The first edition of this book which was brought out in 1980 has gone through more than twenty reprints, i.e. almost one every year. While this was gratifying in one sense, at the same time there were many irritating features like typographical errors, wrong answers to some problems, broken types and others which kept appearing during several reprints. The book definitely required a revision and this advantage was taken to revise the entire book.

The present edition has many new features. As in the earlier edition, the first five chapters deal with the general analysis of mechanics of deformable solids. This approach is adopted for two main reasons. Firstly, this is a second level course which assumes on the part of the student some exposure to elementary strength of materials, which it is believed, has already provided the necessary motivation and the need to go a little deeper into the subject material. The general treatment as presented in the first five chapters will provide a firm foundation to the mechanics of deformable solids which will enable the student to analyse and solve a variety of strength-related design problems that are encountered in practice. The second reason is to bring into focus the assumptions made in obtaining several basic equations. Instances are many where equations presented in hand-books are used to solve practical problems without examining whether the conditions under which equations are obtained are satisfied or not.

Based on these convictions, the treatment starts with Analysis of Stress, Analysis of Strain and Stress-Strain relations for isotropic solids. These chapters are quite exhaustive and include material not usually found in standard books. Chapter 4 dealing with Theories of Failure or Yield Criteria is a general departure from the older texts. This treatment is brought earlier because, in applying any design equation in strength related problems, an understanding of the possible factors for failure, depending on the material properties, is highly desirable. Several sections in all these chapters have been rewritten and enlarged to make the text clearer. Mohr’s theory of failure has been considerably enlarged because of its practical application. Chapter 5 deals with energy methods, which is one of the important topics and hence, is discussed in great detail. The discussions in this chapter are very important because of their applicability to a wide variety of problems. This chapter is quite exhaustive covering the theorems of Virtual work, Castigliano, Kirchhoff, Menabrea and Engesser, and Maxwell-Mohr integrals. Several worked examples illustrate the applications of these theorems.

Bending of beams, Centre of Flexure, Curved Beams, etc. are covered in Chapter 6. This chapter also discusses the validity of Euler-Bernoulli hypothesis in the derivation of beam equations. Torsion is covered in great detail in Chapter 7. Torsion of circular, elliptical, equilateral triangular bars, thin-walled multiple cell sections, etc. are discussed. Another notable inclusion in this chapter is the torsion of bars having multiply connected sections which, in spite of its importance, is not generally found in standard texts. Analysis of axisymmetric problems like composite tubes under internal and external pressures, rotating discs, shafts and cylinders can be found in Chapter 8.

Stresses and deformations caused in bodies due to thermal gradients need special attention because of their frequent occurrences. Usually, these problems are shifted to books on Thermoelasticity. The analysis of thermal stress problems are not any more complicated than the traditional problems treated in books on Advanced Mechanics of Solids. The general analysis of mechanics covered in the first three chapters of the book will enable the student to follow with ease the contents of this chapter.

Elastic instability problems are covered in Chapter 10. In addition to topics on beam columns, this chapter exposes the student to the instability problem as an eigenvalue problem. This is an important concept that a student has to appreciate. Energy methods like those of Rayleigh-Ritz, Timoshenko, use of trigonometric series, etc. to solve buckling problems find their place in this chapter.

Chapter 11 is a new addition. This deals with an introduction to the mechanics of composites. Modern day engineering practices and manufacturing industries make use of a variety of composites. This chapter provides a good foundation to the mechanics of composites and is a natural extension of the constitutive relations and other aspects from isotropic to anisotropic solids, Orthotropic materials, off-axis loading, angle-ply and cross-ply laminates, failure criteria for composites, effects of Poisson's ratio, etc. are covered with adequate number of worked examples.

All problems at the end of each chapter are provided with answers. While SI units are used in most of the numerical examples and problems, a few of them are found with kgf, meter and second units. This is done deliberately to make the student conversant with the use of both sets of units since in daily life kgf is used for weight and force measurements; also, kgf/cm2 for pressure measurements. In those problems, where the units of kgf are used, their equivalents in SI units are also given.

In the preparation of the new edition, it is a pleasure to acknowledge the financial assistance provided by the Curriculum Development Cells-CCE of the Indian Institute of Technology, Chennai, and the Indian Institute of Science, Bangalore.

L S SRINATH