ch3 sami (1) introduction of engineering

8/9/2019 ch3 sami (1) introduction of engineering

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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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$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



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%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



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%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



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%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



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%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



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%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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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.


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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%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



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%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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• 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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• 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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• 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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• 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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• 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



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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



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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



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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



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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



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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



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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?



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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



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Eample of an engineered product that adhere to many standards



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Eample of products conforming to the I%O

ch3 sami (1) introduction of engineering

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