundamentals: Second Edition, Revised and Expanded, D. M. Pirro
and A. A. Wessol138. Mechanical Life Cycle Handbook: Good Environmental Design and Manufacturing,
edited by Mahendra S. Hundal139. Micromachining of Engineering Materials, edited by Joseph McGeough140. Control Strategies for Dynamic Systems: Design and Implementation,
John H. Lumkes, Jr.141. Practical Guide to Pressure Vessel Manufacturing, Sunil Pullarcot142. Nondestructive Evaluation: Theory, Techniques, and Applications, edited by
Peter J. Shull143. Diesel Engine Engineering: Thermodynamics, Dynamics, Design, and Control,
Andrei Makartchouk144. Handbook of Machine Tool Analysis, Ioan D. Marinescu, Constantin Ispas,
and Dan Boboc145. Implementing Concurrent Engineering in Small Companies, Susan Carlson Skalak146. Practical Guide to the Packaging of Electronics: Thermal and Mechanical Design
and Analysis, Ali Jamnia147. Bearing Design in Machinery: Engineering Tribology and Lubrication, Avraham Harnoy148. Mechanical Reliability Improvement: Probability and Statistics for Experimental Testing,
R. E. Little149. Industrial Boilers and Heat Recovery Steam Generators: Design, Applications,
and Calculations, V. Ganapathy150. The CAD Guidebook: A Basic Manual for Understanding and Improving
Computer-Aided Design, Stephen J. Schoonmaker151. Industrial Noise Control and Acoustics, Randall F. Barron
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page v 27.7.2007 9:35pm Compositor Name: VBalamugundan
152. Mechanical Properties of Engineered Materials, Wol Soboyejo153. Reliability Verification, Testing, and Analysis in Engineering Design,
Gary S. Wasserman154. Fundamental Mechanics of Fluids: Third Edition, I. G. Currie155. Intermediate Heat Transfer, Kau-Fui Vincent Wong156. HVAC Water Chillers and Cooling Towers: Fundamentals, Application, and Operation,
Herbert W. Stanford III157. Gear Noise and Vibration: Second Edition, Revised and Expanded, J. Derek Smith 158. Handbook of Turbomachinery: Second Edition, Revised and Expanded, edited by
Earl Logan, Jr. and Ramendra Roy159. Piping and Pipeline Engineering: Design, Construction, Maintenance, Integrity,
and Repair, George A. Antaki160. Turbomachinery: Design and Theory, Rama S. R. Gorla and Aijaz Ahmed Khan161. Target Costing: Market-Driven Product Design, M. Bradford Clifton, Henry M. B. Bird,
Robert E. Albano, and Wesley P. Townsend162. Fluidized Bed Combustion, Simeon N. Oka163. Theory of Dimensioning: An Introduction to Parameterizing Geometric Models,
Vijay Srinivasan164. Handbook of Mechanical Alloy Design, edited by George E. Totten, Lin Xie,
and Kiyoshi Funatani165. Structural Analysis of Polymeric Composite Materials, Mark E. Tuttle166. Modeling and Simulation for Material Selection and Mechanical Design, edited by
George E. Totten, Lin Xie, and Kiyoshi Funatani167. Handbook of Pneumatic Conveying Engineering, David Mills, Mark G. Jones,
and Vijay K. Agarwal168. Clutches and Brakes: Design and Selection, Second Edition, William C. Orthwein169. Fundamentals of Fluid Film Lubrication: Second Edition, Bernard J. Hamrock,
Steven R. Schmid, and Bo O. Jacobson170. Handbook of Lead-Free Solder Technology for Microelectronic Assemblies, edited by
Karl J. Puttlitz and Kathleen A. Stalter171. Vehicle Stability, Dean Karnopp172. Mechanical Wear Fundamentals and Testing: Second Edition, Revised and Expanded,
Raymond G. Bayer173. Liquid Pipeline Hydraulics, E. Shashi Menon174. Solid Fuels Combustion and Gasification, Marcio L. de Souza-Santos175. Mechanical Tolerance Stackup and Analysis, Bryan R. Fischer176. Engineering Design for Wear, Raymond G. Bayer177. Vibrations of Shells and Plates: Third Edition, Revised and Expanded, Werner Soedel178. Refractories Handbook, edited by Charles A. Schacht179. Practical Engineering Failure Analysis, Hani M. Tawancy, Anwar Ul-Hamid,
and Nureddin M. Abbas180. Mechanical Alloying and Milling, C. Suryanarayana181. Mechanical Vibration: Analysis, Uncertainties, and Control, Second Edition,
Revised and Expanded, Haym Benaroya182. Design of Automatic Machinery, Stephen J. Derby183. Practical Fracture Mechanics in Design: Second Edition, Revised and Expanded,
Arun Shukla184. Practical Guide to Designed Experiments, Paul D. Funkenbusch185. Gigacycle Fatigue in Mechanical Practive, Claude Bathias and Paul C. Paris186. Selection of Engineering Materials and Adhesives, Lawrence W. Fisher187. Boundary Methods: Elements, Contours, and Nodes, Subrata Mukherjee
and Yu Xie Mukherjee188. Rotordynamics, Agnieszka (Agnes) Musznyska189. Pump Characteristics and Applications: Second Edition, Michael W. Volk190. Reliability Engineering: Probability Models and Maintenance Methods, Joel A. Nachlas
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page vi 27.7.2007 9:35pm Compositor Name: VBalamugundan
191. Industrial Heating: Principles, Techniques, Materials, Applications, and Design,Yeshvant V. Deshmukh
192. Micro Electro Mechanical System Design, James J. Allen193. Probability Models in Engineering and Science, Haym Benaroya and Seon Han194. Damage Mechanics, George Z. Voyiadjis and Peter I. Kattan195. Standard Handbook of Chains: Chains for Power Transmission and Material Handling,
Second Edition, American Chain Association and John L. Wright, Technical Consultant196. Standards for Engineering Design and Manufacturing, Wasim Ahmed Khan
and Abdul Raouf S.I.197. Maintenance, Replacement, and Reliability: Theory and Applications,
Andrew K. S. Jardine and Albert H. C. Tsang198. Finite Element Method: Applications in Solids, Structures, and Heat Transfer,
Michael R. Gosz199. Microengineering, MEMS, and Interfacing: A Practical Guide, Danny Banks200. Fundamentals of Natural Gas Processing, Arthur J. Kidnay and William Parrish201. Optimal Control of Induction Heating Processes, Edgar Rapoport
and Yulia Pleshivtseva202. Practical Plant Failure Analysis: A Guide to Understanding Machinery Deterioration
and Improving Equipment Reliability, Neville W. Sachs, P.E.203. Shaft Alignment Handbook, Third Edition, John Piotrowski204. Advanced Vibration Analysis , S. Graham Kelly205. Principles of Composite Materials Mechanics, Second Edition, Ronald F. Gibson206. Applied Combustion, Second Edition, Eugene L. Keating207. Introduction to the Design and Behavior of Bolted Joints, Fourth Edition:
Non-Gasketed Joints, John H. Bickford
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page vii 27.7.2007 9:35pm Compositor Name: VBalamugundan
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page viii 27.7.2007 9:35pm Compositor Name: VBalamugundan
Introduction to theDesign and Behavior
of Bolted Joints
John H. Bickford
Non-Gasketed Joints
Fourth Edition
CRC Press is an imprint of theTaylor & Francis Group, an informa business
Boca Raton London New York
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page ix 27.7.2007 9:35pm Compositor Name: VBalamugundan
CRC PressTaylor & Francis Group6000 Broken Sound Parkway NW, Suite 300Boca Raton, FL 33487-2742
2008 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government worksPrinted in the United States of America on acid-free paper10 9 8 7 6 5 4 3 2 1
International Standard Book Number-10: 0-8493-8176-2 (Hardcover)International Standard Book Number-13: 978-0-8493-8176-8 (Hardcover)
This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use.
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 informa-tion storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.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 provides licenses and registration for a variety of users. For orga-nizations 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
Introduction to the design and behavior of bolted joints. -- 4th ed.p. cm.
Includes bibliographical references and index.ISBN 978-0-8493-8176-8 (alk. paper)1. Bolted joints. I. Bickford, John H., 1926- Non-gasketed joint. II. Title.
TA492.B63B5 2007621.882--dc22 2007007723
Visit the Taylor & Francis Web site athttp://www.taylorandfrancis.comand the CRC Press Web site athttp://www.crcpress.com
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page x 27.7.2007 9:35pm Compositor Name: VBalamugundan
Dedication
Once again to my wife, Anne,
to our children David, Peter, and Leila,
and to Leilas childrenour delightful
granddaughtersZoe and Arden Sawyer.
Also to their father Hal Sawyer and to
Greg McCarthy. None of these people will
ever have to read this book, though
Hal probably will.
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xi 27.7.2007 9:35pm Compositor Name: VBalamugundan
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xii 27.7.2007 9:35pm Compositor Name: VBalamugundan
Table of Contents
Preface to the Fourth Edition .............................................................................................xxix
Acknowledgments for Volume 1 of the Fourth Edition .......................................................xxxi
