# Statics and Mechanics of Materials:

## Introduction/Purpose

The purpose of courses in engineering mechanics is to describe the effects that forces have on bodies and structures. The traditional introduction to mechanics consists of a course in statics followed by a course in mechanics of materials. The principles of statics are used to determine the forces that act on or in a structure, assuming that the structure is perfectly rigid and does not deform. These forces, along with the theory developed in mechanics of materials, are then used to determine how the material deforms or reacts.

This book approaches the teaching of mechanics using the just-in-time approach. As soon as the student has studied equilibrium of concurrent force systems, he or she is ready to calculate stretches of wires and rods using a one-dimensional Hooke's law. After studying rigid-body equilibrium, the student is ready to calculate stresses and deformation in members such as shafts and beams. When the two subjects are integrated in a unified course in this manner, students can immediately see the use of the principles of statics, they can see the relationship of statics and mechanics of materials.

## Organization

After a brief introduction to mechanics in Chapter 1, Chapter 2 describes the characteristics of forces and develops the mathematics necessary to work with concurrent forces. These concepts are immediately used in Chapter 3 to calculate the forces acting on a particle in equilibrium. The basic discussion is completed in Chapter 4 where stress, strain, and the relationship between loads and deformation is presented.

Chapter 5 continues the description of forces, develops the concept of equivalent force-couple systems, and explores the effects of forces and couples on rigid bodies. Chapter 6 presents the equilibrium of rigid-bodies and its use in several structural applications. The final five chapters consist of standard topics of mechanics of materials--torsion of circular shafts (Chapter 7), flexural stresses in beams (Chapter 8), deflections of beams (Chapter 9), combined loadings (Chapter 10), and columns and other compressive members (Chapter 11).

Second moments of areas are introduced and developed where needed in Chapters 7 and 8.

## Engineering Emphasis

This book is designed to emphasize the required fundamental principles, with numerous applications to demonstrate and develop logical and orderly methods of procedure. Instead of deriving numerous formulas for all types of problems, we have stressed the use of free-body diagrams and the equations of equilibrium, together with the geometry of the deformed body and the observed relations between stress and strain, for the analysis of the force system acting on the body.

The emphasis is always on keeping the material understandable to the student. Clarity is never sacrificed for the sake of mathematical elegance. Calculus and vector methods are used where necessary and where appropriate. However, if scalar methods are more appropriate and/or are more commonly used by practicing engineers, then these methods are generally used in the Example Problems. Likewise, students are encouraged to develop the ability to select the mathematical tools most appropriate for the particular problem they are attempting to solve.

## Sample Syllabi

Because we have been asked, we make available the following abbreviated syllabi for courses using our Statics and Mechanics of Materials text. The following pointers are to 60-hour (6 quarter credit or 4 semester credit), 75-hour (5 semester credit), 90-hour (9 quarter credit or 6 semester credit) variants of an integrated Statics and Mechanics of Materials syllabus.

These syllabi are purposely vague and obviously are only a few of the many variations possible. More detailed syllabi will depend on whether the courses are intended primarily for civil engineering students or for mechanical engineering students; on whether the courses are primarily taken by freshman students or sophomore students; on whether the students will be taking additional mechanics courses or not; etc.

However, we hope that these brief outlines will be useful to instructors as you make up your syllabi.

An abbreviated syllabus for a 6 quarter credit or a 4 semester credit Statics and Mechanics of Materials course.

An abbreviated syllabus for a 5 semester credit Statics and Mechanics of Materials course.

An abbreviated syllabus for a 9 quarter credit or a 6 semester credit Statics and Mechanics of Materials course.

Comments and suggestions should be sent to:
 sturges@iastate.edu Leroy D. Sturges 2019 Black Engineering Iowa State University Ames, Iowa 50011-2162 515-294-6242

©1998, Leroy D. Sturges (revised 3 August 1998)