Foundation of Engineering

1. FOUNDATIONS OF
ENGINEERING

2. CHAPTER # 5
Introduction to design

3. WHAT IS DESIGN ?
The ability to create something out of nothing is called Design.
ENGINEERING METHOD
Synthesis – combining various elements into an integrated whole
Analysis – using mathematics, science, engineering techniques and
economics to quantify the performance of various options
Communication – writing and oral presentations
Implementation – executing the plan
Iterative process in some steps
Not strict method just a general procedure
NOTE

4. 1. Identify the need& define the problem
2. Assemble design team
3. Identify constraints & criteria for success
4. Search for solutions
Synthesis
THE ENGINEERING METHOD

5. Feasibility
Study
Detailed
Design
Preliminary
Design
8. Communicate the solution to managment
7. Document the solutions
6. Choose the “best” solutions
5. Analyze each potential solution
Synthesis &
Analysis
Communication
• Feasibility Study
– where ideas are
roughed out
• Preliminary
Design – where
some of the
more promising
ideas are
explored in more
detail
• Detailed Design
- where highly
detailed drawing
and
specifications
are prepared for

6. 10. Verify and evaluate
9. Construct the solutionImplementation
Analysis

7. Step 1# Identify the Need and Define the Problem
Need may be create by a creative engineer (Military countermeasure example)
Sales or management personnel -> familiar with market -> spot a new need
Government regulations -> need -> regulation on pollution and safety
Politician -> create need -> promising their constituents new roads and
buildings
Engineer often doesn’t identify the need
PROBLEM: Once the need is identified the problem must be defined
Suppose that a high way is congested and causing troublesome delay for
commuters
“HOW DO WE WIDEN THE ROAD TO ACCOMMODATE MORE TRAFFIC”
“HOW DO WE CREATE A TRANSPORTATION SYSTEM TO MOVE MORE PEOPLE
QUICKLY AND EFFICIENT”

8. Step 2# Assembly Design Team
Design is done with team of individuals who have complementary skills due to
complexity of modern engineering projects
For example: an automobile were being designed. 1st the Stylist would decide
the shape. 2nd Mechanical Engg -> how to form body parts & fit the engine
under hood. 3rd Electrical Engg -> Electrical Systems. 4th Production Engg ->
Production Line. 5th Marketers -> advertising campaign
Sequential -> locally optimum & Not globally Optimum
Global Optimum: Specialist to work together right from beginning using an
approach called Concurrent Engg
For example: While automobile is being conceptualized, the Marketer & Stylist
-> highly salable design. Further Mechanical Engg would be involved so that
the body style can accommodate the engine. Production Engg would be
engaged because of new materials will make a big impact on the
manufacturing method. Further Design objectives can be met only by using
hybrid engine.

9. STEP 3# IDENTIFY CONSTRAINTS
AND CRITERIA FOR SUCCESS
Budget – know the proposed budget because it affect the resources
Time – Engineer must the time, because it determines the number and type of option they can
consider
Personnel – No of peoples and their skills (A large budget with ample time doesn’t forecast
success until skilled individuals are working on project)
Legal – It can be restrictive in today’s world. A large project has to go through (water
pollution, air pollution, sewage, traffic control)
Materials properties & availability – Engineers are always constrained by material properties.
E.g. car engine -> efficiency improves -> high temperature -> such materials -> not on
commercial scale -> of no use to project
Off-the-shelf construction – Engineers must know whether they are restricted to off the shelf
components or to custom design. Off the shelf are available quickly and are well tested.
However they can compromise ultimate success if they are not customized to our requirement
Competition - Whether the product is unique or it will compete against other similar
products
Manufacturability - Many items can be made in small quantities in a lab/ machine shop but
may be unsuitable for mass production. For example Fighter jet uses materials for high
performance which is built in small numbers (may be 50/year). These materials are not
suitable for automobiles which are produced in higher quantities (10000/year)

10. Aesthetics – It doesn’t matters how rugged, reliable or functional the product is; If
the product is ugly it will not sell. Each component of the product serves a useful
function. Automobiles in 1950s & 1960s sometimes they had fins added for style
purpose -> had no function -> become fad with time
Performance – The performance is generally determined by the producer unless the
project respond to a specific customer request. E.g. 0-60 mph acceleration =10s, 60-
0 mph braking = 150ft & fuel economy = 25 miles/gallon
Quality – Defined as ”fitness for use”. Determined by consumer. E.g. A consumer may
expect 0-60 mph acceleration =6s, 60-0 mph braking = 110ft & fuel economy = 40
miles/gallon
Human factors – User friendly like controls at finger tips, pedals that are well spaced
and don’t need to be pushed too much, power steering at right heights
Cost – Having all above qualities it may still fail if it cost too much. Moderate price >
Low price with high maintenance, insurance, labor etc
Capital Cost
Life Cycle Cost
Safety – Impossible to design completely safe products because they would be too
costly. E.g. standards are being increased Air bags
Operating Environment - The Engineer must know the operating environment in
mind e.g. corrosive environment, vibration level, Temperature and Pressure level.
Interface with other system – Many products interface with others eg. An automobile

