Table Of Content

SIX TH EDIT ION Applied Strength of Materials SIX TH EDIT ION Applied Strength of Materials Robert L. Mott Joseph A. Untener CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2017 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper Version Date: 20160502 International Standard Book Number-13: 978-1-4987-1675-8 (Hardback) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. 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Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and expla- nation without intent to infringe. Library of Congress Cataloging‑in‑Publication Data Names: Mott, Robert L. | Untener, Joseph A. Title: Applied strength of materials / Robert L. Mott and Joseph A. Untener. Description: Sixth edition. | Boca Raton : Taylor & Francis, CRC Press, 2017. | Includes bibliographical references and index. Identifiers: LCCN 2016007413 | ISBN 9781498716758 (alk. paper) Subjects: LCSH: Strength of materials. Classification: LCC TA405 .M68 2017 | DDC 620.1/12--dc23 LC record available at http://lccn.loc.gov/2016007413 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Contents Preface xi 1 Basic Concepts in Strength of Materials 1 The Big Picture 2 1–1 Objective of This Book: To Ensure Safety 6 1–2 Objectives of This Chapter 15 1–3 Problem-Solving Procedure 15 1–4 Basic Unit Systems 16 1–5 Relationship among Mass, Force, and Weight 18 1–6 Concept of Stress 20 1–7 Direct Normal Stress 22 1–8 Stress Elements for Direct Normal Stresses 25 1–9 Concept of Strain 26 1–10 Direct Shear Stress 27 1–11 Stress Elements for Shear Stresses 33 1–12 Preferred Sizes and Screw Threads 33 1–13 Structural Shapes 34 1–14 Experimental and Computational Stress Analysis 42 1–15 Review of the Fundamentals of Statics 46 2 Design Properties of Materials 70 The Big Picture 71 2–1 Objectives of This Chapter 73 2–2 Design Properties of Materials 73 2–3 Steel 89 2–4 Cast Iron 97 2–5 Aluminum 98 2–6 Copper, Brass, and Bronze 100 2–7 Zinc-, Magnesium-, Titanium-, and Nickel-Based Alloys 101 v vi Contents 2–8 Nonmetals in Engineering Design 102 2–9 Wood 102 2–10 Concrete 104 2–11 Plastics 106 2–12 Composites 109 2–13 Materials Selection 123 3 Direct Stress, Deformation, and Design 133 The Big Picture 134 3–1 Objectives of This Chapter 137 3–2 Design of Members under Direct Tension or Compression 138 3–3 Design Normal Stresses 138 3–4 Design Factor 139 3–5 Design Approaches and Guidelines for Design Factors 142 3–6 Methods of Computing Design Stress 146 3–7 Elastic Deformation in Tension and Compression Members 151 3–8 Deformation due to Temperature Changes 158 3–9 Thermal Stress 162 3–10 Members Made of More Than One Material 165 3–11 Stress Concentration Factors for Direct Axial Stresses 169 3–12 Bearing Stress 173 3–13 Design Bearing Stress 177 4 Design for Direct Shear, Torsional Shear, and Torsional Deformation 199 The Big Picture 200 4–1 Objectives of This Chapter 205 4–2 Design for Direct Shear Stress 206 4–3 Torque, Power, and Rotational Speed 210 4–4 Torsional Shear Stress in Members with Circular Cross Sections 214 4–5 Development of the Torsional Shear Stress Formula 217 4–6 Polar Moment of Inertia for Solid Circular Bars 219 4–7 Torsional Shear Stress and Polar Moment of Inertia for Hollow Circular Bars 219 4–8 Design of Circular Members under Torsion 222 4–9 Comparison of Solid and Hollow Circular Members 225 4–10 Stress Concentrations in Torsionally Loaded Members 229 4–11 Twisting: Elastic Torsional Deformation 236 4–12 Torsion in Noncircular Sections 247 Contents vii 5 Shearing Forces and Bending Moments in Beams 269 The Big Picture 270 5–1 Objectives of This Chapter 277 5–2 Beam Loading, Supports, and Types of Beams 277 5–3 Reactions at Supports 286 5–4 Shearing Forces and Bending Moments for Concentrated Loads 290 5–5 Guidelines for Drawing Beam Diagrams for Concentrated Loads 296 5–6 Shearing Forces and Bending Moments for Distributed Loads 302 5–7 General Shapes Found in Bending Moment