Download - ECET 4550: Alternate Energy fall 2011
Florian Misoc, 2010
ECET 4550:Alternate Energy
fall 2011Laboratory Topic:
The Design Process
Florian Misoc, 2010
Announcement
• Third week in October (15-21): FE examination practice
• Contact Dr. John Krohn, Mechanical Engineering Department
• Suggestion: every graduating engineering student should take the FE exam (Fundamentals of Engineering)
Florian Misoc, 2010
Chapter Objectives
• Description and Prescription• Strategies, Methods & Means• Managing the Design Process• Case Study & Examples
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Introduction
• Design Process ≠ “cooking” recipe• Design Process = Σ design tasks = task-1 +
task-2 + …. + task-n• Design Process = “framework”• Design process = process of questioning
“knowledge resides in the questions that can be asked and the answers that can be provided” Aristotle
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Introduction
• Task # 1: Clarify what the client wants• Task # 2: Translate “want” into meaningful
objectives• Task # 3: Determine the constrains (limitations)
associated with client’s “want”• Task # 4: Establish the “function” of the future
system (what does it do?)
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Introduction
• Task # 5: Establish set of requirements (specs)• Task # 6: Generate design alternatives• Task # 7: Model and analyze designs• Task # 8: Test and evaluate design alternatives• Task # 9: Refine and optimize the design• Task # 10: Document the design process• Task # 11: Communicate the completed design
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Questions
• Task # 1: Clarify what the client wants:a. Why do you want another system, device, etc.?b. How it will have to work?c. How much can it cost?
• Task # 2: Translate “want”;i. What does “safe” means?ii. What would the system would be used for?
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Questions
• Task # 3: Determine the constrains:1. What are the conditions of operations?2. What is the system impact on people’s safety?
• Task # 4: Establish the “function”:i. What is the weight, volume, mass distribution,
etc. that the system should accommodate?ii. Would the system operate indoors /outdoors?
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Questions
• Task # 5: Establish set of requirements (specs)a. How much weight, voltage, current, should the
system withstand?b. What is the expected “breaking point”?
• Task # 6: Generate design alternativesi. Could the system be modular?ii. What are the alternative materials to be used?
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Questions
• Task # 7: Model and analyze designsa. What are the maximum stresses (weight,
current, etc.) on the system?b. How do stresses affect the material(s)
• Task # 8: Test and evaluate design alternativesi. Does the system meet OSHA requirements?ii. Can the system accommodate a wide
spectrum of users?
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Questions
• Task # 9: Refine and optimize the designa. Are there other methods of assembly?b. Can the amount of material/components used,
be reduced?
• Task # 10: Document the design processi. What are the justifications for choosing “this
design”?ii. What information is needed for manufacture?
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Design Process: Description and PrescriptionA. Describing the Design ProcessB. Prescribing the design ProcessC. Feedback from the ClientD. Iteration(s) in the design ProcessE. Opportunities and Limits
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Describing the Design Process
• Three-phase design process:1. Generation: designer generates various
design concepts2. Evaluation: designer tests the chosen design
against objectives and requirements3. Communication: designer communicates the
final design to the client and to the manufacturer
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Describing the Design Process
• Alternate three-phase design process:1. Research: designer reviews the existing
literature on the subject2. Creating: designer generates design prototype3. Implementing: designer implements & tests
design prototype
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Describing the Design Process
• Three stage linear model for design process
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Describing the Design Process
• Five stage linear model for design process
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Describing the Design Process
A. Problem Definition: • Pre-process stage• Frames the problem• Clarifies the client’s original problem statement
B. Design Communication:• Post-process stage• Identifies the work done• Presents final design & manufacture specs
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Prescribing the design Process
• Five-phase prescriptive model:
Client’s Problem Statement1. Problem Definition2. Conceptual Design3. Preliminary Design4. Detailed Design5. Design CommunicationDocumentation for Final Design
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1. Problem Definition
• Clarify objectives• Establish metrics for objectives• Identify constrains• Revise client’s Problem Statement
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2. Conceptual Design
• Establish functions• Establish requirements (specifications)• Establish means for functions• Generate design alternatives• Refine & apply metrics to design alternatives• Choose a design
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3. Preliminary Design
• Model design• Analyze design performance• Test chosen design• Evaluate chosen design: compare design
performances with specifications
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4. Detailed Design
• Refine & optimize chosen design: improve design performances
• Assign & fix design details
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5. Design Communication
• Document final design• Present chosen design performances to the
client• Emphasize design performance (vis-à-vis specs)• Present possible improvements (as a future
option)
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Feedback from the Client
• Design process: nonlinear, not sequential
• Required elements:a. Feedbackb. Iteration
NotePrimary focus: Conceptual Design
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a. Feedback
• Two (2) types:1. Internal feedback loops: tests & evaluation
results used to validate/verify design performances. Occurs during the design process
2. External feedback loops: results provided by the user(s) are used to validate the design. Occurs after the design reaches the market
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b. Iterations
• Definition: repeatedly applying a common method/technique at different points during the design/analysis
• It occurs at different levels of abstraction (different degrees of detail)
• More detail → less abstract
• Don’t loose focus on the original objectives!