Preface to the Third Edition............................................................................................. xxxiii
Preface to the Second Edition ........................................................................................... xxxv
Preface to the First Edition ............................................................................................. xxxvii
Acknowledgments for the First Three Editions ......................................................................xli
Editor..................................................................................................................................xliii
Abstract ...............................................................................................................................xlv
Chapter 1
Basic Concepts .......................................................................................................................1
1.1 Two Types of Bolted Joints ...........................................................................................1
1.2 Bolts Job .......................................................................................................................1
1.2.1 Tensile Joints ......................................................................................................1
1.2.2 Shear Joints ........................................................................................................3
1.3 The Challenge ................................................................................................................3
1.3.1 Assembly Process................................................................................................4
1.3.2 In-Service Behavior.............................................................................................5
1.3.2.1 Joints Loaded in Tension ..................................................................... 5
1.3.2.2 Shear Joints .......................................................................................... 5
1.4 Failure Modes................................................................................................................6
1.5 Design ............................................................................................................................7
1.5.1 In General...........................................................................................................7
1.5.2 Specific Goals of the Designer............................................................................7
1.6 Layout of the Book........................................................................................................8
Exercises .................................................................................................................................8
Chapter 2
Materials ..............................................................................................................................11
2.1 Properties That Affect the Clamping Force.................................................................11
2.1.1 Magnitude of the Clamping Force ...................................................................11
2.1.2 Stability of the Clamping Force .......................................................................12
2.1.2.1 Thermal Expansion or Contraction ................................................... 12
2.1.2.2 Corrosion ........................................................................................... 12
2.1.2.3 Fatigue Rupture ................................................................................. 12
2.1.2.4 Loss of Strength with Temperature.................................................... 12
2.1.2.5 Loss of Clamping Force with Temperature ....................................... 13
2.1.2.6 Elastic Stiffness of the Parts ............................................................... 13
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xiii 27.7.2007 9:35pm Compositor Name: VBalamugundan
xiii
2.1.2.7 Change in Stiffness with Temperature............................................ 13
2.1.2.8 Brittle Fracture ............................................................................... 13
2.1.3 Miscellaneous Properties...............................................................................13
2.2 Fastener Standards.....................................................................................................14
2.3 Selecting an Appropriate Standard ............................................................................14
2.4 Bolting Materials........................................................................................................16
2.5 Tensile Strength of Bolting Materials ........................................................................16
2.5.1 General Purpose=Automotive Group............................................................172.5.2 Structural Steel Group ..................................................................................17
2.5.3 Petrochemical=Power Group.........................................................................172.5.4 Metric Group ................................................................................................17
2.5.5 Extreme-Temperature Materials ...................................................................18
2.5.5.1 American Society for Testing and Materials (ASTM)
F2281 Materials.............................................................................. 18
2.5.5.2 Traditional High-Temperature Materials ....................................... 18
2.5.6 Corrosion-Resistant Group...........................................................................19
2.5.7 Two New ASTM Bolting Standards.............................................................19
2.5.7.1 Room Temperature Strengths of ASTM F2281
and F2282 Materials....................................................................... 20
2.6 Metric Fasteners.........................................................................................................20
2.7 Equivalent Materials ..................................................................................................21
2.8 Some Comments on the Strength of Bolting Materials .............................................21
2.8.1 In General .....................................................................................................21
2.8.2 Shear Strength...............................................................................................21
2.8.3 Bearing Yield Strength..................................................................................23
2.8.4 Hardness versus Strength..............................................................................23
2.9 Nut Selection..............................................................................................................24
2.10 Effects of Temperature on Material Properties..........................................................26
2.10.1 Thermal Expansion .......................................................................................27
2.10.2 Miscellaneous Temperature Problems...........................................................31
2.11 Other Material Factors to Consider...........................................................................32
2.11.1 Fatigue Properties .........................................................................................32
2.11.2 Corrosion ......................................................................................................32
2.11.3 Miscellaneous Considerations .......................................................................32
2.12 Joint Materials ...........................................................................................................32
Exercises ...............................................................................................................................35
References and Bibliography................................................................................................35
Chapter 3
Stress and Strength Considerations......................................................................................39
3.1 Types of Strength .......................................................................................................39
3.1.1 Tensile Strength ............................................................................................39
3.1.2 Thread-Stripping Strength ............................................................................39
3.1.3 Shear Strength...............................................................................................40
3.1.4 Brittle Fracture Strength...............................................................................40
3.1.5 Strengths at High and Low Temperatures ....................................................40
3.1.6 Fatigue Strength............................................................................................40
