Design Functions and Solutions

C h r i s t o p h e r S a l d a n a , P h . D .W o o d r u f f S c h o o l o f M e c h a n i c a l E n g i n e e r i n gG e o r g i a I n s t i t u t e o f T e c h n o l o g yA t l a n t a , G e o r g i a , U S A

2

Phases of DesignCustomer

• Understand the Design Process

Specification Development• Specification of Information

Conceptual Design• Specification of a Principle• Functional Decomposition• Generate Concepts• Concept Evaluation• Concept Selection• Preliminary Design/Embodiment

Detail DesignSpecification of Production

• Process Planning

Manufacture

3

Concept Generation/SelectionCreating, screening, scoring alternatives

4

5

6

Apple’s design approachPixel-perfect design mockups

10 to 3 to 1 design down-select

Paired design meetings – brainstorming/production

Pony meetings – design review for managers

Integrated business process design

Customer experience focus

Alternatives (Project Purple - iPhone)

Walters, Helen. "Apple's Design Process, Bloomberg Businessweek." (2008).

7

Alternatives (Project Purple - iPhone)

Samsung Electronics Co., Ltd., et al. v. Apple Inc. (2016), SCOTUS Case 15-777.Kahney, L. (2013). Jony Ive: The Genius Behind Apple's Greatest Products. Penguin.

Kahney, L., ”Birth of the iPhone”, Cult of Mac, June 26, 2017

Initial Concepts

‘Sandwich’ ‘Extrudo’

Alternative 1 - P1 design

Alternative 2 - P2 design

Design IterationsP2 design prototypes P2 refined designs

Concept screen,

prototype and score

Make, iterate

and finalize

8

Identify design functions and sub-functions (Function Tree)

Identify solutions for different functions/sub-functions (Morphological Chart)

Combining individual solutions to generate conceptual alternatives

Learning Objectives

9

Consider what not how• Draw a box• Identify a verb• Identify a noun(s) on which the verb acts

Follow flows of energy, material, and information/signals. Consider interactions with external energy, materialBreak the function down as finely as needed• Fine enough to address customer needs• Fine enough for a single basic solution principle to satisfy each sub-function.

Guidelines for Functional Modeling

10

Define overall functionIdentify system boundariesIdentify flows of Energy (E), Material (M), and Information (I)Identify interfacing objects that exchange E, M, or IConserve E and M

Black Box Models

11

Material Flow Main Function System Boundary

Stamp Form

Length

Separate Offcuts

Check Quality

Count Squares

Combine in lots Pack DispatchMaterial

Overall Function

Loose carpet squares stamped out of the length

Carpet squares packed in lots

Function Structure

Function Block DiagramsExample: Packing of Carpet Squares

12

Test Specimen (Force

Deformation)

E load

Specimen

E deformationSpecimen deformedI forceI deformationI

Change energy into

force & movement

Measure force

Measure deformation

Load specimen

I F

I ∆

E load

I

Specimen E deformationSpecimen deformed

Function Block DiagramsExample: Material Testing Machine

13

Change energy into

force & movement

Measure force

Measure deformation

Load specimen

I F

I ∆

E load

I

SpecimenE deformationSpecimen deformed

Hold specimen

Adjust energy flow

Compare target with actual

values

Amplify measurements

E auxil.

I F targetI ∆ target

E loss

Function Block DiagramsExample: Material Testing Machine

14

Determining Functional Variants

Shape DoughShaped Dough

ElossDoughAdditives

I

E

1 2 3 54 6

7

1 2 3+4 5 6

7

Feed in1

Prepare2

Dispense3

Shape4

Separate5

Feed Out6

Return7

Dough ShapedDough

Waste Waste WasteAdditives

1 2 3+4+5 6

7

1 2+3 4+5 6

7

Overall function and function structure variants of a dough-shaping machine for the manufacture of biscuits (in respect of the main flow only)

Example: Dough Shaping Machine

15

Function Tree

Function

SF1 SF2 SF3

SF11 SF12 SF13 SF21 SF22 SF23 SF31 SF32 SF33

16

Function Tree Example

17

Developing Solution Principles

Sub-FunctionPhysical Effect

(Independentof Solution)

Physical Principle(Sub-function

& Physical Effect)

Solution Principle(Physical Principle &

form Design Features)

TransferTorque

TT

Amplifymuscular

force

FA FB

Closecontact

when T≥Ta

LL

T

TransferTorque by

FrictionFT=FF=µFN

TT

AmplifyMuscular

Force by LeverFB=FA(a/b)

FA FB

Close Contactby Expanding

Mercury∆L=(α)(L)(∆T)

LL

T

FF=µFN

Friction

bFB=aFA

Lever

∆L=(α)(L)(∆T)

Expansion

Fulfilling sub-functions by solution principles built up of physical principlesand form design features

FF

FN

VFBFA ba

Friction Surface

18

Solution Principle Matrix

Sub-func.

