1. Engineering Design Process

2. Objectives Apply the engineering design process Define a problem (need) and develop alternatives for solving Build, test, evaluate prototypes

3. Engineering design is… the process of devising a system, component or process to meet needs a decision-making process in which science and mathematics are applied to convert resources to meet objectives establishing objectives & criteria, analysis, construction, testing, and evaluation

4. 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

5. 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.”

6. The Design Process 1. Identify a need, who is the “customer” 2. Establish design criteria and constraints 3. Evaluate alternatives (systems or components) 4. Build a prototype 5. Test/evaluate prototype against criteria 6. Analyze, “tweak” ( ), redesign (  ), retest 7. Document specifications, drawings to build

7. The Engineering Design Process

8. Step 1: Need Have a need, have a customer External vs internal; Implied vs explicit Often stated as bigger, cheaper, faster, lighter

9. 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

10. Some Design Constraints Cost Time Knowledge Legal, ethical Physical: size, weight, power, durability Natural, topography, climate, resources Company practices

11. Step 3: Evaluate Alternatives Likely to find good alternatives for cheapest, fastest, lightest, and encourage discovery Research should reveal what has been done Improve on what has been done Play alternatives off criteria and constraints

12. Best Design Choose best design that meets criteria Demonstrate tradeoff analyses (among criteria and constraints) Resist overbuilding; drives complexity, cost, time, resources A quality design meets customers expectations!

13. Step 4: Prototype Prototype is implementation of chosen design alternative It is a proof of design, production and suitability Prototypes are often cost prohibitive: Models and simulations may suffice

14. Prototype picture of 747

15. Step 5: Test it Well Test and optimize design against constraints and customer expectations. Test in the conditions of use Good test plan shows what test, expected results how to test, and what analyses will be.

16. Activity: Light Bulb Test Base fit-yes/no-first article demo Brightness-lumens-measure Life-hours-statistical sample Packaging-drop test-do last Robustness-vibration, temperature-test article Duty cycle-count on/off-prototype Production assembly-time-demonstration

17. Step 6: Test and Redesign

18. Test Results Successful Test: Satisfying Test Failure: Priceless

19. Step 7: Documentation Project data book A complete record All key decisions Good drawings Test plans Results Conclusions Things learned

20. Product Sketches