3.1.7 Stress Corrosion Cracking Strength..............................................................40
3.2 Bolt in Tension...........................................................................................................41
3.2.1 Elastic Curves for Bolts in Tension...............................................................41
3.2.2 Elastic Curves under Repeated Loading .......................................................42
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xiv 27.7.2007 9:35pm Compositor Name: VBalamugundan
xiv
3.2.3 Stress Distribution under Tensile Load ........................................................42
3.2.4 Stress Concentrations....................................................................................43
3.2.5 Magnitude of Tensile Stress ..........................................................................43
3.2.6 Stress in the Nut ...........................................................................................45
3.3 Strength of a Bolt.......................................................................................................48
3.3.1 Proof Strength...............................................................................................48
3.3.2 Tensile Stress Area ........................................................................................49
3.3.3 Other Stress Area Equations.........................................................................50
3.3.4 Stress AreasMetric Threads.......................................................................51
3.3.5 Strength of the Bolt under Static Loads .......................................................53
3.4 Strength of the Joint ..................................................................................................54
3.4.1 Contact Stress between Fastener and Joint...................................................54
3.4.2 Stresses within and between the Joint Members ...........................................56
3.4.3 Static Failure of the Joint .............................................................................56
3.5 Other Types of Load on a Bolt..................................................................................57
3.5.1 Strength under Combined Loads ..................................................................59
Exercises and Problems ........................................................................................................59
References and Bibliography................................................................................................59
Chapter 4
Threads and Their Strength .................................................................................................61
4.1 Thread Forms ............................................................................................................61
4.1.1 Thread Forms in General .............................................................................61
4.1.2 Inch Series Thread Forms.............................................................................61
4.1.3 Metric Thread Forms....................................................................................63
4.2 Thread Series..............................................................................................................63
4.3 Thread Allowance, Tolerance, and Class...................................................................64
4.3.1 Inch Series Threads .......................................................................................64
4.3.1.1 Allowance ....................................................................................... 64
4.3.1.2 Tolerance ........................................................................................ 64
4.3.1.3 Class ............................................................................................... 64
4.3.2 Metric Threads..............................................................................................65
4.3.2.1 Tolerance Position (the Allowance)................................................ 66
4.3.2.2 Tolerance Grade (the Tolerance).................................................... 66
4.3.2.3 Tolerance Class (the Class)............................................................. 66
4.3.3 Inch Series and Metric Thread Classes, Compared ......................................66
4.3.4 Coating Allowances ......................................................................................67
4.3.5 Tolerances for Abnormal Lengths of Engagement .......................................67
4.4 Inspection Levels........................................................................................................68
4.5 Thread Nomenclature ................................................................................................69
4.5.1 Inch Series .....................................................................................................69
4.5.2 Metric Thread ...............................................................................................69
4.6 Coarse- versus Fine- versus Constant-Pitch Threads .................................................70
4.6.1 Coarse-Pitch Threads....................................................................................70
4.6.2 Fine-Pitch Threads........................................................................................70
4.6.3 Constant-Pitch Threads ................................................................................70
4.6.4 Miscellaneous Factors Affecting Choice .......................................................70
4.7 The Strength of Threads ............................................................................................71
4.7.1 Basic Considerations .....................................................................................71
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xv 27.7.2007 9:35pm Compositor Name: VBalamugundan
xv
4.7.2 Thread Strength Equations ...........................................................................71
4.7.3 Thread Strength Computations When Le D .............................................724.7.4 Basic ProcedureAn Example .....................................................................73
4.7.5 Thread Strength Calculations When Le 6D .................................................734.7.6 Other Stress Area Formulas..........................................................................74
4.8 What Happens to Thread Form under Load? ...........................................................76
4.9 Things That Modify the Static Strength of Threads ..................................................76
4.9.1 Common Factors ..........................................................................................76
4.9.2 Which Is Usually StrongerNut or Bolt? ....................................................79
4.9.3 Tables of Tensile Stress and Shear Areas......................................................79
4.10 Other Factors Affecting Strength...............................................................................81
4.10.1 Pitch Diameter ..............................................................................................81
4.10.2 Other Thread Parameters..............................................................................81
Exercises and Problems ........................................................................................................82
References and Bibliography................................................................................................82
Chapter 5
Stiffness and Strain Considerations......................................................................................85
5.1 Bolt Deflection ...........................................................................................................85
5.1.1 Basic Concepts ..............................................................................................85
5.1.2 Change in Length of the Bolt .......................................................................87
5.1.2.1 Effective Length.............................................................................. 87
5.1.2.2 Cross-Sectional Areas of the Bolt................................................... 89
5.1.3 Computing Change in Length of the Bolt ....................................................89
5.2 Bolt Stiffness Calculations .........................................................................................90
5.2.1 Basic Concepts ..............................................................................................90
5.2.2 Example ........................................................................................................90
5.2.3 Actual versus Computed Stretch and Stiffness .............................................92
5.2.4 Stiffness of BoltNutWasher System ..........................................................92
