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Design Tools 1 William Oakes, P.E Director of EPICS Assoc. Prof. Engineering Education.

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Presentation on theme: "Design Tools 1 William Oakes, P.E Director of EPICS Assoc. Prof. Engineering Education."— Presentation transcript:

1 Design Tools 1 William Oakes, P.E Director of EPICS Assoc. Prof. Engineering Education

2 Learning Objectives At the end of this session, you will be able to: 1.Describe a specification 2.Describe a decision matrix 3.Categorize potential failures for a design 4.Perform a functional decomposition 5.Create a personna

3 EPICS Balance Service-learning is a balance of the learning of design and the service we contribute the communities through completed designs and support Service To our partners, meeting needs in the community Learning Becoming good designers, professionals & active citizens Complimentary goals that enhance each other

4 Design Tool: Engineering specifications

5 Specifications Development What does your project partner need? oDont just rely on what they want, find out what they need oUnderstand the problems and issues you are addressing oWho will use product and who will benefit from it? Gather Data oTalk to Project Partner and others impacted by the project How will the problem be worked? oCriteria for design teams oHow will teams be integrated oTransition plans for multiple semesters Gather input from project partner on specifications oDevelop a specifications document and share it

6 Customer Requirements Types of customer requirements oFunctional performance oHuman factors oPhysical oTime (reliability) oCost oStandards oTest Method oService & maintenance

7 Customer Requirements For a cell phone, make a list of Ten customer requirements

8 Design Specifications Answers the how question Quantified oShould be able to measure whether you meet it Objective quantities A set of units should be associated with each specification Forms the basis for your specifications document

9 Design Requirements Starting with the customer requirements for a cell phone, make a list of design requirements

10 Defining Requirements Benchmarks oWhat is available oWhy did they use their approach oPatent searches avoid infringement Protect IP Are we smarter than everyone else? oOr did we miss something?

11 Design Targets Set standards to meet with your design How good is good Can be a living document oDont compromise on goals, but refine as the design progresses Tool make design trade offs oDesign decisions oCommunication with project partner

12 Decision Matrix Table with alternatives Quantify categories and score alternatives oImportance in different categories Use judgement to do reality checks Leaves documentation of thought process of design oCan be shared in design reviews

13 Decision Matrix Ideas to be compared Criteria for Comparison Weights Scores Totals

14 Decision Matrix Example: Getting a Job CriteriaWtsCo. ACo. BCo. CCo. D Location 55x5=255x1=55x3=155x4=20 Salary 4 Bonus 2 Job 3 Training 2 Boss 2 Totals

15 Design Tool: Defining the System

16 Functional Decomposition Breaking tasks or functions of the system down to the finest level Create a tree diagram starting at the most general function of your system oWhat is the purpose of your system? Break this function down into simpler subtasks or subfunctions Continue until you are at the most basic functions or tasks

17 Functional Decomposition Diagram Overall Function Subfunction 1 Subfunction 2 Subfunction 3

18 Sample Diagram – Bike Fender Protect rider from water and dirt off wheel Shield rider Steer water away from rider Attach Splashguard

19 Functional Decomposition Each function has a box with oAn action verb oThe object(s) on which the verb acts oPossibly a modifier giving details of the function oKnown flows of materials, energy, control or information Consider WHAT not HOW

20 Create a functional decomposition diagram for a mechanical pencil Prepare them to share

21 DFMEA : Design for Robustness

22 DFMEA Steps 1.Review the design 2.Brainstorm potential failure modes 3.List potential effects of failure 4.Rank failures a)Severity b)Occurrence c)Detection d)RPN = Severity X Occurrence X Detection 5.Develop action plan 6.Implement fixes 7.Revisit potential failure risks

23 In a group, Identify one project to use as an example for this exercise Describe the project so the whole group understands it

24 Brainstorm Failures What could go wrong? What could break? Are there systems your design relies upon? oe.g. myEPICS software authenticates through Purdues career accounts. What if the server goes down? Are there things that could fail over time?

25 Brainstorm a list of potential failures for the project

26 Rate failures Rating (1 to 10) Severity How severe are the consequences to the failure Occurrence How often are the failures likely to occur? Detection How easily are the failures detected?

27 DFMEA Calculations Scores for Severity, Occurrence and Detection o1 to 10 o1 = Low o10 = High Risk Priority Number (RPN) oRPN =Severity X Occurrence X Detection

28 DFMEA Matrix Failure mode Effect of Failure SeverityOccurrenceDetectionRPN Rating

29 Example accessed 22 Aug. 2011

30 Example Chart

31 Identify the failure scenario that should be addressed first

32 Develop an action plan to address the failure scenario

33 Continue the process Implement the plan to eliminate the failure scenario Revisit other potential failure risks oPrioritize oEliminate failure scenarios Continue until risks are below determined thresholds oShow to the design reviews for confirmation

34 Questions/Discussion


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