Engineering Design I Chapter 1: Introduction Richard Hornsey Departments of Computer Science & Physics Fall 2002.

Engineering Design IChapter 1: Introduction

Richard Hornsey

Departments of Computer Science & Physics

Fall 2002

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About Me

Ancient history MA, MSc, DPhil, Oxford University Hitachi Central Research Labs, Tokyo Microelectronics Research Lab., Cambridge University

Electrical and Computer Engineering, University of Waterloo, 1994 - 2001

Research areas: electronic materials, manufacture of microelectronic devices nanostructures thin-film electronics integrated sensors

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Outline of Introduction

What is an Engineer? What is Engineering? Where is Engineering going? Skills required by and Engineer Engineering Design The design process Case study

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What is an Engineer?

www.unitedmedia.com

www.startrek.com

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Other Engineers

Isambard Kingdom Brunel

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William Gates

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Mechanical Engineering

Bombardier’s snowmobile(1923)

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Donald Smith and the“last spike” (1885)Brunel’s Clifton

Suspension Bridge(designed 1830)

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Religious Engineering

Pyramids(c. 2500BC)

Stonehenge(c. 2500BC)

Leaning tower of Pisa (1173)

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Military Engineering

Great Wall of China(200BC)

http://abe.www.ecn.purdue.edu/~agenhtml/agenmc/china/images/scenery/gw0.gif

medieval trebuchet(1300s)

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B-2 Stealth Bomber (1990s)

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Civil Engineering

CN Tower, Toronto (1976)

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Pont du Gard, France (20BC)

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Petronas TowersKuala Lumpur (1998)

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Newer Engineering

Canadarmwww.mdrobotics.ca

Intel Pentium 4

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What differences?

What are the differences between the traditional and the newer forms of engineering?

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So … What is Engineering?

Profession devoted to designing, constructing, and operating the structures, machines, and other devices of industry and everyday life

Discipline dealing with the art or science of applying scientific knowledge to practical problems

better – it implies a scientific basis while acknowledging that there is an artistic component and that engineers solve practical problems

“Doing for seventy cents what any fool can do for a dollar” not precise, but sums up the economics

“I fix things; that’s what Engineers do.” Chief Miles O’Brien, StarTrek Deep Space

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Textbook Definitions

Association of Professional Engineers of Ontario (APEO) “any act of designing … that involves third-party concerns … and that

requires the application of engineering principles” Professional Engineers Act, Ontario

1. any act of designing, composing, evaluating, advising, reporting, directing or supervising;

2. wherein the safeguarding of life, health, property or the public welfare is concerned, and

3. that requires the application of engineering principles, but does not include practising as a natural scientist.

Textbook for this course “an innovative and methodical application of scientific knowledge and

technology to produce a device, system or process, which is intended to satisfy human need(s)”

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Key Concepts

Engineering is a profession what does it mean to be a professional?

Engineering is legally regulated use of the title “Engineer” is restricted

Key words in these definitions design third-party concerns; safety and public welfare innovative methodical scientific knowledge; technology produce device, system, or process

Engineers Act serves to protect the public for more information on the Professional Engineers of Ontario (PEO),

see http://www.peo.on.ca

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“Engineering” Designation

Canadian Council of Professional Engineers and Microsoft Corp. Agree on use of “Engineer” title

Ottawa, Ont., May 11, 2001 – After discussions with Canada’s engineering profession, Microsoft Corp. will advise Canadian holders of its MCSE certification not to call themselves engineers or use the full title Microsoft Certified System Engineers.

Microsoft’s decision should prevent Canadian holders of the MCSE certification from inadvertently breaking provincial and territorial laws, which protect the public by restricting the use of the titles “engineer” and “engineering” and the practice of engineering in Canada to licensed professional engineers. It should also ensure that the engineering profession’s licensing bodies will not be required to take enforcement action against MCSE holders who mistakenly use the title engineer or otherwise hold themselves out as having been qualified to practice engineering.

“We are very pleased by Microsoft’s decision,” said Marie Lemay, P.Eng., CEO of the Canadian Council of Professional Engineers (CCPE). “Microsoft has demonstrated corporate leadership by acting in the best interest of the MCSE community. Holders of the MCSE certification are not licensed or regulated by the engineering profession. If they mistakenly use the titles “engineer” and “engineering” the provincial or territorial engineering associations/order would have to take enforcement action against them. Its decision is good for the information technology industry, good for MCSE holders, and good for the engineering profession.”