5.2.5 Alternative Expression for Bolt Stiffness ......................................................92
5.2.6 Energy Stored in the Bolt .............................................................................93
5.3 The Joint ....................................................................................................................94
5.3.1 Basic Concepts ..............................................................................................94
5.3.2 Computing Joint Stiffness .............................................................................95
5.3.2.1 Stiffness of Concentric Joints ......................................................... 96
5.3.2.2 Stiffness of Eccentric Joints ............................................................ 97
5.3.3 Stiffness in Practice .....................................................................................100
5.3.3.1 A Quick Way to Estimate the Stiffness of Non-Gasketed
Steel Joints.................................................................................... 100
5.4 Gasketed Joints ........................................................................................................ 101
5.5 An Alternate Way to Compute Joint Stiffness ........................................................ 103
5.6 Joint Stiffness Ratio or Load Factor ....................................................................... 104
5.7 StiffnessSome Design Goals ................................................................................. 104
5.7.1 Energy Stored in the Joint Members ..........................................................104
5.7.2 Relationship between Stiffness and Stored Energy .....................................105
5.7.3 Stiffness Ratio.............................................................................................106
Exercises and Problems ...................................................................................................... 106
References .......................................................................................................................... 107
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xvi 27.7.2007 9:35pm Compositor Name: VBalamugundan
xvi
Chapter 6
Introduction to Assembly...................................................................................................109
6.1 Initial versus Residual Preload .................................................................................. 109
6.2 Starting the Assembly Process ...................................................................................110
6.2.1 Assembling the Parts ......................................................................................110
6.2.2 Tightening the First Bolt ................................................................................ 110
6.3 Bolt Preload versus Clamping Force on the Joint .....................................................114
6.3.1 Effects of Hole Interference ............................................................................114
6.3.2 Resistance from Joint Members ..................................................................... 116
6.4 Continuing the Snugging Pass ...................................................................................119
6.5 Short-Term Relaxation of Individual Bolts ...............................................................119
6.5.1 Sources of Short-Term Relaxation ................................................................. 119
6.5.1.1 Poor Thread Engagement ................................................................ 120
6.5.1.2 Thread Engagement Too Short........................................................ 120
6.5.1.3 Soft Parts.......................................................................................... 121
6.5.1.4 Bending ............................................................................................ 121
6.5.1.5 Nonperpendicular Nuts or Bolt Heads ............................................ 121
6.5.1.6 Fillets or Undersized Holes .............................................................. 121
6.5.1.7 Oversized Holes................................................................................ 121
6.5.1.8 Conical Makeups ............................................................................. 121
6.5.2 Factors Affecting Short-Term Relaxation ...................................................... 122
6.5.2.1 Bolt Length ...................................................................................... 123
6.5.2.2 Belleville Washers............................................................................. 123
6.5.2.3 Number of Joint Members ............................................................... 123
6.5.2.4 Tightening Speed.............................................................................. 123
6.5.2.5 Simultaneous Tightening of Many Fasteners................................... 124
6.5.2.6 Bent Joint Members ......................................................................... 124
6.5.3 Amount of Relaxation to Expect....................................................................124
6.5.4 Torsional Relaxation ......................................................................................125
6.6 Elastic Interactions between Bolts ............................................................................. 127
6.7 The Assembly Process Reviewed ............................................................................... 132
6.8 Optimizing Assembly Results .................................................................................... 134
Exercises ............................................................................................................................. 135
References .......................................................................................................................... 135
Chapter 7
Torque Control of Preload................................................................................................. 137
7.1 Importance of Correct Preload .................................................................................. 137
7.1.1 Problems Created by Incorrect Preload..........................................................138
7.1.2 How Much Preload? ....................................................................................... 138
7.1.3 Factors That Affect the Working Loads on Bolts.......................................... 139
7.2 Torque versus PreloadThe Long-Form Equation .................................................. 140
7.3 Things That Affect the TorquePreload Relationship............................................... 142
7.3.1 Variables That Affect Friction........................................................................ 142
7.3.2 Geometric Variables ....................................................................................... 143
7.3.3 Strain Energy Losses ......................................................................................144
7.3.4 Prevailing Torque ...........................................................................................144
7.3.5 Weight Effect ..................................................................................................144
7.3.6 Hole Interference ............................................................................................ 145
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xvii 27.7.2007 9:35pm Compositor Name: VBalamugundan
xvii
7.3.7 Interference Fit Threads ............................................................................... 145
7.3.8 The Mechanic.............................................................................................. 145
7.3.9 Tool Accuracy.............................................................................................145
7.3.10 Miscellaneous Factors................................................................................. 145
7.4 Torque versus PreloadThe Short-Form Equation................................................146
7.5 Nut Factors..............................................................................................................147
7.5.1 Some General Comments............................................................................ 147
7.5.2 Nut Factor Examples and Case Histories................................................... 148
7.5.3 Coefficient of Friction versus Nut Factor................................................... 151
7.6 Torque Control in Practice ...................................................................................... 151
7.6.1 What Torque Should I Use? ....................................................................... 151
7.6.2 Initial Preload Scatter ................................................................................. 152
