Engineering Design

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Engineering Design

• H.J. Sommer III
• Professor of Mechanical Engineering
• The Pennsylvania State University
• www.me.psu.edu/sommer

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Fundamental Principlesof Design

• Design requires clear objectives
• Design requires creativity
• Design requires evaluation
• Design requires communication

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Em c2

• E effectiveness of an engineer
• m mastery of technical issues
• c communication skills

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The Design Process

• 1) Recognize the need
• 2) Define the problem (not a solution)
• 3) Plan the project
• 4) Collect information
• 5) Formulate alternative concepts

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The Design Process

• 6) Evaluate alternatives
• 7) Optimize alternatives
• 8) Select the best alternative
• 9) Communicate the design
• 10) Implement the design

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Design is iterative

• Be ready to revisit any prior steps in the process

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1) Recognize the need

• Market assessment
• Customer feedback
• Request for proposal (RFP)

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Need statement

• Often expresses dissatisfaction with the current
  situation
• Negative emphasis contrasts with positive future
  goal
• Should never present a solution looking for a
  problem

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2) Define the problem(not a solution)

• Goal statement
• Objectives (quantifiable measures)
• Constraints (permissible envelopes)

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Goal statement

• Brief general ideal response to the need
• Refined by objectives
• Allows alternative solutions

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Objectives

• Quantifiable expectations of performance
• Specify operating conditions
• Specify evaluation criteria if possible

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Constraints

• Permissible envelopes for objectives
• Permissible envelopes for design features
• Conform to industry, professional and regulatory
  standards

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3) Plan the project

• Temporal milestones
• Performance milestones
• Deliverables
• Timeline
• Budget

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4) Collect information

• Assumptions
• Data
• Institutional knowledge
• Standards

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5) Formulate alternative concepts

• Modify
• Redesign
• Reverse engineer
• Brainstorm
• Observe
• Unrelated products
• Nature

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6) Evaluate alternatives

• Consistent metrics
• Prototype
• Computational models
• Manufacturability and assembly
• Life-cycle

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Life-cycle assessment

• Raw materials
• Components and subassemblies
• Product
• Packaging and distribution
• Customer
• Repair
• Recycle and discard

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7) Optimize alternatives

• Computational optimization
• Iterative prototype testing
• Competing teams

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8) Select the best alternative

• Group decision
• Customer based
• Chief Engineer
• Ongoing iterative design with your customer
  in-the-loop

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9) Communicate the design

• Proposal
• Preliminary Design Review
• Final Design Review

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10) Implement the design

• Should not cause trepidation if you follow the
  process, iterate and communicate