3-1 CHAPTER 3 Introduction to Engineering Design © 2011 Cengage Learning Engineering. All Rights...

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CHAPTER 3Introduction to Engineering Design

© 2011 Cengage Learning Engineering. All Rights Reserved.

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Engineering – An Exciting Profession

• Introduction to engineering profession

• Preparing for an engineering career

• Introduction to engineering design

• Engineering communication

• Engineering Ethics


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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 considering sustainability in design


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Outline (continued)

• Introduce important design factors such as Economic consideration Material selection Teamwork Project scheduling Engineering standards and codes

• Present cases studies in civil, mechanical/ electrical engineering


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Objectives

The main objective of this chapter is:

To introduce the steps engineers follow to successfully design products or provide services that we use in our everyday lives


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Design Process – Basic Steps

1. Recognizing the need for a product or a service

2. Problem definition and understanding

3. Research and preparation

4. Conceptualization

5. Synthesis

6. Evaluation

7. Optimization

8. Presentation


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Design Process – Basic Steps (continued)

Step 1: Recognizing the need for a product or a service


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Step 2: Problem definition and understanding

• This is the most important step in any design process

• Before you move on to the next step Make sure you understand the problem Make sure that the problem is well defined

• Good problem solvers are those who first fully understand what the problem is


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Step 3: Research and preparation

• Collect useful information Search to determine if a product already exists Perhaps you could adopt or modify existing

components Review and organize the information collected in a

suitable manner

Step 4: Conceptualization

Generate ideas or concepts that could offer reasonable solutions to your problem


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Step 5: Synthesis

• At this point you begin to consider details

• Perform calculations, run computer models, narrow down the type of materials to be used, size the components of the system, and answer questions about how the product is going to be fabricated

• Consult pertinent codes and standards for compliance


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Step 6: Evaluation

• Analyze the problem in more detail

• Identify critical design parameters and consider their influence in your final design

• Make sure that all calculations are performed correctly

• Best solution must be identified from alternatives

• Details of design must be worked out fully


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Step 7: Optimization – minimization or maximization

• Optimization is based on some particular criterion such as cost, strength, size, weight, reliability, noise, or performance.

• Optimizing individual components of an engineering system does not necessarily lead to an optimized system


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An optimization procedure


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Step 8: Presentation

• You need to communicate your solution to the client, who may be your boss, another group within your company, or an outside customer

• Engineers are required to give oral and progress reports on regular basis to various groups, consequently presentation could well be an integral part of many other design steps


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Example 3.1 – Optimization

Given: To purchase storage tanks with a budget of $1680. Available floor space is 90 ft2

Manufacturer A:16 ft3 capacity @ $120 each, requires 7.5 ft2 floor space

Manufacturer B:24 ft3 capacity @ $240 each, requires 10 ft2 floor space

Find: Greatest storage capacity within the budgetary and floor-space limitation


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:sconstraint following thesubject to

2416 maximize 21 xxZ

Solution: Let x1 = 16 ft3 capacity and x2 = 24 ft3 capacity. Then the objective function Z

we wish to maximize becomes

0

0

90105.7

1680240120

2

1

21

21

x

x

xx

xx


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Region as given by linear inequality

1680240120 21 xx

Feasible solution


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Civil Engineering Design Process

• Civil engineering design process is slightly different from other disciplines

• Civil engineering is concerned with providing public infrastructures and services such as the design and construction of

Buildings Roads and highways Bridges Dams Tunnels Mass transit systems Airports Water supply systems Sewage systems


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Civil Engineering Design Process (continued)

• Civil Engineers must follow specific procedures, regulations, and standards that are established by local, state, or federal agencies

• For example, design procedures for a bridge will be different than for a building or a mass transit system


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Civil Engineering Design Process (continued)

• Design process for buildings:1. Recognizing the need for a building

(similar to previous step 1 for other engineering disciplines)

2. Define the usage of the building (similar to previous step 2: problem definition and understanding)

3. Project planning (similar to previous step 3: research and preparation)

4. Schematic design phase (similar to previous steps 4 & 8: conceptualization and presentation)

5. Design development phase (similar to previous steps 5, 6 & 8: synthesis, evaluation, and presentation)

6. Construction documentation phase (similar to previous steps 5 & 7: synthesis and optimization)

7. Construction administration phase


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Design Process for Buildings

Step 1: Recognizing the need for a building

• For example: build a new elementary school or expand existing one to accommodate the increase in children’s ages between 6 and 12, or