7.6.3 Low Friction for Best Control ....................................................................153
7.6.4 The Lines Arent Always Straight...............................................................153
7.6.5 Other Problems ........................................................................................... 154
7.7 Some Tools for Torque Control ..............................................................................155
7.7.1 Some Generalities ....................................................................................... 155
7.7.2 Reaction Forces Created by the Tool .........................................................157
7.7.2.1 Shear Loads Created by Torque Wrenches .................................. 157
7.7.2.2 Reaction Torques ......................................................................... 158
7.7.3 In the BeginningA Search for Accuracy..................................................159
7.7.3.1 Manual Torque Wrenches ............................................................ 159
7.7.4 More Torque for Large Fasteners ..............................................................160
7.7.4.1 Torque Multipliers and Geared Wrenches ................................... 160
7.7.4.2 Hydraulic Wrenches ..................................................................... 160
7.7.5 Toward Higher Speed ................................................................................. 160
7.7.5.1 Impact Wrenches .......................................................................... 161
7.7.5.2 Pulse Tools ................................................................................... 161
7.7.5.3 Nut Runners ................................................................................. 161
7.7.6 Add Torque Calibration or Torque Monitoring......................................... 162
7.7.7 Add Torque Feedback for Still Better Control...........................................164
7.7.8 For More Information ................................................................................164
7.8 Fasteners That Limit Applied Torque ..................................................................... 164
7.8.1 The Twist-Off Bolt...................................................................................... 164
7.8.2 The Frangible Nut ...................................................................................... 165
7.9 Is Torque Control Any Good?................................................................................. 166
7.10 Testing Tools............................................................................................................166
7.11 The Influence of Torque Control on Joint Design................................................... 167
7.12 Using Torque to Disassemble a Joint ......................................................................168
Exercises and Problems ...................................................................................................... 169
References and Bibliography.............................................................................................. 169
Chapter 8
Torque and Turn Control ..................................................................................................173
8.1 Basic Concepts of Turn Control ..............................................................................173
8.2 Turn versus Preload ................................................................................................. 175
8.2.1 Common TurnPreload Relationship .........................................................175
8.2.2 Other TurnPreload Curves........................................................................176
8.2.2.1 Sheet Metal Joint.......................................................................... 176
8.2.2.2 Gasketed Joint.............................................................................. 177
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xviii 27.7.2007 9:35pm Compositor Name: VBalamugundan
xviii
8.3 Friction Effects......................................................................................................... 177
8.4 Torque and Turn in Theory..................................................................................... 179
8.4.1 Torque, Turn, and Energy ............................................................................179
8.4.2 TorqueTurnPreload Cube .........................................................................179
8.4.3 The Broader View......................................................................................... 179
8.5 Turn-of-Nut Control................................................................................................181
8.5.1 The Theory ...................................................................................................181
8.5.2 The Practice ..................................................................................................182
8.5.2.1 Structural Steel ............................................................................... 182
8.5.2.2 Turn-of-Nut Procedure in Production Operations ......................... 183
8.5.2.3 Turn-of-Nut Procedure in Aerospace Assembly ............................ 183
8.6 Production Assembly Problems ............................................................................... 184
8.7 Popular Control Strategies....................................................................................... 186
8.7.1 TorqueAngle Window Control ................................................................... 186
8.7.2 TorqueTime Window Control ....................................................................187
8.7.3 Hesitation and Pulse Tightening................................................................... 187
8.7.4 Yield Control ................................................................................................188
8.7.5 Turn-of-Nut Control .................................................................................... 190
8.7.6 Prevailing Torque Control ............................................................................191
8.7.7 PlusPermanent Records ............................................................................191
8.7.8 Meanwhile, Out in the Field .........................................................................191
8.8 Monitoring the Results ............................................................................................ 192
8.9 Problems Reduced by TorqueAngle Control ......................................................... 193
8.10 How to Get the Most Out of TorqueAngle Control..............................................193
Exercises and Problems ...................................................................................................... 194
Bibliography and References..............................................................................................194
Chapter 9
Other Ways to Control Preload ......................................................................................... 197
9.1 Stretch Control: The Concept .................................................................................. 197
9.2 Problems of Stretch Control .................................................................................... 198
9.2.1 Dimensional Variations ................................................................................ 198
9.2.2 Change in Temperature ................................................................................ 199
9.2.3 Plastic Deformation of the Bolt....................................................................199
9.2.4 Bending and Nonperpendicular Surfaces...................................................... 199
9.2.5 Grip Length ..................................................................................................199
9.3 Stretch Measurement Techniques ............................................................................199
9.3.1 Micrometer Measurements ........................................................................... 199
9.3.1.1 Irregular Measurement Surfaces..................................................... 199
9.3.1.2 Operator Feel ................................................................................. 200
9.3.1.3 Measurement Accuracy Required .................................................. 200
9.3.1.4 Depth Micrometers ........................................................................ 200
9.3.2 Other Techniques .......................................................................................... 201
9.3.2.1 Dial Gages...................................................................................... 201
9.3.2.2 Commercially Available Gage Bolt ................................................ 202
9.3.2.3 Ultrasonic Measurements............................................................... 202
