Forward

“Throughout the wide fields of engineering, the most fundamental requirement is a sound knowledge of the first principles of mechanics coupled with an intimate understanding of the properties of materials.  More problems arise from weaknesses in mechanical design than from any other cause, impressing upon us the necessity of being well versed in the basic principles of mechanical engineering.” -

Sir George H. Nelson
Institution of Electrical Engineers

Re-Work of 25.465

Students are expected to review chapters 4 & 5 in the text.  The ability to draw shear and bending moment diagrams, compute stresses and determine principal stresses using Mohr’s circle are assumed.

Preface

These class notes are being used for the Machine Design course in the Mechanical and Industrial Engineering Department of the University of Manitoba in the fall term of 2000.  They cover all the materials required in this course.  The team design project, which is required for the course, is not included in these notes.  The text book used for the class is Fundamentals of Machine Elements – 1^st Edition, written by Hamrock, Jacobson and Schmid, published by McGraw-Hill.  Therefore, all the page numbers, figures, tables and problems referred to in the notes mean those in the text book.

Table of Contents

Forward
Preface

Chapter One (Failure Theories)
1.1  Introduction
1.2  Stress-strain Diagrams and Factor of Safety
1.3  Failure Theories of Ductile Materials with Steady Loading
1.4  Failure of Brittle Materials with Steady Loading
1.5  Stress Concentration Factors

Chapter Two (Fatigue Failure)
2.1  Introduction
2.2  Fatigue Strength under Fluctuating Loads
2.3  Construction of the S-M Diagram
2.4  Endurance Limit Modification
2.5  Non-Zero Mean Stress
2.6  Loading in the Finite Range

Chapter Three (Thickwall Cylinders & Press Fits)
3.1  Introduction
3.2  Thick-walled Cylinders
3.3  Compound Cylinders

Chapter Four (Shafts and Couplings)
4.1  Introduction
4.2  Shaft Design
4.3  Torsion of Non-circular Shafts
4.4  Keys
4.5  Couplings
4.6  Flywheels

Chapter Five (Lubrication, Friction, Wear, and Hydrostatic Bearings)
5.1  Introduction
5.2  Tribology
5.3  Elastohydrodynamic Lubrication
5.4  Characterisation of surface roughness
5.5  Using surface roughness
5.6  Viscosity
5.7  Hydrodynamic Bearings

Chapter Six (Anti-friction Bearings)
6.1  Introduction
6.2  Types of Anti-Friction Bearings
6.3  Design Aspects
6.4  Bearing Loading
6.5  Bearing Life
6.6  Life of Anti-Friction Bearings
6.7  Selection of Bearings for Variable Loading
6.8  Lubrication of Anti-Friction Bearings

Chapter Seven (Spur Gears and Bevel Gears)
7.1  Introduction
7.2  Spur Gears
7.3  Allowable Stresses on Gear Teeth
7.4  Bevel Gears

Chapter Eight (Helical Gears and Worm Gears)
8.1  Introduction
8.2  Helical Gears
8.3  Worm Gears

Chapter Nine (Springs)
9.1  Materials
9.2  Basic Equation
9.3  Helical Compression Springs
9.4  Shear Stresses in Wire
9.5  Spring Buckling
9.6  Fatigue
9.7  Extension Helical Springs
9.8  Helical Torsion Springs
9.9  Leaf Springs

Chapter Ten (Clutches and Brakes)
10.1  Introduction
10.2  Clutches
10.3  Brakes
10.4  Band Brake

Chapter Eleven (Belts, Cables, and Chains)
11.1  Introduction
11.2  V-belts
11.3  Roller Chains

Chapter Twelve (Threaded Fasteners & Power Screws)
12.1  Introduction
12.2  Thread Terminology and Standards
12.3  Bolt Stresses under Steady Loading
12.4  Bolt Stresses under Fluctuating Loads
12.5  Power Screws