• Build a new medical clinic due to an increase in medical needs and convenience to patients, or

• Replace or expand factory to increase production due to market demand, or

• Build, replace, or expand bridge due to increase in traffic volume


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Design Process for Buildings (continued)

Step 1: Recognizing the need for a building (continued)

• In private sector The need is usually identified by the owners of a

business or real estate

• In public sector The need is usually identified by others, such as a

school principal, a city engineer, or a district engineer The need must be approved by corresponding

oversight body, such as a school board, city council, or the department of transportation and state legislation


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Step 2: Define the usage of the building

• Owner (client) determines types of activities that would take place in the building

New elementary school: principal forecasts the number of students enrolled in the future; determines the number of classrooms and computer labs, and the need for a library or a cafeteria

Medical clinic: staff determine number of examination rooms, x-ray labs, reception areas, record rooms, and so on

• The usage will help architect determine the amount of area that would be required


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Step 3: Project planning

• Client selects potential sites for the new building

• Factors influence site selection: Cost and location Zoning Environmental impact Archaeology impact Traffic flow

• Client selects an architect firm or a contractor to initiate the design phase


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Step 4: Schematic design phase

• Architect consults with client to fully understand the intended usage of the building and to obtain approximate budget for the project

• Architect prepares multiple schematic designs for the building

• Client and architect narrow down the options to one or two designs

• Schematic design includes: material type, framing system, and layout of rooms and spaces


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Step 5: Design development (DD) phase

• Architect continues to finalize layout of the building

• Architect consults with a structural engineer to determine the limits of column size and beam size

• The structural engineer then performs a preliminary design for the building

• The mechanical engineer performs the preliminary design for the HVAC system

• The electrical engineer performs the preliminary electrical design


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Step 5: Design development (DD) phase (continued)

• The interior designer performs a preliminary design for the interior of the building

• The contractor provides a cost estimate for the project

• The architect meets with the client to present the preliminary design and seek feedback


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Step 6: Construction documentation (CD) phase

• All the detail work is done in this phase

• Construction document includes Design specification and drawings from the

architect, civil, structural, mechanical, and electrical engineers, and the interior designers

Work of landscape architect may be included


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Step 6: Construction documentation (CD) phase (continued)

• Civil engineer provides site plan design which includes: Grading of the ground from the perimeter of

building to sidewalk Grading of the parking area Drainage for surface runoff Demolition plan and the relocation of power-lines

as needed


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• Structural engineer provides all the design details for structural components including:

Foundation, beams and columns, interior and exterior walls, and connections

Roof and floor supports and supports for opening such as windows, doors

Canopies ……..

• Structural engineer must bear in mind all the design specifications required by the building codes as established by local government


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• Construction document must be reviewed and approved by the building inspectors

• If the client has not selected a contractor, as it is common for publicly funded projects, interested contractors would purchase a hard copy of the construction document or download it from the architect’s web site for bid preparation


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An example of design detail included in a construction document


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Step 7: Construction administration phase

• Contractor will have a superintendent on site to manage the construction and its progress and coordinates all the subcontractors

• Project manager representing the architect would meet with the site superintendent and the client on a regular basis to review the construction progress and to any issues that require further attention

• Structural engineer visits the construction site periodically to observe the progress of the project


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Step 7: Construction administration phase (continued)

• Structural engineer is responsible for reviewing the shop drawings submitted by the fabricators through the general contractor

• When the project is completed, the project manager will walk through the building with the client and the superintendent to go through a “punch” list

• The building must be approved by the building inspector prior to being occupied


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Other Engineering Design Considerations

• Engineering economics

• Material selection

• Teamwork

• Conflicts Resolution

• Project 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 in engineering design decision making

• Products that are too expensive cannot be sold at a price that consumers can afford and still be profitable to the company

• Products must be designed to provide services not only to make our lives better but also to make profits for the manufacturer

More in Chapter

20


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Material Selection

Selection of material is an important design decision

• Examples of properties to consider when selecting materials

Density Ultimate strength Flexibility Machinability Durability Thermal expansion Electrical & thermal conductivity Resistance to corrosion


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Material Selection (continued)

• Examples of questions design engineers may ask when selecting materials

How strong will the material be when subjected to an expected load?

Would it fail, and if not, how safely would the material carry the load?

How would the material behave if its temperature were changed?

Would the material remain as strong as it would under normal conditions if its temperature is increased?