9.4 How Much Stretch? ................................................................................................. 202
9.5 Problems Reduced by Stretch Control..................................................................... 203
9.6 How to Get the Most Out of Stretch Control ......................................................... 204
9.7 Direct Preload ControlAn Introduction...............................................................204
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xix 27.7.2007 9:35pm Compositor Name: VBalamugundan
xix
9.7.1 Strain-Gaged Bolts...................................................................................... 205
9.7.2 Strain-Gaged Force Washers ......................................................................205
9.7.3 Direct Tension Indicators ...........................................................................205
9.7.4 Squirter Self-Indicating DTIs......................................................................207
9.7.5 Twist-Off Tension-Control Bolts ................................................................ 207
9.7.6 Alternative-Design Fasteners ......................................................................208
9.8 Bolt Tensioners ........................................................................................................ 208
9.8.1 The Hardware .............................................................................................208
9.9 Bolt Heaters ............................................................................................................. 210
9.10 Problems Reduced by Direct Preload Control.........................................................210
9.10.1 Direct Tension Indicators ...........................................................................210
9.10.2 Twist-Off Bolts............................................................................................ 211
9.10.3 Hydraulic Tensioners ..................................................................................211
9.10.4 Bolt Heaters ................................................................................................ 211
9.11 Getting the Most Out of Direct Preload Control ....................................................211
9.11.1 Twist-Off Bolts and DTI Washers ..............................................................211
9.11.2 Bolt Tensioners ........................................................................................... 212
9.11.3 Bolt Heaters ................................................................................................ 212
9.12 Ultrasonic Measurement of Stretch or Tension .......................................................213
9.12.1 In General ................................................................................................... 213
9.12.2 Principle of Operation................................................................................. 213
9.12.3 How Its Used .............................................................................................214
9.12.4 Calibration of the Instrument ..................................................................... 214
9.12.5 Presently Available Instruments.................................................................. 215
9.13 Ultrasonic Measurements Using Plasma-Coated, Thin Film Transducers .............. 215
Exercises and Problems ...................................................................................................... 215
References .......................................................................................................................... 216
Chapter 10
Theoretical Behavior of the Joint under Tensile Loads .....................................................219
10.1 Basic Joint Diagram................................................................................................. 220
10.1.1 Elastic Curves for Bolt and Joint Members ................................................220
10.1.2 Determining Maximum and Minimum Residual Assembly Preload ..........220
10.1.2.1 The Equations............................................................................. 220
10.1.2.2 An Example ................................................................................ 222
10.1.3 Joint Diagram for Simple Tensile Loads ....................................................224
10.1.4 The Parable of the Red Rolls Royce........................................................... 226
10.1.5 Back to the Joint DiagramSimple Tensile Load......................................227
10.2 Details and Variations .............................................................................................228
10.2.1 Changing the Bolt or Joint Stiffness ........................................................... 228
10.2.2 Critical External Load ................................................................................229
10.2.3 Very Large External Loads.........................................................................230
10.2.4 Another Form of Joint Diagram ................................................................ 230
10.3 Mathematics of the Joint ......................................................................................... 232
10.3.1 Basic Equations........................................................................................... 232
10.3.2 Continuing the Example .............................................................................234
10.4 Loading Planes.........................................................................................................235
10.4.1 Tension Applied to Interface of Joint Members ......................................... 236
10.4.2 Mathematics of a Tension Load at the Interface........................................238
10.4.3 Significance of the Loading Planes ............................................................. 238
10.4.4 Loading Planes within the Joint Members..................................................239
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xx 27.7.2007 9:35pm Compositor Name: VBalamugundan
xx
10.4.5 Modifying Our Example to Include the Effects of Internal
Loading Planes............................................................................................ 243
10.5 Dynamic Loads on Tension Joints........................................................................... 243
10.6 The Joint Under a Compressive Load ..................................................................... 245
10.7 A Warning ...............................................................................................................245
Exercises and Problems ...................................................................................................... 246
References .......................................................................................................................... 247
Chapter 11
Behavior of the Joint Loaded in Tension: A Closer Look................................................. 249
11.1 Effect of Prying Action on Bolt Loads ....................................................................250
11.1.1 Definition of Prying .................................................................................... 250
11.1.2 Discussion of Prying ...................................................................................251
11.1.3 Prying Is Nonlinear..................................................................................... 255
11.2 Mathematics of Prying.............................................................................................256
11.2.1 In General ...................................................................................................256
11.2.2 VDIs Analytical Procedure ........................................................................ 256
11.2.3 Critical Loads and the Preloads Required to Prevent Joint Separation ..... 260
11.2.4 Bending Stress in the Bolt before Liftoff .................................................... 261
11.2.5 Effects of Very Large External Loads......................................................... 263
11.3 Other Nonlinear Factors.......................................................................................... 263
11.3.1 NutBolt System ......................................................................................... 263
11.4 Thermal Effects ........................................................................................................266
11.4.1 Change in Elasticity .................................................................................... 266
11.4.2 Loss of Strength.......................................................................................... 267
11.4.3 Differential Thermal Expansion..................................................................267
11.4.4 Stress Relaxation......................................................................................... 271
