1. No category

1
MECH 344/M
Machine Element Design
Time: M _ _ _ _14:45 - 17:30
Lecture 1
Contact Details
Instructor: Dr. S. Narayanswamy
Office Room: EV – 004.124
Phone: 848-2424 (7923)
Office Hours: M _ _ _ _ 11:00 –12:00 or by appointment
e-mail: [email protected]
Web site: http://users.encs.concordia.ca/~nrskumar
About the course

This course covers the basic principles employed in the
design of standard mechanical components subjected
to operating force and moment fields

Lectures - 3 hours each

13 Lectures of all - one is an introductory lecture

2 Term Tests

Final exam
Class logistics

3 Continuous teaching hours/week --W--
14:45 –17:30 @ FGB040

13 lectures + 2 Term Tests + Final

Course Web Page

http://users.encs.concordia.ca/~nrskumar
Text book and other reference
•
TEXTBOOK
•
“Fundamentals of Machine Component Design”
Robert C. Juvinall and Kurt M, Marshek, Wiley; 5th edition.
•
REFERENCES
1. Richard G. Budynas and Keith Nisbett, “Shigley’s Mechanical
Engineering Design,” 10th Edition, McGraw-Hill, 2014.
2. M. F. Spotts, T. E. Shoup and L. E. Hornberger, “Design of Machine
Elements,” 8th Edition, Prentice-Hall, 2004.
3. Robert L. Norton, “Machine Design– An Integrated Approach,” 5th
Edition, Prentice Hall, 2013.
4. S. R. Schmid, B. J. Hamrock, and B. Jacobson, “Fundamentals of
Machine Elements,” 3rd Edition, CRC press, 2013.
The Tutorial

There will be 1 and half hour tutorial on Thursdays for
2 different sections


Tut MA
---J- (17:45-19:25)
SGW H-564

Tut MB
---J- (17:45-19:25)
SGW H-544
There will be TAs who will provide more details on
the problem solving

Attending tutorials is necessary as this will help in
preparing you for the exams
Term Tests

There will be two term tests in all during the term

The tests will be for 75 minutes on the 6th and 11th week during
Tutorial hours

Test #1: Thursday February 19, 2015 (Open Book-textbook only)

Test #2: Thursday April 02, 2015 (Open Book-textbook only)

Material covered for each test will be given in class one week prior
to the date of the test (definitely not by email)

Duration of the test will be 75 Minutes

Open Book-textbook only

20% weightage towards final grade
Grading Scheme


Grade composition:

Two Term Tests :
40%

Final:
60%
To pass the course you have to

Pass the final

Attend the term tests as well as midterm and get good marks
Final Test

The final exam will have problems similar to the ones in
tutorials

Conducted during the university wide exam period

Duration of the test: 3 hours.

Write the final exam with confidence that you will do
very well

It is IMPERATIVE to pass the final to pass the course
10
General Notes

In order to pass the course you have to obtain at least 50%
of mark from the Final Exam.

Electronic communication devices (including cell phones)
are not allowed in examination rooms.

Only “Faculty Approved Calculators” will be allowed in
examination rooms.