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How much would the material expand when its temperature is increased?

How heavy and flexible is the material? What are its energy absorbing properties? Would the material corrode? How would it react in the presence of some

chemicals? How expensive is the material? Would it dissipate heat effectively? Would the material act as a conductor or as an

insulator to the flow of electricity?


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• Other application specific questions to be considered: for example, for bioengineering applications

Is the material toxic to the body? Can the material be sterilized? When the material comes into contact with body

fluid will it corrode or deteriorate? How would material react to mechanical shock

and fatigue? Are the mechanical properties of the implant

material compatible with those of bone to ensure appropriate stress distributions at contact surface

More in chapter 17


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Material Properties (continued)

• Material properties depend on many factors How the material was processed Its age Its exact chemical composition Any nonhomogenity or defect within the material

• Change with temperature and time as the material ages

• In practice, you use property values provided by the manufacturer for design; textbook values are typical values


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• Electrical resistivity Measure of resistance of material to flow

of electricity Plastics and ceramics typically have high

resistivity Metal typically has low resistivity Silver and copper are one of the best

conductors of electricity


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• Density Defined as mass per unit volume Measure of how compact the material is

for a given volume Average density of

• aluminum alloys = 2700 kg/m3

• steel = 7850 kg/m3


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• Modulus of elasticity (Young’s modulus) Measure of how easily a material will

stretch when pulled Measure of how well material will shorten

when pushed The larger the modulus of elasticity, the

larger the force required to stretch or shorten a piece of material

Modulus of elasticity for• aluminum alloy = 70 to 90 GPa• steel = 190 to 210 GPa


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• Modulus of rigidity (shear modulus) Measure how easily a material can be

twisted or sheared Value of shear modulus shows the

resistance of a given material to shear deformation

Shear modulus for • aluminum alloys = 26 to 36 GPa• steel = 75 to 80 GPa


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• Tensile strength Determined by measuring the maximum

tensile load a material specimen in the shape of a rectangular bar or cylinder can carry without failure

Tensile strength or ultimate strength is expressed as the maximum tensile force per unit cross-sectional area of the specimen


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Tensile Test of Metal Specimen

Tensile test set up

Original specimen Final

specimen


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• Compressive strength Is determined by measuring the maximum

compressive load a material specimen in the shape of a rectangular bar, cylinder, or cube can carry without failure

Is expressed in force per unit cross-sectional area of specimen

In concrete ranges between 10 to 70 MPa


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• Modulus of resilience Mechanical property that shows how

effective the material is in absorbing mechanical energy without going through any permanent damage

• Modulus of toughness Mechanical property that indicates the

ability of the material to handle overloading before it fractures


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• Strength-to-weight ratio Ratio of strength of the material to its

specific weight Either tensile strength value or yield

strength value can be used to determine the ratio


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• Thermal expansion Shows the change in the length of a

material that would occur if the temperature of the material were changed

Important material property to consider when designing products and structures that are expected to experience a relatively large temperature swing during their service lives


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Thermal conductivity

Shows how good a material is in transferring thermal energy (heat) from a high temperature region to a low temperature region within the material


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• Heat capacity Represents the amount of thermal energy

required to raise the temperature of 1 kg mass of material by 1oC, or 1 lb-mass of material by 1oF

Materials with large heat capacity values are good at storing thermal energy


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• Viscosity Fluid property that measures how easily a

given fluid can flow The higher the viscosity value is, the more

resistance the fluid will offer to flow For example, less energy is needed to

transport water in a pipe than to transport motor oil or glycerin


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• Vapor pressure Under the same conditions, fluids with low

vapor-pressure values will not evaporate as quickly as those with high values of vapor pressure

For example, water has a higher vapor pressure value than glycerin


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• Bulk modulus of compressibility Measures how compressible a fluid is Represents how easily can one reduce the

volume of fluid when the fluid pressure is increased

For example, it would take 2.24x109 N/m2 of pressure to reduce 1 m3 of water to 0.99 m3, a change of 1%


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Teamwork

• Design team

a group of individuals with complementary expertise, problem solving skills, and talent who are working together to solve a problem or achieve 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 team environment


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Common Traits of Good Teams

Successful teams have the following components:

•The project that is assigned to a team must have clear and realistic goals. These goals must be understood and accepted by all members of the team.

•The team should be made up of individuals with complementary expertise, problem solving skills, background, and talent.

