net CONVERSIONS BETWEEN U. CUSTOMARY UNITS AND SI UNITS Times conversion factor U. Customary unit Equals SI unit Accurate Practical Acceleration (linear) foot per second squared ft/s2 0.305 meter per second squared m/s2 inch per second squared in.0254 meter per second squared m/s2 Area square foot ft2 0.0929 square meter m2 square inch in.16* 645 square millimeter mm2 Density (mass) www.net slug per cubic foot slug/ft3 515.379 515 kilogram per cubic meter kg/m3 Density (weight) pound per cubic foot lb/ft3 157.087 157 newton per cubic meter N/m3 pound per cubic inch lb/in.447 271 kilonewton per cubic meter kN/m3 Energy; work foot-pound ft-lb 1.36 joule (Nm) J inch-pound in.113 joule J kilowatt-hour kWh 3.6 megajoule MJ British thermal unit Btu 1055.06 1055 joule J Force pound lb 4.45 kilonewton kN Force per unit length pound per foot lb/ft 14.6 newton per meter N/m pound per inch lb/in.127 175 newton per meter N/m kip per foot k/ft 14.6 kilonewton per meter kN/m kip per inch k/in.127 175 kilonewton per meter kN/m Length foot ft 0.305 meter m inch in.4 millimeter mm mile mi 1.61 kilometer km Mass slug lb-s2/ft 14.6 kilogram kg Moment of a force; torque pound-foot lb-ft 1.36 newton meter N·m pound-inch lb-in.113 newton meter N·m kip-foot k-ft 1.36 kilonewton meter kN·m kip-inch k-in.113 kilonewton meter kN·m www.net CONVERSIONS BETWEEN U. CUSTOMARY UNITS AND SI UNITS (Continued) Times conversion factor U.
Customary unit Equals SI unit Accurate Practical Moment of inertia (area) inch to fourth power in.4 416,231 416,000 millimeter to fourth power mm4 6 6 inch to fourth power 4 in.416 10 meter to fourth power m4 Moment of inertia (mass) slug foot squared slug-ft2 1.36 kilogram meter squared kg·m2 Power www.net foot-pound per second ft-lb/s 1.36 watt (J/s or N·m/s) W foot-pound per minute ft-lb/min 0.0226 watt W horsepower (550 ft-lb/s) hp 745.701 746 watt W Pressure; stress pound per square foot psf 47.9 pascal (N/m2) Pa pound per square inch psi 6894.76 6890 pascal Pa kip per square foot ksf 47.9 kilopascal kPa kip per square inch ksi 6.89 megapascal MPa Section modulus inch to third power in.1 16,400 millimeter to third power mm3 inch to third power in.4 106 meter to third power m3 Velocity (linear) foot per second ft/s 0.305 meter per second m/s inch per second in.0254 meter per second m/s mile per hour mph 0.447 meter per second m/s mile per hour mph 1.61 kilometer per hour km/h Volume cubic foot ft3 0.0283 cubic meter m3 cubic inch in.4 106 cubic meter m3 cubic inch in.4 cubic centimeter (cc) cm3 gallon (231 in.79 liter L gallon (231 in.00379 cubic meter m3 *An asterisk denotes an exact conversion factor Note: To convert from SI units to USCS units, divide by the conversion factor 5 Temperature Conversion Formulas T(°C) [T(°F) 32] T(K) 273.net Mechanics of Materials www.net SEVENTH EDITION James M. Gere Professor Emeritus, Stanford University Barry J. Goodno Georgia Institute of Technology Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States www.net Mechanics of Materials, Seventh Edition © 2009 Cengage Learning James M. Gere and Barry J.