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Opportunities and Limits
• Focus: Conceptual design
• Detailing: Broad themes, logical approaches
• Conceptual Design Tools: Not mathematical algorithms
• Problem Solving: Not necessarily “rigorous”
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Design Process: Strategies, Methods & Means
• Prescriptive design: No information on How to generate the design
• Formal Design Methods:a. Build “Objective Trees”b. Rank “Design Objectives’c. Establish “Metrics”d. Perform “Functional Analysis”e. Elaborate “Requirements/Specifications”
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Means for acquiring information
1. Literature review2. User survey & questionnaires3. Focus groups4. Informal interviews5. Structured interviews6. “Brainstorming”7. Benchmarking8. Reverse engineering
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Means for analyzing information
i. Develop metricsii. Undertake/design experimentsiii. Conduct proof-of-concept testingiv. Implement prototype developmentv. Conduct computer simulationsvi. Conduct computer numerical analysis
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Means for testing outcomes & feedback
I. Scheduled meetings (designer-client-user)II. Formal design review (present design to:
client, selected users, stakeholders), involves trade-off
III. Public hearings (expose the design for public review), increasingly the norm
IV. Focus groups (user input on problem definition), asses user reaction to design
V. Beta testing = almost-but-not-quite-finished version of the product
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Managing the Design Process
• Four-phase process:I. Project definition: develop an initial
understanding of the problem to be solvedII. Project framing: develop & apply a design
planIII. Project scheduling: organize the design
plan/prioritizeIV. Project tracking / evaluation / control: keep
track of TIME, work, cost, etc.
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Managing the Design Process• Design: a social activity• Design: done by teams (seldom by individuals)• Requires: people with different talents, skills,
areas of expertise• Transition from group to functioning team:1. Forming2. Storming3. Norming4. Performing5. Adjourning
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Project Statements-1
Design of a container to deliver a children’s beverage
Designers: Dym, Little, Orwin and Spjut LLCClients: American Beverage Company (ABC)Users: Children living in the United StatesProblem Statement: Design a bottle for a new
children’s juice product
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Project Statements-2
Design a cooling air-flow system for spinal-fusion hydrostatic vest
Designers: Team of students at ATUClient: Memphis Trauma CenterUsers: Victims of accidents that sustained sever
spinal fracturesProject Statement: Design an air-flow cooling
system that will accommodate the existing spinal-fusion vests for patients who sustained severe spinal fractures
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References
• Engineering Design, A Project-Based Introduction, third edition
• Authors: Clive L. Dym, Patricl Little, Elizabeth J. Orwin, Erik R. Spjut
• ISBN: 978-0-470-22596-7• Pages: 18 - 45
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Assignment
• Due date: September 15th, 2010
• Exercises 2.1 – 2.4, page 45
• Case study 2.5.1: Design of a microlaryngeal surgical stabilizer
• Selected Project & team members for the project