•The team must have a good leader


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Common Traits of Good Teams (continued)

• The team leadership and the environment in which discussions take place should promote openness, respect, and honesty.

• The team goals and needs should come before individual goals and needs.


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Secondary Roles of Good Team Members

• The Organizer – experienced and confident; trusted by members of the team and serves as a coordinator for the entire project

• The Creator – good at coming up with new ideas, sharing them with other team members, and letting the team develop the ideas further

• The Gatherer – enthusiastic and good at obtaining things, looking for possibilities, and developing contacts


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Secondary Roles of Good Team Members (continued)

• The Motivator – energetic, confident, and outgoing; good at finding ways around obstacles

• The Evaluator – intelligent and capable of understanding the complete scope of the project; good at judging outcomes correctly

• The Team Worker – tries to get everyone to come together, does not like friction or problems among team members


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Secondary Role of Good Team Members (continued)

• The Solver – reliable and decisive and can turn concepts into practical solution

• The Finisher – can be counted on to finish his or her assigned task on time; detail oriented and may worry about the team’s progress toward finishing the assignment


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Other Factors Influencing Team Performance

• The way a company is organized

• How projects are assigned

• What resources are available to a team to perform their tasks

• Corporate culture: whether openness, honesty, and respect are promoted


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Conflicts

When a group of people work together, conflicts sometimes arise. Conflicts could be the result of

•Miscommunication

•Personality differences

•The way events and actions are interpreted by a member of a team


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Conflict Resolution

• Managing conflicts is an important part of a team dynamic

• In managing conflicts, it is important to recognize there are three types of people:

Accommodating Compromising Collaborative


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Conflict Resolution – Type of People

• Accommodating team members - avoid conflicts

Allow assertive individuals to dominate Making progress as a whole difficult Could lead to poor team decision


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Conflict Resolution – Type of People

• Compromising team members

Demonstrate moderate level of assertiveness and cooperation. By compromising, the team may have sacrificed the best solution for the sake of group unity


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• Collaborative Conflict Resolution Approach High level of assertiveness and

cooperation by the team No finger pointing Team proposes solutions Means of evaluation Combine solutions to reach an ideal

solution

Conflict Resolution


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Project Scheduling and Task Chart

A process that engineering managers use to ensure that a project is completed on time and within the allocated budget


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Evaluating Alternatives

• When a design is narrowed down to a few workable concepts, evaluation of these concepts is needed before detail design is pursued

• Each design would have its own evaluation criteria

An Example of evaluation worksheet


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Patent, Trademark, and Copyright

• Patent, trademark, service marks, and copyrights provide a mean to promote new ideas and inventions and at the same time to protect the inventors’ intellectual properties

• These are examples of means by which intellectual property is protected by the U.S. laws


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Patent

• The right to exclude others from making, using, offering for sale, or selling the invention in U.S. or importing the invention into U.S.

• Does not grant the inventor the right to make, use, or sell the invention, it excludes others for doing so

• New patent is protected for 20 years from the date the patent application is filed

• Design patent is good for 14 years from the time it was granted


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Patent (continued)

• Utility patent lasts for either 17 years from the time it was granted or 20 years from the earliest filing date, whichever is longer

• A utility patent is issued for the way an item works

• A design patent protects the way an item looks


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Trademark

• Trademark is a name, word, or symbol that a company uses to distinguish its products from others

• Excludes others from using the same or similar mark

• It does not prevent others from making the same or similar products


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Service Mark

• Service mark is a name, word, or symbol that a company uses to distinguish its services from others

• Excludes others from using the same or similar mark

• It does not prevent others from providing the same or similar services


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Copyright

• Protection provided by the laws of the U.S. to the authors of “original works of authorship”

• Covers literary, dramatic, musical, artistic, and other types of intellectual works

• Covers both published and unpublished work

• Protects form of expression, not the content or the subject matter


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Copyright (continued)

• After 1/1/1978, copyright laws protect the work for

The author’s life plus 70 years the last surviving author’s life plus 70

years in the case of multiple authors

• Currently, no international copyright laws for worldwide protection


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Engineering Standards and Codes

Developed over the years by various organizations to ensure product safety and reliability in services, and uniformity in parts and components

Why do we need standards and codes?


