Engineering design process

Engineering Design Process

Courtesy of: www.engineering-ed.org/documents/week_1_design_process.ppt

Engineering design is…

the process of devising a system, component or process to meet needsa decision-making process in which science and mathematics are applied to convert resources to meet objectivesestablishing objectives & criteria, synthesis, analysis, construction, testing, and evaluation

Problem Characteristics

Engineering Problem Problem statement

incomplete, ambiguous

No readily identifiable closure

Solutions neither unique nor compact

Solution needs integration of many specialties

Science Problem Succinct problem

statement Identifiable closure Unique solution Problem defined

and solved with specialized knowledge

Typical Design Problems

“Design a system for lifting and moving loads of up to 5000 lb in a manufacturing facility. The facility has an unobstructed span of 50 ft. The lifting system should be inexpensive and satisfy all relevant safety standards.”

Studying Engineering Design

Develop student creativityUse open-ended problemsUse design theory and methodsFormulate design problem statements and specificationsConsider alternative solutionsConsider feasibility

Studying Engineering Design

Know and apply production processesUnderstand concurrent engineering designCreate detailed system descriptionsInclude realistic constraints such as… Economic factors, safety, reliability aesthetics, ethics, social impacts

“Awesome” Engineers…

Place ethics and morals above all elseAre team playersFollow a deterministic design processFollow a scheduleDocument their workNever stop learning

Module Organization: The Design Process

1. Identify a need, who is the “customer”2. Establish design criteria and constraints3. Evaluate alternatives (systems or

components)4. Build a prototype5. Test/evaluate prototype against criteria6. Analyze, “tweak” (), redesign (), retest7. Document specifications, drawings to

build

Engineering Design ProcessBackup Chart

1. Identify a need2. Establish design criteria and

constraints3. Evaluate alternatives4. Build prototype 5. Test/evaluate against design criteria6. Analyze, redesign, retest7. Communicate the design

The Engineering Design Process

Design is an Iterative ProcessBegins with a recognition of need for a product, service, or systemDuring the idea phase encourage a wide variety of solutions through brainstorming, literature search, and talking to usersBest solutions are selected for further refinement

Models or prototypes are made and problems that arise may require new ideas to solve and a return to an earlier stage in the processFinally drawings are released to manufacturing for production

Engineering Design Defined

The crux of the design process is creating a satisfactory solution to a need Harrisberger

Engineering Design Process

Customer Needor Opportunity

Implementation ofOptimal Design

Evaluation of Designs/Selection of Optimal Design

Development ofAlternative Designs

Data & InformationCollection

Problem Definition/Specifications

Source: Accrediting Board For Engineering and Technology

Primary Design Features

1. Meets a need, has a “customer”2. Design criteria and constraints3. Evaluate alternatives (systems or

components)4. Build prototype (figuratively)5. Test/evaluate against test plans (criteria)6. Analyze, “tweak” (), redesign (), retest7. Project book: record, analyses, decisions,

specs

Step 1: Need

Have a need, have a customerExternal vs internal; Implied vs explicitOften stated as functional requirement Often stated as bigger, cheaper, faster, lighterBoilerplate purpose: The design and construction of a (better____something)_____ for (kids, manufacturing, medicine) to do __________.

Step 2: Criteria & Constraints“Design criteria are requirements you specify for your

design that will be used to make decisions about how to build the product”

Aesthetics

Geometry

Physical Features

Performance

Inputs-Outputs

Use Environment

Usability

Reliability

Some Design Constraints

CostTimeKnowledgeLegal, ethical Physical: size, weight, power, durabilityNatural, topography, climate, resourcesCompany practices

Step 3: Evaluate Alternatives

Needs best stated as function, not formLikely to find good alternatives for cheapest, fastest, lightest, and encourage discoveryResearch should reveal what has been doneImprove on what has been donePlay alternatives off criteria and constraintsBrainstorming helps

Simulation

Best Design

Choose best design that meets criteriaDemonstrate tradeoff analyses (among criteria and constraints) are high qualityCost (lifecycle) is always considerationResist overbuilding; drives complexity, cost, time, resourcesA quality design meets customers expectations!

Step 4: Prototype

Prototype is implementation of chosen design alternativeIt is a proof of design, production and suitabilityPrototypes are often cost prohibitive: Models and simulations may sufficeQuality design does not include redesigning a lot of prototypes

Prototype

Prototype

picture of 747

Step 5: Test it Well

Test and optimize design against constraints and customer expectations. Create a test plan showing how to testTest in the conditions of useGood test plan shows what test, expected results how to test, and what analyses will be. It relates to specification requirementse.g. test plan for light bulb (activity)

Step 6: Test and Redesign

Test Results

Successful Test: Satisfying

Test Failure: Priceless

Step 7: Documentation

Project data bookA complete record

All key decisions

Good drawings

Test plans

Results

Conclusions

Things learned

Draw a Good Picture• Drawings for project notebook, application, display

• Photos, sketches, CAD 2-D or 3-D

• Show assembly, components, materials

Product Sketches

Other Drawings