11. Effect on surrounding - With increasing environmental constraints, products
may be designed with lower chemical, noise and electromagnetic emissions. In
USA automobile -> catalytic converter -> reduce the air pollution emitted
from the car.
Logistics – Many products require support systems such as electricity,
cooling, steam, fuel and spare parts.(repair centers and fuel stations)
Reliability – A reliable product will always perform its intended function for
the required time period and in the environment. No product is 100% reliable.
Maintainability – A product that is maintainable can have the required
maintenance performed upon it at the necessary frequency. For Example (Car
vs Space Shuttle)
Serviceability – If a product is easily maintained then it will be easily
serviceable (special tool not present so not serviceable)
Availability – If a product is always ready to use it is available. If it is present
in repair shop it is unavailable

12. STEP 4# SEARCH FOR SOLUTIONS
Can I eliminate the need? For example an automobile engineer is told by his
boss the need as follow “The suspension springs are rusting, so I want to you
to design a coating that protects them”. Perhaps the need has been eliminated
altogether by specifying nonrusting polymers rather than the metal spring.
Be-knowledgeable While searching for the solutions, the design engineer
must become as knowledgeable about the problem as possible. Information
may be obtained from libraries, the internet, government documents,
professional organizations, trade journals, vendor catalogs and other
individuals
Employ apologies By using analogies, a design engineer can exploit
information from other fields and bring this information to the design
problem. For example Wright brothers employed bird wings as an analogy
Personalize the problem By Personalizing you can gain insight by imagining
yourself shrunken down & literally entering the device being designed. Like
you put yourself into it.
Identify the critical parameters For example A component must operate at

13. Switch functions Stationary things can be made to switch function &
resources can be saved. e.g Pump housing
Alter sequence of steps Change of sequence e.g. tea making example -> just
change the step
Reverse the problem Sometimes by reversing the solution we can find the
solution e.g light weight wrench required -> heavy weight required
Repeat components or process steps Sometimes if one is good, two is better
& three is better yet. For example Compression of gas, decomposes ->
compressing it 3 times
Separate functions For example in car engine : air input, fuel input, air/fuel
mixing, compression, combustion, expansion, exhaust, lubrication & wall
cooling. Fuel combustion & wall cooling are incompatible functions. Perhaps
the engine should be improved by performing these functions in separate
pieces of equipments.
Combine functions For example in industries; fuel -> electricity -> steam ;
combine in one step combined heat & power is more efficient
Use vision imagine that you have accomplished the goals & inspecting the
final products. What features would this product have if it were built?
Employ basic engineering principles For a thermodynamics principle review

14. TECHNIQUES
Brainstorming
6-12 group -> 1 Leader
Idea Generator
Don’t underestimate any silly idea -> it may lead to valuable solution
Nominal Group Technique
Leader -> assemble group and poses the problem
Each member individually work on the problem on paper
When stopped work -> explain in group and record on blackboard
Group members -> rated the ideas
No critiques are allowed
Delphi Techniques
Same as above but the problem statement is email to each group member by leader
Reply-> leader pools the response
Group member -> rate the ideas
Those ideas receiving low ratings can be clarified by the originator if desired

15. FEASIBILITY STUDY
It is a “quick and dirty” survey. The goal is to see the big picture & address
the most important features of problem
Step 5: Analyze Each Potential Solution
Step 6: Choose the best solution
Step 7: Document the Solution
Step 8: Communicate the Solution to Management

16. PRELIMINARY DESIGN
If the results are positive in Feasibility study, the engineers now engage in a
preliminary design that is more detailed than the feasibility study.
Step 5: Analyze Each Potential Solution
Step 6: Choose the Best Solution
Step 7: Document the Solution
Step 8: Communicate with Management

17. DETAILED DESIGN
It involves a very large team that works on the solution that emerged from the
preliminary design phase.
Step 5-8: Detailed Design
Step 9: Construct Solution
Step 10: Verify and Evaluate

18. READING ASSIGNMENT
READ !
Step 5 – Step 8
of FEASIBILITY, PREMILINARY, DETAILED