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Engineering Standards and Codes (continued)

• Standards allow for easy way to communicate the size of a product

• For example, if we had global standards for shirts and shoes, then the above cross referenced tables would not be necessary


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Example of an engineered product that adhere to many standards


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Example of products conforming to the ISO


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Other Codes & Standards

• ANSI – American National Standard Institute

• ASTM – American Society for Testing and Materials

• NFPA – National Fire Protection Association

• UL – Underwriters Laboratories

• EPA – Environmental Protection Agency

• ASHRAE – American Society of Heating, Refrigerating and Air-Conditioning Engineers


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Other Codes and Standards (continued)

• CЄ - Conformité Europeenné

• ISO – International Organization for Standardization

• BSI – British Standard Institute

• CSBTS – China State Bureau of Quality & Technical Supervision

• DIN – Germany-Deutsches Institute für Normung


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Examples of Codes and Standards


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Examples of Codes and Standards (continued)


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Examples of Codes and Standards (continued)


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Examples of Codes and Standards Specific to Civil Engineering Field


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Examples of Codes and Standards Specific to Civil Engineering Field (continued)

ASCE 7-05: Minimum Design Loads for Buildings and other Structures


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U.S. Drinking Water Standards

• EPA sets the standards for the maximum contaminants that can be in our drinking water and still be considered safe to drink

• Maximum contaminant level goal (MCLG)Maximum level of a given contaminant in the water that causes no known harmful health effects

• Maximum contaminant level (MCL) Slightly higher levels of contaminants than

MCLG Levels of contaminants that are legally

enforceable


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Examples of Drinking Water Standards


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U.S. Outdoor Air Quality Standards

• Outdoor air pollution may be classified into: Stationary sources: power plants,

factories, and dry cleaners Mobile sources: cars, buses, trucks,

planes, and trains Natural sources: windblown dust, volcanic

eruptions, and forest fires


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U.S. Outdoor Air Quality Standards (continued)

• Clean Air Act of 1970 EPA sets standards for 6 major pollutants:

• Carbon monoxide (CO)• Lead (Pb)

• Nitrogen dioxide (NO2)

• Ozone (O3)

• Sulfur dioxide (SO2)

• Particulate matter (PM)


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U.S. Outdoor Air Quality Standards (continued)

• Clean Air Act of 1990 Required EPA to address the effect of many toxic

air pollutants by setting new standards

• Since 1977, EPA has issued 27 air standards that are to be fully implemented in the coming years

• EPA works with individual states to reduce amount of sulfur in fuels and setting more stringent emission standards for cars, buses, trucks, and power plants

• Need to understand that air pollution is a global concern that can affect not only our health, but also our climate


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U.S. Indoor Air Quality Standards (continued)

• Indoor levels of pollutants may be two to five times higher than outdoor levels

• Indoor air quality is important in homes, schools, and workplaces where we spent approximately 90% of our time

• Indoor air quality is important to our short-term and long-term health, It affects productivity in workplace and the learning environment in our schools


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• According to EPA, some common health symptoms include:

Headache, fatigue, and shortness of breath

Sinus congestion, coughing, and sneezing Eye, nose, throat, and skin irritation Dizziness and nausea


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• Factors influencing air quality Heating, ventilation, and air-conditioning

(HVAC) system Sources of indoor air pollutants Occupants


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• Reasons for more exposure to indoor air pollutants

Tighter built newer houses that have lower air infiltration or exfiltration than older structures

Using more synthetic building materials in newly built homes that could give off harmful vapors

Using more chemical pollutants such as pesticides and household cleaners


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Typical Sources of Indoor Air Pollutants


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Methods to Manage Contaminants

• Source elimination or removal examples Prevent people from smoking inside

buildings Prevent car engines from running idle near

buildings’ outdoor air intakes

• Source substitution example Use a gentle cleaning product rather than

a product that gives off harmful vapors


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Methods to Manage Contaminants (continued)

• Proper ventilation Remove sources of pollutants before they can

be spread through the air distribution system Use exhaust fans to force out harmful

contaminants

• Exposure control ASHRAE establishes codes and standards

for how much fresh outside air must be introduced for various applications


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Methods to Manage Contaminants (continued)

• Air cleaning Removes harmful particulate and gases

from the air as it passes through some cleaning systems. It includes systems that make use of

• Absorption• Catalysis• Air filters


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Sustainability in Design

Sustainability and sustainable engineering can be defined as

“design and development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”


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Sustainability in Design (continued)

• Engineers contribute to both private and public sectors of our society

• In private sector, they design and produce the goods and services that we use in our daily lives to allow us to enjoy a high standard of living

