The Engineering Design

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The Engineering Design Recipe
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Engineering Design Recipe
Separates designing from trial and error
Looping and iterations are common!

• Although the design process is very structured,
  it should not inhibit creativity!

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Engineering Design

• is problem solving!
• Problem My cell phone battery is dead
• Problem I agreed to attend two different
  meetings during the lunch hour
• Define the problem, generate ideas, select a
  solution.but no building or evaluating
• Problem Design a way to conveniently and
  effectively roll up the rim to win.

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Problem Definition

• Ask questions!
• Ask questions as if you were the user AND the
  designer
• User will it fit in my pocket?
• Designer what kind of material will it be made
  of?
• First brainstorming session should be to come up
  with questions to better clarify the problem
• How big can it be? Does it have to work on a full
  cup? What type of people will be using it? What
  does convenient mean? What does effectively
  mean? How much should it cost?

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Problem Definition

• Clarify objectives!
• Objectives of a design are
• Goals you work toward
• What the design should be
• The design should be easy to use
• The design should be inexpensive
• Design options may meet an objective perfectly,
  or they might only meet an objective part way

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Problem Definition

• Establish constraints!
• Constraints of a design are
• Strictures or limitations on the design
• What the design must be
• The design must cost less than 500 to purchase
• The design must be able to carry at least 500 g
  of sand
• Must be able to answer yes/no
• The design must be lightweight ? not a constraint
• The design must weigh less than 10 kg ?
  constraint

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Listing Objectives and Constraints
A method of rolling up the rim should be

• Easy to use
• Lightweight
• Portable (fit in your pocket)
• Safe (no sharp edges or open cutting surfaces)
• Made of non-toxic materials
• Able to open enough of the rim to read the
  printed words
• Able to open the rim without mangling the cup

objective
objective
constraint
objective
constraint
objective
objective
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Ordering Objectives

• Different designs result from the same problem
• Design a device that enables people to reach
  heights they would be otherwise unable to reach

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Ordering Objectives

• Final design will depend on which objectives are
  MOST important
• Objectives
• Portable
• Inexpensive
• Aesthetically pleasing
• Durable
• Safe for people of all ages
• Wide variety of uses

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Pairwise Comparison Chart
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Measuring how well objectives are met (metrics)

• Constraints are yes/no so they are either met or
  they arent
• Objectives may be met part way ? need to assign a
  number value
• Metrics a scale that the designers agree upon to
  measure how well design alternatives meet
  objectives
• Should be unambiguous
• Should actually measure what you want to measure
• Should be repeatable

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Metrics

• Metric scales can be based on actual numbers
• Objective inexpensive to buy
• Metric scale
• lt 500 scores a 10
• gt1000 scores a 1
• Metric scales can be subjective
• Objective safe to use
• Likely to harm self or others scores a 1
• Impossible to harm self or others scores a 10
• Metric scales can be based on actual lab tests
• Objective durable in all types of weather
• Lab test build a scale model or prototype and
  subject it to simulated wind, rain etc. and
  assess the damage after a specific amount of time
• Total destruction scores a 1
• Totally intact scores a 10

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Applying Metrics

• A method of rolling up the rim objectives
• Easy to use
• Safe
• Opens enough of rim to read words
• Doesnt mangle cup

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Applying Metrics

• Metric for easy to use
• Requires extensive training ? 0
• Requires one demonstration ? 5
• Intuitive ? 10
• Metric for safe
• Likely to harm self or others ? 0
• Possible to harm self or others ? 5
• Impossible to harm self or others ? 10

• Metric for opens enough of rim
• lt1 cm ? 0
• 1-3 cm ? 5
• gt3 cm ? 10
• Metric for doesnt mangle
• Words are indistinguishable ? 0
• Words can be made out ? 5
• Words are clear ? 10

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Finishing Defining the Problem

• When you run out of questions, you can continue
  gathering information by searching literature
• State of the art searches ? how do similar
  designs work?
• Web searches, patents, vendor information
• Expert information ? talk to someone with
  experience in the area
• Sometimes more efficient than wading through
  documents
• Visual brainstorming ? looking at images related
  to your design problem can stimulate thought
  process
• Google images, magazines, Science TV

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Next Stage Generate Ideas

• Literature searches can stimulate creative ideas
• Identifying functions and means can also help
  start the creative process

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Functions

• Establish Functions!
• Functions of a design are
• Things the design will do
• Usually characterized with a verb-noun pair
• The design will support a load
• The design will dampen oscillation
• The design will contain liquid
• Try not to worry about how you will achieve the
  function yet

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Help with establishing functions

• Imagine the object disappearing
• Imagine if a bookshelf wasnt there, what would
  happen? The books would all be on the floor in a
  big heap!
• Function support books
• Secondary function organize books
• Think of the object as a black box and examine
  inputs and outputs
• The inputs on a radio are channel/volume
  selection, power, and a radio frequency signal.
  Outputs include sound, indicator lights and
  heat.
• Function convert signal to sound
• Secondary (unwanted) function generate heat

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Morphological Charts

• Brainstorm ways to achieve functions and features

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More on Brainstorming

• Need a specific problem statement
• How can we achieve this function?
• How is this function achieved in other
  situations?
• How can we meet this objective perfectly?
• Anything goes! Do not discuss until after
  session. Write everything down!
• Linking seemingly unrelated things is key to good
  brainstorming

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Establish Design Alternatives

• Choose from your options in the morphological
  chart and use some creativity to put them
  together
• A method of rolling up the rim design options
• Fingers/teeth
• Knife/fingers
• Plastic RimRoller

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Next Stage Select a Solution
A good solution must fulfill requirements, meet
with deadline, and be produced with available
resources.
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Applying Metrics
Doesnt account for relative importance of
objectives!
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Decision Matrices

• First, check to see if alternatives meet all
  constraints
• Constraints portable (fit in pocket) and made of
  non-toxic materials
• Alternatives that meet all constraints can be
  entered into a decision matrix
• Decision matrices involve weighted objectives

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Pairwise Comparison Chart (again)
Apply weightings (subjective, discuss with
group). Total weighting should add up to 100.
Safe 40 Doesnt mangle 30 Easy to use 20
Opens enough 10
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Decision Matrix (with weighted objectives)
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Establish Design Specifications

• Specify
• Materials
• Sizes
• Types of motors
• Sizes of pumps
• Methods of attachment
• Size of holes
• Etc, etc, etc.

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Next Stage Build the Design!
After all the question asking, brainstorming and
evaluating, you should have a good idea of how
the components will go together.
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Next Stage Evaluate!
Test the design in conditions similar to actual
conditions. Modifications may be required, or
alternatives not previously considered may become
obvious!
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Final Stage Communication

• Written and oral reports
• Include all options as well as final option to
  show thought process and consideration for all
  alternatives
• Clear, concise, to the point, well organized

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Working in Groups

• Engineering is multi-disciplinary!
• Communication is key
• Dealing with conflict
• Avoidance
• Smoothing
• Forcing
• Compromise
• Constructive engagement the only way to
  consistently get win-win results

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Making a plan and sticking to it!

• Procrastination can lead to stress and sub-par
  designs!
• Be aware of tasks that can overlap and tasks that
  must be completed before moving on
• Set deadlines for tasks, assign them to group
  members, and stick to the plan!
• Gantt Charts are visual representations of task
  breakdown, overlaps, and critical path

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Sample Gantt Chart
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Summary
Ingredients Brainstorming, objectives,
constraints, functions Pairwise comparison
charts, metrics, decision matrices, morphological
charts Project planning, communication,
creativity, patience