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Chapter 3Chapter 3
Introduction to Engineering
Introduction to Engineering Design
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Introduction to Engineering Design
Engineers, regardless of their backgrounds, followcertain steps when designing the products andservices we use in our every day lives.
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Outline
Outline
In this chapter we will
• Introduce you to the engineering design
process• Discuss the basic steps that most engineers
follow when designing a product
• Discuss the importance of consideringsustainability in design
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Outline
Outline out• Introduce important design factors such as Teamwork Proect scheduling !aterial selection Economic consideration Engineering standards and codes
• Present cases studies in civil, mechanical" electricalengineering
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obective
The main objective of thischapter is:
To introduce the steps engineersfollow to successfully design
products or provide services that we use in our everyday lives
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The Engineering Design Process:
•Engineering is inherently about solving problems. This could
be as simple as solving a homework problem or as complex as
designing and building an airplane.
•As engineering solutions become more complex, a systematic
approach becomes highly beneficial. This systematic approach
to finding solutions is called the engineering design process.
•There are different ways to organize the steps in this process.
The exact number of steps in the process may vary. ur text
introduces an !"step process as shown on the following page.
The Engineering Design Process
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The Engineering Design Process
1. Recognizing the Need for
a Product or Service
2. Problem Definition and
nderstanding
!. Research and Pre"aration
#. $once"tualization
%. S&nthesis
'. Evaluation
(. )"timization
*. Presentation
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1. Recognizing the Need for
a Product or Service
• A product that consumers will like• An item that will be marketable
• #olution to a problem in society
• $road definition first
• Avoid %umping to any particular solution
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
$ase Stud&
&innkota Electric utboard 'rive is designed and
manufactured by (ohnson utdoors in &ankato, &) with
head*uarter in +acine, -
#tep / +ecognizing the need for a product or a service
&arketing department at (ohnson utdoors recognized the
growing interest in environmentally friendly power sources
for their boating industry
&arketing department contacted the engineering department
to discuss the feasibility of developing new generation ofmotors that are environmentally friendly
-ncreasingly, more states were enacting regulations banning
the use of gasoline boat motors in public water ways
including lakes and rivers
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2. Problem Definition and
nderstanding
• -t is important to fully understand the task
ahead of your team.
• 0ow much money is available1
• hat deadlines are involved1
• hat restrictions are involved1• hat criteria must be met1
• #olutions to problems are often handled by
breaking the task into parts. 2ommunication
among group members is critical.
• hat parts of the pro%ect is my group
responsible for1
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
%tep &' Problem definition and understandingThe details of the proect re(uirements were defined
Design specifications included !otor had to move a )* feet long Pontoon at a speed of + mph
minimum
$oat operator had to have the capability to trim and tilt from aremote console
!otor had to be compatible with industry standard steering wheel mechanism
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!. Research and Pre"aration
• 2ollect useful information
• #earch for similar products or components
• Avoid 3re"inventing the wheel4
• 5erhaps you could adopt or modify existing
components
• +eview and organize the information
collected in a suitable manner
• -nternet searches are very useful
• #earch vendor catalogs for the most useful
components
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
%tep ' -esearch and preparationEngineers checked eisting design inventory to determine
if a motor already eists that would meet some or allre(uirements
/ mechanical engineering student was commissioned tolook at state regulations concerning the use of gasoline vs.electric boat motors
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• 6enerate ideas that could offer a reasonable
solution• $rainstorming 7 do not discount any ideas yet
• 5erform enough analysis to determine if each
solution has merit and is worth pursuing
further
• 'evelop a task chart for completion of the
pro%ect
#. $once"tualization
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
%tep 0' 1onceptuali2ationThe engineering designers 3)& of them4 met on weekly
basis to brain storm and bounce ideas off each other.
They reviewed the information that was gathered in %tep
.
