Senior Design I

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Senior Design I

• Dr. R. A. Freeman
• UT - Pan American
• Fall 2008

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Course Outline

• What is Design?
• Problem Formulation
• Concept Generation
• Concept Selection
• Embodiment Design

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What is Design?

• Design versus Analysis
• Up to now in your curriculum you have been
  primarily concerned with the development of your
  understanding of the "unambiguous and never
  changing" laws of science and rules of
  mathematics.
• Having mastered these laws and rules you can
  readily proceed to "analyze" a given system -
  this is relatively speaking an easy task.
• There is typically (if not always) a single
  (correct) answer to a given problem (e.g., given
  m and a, Fma and thats that.).

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What is Design?

• Design versus Analysis
• Design on the other hand requires that you "come
  up with" the system given only a general
  statement of "need." This is a much more
  involved, ambiguous, inconsistent, uncertain, and
  uncomfortable situation.

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What is Design?

• A Definition of Engineering Design
• "Engineering design is a methodical approach to
  solving a particular class of large and
  complicated problems."

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ABET (Accreditation Board for Engineering and
Technology)

• Definition of Design
• "Engineering design is the process of devising a
  system, component, or process to meet desired
  needs.
• It is a decision-making process (often
  iterative), in which the basic sciences,
  mathematics, and engineering sciences are applied
  to convert resources optimally to meet a stated
  objective.
• Among the fundamental elements of the design
  process are the establishment of objectives and
  criteria, synthesis, analysis, construction,
  testing, and evaluation.

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ABET

• The engineering design component of a curriculum
  must include at least some of the following
  features development of student creativity, use
  of open-ended problems, development and use of
  design methodology, formulation of design problem
  statements and specifications, consideration of
  alternative solutions, feasibility
  considerations, and detailed system descriptions.
  Further, it is essential to include a variety of
  realistic constraints such as economic factors,
  safety, reliability, aesthetics, ethics, and
  social impact."

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The Centrality of Design

• "Design is the culmination of all engineering
  activities, employing engineering analysis and
  other engineering activities as tools to achieve
  design objectives."

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A Model of the Engineering Design Process

• There are many different approaches to describing
  how design is done.
• Some of these descriptions have been formalized
  into simplified step-by-step models of the design
  process.
• While no one model has been universally accepted,
  it is helpful to adopt one in an effort to
  organize our activities.

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9-Step Model

• A. Problem Formulation
• Recognizing the Need
• a. Identify the client
• b. Interact with the client
• c. Formulate the needs statement
• d. Market assessment (assume for now that there
  is a sufficient market)
• Define the Problem
• a. Goal(s)
• b. Objectives
• c. Constraints
• d. Relate Customer Requirements to Engineering
  Requirements and Specifications (Quality Function
  Deployment (QFD))
• Plan the Project (make a guess at how long you
  have for each activity)

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9-Step Model

• B. Conceptual Design
• 4. Gather Information
• a. Obtain information about previous similar
  designs/systems/processes and about applicable
  standards/codes
• b. Generate a Functional Breakdown of the
  previous designs Try to breakdown the design
  into a number of sub-functions that are then
  combined to form the total design (System Concept
  gt Function Structure gt Sub-Functions) Form
  follows Function
• c. Continue construction of the Quality
  Function Deployment (QFD) Diagram
• 5. Conceptualize alternative approaches
  Brainstorm
• a. Conceptualize at the System level
• b. Conceptualize at the Sub-Function level
• c. Cont. construction of the Quality Function
  Deployment (QFD) Diagram

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9-Step Model

• C. Concept Selection
• 6. Evaluating the alternatives
• a. Develop Design Criteria (from Objectives and
  Constraints)
• b. Perform/Construct a Design Failure Modes and
  Effects Analysis/Diagram (D-FMEA)
• 7. Selecting the preferred alternative (Decision
  Matrices)
• a. Screening
• b. Method of Pairs
• D. Embodiment Design
• 8. Communicating the Design
• 9. Implementing the Preferred Design

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Recognizing the Need

• Identify the client
• Interact with the client
• Formulate the needs statement
• A statement of dissatisfaction with the current
  situation.
• Market Assessment

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Recognizing the NeedExample from Ullman

• Your Boss
• Your name, we need you to design a stronger
  bumper for our new passenger car.
• You
• Why do we need a stronger bumper?
• Boss
• Well, our current bumper gets easily damaged in
  low-speed collisions, such as those that occur in
  parking lots.

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Recognizing the Need Example

• You
• Well, a stronger bumper may be the way to go,
  but there may be better approaches. For example,
  what about a more flexible bumper that absorbs
  the impact but then returns to its original
  shape?
• Boss
• I never thought of that. I guess I was jumping
  to conclusions. Lets restate the need as there
  is too much damage to bumpers in low-speed
  collisions. That should give you more
  flexibility in exploring alternative design
  approaches.