11.4.5 Creep Rupture ............................................................................................ 273
11.4.6 Compensating for Thermal Effects .............................................................274
11.5 Joint Equations That Include the Effects of Eccentricity
and Differential Expansion ......................................................................................276
11.5.1 The Equations.............................................................................................276
11.5.2 An Example ................................................................................................277
Exercises and Problems ...................................................................................................... 281
References .......................................................................................................................... 281
Chapter 12
In-Service Behavior of a Shear Joint .................................................................................. 283
12.1 Bolted Joints Loaded in Axial Shear .......................................................................283
12.1.1 In General ...................................................................................................283
12.1.2 Friction-Type Joints.................................................................................... 284
12.1.2.1 Bolt Load in Friction-Type Joints .............................................. 284
12.1.2.2 Stresses in Friction-Type Joints .................................................. 285
12.1.3 Bearing-Type Joints .................................................................................... 285
12.1.3.1 Stresses in Bearing-Type Joints................................................... 286
12.2 Factors That Affect Clamping Force in Shear Joints ..............................................286
12.3 Response of Shear Joints to External Loads ........................................................... 288
12.4 Joints Loaded in Both Shear and Tension ...............................................................288
12.5 Present DefinitionsTypes of Shear Joint .............................................................. 290
Exercises ............................................................................................................................. 290
References .......................................................................................................................... 291
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xxi 27.7.2007 9:35pm Compositor Name: VBalamugundan
xxi
Chapter 13
Introduction to Joint Failure .............................................................................................293
13.1 Mechanical Failure of Bolts ...................................................................................293
13.2 Missing Bolts..........................................................................................................294
13.3 Loose Bolts............................................................................................................. 294
13.4 Bolts Too Tight ...................................................................................................... 295
13.5 Which Failure Modes Must We Worry About?.....................................................295
13.6 Concept of Essential Conditions ............................................................................ 295
13.7 Importance of Correct Preload ..............................................................................297
13.7.1 Corrosion ................................................................................................ 297
13.7.2 Stress Corrosion Cracking....................................................................... 297
13.7.3 Fatigue Failure ........................................................................................297
13.7.4 Mechanical Failure..................................................................................297
13.7.5 Self-Loosening of Fastener......................................................................297
13.7.6 Leakage ................................................................................................... 297
13.8 Load Intensifiers ....................................................................................................298
13.9 Failure of Joint Members....................................................................................... 298
13.10 Galling....................................................................................................................300
13.10.1 Discussion ...............................................................................................300
13.10.2 Removing Galled Studs...........................................................................300
Exercises .............................................................................................................................301
References .......................................................................................................................... 302
Chapter 14
Self-Loosening ....................................................................................................................303
14.1 The Problem........................................................................................................... 303
14.2 How Does a Nut Self-Loosen?............................................................................... 303
14.3 Loosening Sequence ...............................................................................................306
14.4 Junkers Theory of Self-Loosening.........................................................................306
14.4.1 The Equations ......................................................................................... 307
14.4.2 The Long-Form Equation in Practice .....................................................308
14.4.3 The Equation When Applied Torque Is Absent .....................................308
14.4.4 Why Slip Occurs? .................................................................................... 309
14.4.5 Other Reasons for Slip ............................................................................ 310
14.4.6 Other Theories of Self-Loosening............................................................310
14.5 Testing for Vibration Resistance............................................................................ 310
14.5.1 NAS Test................................................................................................. 310
14.5.2 Junker Test .............................................................................................. 311
14.6 To Resist Vibration................................................................................................ 312
14.6.1 Maintaining Preload and Friction........................................................... 313
14.6.1.1 Conventional Wisdom............................................................. 313
14.6.2 Preventing Relative Slip between Surfaces .............................................. 314
14.6.3 Countering Back-Off Torque .................................................................. 315
14.6.3.1 Prevailing Torque Fasteners ................................................... 315
14.6.3.2 Nord-Lock Nuts and Washers ................................................ 318
14.6.3.3 In General ............................................................................... 318
14.6.4 Double Nuts............................................................................................ 319
14.6.5 Mechanically Locked Fasteners ..............................................................319
14.6.5.1 Lock Wires and Pins ............................................................... 319
14.6.5.2 Welding ................................................................................... 319
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xxii 27.7.2007 9:35pm Compositor Name: VBalamugundan
xxii
14.6.5.3 Stage 8 Fastening System ........................................................... 319
14.6.5.4 Huck Lockbolt............................................................................ 320
14.6.5.5 Honeybee Robotics..................................................................... 320
14.6.5.6 A-Lock Bolt and Nut ................................................................. 321
14.6.5.7 Omni-Lok Fasteners ................................................................... 322
14.6.6 Chemically Bonded Fasteners ..................................................................... 322
14.6.6.1 Rust ............................................................................................ 322
14.6.6.2 Anaerobic Adhesives .................................................................. 322
