In this book, the study of materials mechanics is based on the understanding of some fundamental concepts and the use of simplified models. This approach enables the development of all necessary equations in a logical manner and the clear formulation of the conditions under which these equations can be safely applied in the analysis and design of real engineering structures and machine elements.

Free body diagrams are extensively used. Throughout the book, free body diagrams are utilized to determine external or internal forces. The use of "equations of shapes" will also help students understand the superposition of loads and the stresses and strains that result. Design concepts are discussed throughout the book whenever appropriate.

In Chapter 1, a discussion of the application of the safety factor in design is presented, where the concepts of allowable design stress and load and limit load factors are introduced. A careful balance is consistently maintained between SI and U.S. measurement units.

Because it is essential for students to effectively manage both SI and U.S. measurement units, half of the examples and problems are stated in SI units and the other half in U.S. units. Since a large number of problems are available, instructors can solve the problems using whichever measurement system they deem most suitable for their class.

Optional sections present advanced or special topics. Topics such as residual stresses, torsion of non-circular thin-walled members, bending of curved members, shear stresses in unsymmetrical members, and failure criteria have been included in the optional sections, and the delivery of these sections depends on the instructor.

To maintain coherence and understanding of the subject, these sections are presented in the appropriate order, where they logically belong. Thus, even when the sections are not taught, students can easily refer to them if needed. For convenience, all optional sections have been marked with an asterisk.