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The revised Needs statement

• is more general than the initial one,
• focuses on what is unsatisfactory with the
  present situation,
• and is silent in terms of the design approach to
  use.

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Engineering Design Process
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Defining the Problem

• Need The current approach (of using plywood
  sheets and screws/nails) for protecting windows
  in the event of hurricanes is unacceptable.
• Goals a brief, general, and ideal response to
  the needs statement. Note that this statement is
  normally both general and restrictive at the same
  time.
• Design an improved method for protecting windows
  in the event of hurricanes.
• This is general in that there is no direction as
  to how to protect the windows, and restrictive in
  that you can't replace the windows.

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Defining the Problem

• Objectives Quantifiable expectations of
  performance.
• These are characteristics that you want your
  design to exhibit, and as such will be used to
  help formulate the criteria on which your various
  design concepts will be compared.
• The design does not absolutely have to satisfy
  each objective, but clearly the ideal design
  would.
• Inexpensive, reusable, easy to install, easy to
  employ, etc.

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Defining the Problem

• Constraints define the permissible range of
  design and performance parameters.
• These are absolute requirements of the design if
  they are not satisfied the design is not viable,
  and so, is not eligible for consideration.
• There can be no damage to the window in up to 150
  mph winds with debris, the cost must be less
  than 20 (or no one will buy it - no market),
  etc.

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Quality Function Deployment
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QFD
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Step 1 Identify the Customers

• Consumer
• Production
• Marketing / Sales

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Step 2 Determine Customer Requirements
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Step 3 Determine the Relative Importance of the
Requirements

• Rank order for each Customer

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Step 5 How will the Customer Requirements be Met?

• Engineering Requirements
• Quantifiable aspects of the system that can
  contribute to satisfying the customers
  requirements
• Must be measurable/quantifiable (has units)
• Design parameters
• Characteristics of the design that the engineer
  can directly manipulate
• Performance parameters
• Characteristics that result from DP selections

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Step 7 Identify Relationships between
Engineering Specifications

• Can include plus and minus signs to indicate
  if an increase in one parameter increases () or
  decreases (-) another

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Step 8 Set Engineering Targets

• Benchmarks
• How much is good enough for your design?

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QFD
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Planning 5 Steps

• Step 1 Identify the Tasks
• Be as specific as possible
• Step 2 State the Objective for each Task
• Defined as information to be refined or developed
  and communicated.
• Completed drawings
• Results of calculations
• Information gathered
• Tests performed
• Easily understood
• Specific
• Feasible Personnel, equipment, and time

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Step 3 Estimate the Personnel, Time, and other
Resources needed to meet the ObjectivesPERT
Time (o 4m p)/6
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Step 4 Develop a Sequencefor the TasksStep
5Estimate the Product Development CostsmSoft
Project
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IDEF Help in Organizing (Steps 1tasks,
2objectives, and 4sequence)
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Oral Communication Dos and Donts

• Dont read slides
• Dont fiddle with things in your pocket
• Dont pass around examples during presentation
• Engage your audience (eye contact, etc.)
• Make sure your slides are visible/legible
• Can use transparencies /or computer slides
  (e.g., PowerPoint) /or document camera
• Have a backup form of presentation (technology
  doesnt always work as expected)
• Usually have all members present
• Try to pre-assign different members to different
  types of questions
• Maybe pass out copies of presentation slides
  before or after presentation?

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Problem Formulation Presentation Outline (10mins)

• Title Slide with group member names (Introduce
  yourself and your group members)
• Tell us what youre going to tell us
• Very brief overview of general situation (do this
  before you give your outline)
• Tell us how youre going to tell us (outline of
  presentation)
• Tell us (body of presentation)
• Company/problem background
• Need statement
• Goal(s)
• Objectives
• Constraints
• Start Quality Function Deployment (focus on
  customer objectives)
• ? Review of existing products/processes
  (benchmarks) ?
• Timeline/Schedule
• Tell us what you told us (summary)
• Questions

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Written Communications

• Design Journal
• Memos
• Technical Reports
• Progress Reports
• Final Report

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Format for Technical Reports

• Letter of transmittal
• Report Cover
• Title Page
• Abstract
• Table of contents (Pagination and captions)
• Introduction
• Results and discussion
• Conclusions
• Recommendations
• References
• Appendices

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Problem Formulation Report Outline

• Abstract (Brief statement of problem and
  result(s), if any!
• Table of Contents, List's of Figures and Tables,
  List of Appendices
• Introduction
• Overview of the situation being addressed
• Company / Client Background
• Proposed Overall Design Methodology
• Proposed Timeline
• Problem Formulation (What is the problem youre
  solving?)
• Overview / Problem Formulation Methodology
• Need Statement
• Problem Definition
• Goal
• Objectives
• Constraints
• QFD
• Summary
• References
• Appendices