• In public sector, they support local, state, and federal mission such as meeting our infrastructure needs, energy and food security, and national defense


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• Increasingly, because of worldwide socioeconomic trends, environmental concerns, and earth’s finite resources, more is expected of engineers

• Future engineers are expected to design and provide goods and services that increase the standard of living and advance health care, while addressing serious environmental and sustainability concerns

• In designing products and services, engineers must consider the link among earth’s finite resources, environmental, social, ethical, technical, and economical factors


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• Potential shortage of engineers with training in sustainability

• ASCE, ASEE, ASME, and IEEE have come out in support of sustainability education in engineering curricula

• Civil engineers play an increasing important role in addressing the climate change and sustainability issues that are being discussed nationally and internationally among policy makers and politicians


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ASCE Sustainability Statement

“The public’s growing awareness that it is possible to achieve a sustainable built environment, while addressing such challenges as natural and man-made disaster, adaptation to climate change, and global water supply, is reinforcing the civil engineer’s changing role from designer/constructor to policy leader and life-cycle planner, designer, constructor, operator, and maintainer (sustainer). Civil engineers are not perceived to be significant contributors to sustainable world.”


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ASCE Actions on Sustainability

• On 11/4/2008, ASCE Board of Direction adopted sustainability as the 4th ASCE priorities followed

renewing the nation’s infrastructure Raising the bar on civil engineering

education Addressing the role of the civil engineers in

today’s changing professional environment


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Five Issues Must be Understood by Engineers on Sustainability

• Appeared on 1/8/2009 ASCE News

• Written by William Wallace, founder and president of Wallace Futures Group, Steamboat Springs, CO

Author of Becoming Part of the Solution: The Engineer’s Guide to Sustainable Development


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Five Issues Must be Understood by Engineers on Sustainability (continued)

1. The world’s current economic development is not sustainable – the world population already uses approximately 20% more of the world’s resources than the planet can sustain.

2. The effects of outpacing the earth’s carrying capacity have now reached crisis proportions – spiking energy costs, extreme weather events causing huge losses, and prospect of rising sea levels threatening coastal cities. Global population increase outstrips the capacity of institutions to address it.


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3. An enormous amount of work will be required if the world is to shift to sustainable development – a complete overhaul of the world’s processes, systems, and infrastructure will be needed.

4. The engineering community should be leading the way toward sustainable development but has not yet assumed that responsibility. Civil engineers have few incentives to change. Most civil engineers deliver conventional engineering designs that meet building codes and protect the status quo.


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5. People outside the engineering community are capitalizing on new opportunity – for example, accounting firms and architects. The architects bring their practices into conformity with the U.S. Green Building Council’s leadership in Energy and Environmental Design (LEED) Green Building Rating System


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IEEE Actions on Sustainability

• In January 2009, the Sustainability Ad Hoc Committee was formed to map and coordinate sustainability-related issues across IEEE

• Created the Global Earth Observation System of Systems (GEOSS) involving in collecting data from thousands of sensors, gages, buoys, and weather stations across the globe.

• Goal of GEOSS is to help foster sustainable development


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Sustainability Concepts, Methods, and Tools

• Key sustainability concepts – understanding Earth’s finite resources and environmental issues; socioeconomic issues related to sustainability; ethical aspects of sustainability; sustainable development.

• Key sustainability methods – life-cycle based analysis; resource and waste management (material, energy); environmental impact analysis

• Key sustainability tools – life-cycle assessment; environmental assessment; use of sustainable-development indicators; USGBC LEED rating system


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Sustainability Concepts, Methods, and Tools (continued)

• USGBC stands for U.S. Green Building Council

• LEED stands for Leadership in Energy and Environmental Design


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USGBC LEED Rating System

“LEED is an internationally recognized green building certification system, providing third-party verification that a building or community was designed and built using strategies aimed at improving perfromance across all the metrics that matter most: energy savings, water efficiency, CO2 emissions reduction, improved indoor environmental quality, and stewardship of resources and sensitivity to their impacts. Developed by the USGBC, LEED provides building owners and operators a concise framework for identifying and implementing practical and measurable green building design, construction, operations and maintenance solutions.”


