ST. FRANCIS XAVIER UNIVERSITY

Department of Engineering

P. O. Box 5000
Antigonish, Nova Scotia

ENGR 235 STRENGTH OF MATERIALS

Instructor: E.C.(Emeka) Oguejiofor, Ph.D., P.Eng.                                            September 2004

Course Objectives     Course Outline     Grading Scheme     Recommended Text     Material Testing

Preface

Regardless of how complex a structure or machine appears, it will be found, upon close examination, to consist of different parts or members connected together in such a way as to withstand externally applied loads. Types of load frequently encountered in engineering can be classified into three groups, namely: axial loads (tension or compression), bending and torsion. In many practical situations, however, a member may be subjected to the action of two or more of these basic types of load in various combinations.

Every engineering structure must be designed to satisfy two criteria: the strength criteria and the serviceability criteria. The strength criteria require that the structure be strong enough to withstand the maximum load it is expected to experience during its life span. The serviceability criteria requires that the structure behaves the way it is expected to, e.g. it must be stiff enough to avoid excessive deflections, vibrations, cracks, settlement etc. Both the strength and stiffness of a structural member are functions of its size, shape and physical properties of the material from which the member is made.

Strength of Materials (or Mechanics of Materials as it is often called) is mainly concerned with the study of analytical methods for determining the strength, stiffness (deformation characteristics) and stability of load carrying members. The main objective of the course is to predict how the geometric and physical properties of a body will influence its behaviour when subjected to loads.

The focus of the course is on analysis as opposed to design. The analysis of a structure involves the calculation of the internal forces, stresses, strains and displacements of the structure under known loading conditions. Usually for structural analysis, the material and dimensions of the structure, as well as the loading on it, are known. Structural design, on the other hand, involves the choice of appropriate material and member dimensions to support a known set of loads according to governing code provisions. Structural design is typically a repetitive process involving trial and correction.

We will be looking at the internal effects of forces acting on a body. Unlike in Statics where bodies are assumed to be perfectly rigid, the deformation of different bodies under a variety of loads is of primary concern in the study of Strength of Materials. Hence, this subject can be viewed as the Mechanics of Solid Deformable Bodies. We will examine the patterns of stress distribution under various types of loads.

Like in Statics, this subject can best be mastered by understanding the basic principles and applying these in solving the problems being considered. Use of properly drawn free body diagrams will greatly simplify many problems as well as assist you in visualizing the problem and the quantities being calculated.

Course Objectives

To develop a working knowledge of the relationship between the loads applied to a non-rigid body and the resulting internal forces, deformations, and stresses induced in the body; to develop a conceptual “feel” for the way a structural member will respond to applied load; to understand the connection between the type of load applied to a material and the material’s failure mechanism; to further develop analytical and problem-solving skills through the application of the fundamental principles of mechanics of materials to the solution of a wide range of problems.

Recommended Text:  Mechanics of Materials, 6th Edition by James M. Gere

Course Outline

Course WebPagehttp://www.stfx.ca/people/eoguejio/235/235intro.html

• Laboratory Test Report                            10%
• Weekly Problem/Tutorial Sessions            10%
• Impromtu Quizzes                                     15%
• Mid-Term Test (October 18)                    25%
• Final Examination (TBA by Registrar)       40%
Problem/Tutorial Schedule:  Mondays: 2.15 p.m. - 5.00 p.m.

Office Hours:  Mon/Tues:  11.00 am. - 12.30 p.m;  Wed/Thurs:  10.00 am. - 12.00. You should feel free to come in at any time and discuss any problems you may have. My phone number and email address are 867-2229 and eoguejio@stfx.ca, respectively.

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