engineering design process
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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
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