1. Functional analysis the “what’s”
1/16/2019
AAE 490B Week 3
Lecture 7
Functional analysis the “what’s”
FUNCTION = task, action, activity performed to achieve a desired outcome
Example: Position an item = grasp, attach
Function is WHAT, DESIGN is HOW the product will do it
“What” is “store energy”
“How” is provide battery
The term FUNCTION means that there is a flow of energy (including forces), material or information between objects – or a change in state of an object caused by one or more flows
Northrop Grumman Private/Proprietary Level I

2. Source: Joyce E. Carpenter, NASA Johnson
Summary
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

3. Copyright 2008 Purdue University
Mission Statement
To improve (provide) wide area surveillance by creating (with) a reliable, upgradeable, cost-efficient, Earth orbiting system that’s (whose) features will meet or exceed those of (the) current (SPOT) systems and will have (has) the capability of being launched in small vehicles while responding quickly to requests for data.
Team 1
January 16, 2019
Copyright 2008 Purdue University

4. Objectives Tree How do I get this? Why is this here?
Provide self-protection
Operational availability
Reliability
Quick operational availability once in orbit
Responsive
Long life
Launch on small rockets with available shrouds
Frequent target re-visit times
How do I get this?
Why is this here?
Wide field of view
Adaptable to unforeseen situations
Emphasize sub-system modularity
Provide optical resolution equal to or greater than SPOT from MEO
Self-repair
Coverage of useful area
Low test to orbit time
Launch from common space centers
Provide opportunity for technology insertion for critical components
Monitor multiple spectra (optical/RF/?)
Reduce system complexity
Easily disposable
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

5. Orbital Earth-viewing Platform Team 9
1/16/2019
Orbital Earth-viewing Platform
Team 9
Multi-Role
Marketable
Reliable
Cutting Edge
Affordable
Adaptable
Repairable
All-Weather
Imaging
Universal Signal Coverage
Production
Time
Military
Commercial
Command & Control
Surveillance
Weather
Mapping
Communication
Upgradeable
Component Launch & Remote Assembly
Field of View
Resolution
Mobile Target Acquisition
January 16, 2019
Copyright 2008 Purdue University
Northrop Grumman Private/Proprietary Level I

6. Team 1 January 16, 2019 Copyright 2008 Purdue University
Provide Wide Area Earth Surveillance
Safety
Cost-Efficient
Team 1
Responsive to Request for Data
Operate at high orbits above the Earth to avoid collisions or attacks
Reliable
Upgradeable
Low Cost to Repair
Long Mission Duration
Ability to Connect Wirelessly
Decrease Ground Check-Out Time
Ability to Assemble Remotely
Modular/Risk of a single failure is removed
Durable
Future component miniaturization will result in less weight
Modular/Costs for failures will be reduced
Easily Refuelable
January 16, 2019
Copyright 2008 Purdue University

7. Modular, Fractionated Space System Advanced Technology Demonstrator
Safe
Reliable
Non-fatal
Operator
Innocent Bystanders
Marketable
Low Cost
Ease of Remote Assembly
>/= SPOT
Upgradeable Systems
Robust
Not susceptible to catastrophic failure
Ease of communication between all system components
Minimal Complexity
Low Maintenance
Innovative
Easily Refuelable
Miniaturized Components
State-of-the-art
Low Energy Usage
Versatile
Wide-area surveillance
Modular
Easy Altitude Change
High-Resolution Photos
Small Launch Vehicles
Low Weight
Low Volume
Imaging
January 16, 2019

8. So – do it again for grading and make it better (Hand this in on Wednesday by noon)
Improve your objectives tree (make it several levels deep) and re-submit
Send Powerpoint slide (or slides) with your objectives tree to me and to Jasmine
Title the file with team number – AAE490B Objectives Tree Team 15
On the tree slide list the project (AAE450 Fall), the team (you are not a group) number and your team member names
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

9. Homework for next Friday Feb. 1
Create a functional flow block diagram (FFBD) for the AAE450 Fall project
Choose a design project from among the following
Spring 2008 AAE450
Spring 2008 AAE451
AIAA DBF current contest
Develop the Mission statement
Develop the objectives tree
Submit the results by noon next Friday February 1.
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