Diagrams 309 5–8 Shearing Forces and Bending Moments for Cantilever Beams 310 5–9 Beams with Linearly Varying Distributed Loads 312 5–10 Free-Body Diagrams of Parts of Structures 313 5–11 Mathematical Analysis of Beam Diagrams 319 5–12 Continuous Beams: Theorem of Three Moments 330 6 Centroids and Moments of Inertia of Areas 349 The Big Picture 350 6–1 Objectives of This Chapter 353 6–2 Concept of Centroid: Simple Shapes 353 6–3 Centroid of Complex Shapes 354 6–4 Concept of Moment of Inertia of an Area 359 6–5 Moment of Inertia of Composite Shapes Whose Parts Have the Same Centroidal Axis 361 6–6 Moment of Inertia for Composite Shapes: General Case—Use of the Parallel Axis Theorem 364 6–7 Mathematical Defnition of Moment of Inertia 367 6–8 Composite Sections Made from Commercially Available Shapes 368 6–9 Moment of Inertia for Shapes with All Rectangular Parts 372 6–10 Radius of Gyration 373 6–11 Section Modulus 377 7 Stress due to Bending 391 The Big Picture 392 7–1 Objectives of This Chapter 395 7–2 Flexure Formula 396 7–3 Conditions on the Use of the Flexure Formula 399 7–4 Stress Distribution on a Cross Section of a Beam 401 7–5 Derivation of the Flexure Formula 403 viii Contents 7–6 Applications: Analysis of Stresses in Beams 405 7–7 Applications: Beam Design and Design Stresses 409 7–8 Section Modulus and Design Procedures 411 7–9 Stress Concentrations 418 7–10 Flexural Center or Shear Center 423 7–11 Preferred Shapes for Beam Cross Sections 427 7–12 Design of Beams to Be Made from Composite Materials 432 8 Shearing Stresses in Beams 455 The Big Picture 456 8–1 Objectives of This Chapter 460 8–2 Importance of Shearing Stresses in Beams 461 8–3 General Shear Formula 462 8–4 Distribution of Shearing Stress in Beams 469 8–5 Development of the General Shear Formula 475 8–6 Special Shear Formulas 478 8–7 Design for Shear 482 8–8 Shear Flow 484 9 Deflection of Beams 497 The Big Picture 498 9–1 Objectives of This Chapter 504 9–2 Need for Considering Beam Defections 504 9–3 General Principles and Defnitions of Terms 506 9–4 Beam Defections Using the Formula Method 509 9–5 Comparison of the Manner of Support for Beams 515 9–6 Superposition Using Defection Formulas 521 9–7 Successive Integration Method 531 9–8 Moment–Area Method 544 10 Combined Stresses 575 The Big Picture 576 10–1 Objectives of This Chapter 579 10–2 Stress Element 580 10–3 Stress Distribution Created by Basic Stresses 582 10–4 Creating the Initial Stress Element 584 Contents ix 10–5 Combined Normal Stresses 590 10–6 Combined Normal and Shear Stresses 597 10–7 Equations for Stresses in Any Direction 603 10–8 Maximum and Minimum Stresses 606 10–9 Mohr’s Circle for Stress 609 10–10 Stress Condition on Selected Planes 625 10–11 Special Case in Which Both Principal Stresses Have the Same Sign 627 10–12 Use of Strain-Gage Rosettes to Determine Principal Stresses 633 11 Columns 654 The Big Picture 655 11–1 Objectives of This Chapter 659 11–2 Slenderness Ratio 659 11–3 Transition Slenderness Ratio 664 11–4 Euler Formula for Long Columns 665 11–5 J.B. Johnson Formula for Short Columns 666 11–6 Summary: Buckling Formulas 667 11–7 Design Factors for Columns and Allowable Load 669 11–8 Summary: Method of Analyzing Columns 670 11–9 Column Analysis Spreadsheet 674 11–10 Effcient Shapes for Column Cross Sections 675 11–11 Specifcations of the AISC 676 11–12 Specifcations of the Aluminum Association 679 11–13 Noncentrally Loaded Columns 680 12 Pressure Vessels 695 The Big Picture 696 12–1 Objectives of This Chapter 699 12–2 Distinction between Thin-Walled and Thick-Walled Pressure Vessels 699 12–3 Thin-Walled Spheres 701 12–4 Thin-Walled Cylinders 703 12–5 Thick-Walled Cylinders and Spheres 707 12–6 Analysis and Design Procedures for Pressure Vessels 708 12–7 Spreadsheet Aid for Analyzing Thick-Walled Spheres and Cylinders 715 12–8 Shearing Stress in Cylinders and Spheres 716 12–9 Other Design Considerations for Pressure Vessels 719 12–10 Composite Pressure Vessels 722