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Concept Generation

• Functional Decomposition First step in
  generating concepts, another step in
  understanding the problem. Forces detailed
  understanding of what product is to be.
• Function/What before Form/How
• Concepts follow function, and products follow
  concepts
• Finer functional detail gt Better understanding
  of the design problem
• Breakdown gt realization that already existing
  components may provide some of the desired
  functionality
• Generate Concept Variants for each subfunction
• Combine subfunction variants to create complete
  concepts

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Functional Decomposition

• Function can be described in terms of the logical
  flow of
• Energy flow (including static forces) Thin line
• Material flow Thick line
• Through-flow material-conserving processes
  (position, lift, hold, support, move, translate,
  rotate, and guide)
• Diverging flow dividing the material into two or
  more bodies (disassemble, separate)
• Converging flow assembling or joining materials
  (mix, attach, and position relative to)
• Information flow Dotted line
• Interacting objects from the top

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Functional Decomposition A Technique

• Step 1 Find the Overall Function That Needs to
  Be Accomplished
• Step 2 Create Subfunction Descriptions
• Step 3 Order the Subfunctions
• Step 4 Refine the Subfunctions

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Step 1 Overall Function
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Overall Function Guidelines

• System boundaries must be clearly identified.
• Energy must be conserved in gt out or stored.
• Material must be conserved in gt out or stored.
• All interfacing objects and known, fixed parts of
  the system must be identified gt Constraints
• When adding information to the diagram, ask the
  question, How will I know if the system is
  performing?

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Step 2 Subfunction Descriptions

• Each subfunction has the following 5 components
• A box
• An action verb
• The object on which the verb acts
• Possibly a modifier giving details of the
  function
• Known flows of materials, energy, and control

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Subfunction descriptions Guidelines

• Consider what, not how.
• No new objects objects gt form, not function.
• Break the function down as finely as possible.
• Brainstorming
• All noun/verb pairs (see action verbs).
• List all the alternative functions.
• Include all input and output energy, materials,
  and information.
• Include input and output states If energy is
  absorbed, include input and output material
  temperature.

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Subfunction descriptions Guidelines

• Consider all operational sequences.
• Preparation gt Use gt Conclusion
• Use standard notation when possible.
• Developing subfunciton ideas can be aided by
  reviewing customer requirements, visualizing the
  flows, reviewing the list of action verbs, or
  acting the role of the product.
• For redesign problems or to understand
  benchmarks, disassemble a sample to find
  subfunctions.

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Types of Mechanical Functions

• Each function represents a change or
  transformation in the flow of material, energy,
  or information.

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Step 3 Order Subfunctions

• Output of one function is the input of another.
  Notice introduction of noun box.

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Order Subfunctions Guidelines

• The flows must be in temporal order.
• Preparation gt Use gt Conclusion
• Output of one subfunction is the input of another
• Redundant subfunctions must be identified and
  combined.
• More than one way to say the same thing
• Functional choices must be identified and either
  left as an option or a decision made.
• More than one way to skin a cat steer,
  interrupt, or collect water
• Functions not within system boundaries must be
  eliminated.
• Energy and material must be conserved as they
  flow through the system.
• For redesign or benchmarking problems, the flow
  can be established during disassembly in the
  previous step.

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Step 4 Refine Subfunctions

• Decompose as finely as possible

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Refinement of Position subfunction
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Generating Concepts from Functions A
Morphological Technique

• Step 1 Developing Concepts for Each Function
• Concepts are a means of providing function
• Determine as many alternative functions as
  possible for each function
• Determine as many alternative means for
  satisfying each function
• Keep all concepts at the same level of
  abstraction
• Almost anything goes at this stage
• Start making sketches

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Step 2Combining Concepts

• Must satisfy all functional requirements
• Pitfalls
• Too many ideas
• Total (SF1)x(SF2)x . x(SFn)
• Assumes each function is independent
• Results may not make sense

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Splashguard Morphology
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Combining Concepts
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Sources for Concept IdeasTechniques to Prime
Creativity

• Patents
• Reference Books and Trade Journals
• Experts
• Brainstorming
• 6-3-5 Method (Members-Ideas-Minutes)
• Existing Products

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Concept Selection

• Design Criteria Customer Objectives
• Concept Variant Screening wrt Design Criteria
• Concept Variant Ranking wrt Design Criteria
• Design Criteria Weighting
• The Method of Pairs (MOP)
• 0-1 comparison scoring
• 0-9 comparison scoring
• Concept Variant Comparison via MOP
• Concept Variant Selection

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Final Report Outline (SDI)
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Final Report Outline (SDII)
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Questions?