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Summary

• You should know the basic design steps that all engineers follow, regardless of their background, to design products and services

• You should realize that economics plays an important role in engineering decision making

• You should realize that the selection of material is an important design decision

• You should be familiar with the common traits of good teams


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Summary (continued)

• You should understand the importance of project management

• You should be familiar with the concepts of patent, trademark, and copyright

• You should know why we need to have standards and codes in engineering

• You should be familiar with the role and mission of some of the larger standardization organizations in the world


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Summary (continued)

• You should be familiar with the role of the EPA and the standards it sets for drinking water, outdoor air quality, and indoor air quality

• You should be able to name some of the sources of indoor and outdoor air pollutants

• You should be able to name some of the sources of water pollutants

• You should understand the importance of sustainability in engineering design


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Civil Engineering Design Process – A Case Study: Health Clinic

• A health service expansion consisted of a physician office building (POB) and a clinic

• The POB was to attach to the existing hospital with the clinic connecting to the POB

• The clinic and POB were treated as separate project with two different design teams worked on them

• Focus of this case study is the Clinic


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Civil Engineering Design Process – A Case Study: Health Clinic (continued)

Step 1: Recognizing the Need for a building

•Board of Directors of a clinic recognized the need for expansion to meet the increasing demand of health service in their city and its surrounding communities.

•To better serve the people in the communities, the Board of Directors decided to build a new clinic.


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Step 2: Define the usage of the building

•The Board defined in detail the types of building usage

•Parameters considered included: number of examination rooms, reception areas, laboratory facilities such as X-ray, MRI rooms, staff rooms, meeting rooms, and managerial and maintenance facilities, anticipated number of patients, visitors, and staff

•Other considerations included future expansions and future expansion potentials


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Step 3: Project planning

• Owner identified possible building sites

• The proximity of the hospital and the future POB were the major factors that led to the building site

• This is a privately funded project, the owner could have selected an architect or contractor to initiate the design phase or requested bids from architects or contractors to lead the project


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Step 4: Schematic design phase

• Architect designer met with the staff of the clinic to learn more about how the new clinic was to be used

• Architect designer and contractor learned about the estimated budget

• Coordinated with architect of the POB because both buildings shared some common columns and foundations

• Clinic was designed as a steel frame structure

• Architect designer prepared multiple schematic designs© 2011 Cengage Learning Engineering. All Rights Reserved.

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Step 5: Design development (DD) phase

• Architect designer laid out the locations, sizes, and orientations of the reception areas, examination rooms, laboratories, business administration offices, maintenance facilities, entrances to the POB and the street

• Gridlines were defined according to column locations

• Structural engineers provided the size of major support components of the building such as beams, columns, and foundations


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Step 5: Design development (DD) phase (continued)

• Mechanical and electrical engineers provided preliminary mechanical and electrical designs

• A set of architectural drawings with superimposed structural, mechanical, and electrical information was provided to the client and the contractor for cost estimates and review


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Step 6: Construction documentation (CD) phase

• All the detailed comprehensive designs: architectural, structural, civil, interior, mechanical, electrical, plumbing, etc. were performed

• Project manager who represented the architect during all construction meetings was responsible for overseeing the completion of the design and document produced

• Project manager compiled a set of specifications for the project and checked that the design conformed to the current building codes


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• Civil engineer was responsible for the grading of the surface outside the building such as parking lot, sidewalk, handicap parking signs, and other signs, drainage of the paved surfaces to the storm water line, connections from the clinic to the city water line and sewer line


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• Structural engineer was responsible for the design of all the load bearing and non-load bearing components and connections.

Designs included sizing of steel beams, steel columns, isolated reinforced concrete footings, bracing necessary to support wind load, steel joists to support the roof and snow loads

Provided design details to support roof top unit and x-ray equipment


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• Structural design documentation included a set of very detailed drawings of

the layout of the beams, columns, and their sizes, steel joist sizes and spacing;

connections between beams and columns, joists and beams, columns and footings;

steel reinforcing details of the footings; masonry wall sizes and steel reinforcements,

metal studs spacing;


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special details to support door and window openings and other architectural components such as canopy at entrance

• Since the clinic and POB share some common columns and foundations, the structural engineer of the clinic provided design information at the common gridline to the engineer for the POB


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Typical connection detail between steel beam and column


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Step 7: Construction administration (CA) phase

• There were weekly meetings between the site superintendent (from the contractor), the project manager (from the architects), representatives from different subcontractors such as electricians, plumbers, steel erectors

• Minutes from each construction meetings were recorded by the project manager and distributed to all parties

• Periodically, the project manager and site superintendent met with the owner, to report the progress of the construction and to address the owner’s concern