10. The new stuff - Process functions what are they?
1/16/2019
The new stuff - Process functions what are they?
A function is a task, action or activity performed to achieve a desired outcome (or objective).
Functions have an input and an output like that shown
Function
“Develop RFP”
Design specifications
Customer needs
How much?
When?
How often?
How fast?
Other Function Examples
(with different input/output)
transmit torque
reduce time
absorb light
inject material
increase pressure
minimize dust
conduct surveillance
These are the Requirements
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring
Northrop Grumman Private/Proprietary Level I

11. System solutions sub-system functions
Provide passenger accommodations
Provide vertical take-off
Store fuel
Provide thrust
Generate lift
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

12. How do we use process functions
How do we use process functions? Functional analysis is a critical part of systems engineering
Functional analysis definition
A technique for identifying and describing all the functions of a system
Objectives of functional analysis
Identify functional requirements
Translate systems requirements (words) into “design to” requirements (numerical)
Partition and connect design functions to show interdependencies (who does what to whom?)
Provide and identify traceability of functions to system requirements and needs
Inputs
Functional and performance requirements, constraints, external system interfaces
Team Activity Involved
Define system/mission with VOC
Identify functions required to make system work
Create functional flow block diagram
Outputs
List of functions organized to resemble a tree
Definition of functional hierarchy
Functional flow block diagram
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

13. A view from NASA agreement to definitions and importance
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

14. Functional analysis – DoD version
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

15. 1/16/2019
Functional analysis cautions identify “what” is required, not “how to do it”
Functional flow block diagrams describe the system and its elements in functional terms
Diagrams show operational and related support activities
Use a hierarchical structure
Covers all activities during the system life cycle
Shows activity time sequences and interface relationships
Process is iterative - it can be modified, expanded or contracted
Worked down to a level where resources are identified and choices of “how” are obvious
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring
Northrop Grumman Private/Proprietary Level I

16. Functional Flow Block Diagrams require us to do more than think about missions and operations
What happens?
What order?
What input output takes place?
Sequencing?
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

17. Source: Joyce E. Carpenter, NASA Johnson
Visualize the Mission
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

18. Sequence of operations Functional Flow Block Diagram (FFBD)
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

19. Example January 16, 2019 Copyright 2008 Purdue University
Aerospace Systems-Spring

20. Knowing what types of function actions happen helps us - look at flows through the function block
As energy flows through a system it is transformed, stored, transferred/conducted, supplied and dissipated – these are “actions” or “action words”
Flow of energy = what type of energy & action flows within the system?
Mechanical, electrical, fluid, thermal
Flow of materials – three different types of flows
Through-flow – material conserving processes – material is manipulated to change position or shape
Position, lift, hold, support, move, translate, rotate, guide
Diverging flow – dividing material into two or more pieces
Disassemble, separate
Converging flow – assembling or joining
Mix, attach, “position relative to”
Information flow – mechanical signals, electrical signals, software
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

21. Try an online thesaurus to locate the proper words
What functions are performed by the product? All functions are preferably only two words – a verb & a noun
Typical Verbs
Absorb, allow
Actuate, assure
Amplify, avoid
Assist, aid
Change, close
Collect,
Conduct
Control, dock
Emit
Repel, resist
Open, close
Transfer, transmit
Nouns
Area, access
Color, current
Damage, density
Emissivity, energy
Flow, fluid
Try an online thesaurus to locate the proper words
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

22. Technique for designing with function Function performed by product (not users)
Step 1 – what overall function needs to be accomplished?
A single statement of the overall function that the customer wants – a simple clause that labels a “Black Box” -
Gather and process hyper-spectral data
Energy, material, information
Hyper-spectral data
Energy must be conserved
Energy that goes in must be stored or must come out
Material must be conserved
Material that goes in must be stored or come out
Identify all interfacing objects and fixed parts of the system
Features, components, assemblies, humans that exchange energy, material or information
Solar energy, communications
Propellants
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring
Source – Ullman, Mechanical Design