In the event of extraordinary circumstances beyond the
University's control, the content and/or evaluation scheme
in this course is subject to change
Contents of today's lecture
•
•
•
•
Introduction
Machine Design
Design Process
Safety Factors
Fundamentals of Machine
Component Design
Fifth Edition
Robert C. Juvinall • Kurt M. Marshek
Chapter 1
Mechanical Engineering Design
in Broad Perspective
Copyright © 2012 by John Wiley & Sons, Inc. All rights reserved.
Whatever area you will choose…
This course is fundamental.
Outline of the course
12-Jan
week 1
Introduction to Design: An overview of the subject, Machine Design Process
Fundamental Topics from Mechanics of Materials:
19-Jan
week 2
26-Jan
week 3
2-Feb
week 4
9-Feb
week 5
16-Feb
week 6
2-Mar
week 7
Stresses due to Axial, Bending, Direct Shear, Transverse Shear and Torsional Loadings; Curved
Beams; Combined Stresses- Mohr Circle; Stress Concentration Factors; Residual Stresses; Thermal
Stresses
Static Failure Theories: Failure of Ductile Materials under Static Loading (Maximum Shear Stress
Theory, Maximum Distortion Energy Theory); Failure of Brittle Materials under Static Loading
(Modified Mohr Theory)
Fatigue Failure Theories: Basic Concepts and Standard fatigue Test; Fatigue Strengths for Reversed
Bending, Reversed Axial Loading and Reversed Torsional Loading; Fatigue Strength for Reversed
Biaxial Loading; Influence of Surface and Size on Fatigue Strength; Effect of Mean Stress on Fatigue
Strength; Effect of Stress Concentration; Fatigue Life Prediction with Randomly Varying Loads
Design of Screws and Fasteners: Thread Forms, Terminology and Standards; Power Screws; Screw
Stresses; Threaded Fasteners; Fasteners Materials and Methods of Manufacture; Bolt Tightening
and Initial Tension; Bolt Tension with External Joint-Separating Force; Bolt Selection for Static
Loading; Bolt Selection for Fatigue Loading
week 8
Design of Springs: Coil Spring Stress and Deflection; Stress and Strength Analysis for Helical
Compression Springs-Static Loading; End Designs of Helical Compression Springs; Bucking
Analysis of Helical Compression Springs; Design Procedure for Helical Compression Springs-Static
Loading; Design of Helical Compression Springs for Fatigue Loading
16-Mar
week 9
Design of Spur Gears: Geometry and Nomenclature; Interference and Contact Ratio; Gear Force
Analysis; Gear-Tooth Strength; Gear-Tooth Bending Fatigue Analysis- Basic Concepts and
Recommended Procedure; Gear Tooth Surface Fatigue Analysis-Basic Concepts and
Recommended Procedure
23-Mar
week 10
30-Mar
week 11
13-Apr
week 12
16-Apr
week 13
9-Mar
Design of Shafts and Keys: Shaft Loads; Attachments and Stress Concentrations; Shaft Stresses;
Rotating-Shaft Dynamics; Overall Shaft Design; Keys
Design of Journal and Rolling-Element Bearings: Rolling-Element Bearing Types; Fitting of RollingElement Bearings; Catalogue Information for Rolling-Element Bearings; Bearing Selection based on
Fatigue Life Requirement
Review
4 (must be
reviewed by
students)
6
(Sections 6.56.12)
8
(Sections 8.18.12)
10
12
(Sections 12.112.8)
15
(Sections 15.115.12)
17
(Sections 17.117.6)
14
15
Engineering design is the process of applying the various
techniques and scientific principles for the purpose of defining a
device, a process, or a system in sufficient detail to permit its
realization.
A Machine is:
(1) An apparatus consisting of interrelated units, or
(2) A device that modifies force or motion
A Structure has no moving parts, e.g. bridges, buildings.
• A machine is a device that
transforms energy
• Has fixed and moving parts
• Connects the source of power and
the work to be done
• In case of motor and generator
electricity is converted to mechanical
movement and vice versa
• In IC engine, connecting rod and
crank shaft transfers energy
The design process
• Design involves constrained creation
• Constraints:
 Technology limits
 Human and environment concerns
 Durability and reliability
 Cost
 Market requirements
 Etc.
Thedesign process
•
•
•
•
•
•
•
•
REPRESENTATION
Basic requirements to be able to
PERCEPTION
perform a design
KNOWLEDGE
All the above interacts in your
judgment even if you are not
INTUITION
aware of it
CONCEPT
You have to train your judgment
PURE CONCEPT
to be able to perform solutionEMPIRICAL CONCEPT solving based thinking
NOTION
• IDEA
The design process
• A design is created after analysis, full
understanding of requirements and
constraints and synthesis
• Two individuals may not come with the
same solution to the same problem
 Example: Connect two straight pipes ND 4” to
avoid leaking of the gas and to permit easy
maintenance of the segment
Solutions to the problem
• Multiple: flanges, clips, clamps, seals, etc.
1. Problem Defn.
2. Concept and
ideas
The design process
3. Solutions
4. Models/Prototype
5. Production and
working drawings
Concurrent engineering
approach
The design process
A Component !
29
30
31
32
33
34
35
36
37
Factor of Safety N =
Material Strength
Design Load
Fundamentals of Machine
Component Design
Fifth Edition
Robert C. Juvinall • Kurt M. Marshek
Chapter 2
Load Analysis
Copyright © 2012 by John Wiley & Sons, Inc. All rights reserved.
39
45
46
47
49
50
The sections chosen for load determination in the previous examples were, by simple
inspection, clearly those subjected to the most critical loading.
In more complicated cases, however, several sections may be critical, and their locations
less obvious.
In such instances it is often helpful to employ an orderly procedure
of following the “lines of force” (approximate paths taken by the force, determined
by simple inspection) through the various parts, and noting along the way any sections
suspected of being critical. Such a procedure is illustrated in the following example.
51
Assumptions:
1. The weight of the yoke connection can be ignored.
2. The load is divided equally between the two prongs of the fork (the loads and
yoke connection are perfectly symmetrical).
3. The load in each prong is divided equally between the portions on each side of
the hole.
4. Distributed loads are represented as concentrated loads.
5. The effects of pin, blade, and fork deflections on load distribution are negligible.
6. The pin fits snugly in the fork and blade.
52
53
54
55