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Learning Objectives
At the end of this session, you will be able to:
1. Describe a decision matrix
2. Categorize potential failures for a design
3. Perform a functional decomposition
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
Specifications Development
What does your project partner need?o Don’t just rely on what they want, find out what they
needo Understand the problems and issues you are
addressingo Who will use product and who will benefit from it?
Gather Datao Talk to Project Partner and others impacted by the
project How will the problem be worked?
o Criteria for design teamso How will teams be integratedo Transition plans for multiple semesters
Gather input from project partner on specificationso Develop a specifications document and share it
Customer Requirements
Types of customer requirementso Functional performanceoHuman factorsoPhysicalo Time (reliability)oCostoStandardso Test MethodoService & maintenance
Engineering Specifications
Answers the “how” questionQuantified
oShould be able to measure whether you meet it
Objective quantitiesA set of units should be associated
with each specificationForms the basis for your
specifications document
Engineering Requirements
Starting with the customer requirements for a cell phone, make a
list of engineering requirements
Defining Requirements
BenchmarksoWhat is availableoWhy did they use their approachoPatent searches
• avoid infringement• Protect IP
Are we smarter than everyone else?oOr did we miss something?
Design TargetsSet standards to meet with your designHow good is goodCan be a living document
oDon’t compromise on goals, but refine as the design progresses
Tool make design trade offsoDesign decisionsoCommunication with project partner
The EPICS Design Cycle
Specification Development
Detailed Design
Production
ServiceMaintenance
Redesign
Retirement
Problem Identification
ConceptualDesign
Disposal
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 systemoWhat 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
Functional Decomposition
Each function has a box withoAn action verbo The object(s) on which the verb actsoPossibly a modifier giving details of the
functionoKnown flows of materials, energy, control
or informationConsider WHAT not HOW
Create a functional decomposition diagram for
a mechanical pencil
Prepare them to share
Generating Ideas - Brainstorming
1. Pick A Facilitator
2. Define The Problem
3. Small Group
4. Explain the Process
5. Record Ideas in a Visible Way
6. Everyone’s Involved
7. No Evaluating
8. Eliminate Duplicates
9. Pick Three
In the same group
Brainstorm ways to implement one of the functions on your diagram and select the best
alternative
Prepare it to share
Decision Matrix
Table with alternativesQuantify categories and score
alternativeso Importance in different categories
Use judgement to do reality checksLeaves documentation of thought
process of designoCan be shared in design reviews
Decision MatrixExample: Getting a Job
Criteria Wts
Co. A Co. B Co. C Co. D
Location 5
Salary 4
Bonus 2
Job 3
Training 2
Boss 2
Totals
Design Phase: Testing for Failures
Planning to avoid failures
Disposal
Specification Development
Detailed Design
Production
ServiceMaintenance
RedesignRetirement
Problem Identification
ConceptualDesign
DFMEA Steps
1. Review the design2. Brainstorm potential failure modes3. List potential effects of failure4. Rank failures
a) Severityb) Occurrencec) Detection
5. Develop action plan6. Implement fixes7. Revisit potential failure risks
In a group, Identify one project to use as an example for this
exercise
Describe the project so the whole group understands it
Brainstorm Failures
What could go wrong?What could break?Are there systems your design relies
upon?o e.g. myEPICS authenticates through
Purdue’s career accountsAre there things that could fail over
time?
Rate failuresRating
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?
Continue the process
Implement the plan to eliminate the failure scenario
Revisit other potential failure risksoPrioritizeoEliminate failure scenarios
Continue until risks are below determined thresholdsoShow to the design reviews for
confirmation