1. Engineering Design GE121 The Design Process (continued – Part III)
Lecture 8B

2. Strategies/Methods/Means in the Design Process
Even formal prescriptive processes don’t tell us HOW to Generate or Create Designs
Will introduce:
Formal Design Methods
Means of Acquiring Design Related Information
Decision-support techniques and tools to explain HOW to design
Describing thought processes or cognitive tasks

3. Strategic Thinking in the Design Process
Least Commitment
Unwise to commit to a concept or configuration until forced to (exhausted information search / alternate designs)
‘Never marry your first design’
Premature commitments can be dangerous and lead to sub-optimal designs
Decomposition: Divide and Conquer
Break down / subdivide / decompose larger problems
Smaller sub-problems or ideas easier to solve / handle
Be careful – sub-problems often interact
‘How do you eat an elephant?’ …….
One bite at a time!

4. Formal Methods for Design Process
Objectives Trees
Used to clarify and better understand Client Statement
Tree-like structure
Clustered by sub-objectives
Have seen an example in the Case Study
Will discuss in detail in section 3.1
Pairwise Comparison Charts
Used to rank-order Design Objectives
Relatively simple
Compare Objectives on a pair-by-pair basis
Have seen an example in Case Study
Will discuss in detail in section 3.3

5. Formal Methods for Design Process (cont’d)
Functional Analysis
‘Black Box’ is the starting point – clearly delineates boundaries between proposed device and its surroundings
Decompose functions into sub-functions
Track flow of material / signals through device & detail what is needed to produce desired functions
Have previously seen the Function-Means tree
Detailed in section 4.1

6. Formal Methods for Design Process (cont’d)
Performance Specifications
Elaboration of Design Specifications
Solution independent attributes and performance specifications
Hard numbers for both desired and required features
Covered in section 5.2
Morphological Charts
Identify the Ways or Means that can be used to make the required functions happen
Provides a framework for visualizing a ‘design space’ of potential solutions
Covered in sections 5.1 and 5.3

7. Formal Methods for Design Process (cont’d)
Quality Function Deployment
More advanced tool
Builds on Performance Specification, with goal of higher quality product
Used widely in product manufacturing
Charts client and user requirements and engineering attributes in matrix form – relate and weight them, one against another
Creates a ‘House of Quality’ that exposes both positive and negative interactions
Described briefly in section 8.5

8. Means of Acquiring/Processing Design Knowledge
Knowledge is a critical component of design
Means for Acquiring Information
Literature reviews
Enhance understanding of potential users, clients and the design problem itself
Prior and existing / competing solutions
Physical properties during conceptual design
Handbooks, codes, and part/component libraries in detailed design
User surveys / questionnaires
Market research
Identify User understanding of problem
Help Designer clarify / understand problem early on
Can be used later during the selection process
In electronics design, manufacturers include typical application circuits for their components to make it easier for designers to use their components.
Circuit design handbooks are essentially compendia of circuits developed by others.

9. Means of Acquiring/Processing Design Knowledge (cont’d)
Focus groups
Expensive
Allow design team to observe response of selected users to potential designs
Also involve knowledge/sophistication in psychology – not often used by students
Informal and structured interviews
Informal Interviews should be focused so as not to waste the time of the interviewee – helpful to send topics or questions ahead of time
Structured Interviews – combines focus of a survey with the flexibility of an informal interview to allow follow-up on areas of interest, or new areas

10. Means of Acquiring/Processing Design Knowledge (cont’d)
Brainstorming
Generate related or even unrelated ideas, without evaluation
Free-wheeling
Opens up new avenues, ideas
Important for all members to maintain respect for the ideas of others
Important to capture ALL ideas as they are offered
Synectics
Environment similar to brainstorming
Explore relationships and similarities between relationships and ideas that initially seem unrelated
Explore similar ideas/solutions (analogies) from different disciplines of engineering
Brainstorming can be an iterative process. Do some evaluation and research on ideas generated in one session. Follow up with elimination of some of the less hopeful ideas. Then have another brainstorming session to generate new ideas that may come from the evaluation and research, or they may have come through further creative thinking by team members.

11. Means of Acquiring/Processing Design Knowledge (cont’d)
Benchmarking
Take competitive products and use them as a ‘benchmark’, or reference, then try to make it better
Reverse engineering
Sometimes referred to as dissection
Literally take it apart to try to determine design intent
Find better ways to perform the same or similar sub-functions

12. Means of Acquiring/Processing Design Knowledge (cont’d)
Means for Analyzing Information / Testing Outcomes
Defining metrics is important – we often need ways of determining a numeric value for metrics, or determine if a specification can be met
Laboratory experiments
May involve physical testing of a basic structure or component
Prototyping
Prototype or test unit is produced to verify functional operation
May not look like final product, and may only have a subset of the key functions tested (saves money / time)

13. Means of Acquiring/Processing Design Knowledge (cont’d)
Proof of concept testing
Idea is to show that design can fulfill functions under certain prescribed conditions
Tested unit may not survive, or perform stated function, but still may prove the concept
Computer models
Simulation software
Discipline-specific CADD (Computer Aided Design and Drafting) software
Means for Obtaining Feedback
Regularly scheduled meetings with Users and Clients!!
Formal Design Review (must learn give and take)
Public Hearings
Focus Groups
Beta testing