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Department of Mechanical and Materials Engineering
The University of Western Australia


Notes on

DESIGN AND ANALYSIS

OF MACHINE ELEMENTS

 

Douglas Wright


 
 
 

CONTENTS

Most photographs may be enlarged by clicking their images.

INTRODUCTION

NOMENCLATURE

DESIGN

What is Design?; why do we design ?; how do we design - problem statement, creating a bank of solution candidates, constraints & criteria, practicalising the candidates, evaluating the candidates, the feasibility study; where do we go from here?; more advanced considerations.
Appendices - an improvement problem; analysis of a spring driven vehicle; springs as energy stores; extract from JCH Roberts, Creativity.
 
STRESS, STRENGTH AND SAFETY
Safety factor; stress concentration; static indeterminacy; elementary load building blocks; stress & strain resolution; failure theories; putting it all together; design equations for static round shafts; power transmission shafts.
Appendix - indeterminate assemblies of multiple components.
 
MISCELLANEOUS STRENGTH TOPICS
Castigliano's theorem; curved beams; asymmetric bending; contact stresses.
 
SPRINGS
Types of springs; close coiled round wire helical compression springs; the spring characteristic; stresses & stiffness; buckling; wire materials; presetting; fatigue loading; spring design.
Appendix - presetting a torsion bar.
 
THREADED FASTENERS
Thread geometry; screw thread mechanics; static failure; loads in an elastic bolted assembly; preload and its control; fluid pressurised joints; bolt fatigue; non-uniformly loaded bolt groups.
 
WELDED JOINTS
Fillet welded joints; geometric properties of lines; traditional analysis; throat stresses and joint safety; unified analysis; conclusion.
Appendix - the compliant lap joint.
 
CYLINDERS
Axial stress; thin cylinders; thick cylinders; design equations; strains; autofrettage; compound cylinders; torsional loading.
 
PRESSURE VESSELS
Corrosion; welded joint efficiency; thin shells of revolution - heads; compensation; pipes and flanges; inspection openings; supports; design.
 
SQUIRREL CAGE MOTORS
Characteristics of a steady load and of a motor; matching a motor to a given steady load; acceleration; periodic loading. Hydraulic couplings.
Appendix - integration in practice.
 
V-BELT DRIVES
Overall geometry; kinetics; fatigue; drive selection; effectiveness; approximate solutions; V-flat and pivoted motor drives. Traction mechanics.
Appendix - commercial selection tables.
 
BRAKES
System dynamics; linings. Brake analysis: translating brakes - short and long shoes; drum brakes - short, long rigid and hinged shoes; twin shoe brakes. The braked wheel; braking of vehicles; wheel lock; the vehicle and brake control characteristics.
 
SPUR GEARS
Overall kinetics of a gear pair; epicyclic trains; conjugate tooth action; the involute tooth; the generation process - tooth systems; profile shift; gear meshing. Gear failure - reliability; tooth forces; bending strength; pitting resistance; varying duty.
Appendices - continued fractions; geometry of the involute gear tooth.
 
BUCKLING
Buckling of thin walled structures; stability of equilibrium; effects of imperfections. Submerged pipelines. Practical columns - design equations.
 
FRACTURE MECHANICS
Fatigue of ductiles; stress concentration; linear elastic fracture mechanics; plasticity; yielding fracture mechanics - the R6 technique; fatigue crack growth. Crack growth kinetics.
 
FINITE ELEMENTS
Linear 1-networks; extension to 2- and 3-networks. The Rayleigh-Ritz method. Finite element theory applied to elasticity - equilibrium of the discretised body; element stiffness. Implementation; condensation and bandwidth; discretisation.
Appendices - the refining process; "FEM1" User's Guide.
 
UNITS, DIMENSIONS & CONVERSION FACTORS

PROGRAM DIRECTORY



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