14.6.7 Vibration-Resistant Washers ...................................................................... 323
14.6.7.1 Washers That Maintain Tension in the Fastener ....................... 323
14.6.7.2 Toothed Washer ......................................................................... 323
14.6.7.3 Helical Spring Washer ................................................................ 324
14.6.7.4 Nord-Lock Washer..................................................................... 324
14.6.8 Comparison of Options ..............................................................................324
Exercises ............................................................................................................................. 324
References and Bibliography..............................................................................................325
Chapter 15
Fatigue Failure ................................................................................................................... 327
15.1 Fatigue Process ........................................................................................................327
15.1.1 Sequence of a Fatigue Failure..................................................................... 327
15.1.1.1 Crack Initiation .......................................................................... 327
15.1.1.2 Crack Growth............................................................................. 328
15.1.1.3 Crack Propagation...................................................................... 328
15.1.1.4 Final Rupture ............................................................................. 328
15.1.2 Types of Fatigue Failure............................................................................. 328
15.1.3 Appearance of the Break ............................................................................329
15.2 What Determines Fatigue Life? ............................................................................... 329
15.2.1 SN Diagrams.............................................................................................330
15.2.2 Material versus The Part.........................................................................332
15.2.3 Summary.....................................................................................................332
15.3 Other Types of Diagram .......................................................................................... 333
15.3.1 Constant Life Diagram ............................................................................... 333
15.3.2 Center Portion of Constant Life Diagram.................................................. 334
15.3.3 Approximate Constant Life Diagram ......................................................... 334
15.3.4 Endurance Limit Diagram .......................................................................... 336
15.3.5 Fatigue Life Data for Fasteners..................................................................337
15.4 Influence of Preload and Joint Stiffness................................................................... 338
15.4.1 Fatigue in a Linear Joint............................................................................. 338
15.4.2 Nonlinear Joints.......................................................................................... 339
15.4.3 What Is the Optimum Preload? ..................................................................341
15.4.4 Fatigue and the VDI Joint Design Equations............................................. 341
15.5 Minimizing Fatigue Problems .................................................................................. 343
15.5.1 Minimizing Stress Levels............................................................................. 344
15.5.1.1 Increased Thread Root Radius................................................... 344
15.5.1.2 Rolled Threads ........................................................................... 344
15.5.1.3 Fillets .......................................................................................... 345
15.5.1.4 Perpendicularity .......................................................................... 345
15.5.1.5 Overlapping Stress Concentrations............................................. 345
15.5.1.6 Thread Run-Out ......................................................................... 345
Bickford/Introduction to the Design and Behavior of Bolted Joints 8176_C000 Final Proof page xxiii 27.7.2007 9:35pm Compositor Name: VBalamugundan
xxiii
15.5.1.7 Thread Stress Distribution........................................................ 345
15.5.1.8 Bending ..................................................................................... 347
15.5.1.9 Corrosion .................................................................................. 347
15.5.1.10 Flanged Head and Nut ............................................................. 347
15.5.1.11 Surface Condition ..................................................................... 348
15.5.2 Reducing Load Excursions .........................................................................348
15.5.2.1 Prevent Prying........................................................................... 348
15.5.2.2 Proper Selection of Preload ...................................................... 348
15.5.2.3 Control of Bolt-to-Joint Stiffness Ratios .................................. 348
15.5.2.4 Achieving the Correct Preload.................................................. 348
15.6 Predicting Fatigue Life or Endurance Limit ............................................................348
15.7 Fatigue of Shear Joint Members ..............................................................................349
15.8 Case Histories ..........................................................................................................351
15.8.1 Transmission Towers ..................................................................................351
15.8.2 Gas Compressor Distance Piece.................................................................. 351
Exercises .............................................................................................................................352
References and Bibliography.............................................................................................. 352
Chapter 16
Corrosion ...........................................................................................................................355
16.1 Corrosion Mechanism.............................................................................................. 355
16.1.1 Galvanic Series............................................................................................ 355
16.1.2 Corrosion Cell.............................................................................................356
16.1.3 Types of Cells.............................................................................................. 357
16.1.3.1 Two-Metal Corrosion ............................................................... 357
16.1.3.2 Broken Oxide Film ................................................................... 358
16.1.3.3 Stress Corrosion Cracking ........................................................ 358
16.1.3.4 Crevice Corrosion ..................................................................... 359
16.1.3.5 Fretting Corrosion .................................................................... 359
16.2 Hydrogen Embrittlement ......................................................................................... 360
16.2.1 Stress Cracking Failure Modes ...................................................................360
16.2.2 Hydrogen Embrittlement Mechanism of Failure ........................................360
16.2.3 Susceptible and Safe Materials.................................................................... 361
16.2.4 Testing for Embrittlement...........................................................................362
16.2.5 Fighting Hydrogen Embrittlement..............................................................363
16.3 Stress Corrosion Cracking ....................................................................................... 363
16.3.1 Mechanism of Failure ................................................................................. 363
16.3.2 The Concept of KISCC ................................................................................. 364
16.3.3 Factors Affecting KISCC ..............................................................................365
16.3.3.1 Bolt Material............................................................................. 365
16.3.3.2 The Environment ...................................................................... 365
16.3.3.3 Thread-Forming Procedure ...................................................... 365
16.3.3.4 Bolt Strength or H