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Purchase any of our products at your local college store or at our preferred online store www. Printed in the United States of America 1 2 3 4 5 6 7 13 12 11 10 www.org To Jean, Leslie, Lori, John, Nicholas and To Judy, Nicholas, Jennifer, Timothy www.org Preface This textbook is intended for use in a first course in mechanics of materials. Programs of instruction relating to the mechanical sciences, such as mechan- ical, civil, and aerospace engineering, often require that students take this course in the second or third year of studies. Because of the fundamental nature of the subject matter, mechanics of materials is often a required course, or an acceptable technical elective in many other curricula. Students must have completed courses in statics of rigid bodies and mathematics through integral calculus as prerequisites to the study of mechanics of materials. This edition maintains the organization of the previous edition. The first eight chapters are dedicated exclusively to elastic analysis, including stress, strain, torsion, bending and combined loading. An instructor can easily teach these topics within the time constraints of a two-or three-credit course. The remaining five chapters of the text cover materials that can be omitted from an introductory course. Because these more advanced topics are not interwoven in the early chapters on the basic theory, the core mate- rial can e‰ciently be taught without skipping over topics within chapters. Once the instructor has covered the material on elastic analysis, he or she can freely choose topics from the more advanced later chapters, as time permits. Organizing the material in this manner has created a significant savings in the number of pages without sacrificing topics that are usually found in an introductory text. The most notable features of the organization of this text include the following: . Chapter 1 introduces the concept of stress (including stresses acting on inclined planes). However, the general stress transformation equations and Mohr’s circle are deferred until Chapter 8. Engineering instructors often hold o¤ teaching the concept of state of stress at a point due to combined loading until students have gained su‰cient experience ana- lyzing axial, torsional, and bending loads. However, if instructors wish to teach the general transformation equations and Mohr’s circle at the beginning of the course, they may go to the freestanding discussion in . Chapter 8 and use it whenever they see fit. Advanced beam topics, such as composite and curved beams, unsym- metrical bending, and shear center, appear in chapters that are distinct from the basic beam theory. This makes it convenient for instructors to . choose only those topics that they wish to present in their course. Chapter 12, entitled ‘‘Special Topics,’’ consolidates topics that are important but not essential to an introductory course, including energy methods, theories of failure, stress concentrations, and fatigue. Some, but not all, of this material is commonly covered in a three-credit course at the discretion of the instructor.org viii Preface . Chapter 13, the final chapter of the text, discusses the fundamentals of inelastic analysis. Positioning this topic at the end of the book enables the instructor to present an e‰cient and coordinated treatment of elastoplastic deformation, residual stress, and limit analysis after . students have learned the basics of elastic analysis. Following reviewers’ suggestions, we have included a discussion of the torsion of rectangular bars. In addition, we have updated our discussions of the design of columns and reinforced concrete beams. The text contains an equal number of problems using SI and U. Cus- tomary units. Homework problems strive to present a balance between directly relevant engineering-type problems and ‘‘teaching’’ problems that illustrate the principles in a straightforward manner. An outline of the applicable problem- solving procedure is included in the text to help students make the sometimes di‰cult transition from theory to problem analysis. Throughout the text and the sample problems, free-body diagrams are used to identify the unknown quantities and to recognize the number of independent equations. The three basic concepts of mechanics—equilibrium, compatibility, and constitutive equations—are continually reinforced in statically indeterminate problems. The problems are arranged in the following manner: . Virtually every section in the text is followed by sample problems and homework problems that illustrate the principles and the problem- . solving procedure introduced in the article. Every chapter contains review problems, with the exception of optional topics. In this way, the review problems test the students’ compre- hension of the material presented in the entire chapter, since it is not always obvious