EML4550 2007 1

EML4550 - Engineering Design Methods

Concept GenerationGenerating ideas and design concepts

Concept SelectionSettling on one or more promising ideas to pursue to final design

Hyman: Chapter 6 and Sec. 9.1 & 9.2Ulrich and Eppinger: Chapters 5 and 6

Dym and Little: Sections 6.1 – 6.3

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Concept Development Diagram (Hyman Chapter 6)

IdentifyCustomerNeeds

EstablishTargetSpecs

GenerateProductConcepts

SelectProductConcept

RefineSpecs

AnalyzeCompetitiveProducts

PerformEconomicAnalysis

PlanDesign/DevelopmentProject

MissionStatement

ActionPlan

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Concept Generation

A ‘conceptual’ design is an approximate representation of the final product

Sketches, 3-D renderings, ‘back-of-the-envelope’ calculations to assess feasibility

Concept generation is typically ‘low-cost’ (5% of project) and somewhat time-consuming (15% of schedule)

Need to explore ALL possible concepts, structured approach to avoid pitfalls:

Consideration of only a few options, failure to consider competitors’ concepts, involvement by just a few people, failure to follow through partial solutions, failure to see entire categories of solutions

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Concept Generation (cont’d)

“Creative” part of the design process Least structured part of the process It is OK to allow some “chaos” during project

inception (shake down the ideas) However, in order to avoid major oversights, we

need to introduce some structure to the concept generation phase

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Models for the creative process

Wallas model

Fabun model

CEF model

Consolidated model

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Wallas model (1926)

Preparation Clarify and define problem (recognizing the need, defining

the problem)

Incubation Formative stage, mind is relaxed and free to receive ideas

Illumination First conscious recognition of an idea (“Eureka!”)

Verification Reality check on the idea

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Fabun model (1968)

Desire Equilibrium broken by appearance of a problem

Preparation (same as Wallas) Manipulation

Mind actively manipulates ideas/gathers information Incubation (same as Wallas) Intimation

Realization we are on the right track Illumination (same as Wallas) Verification (same as Wallas)

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CEF (Creative Education Foundation) model (1976)

Fact finding Collect all facts that may bear on the problem

Problem finding Articulate problem formulation(s)

Idea finding Solutions are presented

Solution finding Solutions are evaluated and one is selected

Acceptance finding Customer buy-off and implementation

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Consolidated model

Exploration Active and concerted search for new ideas with possible

frustrating results (need to pursue further) Incubation

Formative stage when extended period of relaxation without a conscious effort to solve the problem

Intimation Resumption of search effort with the feeling of making

progress Illumination

Breakthrough that produces a new and attractive idea

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Barriers to Creative Thinking

Perceptual (inability to properly perceive problem, unnecessary inference, etc. Most frequently encountered) Patterns, boundaries (can’t think outside the box), illusions,

lenses (can’t see the forest for the trees), meanings

Cultural (imposed by society, how to think unconventionally)

Environmental (anything in the surrounding that stifles creativity, both physical or in terms of personal work conditions such as overly critical and rigid behavior)

Emotional (emotional baggage from personal life) Intellectual (not enough knowledge on the topic life-

long learning to update one’s knowledge)

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Removing Barriers/Techniques to Generate Alternatives

Lateral thinking (as opposed to vertical thinking) Generate as many ideas as possible (crazy is good) Do not go deep into any one idea Do not criticize or pre-judge ideas (don’t evaluate until you

conceptualize all options. Need will power and discipline to resist)

Perseverance Invention is 95% perspiration, 5% invention (Edison)

Mental push-ups Engage on creative design activities often Get involved with other projects

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Removing Barriers/Techniques to Generate Alternatives (Cont’d)

Making lists As an exercise, take common objects and list no less than

20 uses Get used to thinking of common objects in uncommon ways

Word games “Cryptic” crossword puzzles (“meaning” barriers)

Solving puzzles Classical puzzles, cubes, 2-D boards, etc. (“boundary”

barriers)

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Concept Generation

Practical Approaches and Examples

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Concept Generation Methodology

Clarify the problem

Search externally Search Internally

Explore systematically

Reflect on the processand the solutions

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Clarify the problem

Understanding (needs, specs, objectives) Decompose complex problems into simple sub-

problems Decomposition by function

Create ‘boxes’ and function diagrams Create ‘boxes’ and flow diagrams

Decomposition by sequence of user actions Decomposition by needs Decomposition by field of competence

Identify critical sub-problems and concentrate early efforts on them

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Search externally

Interview lead users (customers) Consult experts (consultants) Search patents

Databases: Lexis/Nexis, Dialog, etc. (through Library) US Patent & Trademark Office ( http://www.uspto.gov )

Search published literature Databases (through Library) Trade journals and magazines

Benchmark related products Thomas Register

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Search internally

Ground rules: Suspend judgment until after exercise is complete Generate a lot of ideas Accept ideas that may appear infeasible Use graphical and physical media (models)

Use both group and individual sessions Where ideas come from:

Make analogies Wish and wonder Individual ideas (related stimuli) or random ideas (unrelated

stimuli) presented to group Set quantitative goals (‘nobody leaves until…’) Use gallery method – display a large number of ideas visually

for discussion

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Explore systematically

The internal and external searches should have generated many ideas (or solution “fragments”) - potentially hundreds if the problem is complex enough

Objective is to organize these ideas so that they can be properly evaluated later Concept Classification Tree Concept Combination Table Managing the Exploration Process

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Concept Classification Tree

Identification of independent approaches to the problem Helps clarify the choices; can be used to delegate individual

efforts

Pruning of less promising branches Foster an early elimination

Exposure of undue emphasis on certain branches (solutions) By contrast, finding branches that were overlooked

Refinement of problem decomposition for a particular branch

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Concept Classification Tree: Example

AcceptEnergy

StoreEnergy

Nuclear

Fuel

Hydraulic

Pneumatic

Electrical

Chemical Explosive

Fuel-Cell

Magnet

Battery

EnergySource

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Concept Combination Table

Decompose system by functional steps, or by physical sub-systems (or any other decomposition that makes sense)

Enumerate solution-fragments for each of the categories

Make a table with these entries Problem solution can be arrived at by combining

entries from the table (combination of solution-fragments)

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Example

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Reservoir Square Tank Rectangular Circular Tank

Tank

Morphological Chart

Steel Beams Wood Table

Support

Functions

Medium

AirWater Alcohol

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Concept Generation: Implications to Project

Statement that clarifies the problem and sets boundaries on its scope

A record of the search for ideas (internal and external)

Tables or diagrams presenting all the ideas generated, and concepts that were considered

An exhaustive and well-organized set of ideas and/or conceptual designs