23. Energy, material, information Gather and process hyper-spectral data
Step 1 –continued Tasks = the main reason why the product exists in the eyes of the users
Energy, material, information
Gather and process hyper-spectral data
Hyper-spectral data
Identify all interfacing objects and fixed parts of the system
Identify features, components, assemblies, humans that exchange energy, material or information that cannot be changed – e.g. a launcher
Features, components, assemblies, humans that exchange energy, material or information
How will the customer know that the system is working?
(Helps to identify information flow)
Use action words to convey flow
Source – Ullman, Mechanical Design
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

24. Example – modular space system “WHAT?” not “HOW?”
discrete set of tasks or activities
Create hyper-spectral data
Deliver hyper-spectral data
Assemble satellite
Enable operation
Operate satellite
Deliver satellite
Deploy satellite
Test satellite
What do we have to do
to make this happen?
What function needs to be performed?
What? What? What
Why?
time
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

25. Decompose the overall system functions into basic and sub-functions
Step 2 – Create basic and sub-function descriptions functions performed by product to support top level function
Decompose the overall system functions into basic and sub-functions
Identify sub-functions
Essential to success of product – basis of customer’s buying decisions
Division into finer detail leads to a better understanding of the design problem
Avoid words like “be” or “provide” (“provide cooling” becomes “cool space”
Sub-functioning – shows
An object whose state has changed
An object that has energy, material, or information transferred to it from another object
Decomposition
controls the search for solutions
leads to an awareness that some problems are already solved since some components that fulfill the functions already exist (solar cells and batteries for instance)
Don’t use the name of a part – like telescope - only a function
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

26. Decomposition guidelines a recipe
Consider what – not how
Don’t add a lot of detail
If a specific device is known or required, document the assumptions – e.g. Orbital Express is the propellant delivery device
Use only objects described in the problem specification or overall function – don’t let a component or other system suddenly appear
Break the function down as finely as possible
Consider all operational sequences
A device may have multiple function – e.g. a computer
Is preparation required before a function? – e.g. deployment
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

27. Step 3 – Order the sub-functions
Order the sub-functions so that they lead back to Step 1
Flows must be logical or in temporal (timed) sequence
Output of one function should be an input to the other
Identify redundant functions and combine them
Eliminate functions that are not part of your system – define the system boundaries –
Look at energy conservation, information or material flows and match inputs to outputs
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

28. Step 4 – Refine sub-functions
Can the sub-function be further divided into sub-functions?
Can the sub-function be fulfilled by an existing device or object?
Keep asking “what has to happen?”
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

29. Comments Creating a functional analysis diagram is a struggle!!!
Answer this question - which functions or sub-functions:
Assure convenience?
Raise the product above customary expectations?
Make it faster, better, lighter?
Make it easier to use?
Create longer life?
Add value?
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

30. Guidance Functions are conversion of inputs to outputs Materials
Information
Energy
Establish functions required
Decompose functional requirements into a discrete set of tasks or activities
Stay focused on behavior, not technology
Convert functions to sub-functions
Look for obvious interactions
Do this hierarchically
Scope the project – draw system boundaries
Allocate functions to components
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

31. Advice don’t be stampeded
Customers and managers may press your team to publish design requirements quickly or incompletely so that they can “get on with the design.” They know that they have a tight schedule to meet. Don’t do it!
Take the time to do the job right. Do functional analysis first and then share it with all of your stakeholders to make sure you and they agree on the system functions and boundaries
Designers want to get with the design activity right away – after all they know the correct answer – at least to the problem that they have in mind
Take time to do the functional analysis and see if the “correct” answer can perform the required functions
Mono-disciplinary and sub-system/components experts may not see value in doing functional analysis. After all, they are experts on their sub-systems and know the right answer.
Take time to do the functional analysis first and discuss the results with the whole team
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

32. Source: Joyce E. Carpenter, NASA Johnson
Summary
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

33. Back-up slides

34. Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

35. Applying Functional Analysis
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring

36. Source: Joyce E. Carpenter, NASA Johnson
More references
Source: Joyce E. Carpenter, NASA Johnson
January 16, 2019
Copyright 2008 Purdue University
Aerospace Systems-Spring