which of the principles presented in the chapter apply to . the problem at hand. Most chapters conclude with computer problems, the majority of which are design oriented. Students should solve these problems using a high-level language, such as MATHCAD= or MATLAB=, which minimizes the programming e¤ort and permits them to concentrate on the organization and presentation of the solution. Ancillaries To access additional course materials, please visit www. At the cengagebrain.com home page, search for the ISBN of your title (from the back cover of your book) using the search box at the top of the page, where these resources can be found, for instructors and stu- dents. The following ancillaries are available at www. Study Guide to Accompany Pytel and Kiusalaas Mechanics of Materi- als, Second Edition, J. The goals of the Study Guide are twofold. First, self-tests are included to help the student focus on the salient features of the assigned reading. Second, the study guide uses ‘‘guided’’ problems which give the student an opportunity to work through representative problems before attempting to solve the . problems in the text. The Study Guide is provided free of charge. The Instructor’s Solution Manual and PowerPoint slides of all figures and tables in the text are available to instructors through http://login.org Preface ix Acknowledgments We would like to thank the following reviewers for their valuable suggestions and comments: Roxann M. Hayes, Colorado School of Mines Daniel C. Jansen, California Polytechnic State University, San Luis Obispo Ghyslaine McClure, McGill University J. Mohsen, University of Louisville Hassan Rejali, California Polytechnic State University, Pomona In addition, we are indebted to Professor Thomas Gavigan, Berks Campus, The Pennsylvania State University, for his diligent proofreading. Andrew Pytel Jaan Kiusalaas www.org 1019763_FM_VOL-I.qxp 9/17/07 4:22 PM Page viii 1 2 3 4 5 6 7 8 9 10 11 This page was intentionally left blank 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 S 50 R 51 www.org 1st Pass Pages Contents CHAPTER 1 3.3 Torsion of Thin-Walled Tubes 91 Stress 1 *3.4 Torsion of Rectangular Bars 99 1.2 Analysis of Internal Forces; Stress 2 CHAPTER 4 1.3 Axially Loaded Bars 4 Shear and Moment in Beams 107 a. Saint Venant’s principle 5 4.2 Supports and Loads 108 c. Stresses on inclined planes 6 4.3 Shear-Moment Equations and d. Procedure for stress analysis 7 Shear-Moment Diagrams 109 1. Procedure for determining shear force and bending moment CHAPTER 2 diagrams 110 4.4 Area Method for Drawing Shear-Moment Strain 31 Diagrams 122 2.2 Axial Deformation; Stress-Strain b. Concentrated forces and couples 124 Diagram 32 c. Working stress and factor of safety 36 CHAPTER 5 2.3 Axially Loaded Bars 36 Stresses in Beams 139 2.4 Generalized Hooke’s Law 47 5. Uniaxial loading; Poisson’s ratio 47 5.5 Statically Indeterminate Problems 54 c. Flexure formula; section modulus 143 e. Procedures for determining bending CHAPTER 3 stresses 144 5.3 Economic Sections 158 Torsion 75 a. Standard structural shapes 159 3. Procedure for selecting standard 3.2 Torsion of Circular Shafts 76 shapes 160 a.4 Shear Stress in Beams 164 b. Analysis of flexure action 164 c. Horizontal shear stress 165 d. Vertical shear stress 167 e. Statically indeterminate problems 80 * Indicates optional sections.org xii Contents d. Discussion and limitations of the shear 8.3 Combined Axial and Lateral stress formula 167 Loads 284 e. Rectangular and wide-flange 8.4 State of Stress at a Point sections 168 (Plane Stress) 293 f. Procedure for analysis of shear a. Reference planes 293 stress 169 b. State of stress at a point 294 5.5 Design for Flexure and Shear 177 c. Sign convention and subscript 5.6 Design of Fasteners in Built-Up notation 294 Beams 184 8.5 Transformation of Plane Stress 295 a. Principal stresses and principal CHAPTER 6 planes 296 Deflection of Beams 195 c. Maximum in-plane shear stress 298 6. Summary of stress transformation 6.2 Double-Integration Method 196 procedures 298 a. Di¤erential equation of the elastic 8.6 Mohr’s Circle for Plane Stress 305 curve 196 a. Construction of Mohr’s circle 306 b. Double integration of the di¤erential b. Properties of Mohr’s circle 307 equation 198 c. Verification of Mohr’s circle 308 c. Procedure for double integration 199 8.7 Absolute Maximum Shear Stress 314 6.3 Double Integration Using Bracket a. Plane state of stress 315 Functions 209 b. General state of stress 316 *6.4 Moment-Area Method 219 8.8 Applications of Stress Transformation to a. Moment-area theorems 220 Combined Loads 319 b. Bending moment diagrams by 8.9 Transformation of Strain; Mohr’s Circle for parts 222 Strain 331 c. Application of the moment-area a. Review of strain 331 method 225 b. Transformation equations for plane 6.5 Method of Superposition 235 strain 332 c. Mohr’s circle for strain 333 8.10 The Strain Rosette 338 CHAPTER 7 a.