The engineering profession, represented by CCPE and several provincial engineering regulatory associations, met with Microsoft in Seattle late last year to explain the legal issues surrounding the use of the title “engineer” in Canada, and to ask the corporation to stop referring to holders of the MCSE credential as engineers. Canadian MCSEs have received certification as Microsoft Certified Systems Engineers, which could lead them to mistakenly misuse the title “engineer.”

“We are very pleased to have reached an agreement with the engineering profession and to support it,” said Anne Marie McSweeney, the acting Director of Microsoft Certification and Skills Assessment. “It opens the door for closer cooperation among all organizations in the information technology industry and the engineering profession in Canada. As the Microsoft credentials continue to evolve, it is our goal to ensure they maintain the highest level of relevance to the industry and represent leaders in cutting-edge technology.”

Microsoft is currently researching alternatives for the MCSE credential worldwide, which could result in a new name for the credential later this year.

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Whither Engineering?

Based on out definitions, is this engineering?

Or this?

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Top 10 Skills of an Engineer

• From the text book:1. Problem-solving skills

2. Effective communication skills

3. Highly ethical and professional behaviour

4. Open mind and positive attitude

5. Proficiency in math and science

6. Technical skills

7. Motivation for “lifelong learning”

8. Knowledge of business strategies and management practices

9. Computer literacy

10. Understanding of world affairs and cultures

• Be good at everything!• The engineering profession is changing

• no longer do people stay with one company• the above skills ensure that an engineer remains flexible

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Accreditation Board for Engineering and Technology (ABET)

Engineering programs must show that their graduates have: an ability to apply knowledge of mathematics, science, and engineering an ability to design and conduct experiments, as well as to analyse and

interpret data an ability to design a system, component, or process to meet desired

needs an ability to function on multi-disciplinary teams an ability to identify, formulate, and solve engineering problems an understanding of professional and ethical responsibility an ability to communicate effectively the broad education necessary to understand the impact of engineering

solutions in a global and societal context a recognition of the need for, and an ability to engage in life-long learning a knowledge of contemporary issues an ability to use the techniques, skills, and modern engineering tools

necessary for engineering practice.

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Half-life of Knowledge

Half-life is the time after which half of our (technical) knowledge is obsolete

~12 years in 1940 ~5 years in 2000 ~3 years for software professionals

time

long half-life knowledge

time

short half-life knowledge

Fundamentals

e.g. science & math, communication, creativity, process

Application Specific

e.g. software packages, exam cramming

acquisition depreciation

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What is “Design”?

From Oxford English Dictionary to make the plans and drawings necessary for the construction of (a

building, ship, machine, etc.), which the workmen have to follow out from Latin, to mark out, from de- + signare to mark

Engineering Design is the systematic, intelligent generation and evaluation of

specifications for artifacts whose form and function achieve stated objectives and satisfy specified constraints (Dym & Little)

how is this different from the definition of “engineering”? Key words

systematic generation and evaluation specifications, stated objectives artifacts form and function constraints

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Engineering Design is a Process

The underlying philosophy of this course is that engineering design is a process that can be learned

It is this process that distinguishes an engineer from an inventor

indeed, good professional practice requires that the appropriate process be followed

Such management practices are being standardised in such generic standards as ISO 9000

“The ISO 9000 family of standards represents an international consensus on good management practices with the aim of ensuring that the organization can time and time again deliver the product or services that meet the client's quality requirements. These good practices have been distilled into a set of standardized requirements for a quality management system, regardless of what your organization does, its size, or whether it's in the private, or public sector.”

this is not specifically for engineering, but the same idea applies

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Design Process Cycle

Other books use slightly different models, e.g. Dym & Little1. Client Statement

2. Problem Definition

3. Conceptual Design

4. Preliminary Design

5. Detailed Design

6. Design Communication

7. Final Design Are these the same? Which do you prefer? The 6 steps in the cycle are well described in the text (§1.2)

From textbook: Needsassessment

Problemformulation

Abstractionand synthesis

Analysis

Implementation(Evaluation)

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Needs Assessment

Identify the objectives and/or needs may be supplied by the client may require ‘education’ of the client