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For your course and learning solutions, visit academic.com Purchase any of our products at your local college store or at our preferred online store www.com Printed in the United States of America 1 2 3 4 5 6 7 11 10 09 08 www.net Contents James Monroe Gere ix Photo Credits x www.net Preface xi Symbols xv Greek Alphabet xviii 1 Tension, Compression, and Shear 2 1.1 Introduction to Mechanics of Materials 5 1.2 Normal Stress and Strain 7 1.3 Mechanical Properties of Materials 15 1.4 Elasticity, Plasticity, and Creep 24 1.5 Linear Elasticity, Hooke’s Law, and Poisson’s Ratio 27 1.6 Shear Stress and Strain 32 1.7 Allowable Stresses and Allowable Loads 43 1.8 Design for Axial Loads and Direct Shear 49 Chapter Summary & Review 55 Problems 57 2 Axially Loaded Members 88 2.2 Changes in Lengths of Axially Loaded Members 91 2.3 Changes in Lengths Under Nonuniform Conditions 100 2.4 Statically Indeterminate Structures 107 2.5 Thermal Effects, Misfits, and Prestrains 116 2.6 Stresses on Inclined Sections 128 2.9 Repeated Loading and Fatigue 162 ★2.11 Nonlinear Behavior 170 ★ Specialized and/or advanced topics iii iv CONTENTS www.12 Elastoplastic Analysis 175 Chapter Summary & Review 181 Problems 182 3 Torsion 220 3.2 Torsional Deformations of a Circular Bar 223 3.3 Circular Bars of Linearly Elastic Materials 226 3.5 Stresses and Strains in Pure Shear 245 3.6 Relationship Between Moduli of Elasticity E and G 252 www.7 Transmission of Power by Circular Shafts 254 3.8 Statically Indeterminate Torsional Members 259 3.9 Strain Energy in Torsion and Pure Shear 263 3.10 Thin-Walled Tubes 270 ★3.11 Stress Concentrations in Torsion 279 Chapter Summary & Review 282 Problems 283 4 Shear Forces and Bending Moments 304 4.2 Types of Beams, Loads, and Reactions 306 4.3 Shear Forces and Bending Moments 313 4.4 Relationships Between Loads, Shear Forces, and Bending Moments 320 4.5 Shear-Force and Bending-Moment Diagrams 325 Chapter Summary & Review 337 Problems 338 5 Stresses in Beams (Basic Topics) 350 5.2 Pure Bending and Nonuniform Bending 353 5.3 Curvature of a Beam 354 5.4 Longitudinal Strains in Beams 356 5.5 Normal Stresses in Beams (Linearly Elastic Materials) 361 5.6 Design of Beams for Bending Stresses 374 5.8 Shear Stresses in Beams of Rectangular Cross Section 387 5.9 Shear Stresses in Beams of Circular Cross Section 397 5.10 Shear Stresses in the Webs of Beams with Flanges 400 www.11 Built-Up Beams and Shear Flow 408 ★★5.12 Beams with Axial Loads 412 ★★5.13 Stress Concentrations in Bending 418 Chapter Summary & Review 421 Problems 424 6 Stresses in Beams (Advanced Topics) 454 6.3 Transformed-Section Method 466 6.4 Doubly Symmetric Beams with Inclined Loads 472 www.5 Bending of Unsymmetric Beams 479 6.6 The Shear-Center Concept 487 6.7 Shear Stresses in Beams of Thin-Walled Open Cross Sections 489 6.8 Shear Stresses in Wide-Flange Beams 492 6.9 Shear Centers of Thin-Walled Open Sections 496 ★★6.10 Elastoplastic Bending 504 Chapter Summary & Review 514 Problems 516 7 Analysis of Stress and Strain 536 7.3 Principal Stresses and Maximum Shear Stresses 548 7.4 Mohr’s Circle for Plane Stress 558 7.5 Hooke’s Law for Plane Stress 575 7.7 Plane Strain 584 Chapter Summary & Review 600 Problems 602 8 Applications of Plane Stress (Pressure Vessels, Beams, and Combined Loadings) 618 8.2 Spherical Pressure Vessels 621 8.3 Cylindrical Pressure Vessels 627 8.4 Maximum Stresses in Beams 635 8.5 Combined Loadings 645 Chapter Summary & Review 661 Problems 663 ★★ Advanced topics vi CONTENTS www.net 9 Deflections of Beams 676 9.2 Differential Equations of the Deflection Curve 679 9.3 Deflections by Integration of the Bending-Moment Equation 685 9.4 Deflections by