Objectives of the Book
Applied Strength of Materials, Fourth Edition, provides a comprehensive coverage of the important topics in strength of materials with an emphasis on applications, problem solving, and design of structural members, mechanical devices, and systems. The book is written for the student in a course called Strength of Materials, Mechanics of Materials, or Solid Mechanics in an engineering technology program at the baccalaureate or associate degree level, or in an applied engineering program.
It is the intent of this book to provide good readability for the student, appropriate coverage of the principles of strength of materials for the faculty member teaching the subject, and a problem solving and design approach that is useful for the practicing designer or engineer. Educational programs in the mechanical, civil, construction, and manufacturing fields should find the book to be suitable for an introductory course in strength of materials.
Style
There is a heavy emphasis on the
applications of the principles of strength of materials to mechanical, structural, and construction problems while providing a firm foundation of understanding of those principles. At the same time, the
limitations on the use of analysis techniques are emphasized to ensure that they are applied properly. Both analysis and design approaches are used in the book.
Units are a mixture of SI Metric and U.S. Customary units, in keeping with the dual usage evident in U.S. industry and construction.
Prerequisites
Students are expected to be able to apply the principles of statics prior to using this book. For review, there is a summaryof the main techniques of the analysis of forces and momentum in the Appendix. Several example problems are included that are similar to the statics needed in practice problems in this book.
While not essential, it is recommended that students have completed an introductory course in calculus prior to studying this course. As called for by accrediting agencies, calculus is used to develop the key principles and formulas used in this book. The application of the formulas and most problem solving and design techniques can be accomplished without the use of calculus.
Features of the Book
The Big Picture. Students should see the relevance of the material they study. They should be able to visualize where devices and systems that they are familiar with depend on the principles of strength of materials. For this reason each chapter starts with a section called The Big Picture. Here the basic concepts to be developed in the chapter are identified and students are asked to think about examples from their own experience where these concepts are used. Sometimes they are asked to explore new things on their own to discover how a product works or how it can fail. They are coached to make observations about the behavior of common mechanical devices, vehicles, industrial machinery, consumer products, and structures. Educational philosophy indicates that students learn better and retain more when such methods are employed.
Problem-Solving Techniques. Students must also be able to solve real problems, complete the necessary calculations, manipulate units in equations, seek appropriate data, and make good design decisions. The example problems in this book are designed to help students master these processes. In addition, students must learn to communicate the results of their work to others in the field. One important means of communication is the presentation of the problem solutions in an orderly, well-documented manner using established methods. Example problems are set off with a distinctive graphic design and type font. Readers are guided in the process of formulating an approach to problem solving that includes:
a) Statement of the objective of the problem
b) Summary of the given information
c) Definition of the analysis technique to be used
d) Detailed development of the results with all of the equations used and unit manipulations
e) At times, comments on the solution to remind the reader of the important concepts involved and to judge the appropriateness of the solution.
f) At times, the comments present alternate approaches or improvements to the machine element or structural member being analyzed or designed.
The reader's thought process is carried beyond the requested answer into a critical review of the result. With this process, designers gain good habits of organization when solving their own problems.
Design Approaches. There is much more information about guidelines for design of mechanical devices and structural members than in most books on this subject. The design approaches are based on another book of mine, Machine Elements in Mechanical Design, Third Edition, 1999, from Prentice Hall. Learning about design in addition to analysis increases the usefulness of the book to students and professional users. There are some students who will not go on to a following course that emphasizes design. They should get some introduction to the principles of design in the introductory course in strength of materials. For those who do proceed to a design course, they should enter that course with a higher level of capability.
Extensive Appendix. To complement the use of design approaches, the Appendix provides a large amount of information on material properties, geometry of common areas and commercially available structural shapes, stress concentration factors, formulas for beam deflection, conversion factors, and many others. This allows for a wider variety of problems in the book and for creating tests and projects. It adds to the realism of the book and gives the student practice in looking for the necessary information to solve a problem or to complete a design.
Design Properties of Materials. Chapter 2 includes much information and discussion on the selection and proper application of engineering materials of many types, both metallic and nonmetallic. There is an extensive introduction to the nature of composite materials given along with commentary throughout the book on the application of composites to various kinds of load-carrying members. Readers are given information about the advantages of composites relative to traditional structural materials such as metals, wood, concrete, and plastics. The reader is encouraged to seek more education and experience to learn the unique analysis and design techniques required for the proper application of composite materials. Such materials are, in fact, tailored to a specific application and general tables of material properties are not readily available.
End-of-Chapter Problems. There is an extensive set of problems for student practice at the end of each chapter. They are typically organized around the main topics in the chapter. In general, they are presented in a graded manner with simpler problems followed by more comprehensive problems. With this edition, there are many additional problems at the end of each chapter for practice, review, and design.
Electronic Aids to Problem Solving and Design
Most chapters include computer assignments along with suggestions for the use of spreadsheets, computer programs, computer algebra software, and graphing calculators pertinent to strength of materials. Such electronic aids, when used to supplement the basic understanding of the principles presented in the book, lead to a deeper appreciation of those principles and their application to more problems and more complex problems. Examples of spreadsheets are given in the chapters on column analysis and pressure vessels.
Acknowledgments
I appreciate the feedback provided by both students and instructors who have used the earlier editions of this book. I am also grateful to my colleagues at the University of Dayton. I would like to thank S. David Dvorak, University of Maine, and Robert J. Michael, Penn State (Erie), who reviewed the book and offered helpful suggestions for improvements. I hope this edition has implemented those suggestions in a manner consistent with the overall approach of the book.
Robert L. Mott
University of Dayton
