Functional Analysis

1
Functional Analysis

• Functional Analysis (Decomposition) helps with
• Breaking down complex processes
• Organizing main requirements
• Creating alternative solutions
• Making decisions explicit
• Expanding or contracting problem scope
• Facilitates teamwork

2
Functional Decomposition

• Start with the most important function
• Identify the system boundary
• Show material, energy, and signals

Transport 8z of water between two cups
Water in Cup A
Water in Cup B
3
Functional Decomposition

• Format of box contents
• Verb noun modifier
• Transfer water between cups

Electrical energy
Kinetic energy of air molecules
Convert wind energy to electricity
Air molecules
Air molecules
4
Typical Functions

• Absorb Actuate Amplify Assemble
• Change Channel Clear Collect
• Conduct Control Convert Couple
• Direct Dissipate Drive Hold
• Increase Interrupt Join Lift
• Limit Locate Move Orient
• Position Protect Release Rectify
• Rotate Secure Shield Start/Stop
• Steer Store Supply Support
• Transform Translate Verify

5
Functional Analysis

• Example A Personal coffee-maker

Ground Coffee
Make coffee
Coffee in mug
Cold Water
System Boundary
6
Functional Analysis
Coffee
Water
Heat Water
Mix coffee water
Transport into mug
Filter Coffee
Energy
Used coffee
7
Functional Analysis
Coffee
Used coffee
Mechanical Energy
Mix coffee water
Filter Coffee
Transport into mug
Hold Water
Hot Water
Filter after mixing Keep coffee contained
Lifting pouring Gravity dripping
Water thru coffee Coffee thru water Free mixing
Small pot Coffee mug
8
Functional Decomposition

• Nut Cracker

nut
De-shell nut
Un-cracked Nut
Hand energy
Vaporize shell Crush and sift Crack shell
Shell
9
Functional Decomposition
nut
Shell
Hand energy
nut
Increase mechanical advantage
Un-cracked nut
Control stroke
Secure nut
Lever action Four-bar linkage Slider-crank
linkage Power screw Cam mechanism
Mechanical stop Limited motion
Chamber Friction Groove
10
Functional DecompositionComputer Mouse
Allow easy sliding of the mouse
Convert user energy into screen position signal
Convert mouse movements into internal movements
Verify pick selection
Convert user energy into selection signal
Fit user hands ergonomically
Support users arm
Convert internal movements into electronic signal
Convert user arm or finger movements into pick
signals
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Functional Decomposition

• Functional decomposition can proceed after some
  decisions are made.

Water in A
Water in B
Remove
Measure
Transfer
Deposit
Trigger signal
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Functional Decomposition

• The choices regarding remove are
• Using no containers
• Using one container
• Using multiple containers
• Using pump action
• The team chooses one container, the Functional
  decomposition proceeds
• Fill container, Lift container, etc.