Integration of the Shear-Force and Load Equations 696 9.5 Method of Superposition 702 9.6 Moment-Area Method 711 9.8 Strain Energy of Bending 725 ★★9.9 Castigliano’s Theorem 731 www.10 Deflections Produced by Impact 744 ★★9.11 Temperature Effects 746 Chapter Summary & Review 749 Problems 751 10 Statically Indeterminate Beams 770 10.2 Types of Statically Indeterminate Beams 773 10.3 Analysis by the Differential Equations of the Deflection Curve 777 10.4 Method of Superposition 784 ★★10.6 Longitudinal Displacements at the Ends of a Beam 801 Chapter Summary & Review 805 Problems 806 11 Columns 816 11.2 Buckling and Stability 819 11.3 Columns with Pinned Ends 823 11.4 Columns with Other Support Conditions 834 11.5 Columns with Eccentric Axial Loads 845 11.6 The Secant Formula for Columns 850 11.7 Elastic and Inelastic Column Behavior 856 ★★ Advanced topics www.net CONTENTS vii 11.9 Design Formulas for Columns 863 Chapter Summary & Review 882 Problems 883 12 Review of Centroids and Moments of Inertia 900 12.2 Centroids of Plane Areas 902 12.3 Centroids of Composite Areas 905 12.4 Moments of Inertia of Plane Areas 909 12.5 Parallel-Axis Theorem for Moments of Inertia 912 www.6 Polar Moments of Inertia 916 12.7 Products of Inertia 918 12.8 Rotation of Axes 921 12.9 Principal Axes and Principal Moments of Inertia 923 Problems 927 References and Historical Notes 935 Appendix A Systems of Units and Conversion Factors 943 A.1 Systems of Units 943 A.5 Conversions Between Units 953 Appendix B Problem Solving 956 B.1 Types of Problems 956 B.2 Steps in Solving Problems 957 B.5 Rounding of Numbers 961 Appendix C Mathematical Formulas 962 Appendix D Properties of Plane Areas 966 Appendix E Properties of Structural-Steel Shapes 972 viii CONTENTS www.net Appendix F Properties of Structural Lumber 983 Appendix G Deflections and Slopes of Beams 984 Appendix H Properties of Materials 990 Answers to Problems 995 Name Index 1016 Subject Index 1017 www.net James Monroe Gere 1925–2008 James Monroe Gere, Professor Emeritus of Civil Engineering at Stanford University, died in Portola Valley, CA, on January 30, 2008. Jim Gere was born on June 14, 1925, in Syracuse, www. He joined the U. Army Air Corps at age 17 in 1942, serving in England, France and Germany.
After the war, he earned undergraduate and master’s degrees in Civil Engineering from the Rensselaer Polytechnic Institute in 1949 and 1951, respectively. He worked as an instructor and later as a Research Associate for Rensselaer between 1949 and 1952. He was awarded one of the first NSF Fellowships, and chose to study at Stanford. He received his Ph.
in 1954 and was offered a faculty position in Civil Engineering, beginning a 34-year career of engaging his students in challenging topics in mechanics, and structural and earth- quake engineering. He served as Department Chair and Associate Dean of Engineering and in 1974 co-founded the John A. Blume Earthquake Engineering Center at Stanford. In 1980, Jim Gere also became the founding head of the Stanford Committee on Earthquake Preparedness, which urged campus members to brace and strengthen office equipment, furniture, and other contents items that could pose a life safety hazard in the event of an earthquake.
That same year, he was invited as one of the first foreigners to study the earthquake-devastated city of Tangshan, China. Jim retired from Stanford in 1988 but con- tinued to be a most valuable member of the Stanford community as he gave freely of his time to advise students and to guide them on various field trips to the California earthquake country. Jim Gere was known for his outgoing manner, his cheerful personality and wonderful smile, his athleticism, and his skill as an educator in Civil Engineering.