They developed few concepts to pursue further
/n additional idea that surfaced was the use of an electriclinear actuator in place of a hydraulic actuator. The idea
was pursued further.
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%. S&nthesis
• 'etails of possible design solutions are
considered here
• 5erform calculations
• 8se computer simulation
• narrow down the type of materials to be
used,.
• size the components of the system.
• answer *uestions about how the product is
going to be fabricated• 2onsult pertinent codes and standards for
compliance
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
%tep +' %ynthesisThe design engineers began to
consider details
They consulted pertinent codes and
standards to make sure that theirdesign was in compliance
!ost of the design was done in ProE5
and prototypes were built in machine
and electrical labsThe uni(ue design of the propeller
re(uired the use of a manufacturingprocess known as investment casting
Exploded diagram of motor
i i %
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• Analyze the problem in more detail• $uild and test prototype models
• 'etermine the best solution from the
alternatives 9see evaluation tool in text:
• -dentify critical design parameters and
consider their influence in your final design
• &ake sure that all calculations are performed
correctly
'. Evaluation
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
%tep 6' Evaluation7umerical eperiments were conducted using
Pro!echanica5
8inite element techni(ues were used to look at stresses in
critical components of the motor itself and the mounting bracket and the lifting mechanism
7umerical eperiments were performed to study thehydrodynamics of propeller designs including thrust,
cavitation, speed, and drag
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Design Process # $asic %teps Design Process # $asic %teps
Step 6: Evaluation (continued)•Using GPS t!e speed of t!e "oat #as
measured over a period of several !ours to
$uantif% t!e motors& speed a s a function of
time
•'!e collected data #ere used to compare
to competitors& motors
Engineers used Proec!anica to conduct numerical
experiments on t!e motor
Stress results from finite element
anal%sis
D i P $ i %
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(. )"timization
• ptimization ; minimization or maximization
• A functional design meets all of the design
re*uirements.
• An optimized design improves on the functional
design in areas such as cost, strength, speed,
weight, etc.
• ptimizing individual components of an
engineering system does not necessarily lead to
an optimized system
• ptimization is often an iterative procedure. #ee
the procedure shown on the next page.
Design Process # $asic %teps Design Process # $asic %teps
D i P $ i %t
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This process is considered to
be iterative. This means thatcertain portions of the process
may need to be repeated.
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Design Process # $asic %teps Design Process # $asic %teps
%tep *' Optimi2ation$ased on results obtained from %tep 6,
modifications were made to the designand additional analyses performed
-esults of numerical eperiments wereused to optimi2ed the design ofpropeller and mounting bracket
1onducted many hours of actual field
testing in water and simulated lifetesting in labs to help withoptimi2ation of final design
*ctual testing of t!e s%stem
in a la+e
'esting of t!e s%stem in ala"orator% setting
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• 2ommunicate your solution to the client
• This might include/• ral reports
• ritten reports
• 5erformance data
• 2A' drawings = schematics
• 5arts lists
• -nstruction = training manuals
• Etc.
*. Presentation
Design Process # $asic %teps Design Process # $asic %teps
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Design Process # $asic %teps Design Process # $asic %teps
%tep 9' Presentation The product development process took approximately two years
'uring this period design engineers gave
weekly progress reports to the rest of design group>
*uarterly status oral and written reports to the marketing department and group vice
president final presentation to the $oard of 'irectors
5resentation duration ranged from ? minutes to an entire afternoon
5resentation addressed several issues including
'evelopment cost
8nit cost
&arket outlook
5erformance characteristics
Testing results
Environmental impact
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Other Engineering Design 1onsiderations
• Engineering economics
• !aterial selection
• Teamwork
• 1onflicts -esolution
• Proect scheduling and task chart
• Evaluating alternatives
• Patent, trademark, and copyright
• Engineering standards and codes
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Engineering Economics
• Economic factors always play important roles inengineering design decision making
• Products that are too epensive cannot be sold at a
price that consumers can afford and still beprofitable to the company
• Products must be designed to provide services not
only to make our lives better but also to make goodprofits for the manufacturer
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!aterial Properties
• !aterial properties depend on many factors
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>ist of %ome !aterial Properties
• Electrical resistivity ' a measure of resistance of material to flow of electricity.• Density ' ' how compact the material is for a given volume.• !odulus of Elasticity ' how easily material will stretch or shorten.• !odulus of -igidity ' a measure of how easily a material can be twisted or
sheared.