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Step 7: Construction administration (CA) phase (continued)

• Structural engineer, though not required but strongly recommended, visited the site to observe the construction process especially during foundation construction and framing of the building and to attend the construction meeting periodically during that time

• Structural engineer reviewed all the shop drawings of structural components such as beam sizes and length, connection details

• After the framing was done, other contractors went on site to do the wiring, plumbing, roofing, installing equipment


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Structural engineer’s site observation during construction


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• Interior designers began their part of the projects after the interior part of the buildings was ready such as walls, floors, and ceilings

• After the building inspector issued the permit of occupancy, the clinic staff started using the new clinic


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• Punch list Project manager, site superintendent, and the owner

performed a walk-through checking everything to make sure they were acceptable

Contractor and project manager took notes of all the fixes needed and items remained to be finished such as touch up paint, cleaning, missing cover plate on light switches

Owner would hold back the last 5 to 10% of the payment until he/she is completely satisfied with the construction


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Mechanical/Electrical Engineering Design Process – A Case Study: Minnkota Electric Outboard Drive

• Minnkota Electric Outboard Drive is designed and manufactured by Johnson Outdoors in Mankato, MN with headquarter in Racine, WI


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Mechanical/Electrical Engineering Design Process – A Case Study: Minnkota Electric Outboard Drive (continued)

Step 1: Recognizing the need for a product or a service

• Marketing department at Johnson Outdoors recognized the growing interest in environmentally friendly power sources for their boating industry

• Marketing department contacted the engineering department to discuss the feasibility of developing new generation of motors that are environmentally friendly

• Increasingly, more states were enacting regulations banning the use of gasoline boat motors in public water ways including lakes and rivers


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Step 2: Problem definition and understanding

• The details of the project requirements were defined

• Design specifications included Motor had to move a 17 feet long Pontoon at a

speed of 5 mph minimum Boat operator had to have the capability to trim and

tilt from a remote console Motor had to be compatible with industry standard

steering wheel mechanism


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Step 3: Research and preparation

• Engineers checked existing design inventory to determine if a motor already exists that would meet some or all requirements

• A mechanical engineering student was commissioned to look at state regulations concerning the use of gasoline vs. electric boat motors


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Step 4: Conceptualization

• The engineering designers (12 of them) met on weekly basis to brain storm and bounce ideas off each other.

• They reviewed the information that was gathered in Step 3.

• They developed few concepts to pursue further

• An additional idea that surfaced was the use of an electric linear actuator in place of a hydraulic actuator. The idea was pursued further.


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Step 5: Synthesis

• The design engineers began to consider details

• They consulted pertinent codes and standards to make sure that their design was in compliance

• Most of the design was done in ProE® and prototypes were built in machine and electrical labs

• The unique design of the propeller required the use of a manufacturing process known as investment casting


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Step 5: Synthesis

Exploded diagram of motor


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Step 6: Evaluation

• Numerical experiments were conducted using ProMechanica®

• Finite element techniques were used to look at stresses in critical components of the motor itself and the mounting bracket and the lifting mechanism

• Numerical experiments were performed to study the hydrodynamics of propeller designs including thrust, cavitation, speed, and drag


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Step 6: Evaluation (continued)

Stress results from finite element analysis


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• Using GPS, the speed of the boat was measured over a period of several hours to quantify the motors’ speed a s a function of time

• The collected data were used to compare to competitors’ motors


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Engineers used ProMechanica® to conduct numerical experiments on the motor


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Step 7: Optimization

• Based on results obtained from Step 6, modifications were made to the design and additional analyses performed

• Results of numerical experiments were used to optimized the design of propeller and mounting bracket

• Conducted many hours of actual field testing in water and simulated life testing in labs to help with optimization of final design


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Step 7: Optimization (continued)

Actual testing of the system in a lake


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Step 7: Optimization (continued)

Testing of the system in a laboratory setting


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• The product development process took approximately two years

• During this period design engineers gave weekly progress reports to the rest of design group; quarterly status oral and written reports to the

marketing department and group vice president final presentation to the Board of Directors

• Presentation duration ranged from 15 minutes to an entire afternoon


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Step 8: Presentation (continued)

• Presentation addressed several issues including Development cost Unit cost Market outlook Performance characteristics Testing results Environmental impact


3-1 CHAPTER 3 Introduction to Engineering Design © 2011 Cengage Learning Engineering. All Rights...

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