Who will benefit from the solution? How? What solutions, if any, already exist?

strengths and weaknesses? What are the constraints?

may be apparent or hidden How will you know if the needs have been met?

testability, design for test verification manufacturability

For example, we are asked to build an aeroplane (based loosely on case studies of the Wright brothers in Ch.1 of text) it must be capable of powered flight

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Unanticipated Constraints - Challenger

An unanticipated constraint in the Chellenger design ‘O’-ring seals do not seal effectively at low temperatures

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Problem Formulation

Define the ‘real’ problem re-interpret the objectives in the light of what is possible

The goal is to break down the problem into a set of design objectives which can lead to a full solution

check that the sum of the parts still equals the whole, i.e. the individual steps together solve the original problem

For our aeroplane require enough lift must overcome drag need a low-mass engine must have enough control (pitch, roll, yaw)

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Abstraction and Synthesis

Develop general methods for solving the problems, including alternatives

Each of the problems must be tackled methodically, based on experience technical knowledge creativity input from others

If necessary, additional knowledge should be gained from published material or from experimentation/theory

For example determine how the the drag and lift are affected by the shape and area

of the wing, hence propose appropriate wing geometries find someone to build a lightweight engine to your specifications test a number of control strategies on un-powered gliders before

designing the final version

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Approximations

The world is not an ideal place non-idealities lead to very complex – and not necessarily solvable –

calculations even ideal situations have no straightforward solution e.g. the motion of a pendulum with just one extra joint is chaotic

However, engineers must find a workable solution Sometimes a brute-force approach is used, such as numerical

simulation but this is still only as good as the knowledge used to construct the

simulator Typically, the skill of an engineer is to determine which

approximations to use in order to reach an acceptable solution e.g. Sydney Opera House

the architect originally wanted parabolic roofs but the stress calculations were so complex that engineers eventually

substituted arcs of circles

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Analysis

Determine which of your designs is best technically economically ethically, environmentally to manufacture (linked to economics) for product life cycle for human factors satisfies the customer

Construct prototypes to evaluate close contenders the Wright brothers made numerous revisions and modifications to

their gliders based on trials of the prototypes

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Implementation and Evaluation

Build it and sell it! Typically, pre-production models will be tested before full-

scale manufacture by the customer by focus groups by interest groups, e.g. beta testing of software

The design process is iterative i.e. it repeats continuously, (hopefully) approaching the optimum

solution How do we know that the solution is getting more optimal?

evaluation, feedback from customers, litigation for mass produced products, there is more feedback, but the

consequences of an error are larger e.g. recent Bridgestone-Firestone tire recall

It is very expensive if it is the customer who finds the fault in your product

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Flaws in Evaluation

The Pentium Bug a subtle fault which appeared in 1994 that could produce significant

errors in mathematical calculations Intel initially responded that only people doing ‘serious’ math would get

a replacement company eventually gave in under intense pressure and offered

replacements for everyone New Intel slogans

Q: How many Pentium designers does it take to screw in a light bulb?

A: 1.99995827903, but that's close enough for non-technical people. At Intel, quality is job 0.999999998.

http://www.maa.org/mathland/mathland_5_12.html

Law of ten cost of catching a mistake increases tenfold at each stage concept, schematic, layout, manufacture, packaging, verification,

customer

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Summary

Engineers are highly skilled and versatile professionals with understanding both of the technical theory and the methods for

solving problems Problem solving is structured

several different methodologies are possible but the outcome is similar This combination makes the professional engineer different

from both the technologist and the inventor We concluded this introduction with a brief overview of each

of the stages of the design process These stages will be examined in detail in the remainder of the

term

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Other Books to Read

C.L. Dym & P. Little, "Engineering Design: A Project-Based Approach", Wiley, 2000, ISBN 0-471-28296-0

P. Dominick et. al., "Tools and Tactics of Design", Wiley, 2001, ISBM 0-471-38648-0.

M. Horenstein, "Design Concepts for Engineers”, Prentice Hall, 1999, ISBN 0-13-081369-9

C. Fleddermann, "Engineering Ethics", Prentice Hall, 1999 ISBN 0-13-784224-4

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Homework

Read and understand the section on report writing in textbook (§1.5)

Read the case studies at the end of Ch.1 Chapter 1 problems