• !odulus of resilience ' a mechanical property of a material that shows howeffective the material is in absorbing mechanical energy without goingthrough any permanent damage.
• !odulus of toughness ' a mechanical property of a material that indicates theability of the material to handle overloading before it fractures.
• Thermal epansion ' the change in the length of a material that would occur ifthe temperature of the material is changed.
• Thermal conductivity ' how good the material is in transferring thermalenergy .
•
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!aterial Properties 3?uid properties4
• @iscosity ' a measure of how easily the given ?uidcan ?ow. The higher the viscosity value is, the moreresistance the ?uid offers to ?ow.
• @apor pressure ' ?uids with low vaporApressure values will not evaporate as (uickly as those withhigh values of vapor pressure.
• $ulk modulus of compressibility ' represents how
compressible the ?uid is.
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Teamwork
• Design team
a group of individuals with complementaryepertise, problem solving skills, and talent
who are working together to solve a problem orachieve a common goal
• Employers are looking for individuals who not only
have a good grasp of engineering fundamentals but who can also work well with others in a teamenvironment
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1ommon Traits of Bood Teams
Successful teams have the following components:
• The proect that is assigned to a team must haveclear and realistic goals. These goals must be
understood and accepted by all members of theteam.
• The team should be made up of individuals withcomplementary epertise, problem solving skills,
background, and talent.
• The team must have a good leader.
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1ommon Traits of Bood Teams
• The team leadership and theenvironment in which discussions takeplace should promote openness,respect, and honesty.
• The team goals and needs should come
before individual goals and needs.
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%econdary -oles of Bood Team !embers
• The Organi2er # eperienced and confident=trusted by members of the team and serves as acoordinator for the entire proect
• The 1reator # good at coming up with new ideas,sharing them with other team members, and lettingthe team develop the ideas further
• The Batherer # enthusiastic and good at obtainingthings, looking for possibilities, and developingcontacts
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%econdary -oles of Bood Team !embers
• The !otivator # energetic, confident, andoutgoing= good at finding ways around obstacles
• The Evaluator # intelligent and capable of
understanding the complete scope of the proect=good at udging outcomes correctly
• The Team Corker # tries to get everyone to come
together, does not like friction or problems amongteam members
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%econdary -oles of Bood Team !embers
• The %olver # reliable and decisive and can turnconcepts into practical solution
• The 8inisher # can be counted on to finish his or
her assigned task on time= detail oriented and may worry about the teams progress toward finishingthe assignment
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1onflicts
Chen a group of people work together, conflictssometimes arise. Conflicts could be the result of
• !iscommunication
• Personality differences
• The way events and actions are interpreted by amember of a team
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1onflict -esolution
• !anaging conflicts is an important part of a teamdynamic
• In managing conflicts, it is important to recogni2e
there are three types of people' /ccommodating 1ompromising
1ollaborative
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1onflict -esolution # Type of People
• /ccommodating team members A avoidconflicts /llow assertive individuals to dominate!aking progress as a whole difficult1ould lead to poor team decision
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1onflict -esolution # Type of People
• 1ompromising team members
Demonstrate moderate level ofassertiveness and cooperation. $y
compromising, the team may havesacrificed the best solution for the sake ofgroup unity
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1onflict -esolution
• 1ollaborative 1onflict -esolution /pproach
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Proect %cheduling and Task 1hart
/ process that engineering managers use to ensure that a proect iscompleted on time and within the allocated budget
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Evaluating /lternatives
• Chen a design is narrowed down to afew workable concepts, evaluation ofthese concepts is needed before detaildesign is pursued
• Each design would have its own
evaluation criteria
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/n Eample of evaluation worksheet
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%ustainability in Design
%ustainability and sustainableengineering can be defined as
design and development that meets theneeds of the present withoutcompromising the ability of future
generations to meet their own needs.”
