5R24. Mechanics of Materials. - A Bedford and K Liechti (Dept of Aerospace Eng and Eng Mech, Univ of Texas, Austin TX). Prentice Hall, Upper Saddle River NJ. 2000. 627 pp. CD-ROM included. ISBN 0-201-89552-8. $103.00.
Reviewed by M Epstein (Dept of Mech Eng, Univ of Calgary, 2500 University Dr NW, Calgary AB, T2N 1N4, Canada).
In a market already flooded with textbooks on Mechanics of Materials, the appearance of yet another one is greeted with a mixture of skepticism and hope. The preface to this book starts by feeding the latter when it declares that the “long-held dream of the merger of continuum solid mechanics and material science into a unified field” is near at hand. Whether or not this is true, or even desirable, this book does little to contribute in pointing the prospective student in that direction. After a statement containing an almost unforgivable spelling error (“the principle emphasis”), the preface gives us a description of the contents of the book. It is practically identical to that of any of the textbooks already available at the same level. Perhaps the only difference is the introduction of the discussion of general states of stress and strain after the treatment of torsion and before the treatment of bending. As usual, however, stress-strain relations are included as a part of the chapter on strain, rather than as a separate chapter on constitutive behavior, thus doing little to advance the long-held dream just mentioned.
Having said all that, the book is professionally produced, with excellent figures and interesting examples. An accompanying CD offers interesting interactive opportunities for practice beyond the problems appearing in the book itself. This feature will certainly be very attractive to students and instructors alike.
The book is organized in 12 chapters and 7 appendices. Chapter 1 consists mainly of a review of Statics. The vector equilibrium equations are stated, but there seems to be no review of the concept of the moment of a force as a vector product. All of the examples discussed are planar, but at the end of the chapter a couple of examples are spatial. It is not clear, therefore, what the student is expected to do. Chapter 2, entitled “Measures of stress and strain,” is a good elementary introduction to particular cases where these can be calculated by simple means. In the next chapter, on axially loaded bars, the standard method of introducing Young’s modulus and Poisson’s ratio is followed. There is a danger here that the student might elevate these concepts to universal truths for all materials, but this is preempted by a good discussion at the end of the chapter on general features of material behavior, particularly under a uniaxial test. Elementary statically indeterminate situations are presented, and a discussion is attempted of the basic two methods (flexibility and stiffness). Unfortunately, this discussion is not very illuminating, and the conceptual difference between the formulations is dismissed in the context of the problems to be treated. One wonders what a student is supposed to do or think with such a piece of information.
Chapter 4 is devoted to torsion of shafts, including some plasticity and simply connected thin-walled tubes. As already mentioned, the next two chapters are devoted to a discussion of the concepts of general states of stress and strain, including Mohr’s circle for both. A welcome treatment of the tetrahedron argument and its consequences is one of the nice features of this part of the book. Spherical and cylindrical pressure vessels are used to produce non-trivial examples. Chapter 7 presents the concepts of internal forces in planar beams, including the differential relations between bending moment and shear force.
Chapter 8, at 70 pages the longest of the book, deals with in beams, including the shear formula, composite beams, and elastoplastic response. Chapter 9, on small deflections of planar elastic beams, is adequate, but omits the method of singularity functions. The book ends with three chapters on special topics. Chapter 10 is an introduction to Euler buckling, Chapter 11 deals with energy methods (including Castigliano’s second theorem), and Chapter 12 discusses some criteria of failure.
Overall, although not attempting a new methodology, this is a good book that can be used as a textbook for a first course in Mechanics of Materials.