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%ustainability in Design
• Engineers contribute to both private and publicsectors of our society
• In private sector, they design and produce the goods
and services that we use in our daily lives to allow usto enoy a high standard of living
• In public sector, they support local, state, and federalmission such as meeting our infrastructure needs,energy and food security, and national defense
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%ustainability in Design
• Engineers contribute to both private and publicsectors of our society
• In private sector, they design and produce the
goods and services that we use in our daily lives toallow us to enoy a high standard of living
• In public sector, they support local, state, and
federal mission such as meeting our infrastructureneeds, energy and food security, and nationaldefense
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%ustainability in Design
• Increasingly, because of worldwide socioeconomictrends, environmental concerns, and earths finiteresources, more is epected of engineers
• 8uture engineers are epected to design and providegoods and services that increase the standard ofliving and advance health care, while addressingserious environmental and sustainability concerns
•In designing products and services, engineers mustconsider the link among earths finite resources,environmental, social, ethical, technical, andeconomical factors
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Patent, Trademark, and 1opyright
Patent, trademark, service marks, andcopyrights provide a mean to promote newideas and inventions and at the same time toprotect the inventors intellectual properties
These are eamples of means by whichintellectual property is protected by the :.%.laws
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Patent
The right to eclude others from making, using, offeringfor sale, or selling the invention in :.%. or importing theinvention into :.%.
Does not grant the inventor the right to make, use, or
sell the invention, it ecludes others for doing so7ew patent is protected for &F years from the date the
patent application is filed
Design patent is good for )0 years from the time it was
granted
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Patent 3continued4
:tility patent lasts for either )* years from the time it was granted or &F years from the earliest filing date, whichever is longer
/ utility patent is issued for the way an item works
/ design patent protects the way an item looks
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Trademark
Trademark is a name, word, or symbol that acompany uses to distinguish its products fromothers
Ecludes others from using the same or similarmark
It does not prevent others from making thesame or similar products
© 2011 Cengage Learning Engineering. All Rights Reserved.
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%ervice !ark
%ervice mark is a name, word, or symbol that acompany uses to distinguish its services from others
Ecludes others from using the same or similar mark
It does not prevent others from providing the same orsimilar services
© 2011 Cengage Learning Engineering. All Rights Reserved.
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1opyright
Protection provided by the laws of the :.%. to theauthors of original works of authorshipG
1overs literary, dramatic, musical, artistic, and othertypes of intellectual works
1overs both published and unpublished work
Protects form of epression, not the content or thesubect matter
© 2011 Cengage Learning Engineering. All Rights Reserved.
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1opyright 3continued4
/fter )")")H*9, copyright laws protect the work forThe authors life plus *F years
the last surviving authors life plus *F years in the case ofmultiple authors
1urrently, no international copyright laws for worldwide protection
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Engineering %tandards and 1odes
Developed over t!e %ears "% variousorgani,ations to ensure product safet% and
relia"ilit% in services and uniformit% in parts
and components
Why do we need standards and codes?
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Engineering %tandards and 1odes 3continued4
%tandards allow for easy way to communicate the si2e of a product
8or eample, if we had global standards for shirts and shoes, then theabove cross referenced tables would not be necessary
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Engineering %tandards and 1odes 3continued4
Eample of an engineered product that adhere to many standards
© 2011 Cengage Learning Engineering. All Rights Reserved.
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Engineering %tandards and 1odes 3continued4
Eample of products conforming to the I%O