Solution Principles(Idea/ Source)

1Idea: (Mechanical)Rub on Material

(Mechanical)Squirt Material

(Mechanical)Place Material(like Letterset)

(Chemical)Change paper composition

Source: Standard product Team #2 Letterset Acid etching

1(Chemical)

Change paper color(like Litmus paper)

(Electrical)Burn paper (spark)

(like old fashioned stripchart recorders)

(Electrical)Electrify Paper (glow

discharge)

(Electrical)Static charge to hold mark

on(like Etch-A-Sketch)

Fisher Scientific Team #3 Team #1 Etch-A-Sketch

1(Thermal)

Burn paper (flame)(Thermal)

Heat paper (glow discharge)(Thermal)

Melt on Mark(Magnetic)

Attach magnetic material(like refrigerator magnets)

Team #2 Team #2 Wax seals Gift Store

1(Biological)

Grow bacteria, fungus(Biological)

Modify (digest?) paper(Optical)

Change light properties ofpaper (reflectance, polarity)

(Optical)Change light (hologram)

Team #2 BioTech Magazine Team #2 Team #2

2(Mechanical)

Rub off Material(Mechanical)

Take off material(Mechanical)Cover mark

(like white out)

(Chemical)Change paper composition

Standard product Team #2 Team #1 Team #2

2(Chemical)

Change paper color(like dying fabric the same

color as a stain)

(Chemical)Change mark (e.g., bleach)

(Electrical)Burn off mark (spark)

ETC.

Team #1 Team #2 Team #2

Example: Design of a PencilSub-function 1: Make an Erasable MarkSub-function 2: Erase an Erasable Mark

Sub-func.

Solution Principles

(Idea/ Source)

1

Idea: (Mechanical)

Rub on Material

(Mechanical)

Squirt Material

(Mechanical)

Place Material

(like Letterset)

(Chemical)

Change paper composition

Source: Standard product

Team #2

Letterset

Acid etching

1

(Chemical)

Change paper color

(like Litmus paper)

(Electrical)

Burn paper (spark)

(like old fashioned strip chart recorders)

(Electrical)

Electrify Paper (glow discharge)

(Electrical)

Static charge to hold mark on

(like Etch-A-Sketch)

Fisher Scientific

Team #3

Team #1

Etch-A-Sketch

1

(Thermal)

Burn paper (flame)

(Thermal)

Heat paper (glow discharge)

(Thermal)

Melt on Mark

(Magnetic)

Attach magnetic material

(like refrigerator magnets)

Team #2

Team #2

Wax seals

Gift Store

1

(Biological)

Grow bacteria, fungus

(Biological)

Modify (digest?) paper

(Optical)

Change light properties of paper (reflectance, polarity)

(Optical)

Change light (hologram)

Team #2

BioTech Magazine

Team #2

Team #2

2

(Mechanical)

Rub off Material

(Mechanical)

Take off material

(Mechanical)

Cover mark

(like white out)

(Chemical)

Change paper composition

Standard product

Team #2

Team #1

Team #2

2

(Chemical)

Change paper color

(like dying fabric the same color as a stain)

(Chemical)

Change mark (e.g., bleach)

(Electrical)

Burn off mark (spark)

ETC.

Team #1

Team #2

Team #2

19

Different Principles to Store Energy

Different working principles to satisfy the function “store energy” by varying the type of energy.

1

2

3

4

5

6

Mechanical Hydraulic Electrical Thermal

FlowingLiquid

HeatedLiquid

SuperheatedSteam

Type of EnergyWorking Principle

Battery

Capacitor(Electric Field)

C

Pot. Energy

mh

Hydraulic reservoire.g, Piston

Moving Massm

v

MassM, s, T

Flywheelω

J

+V-

J

vωWheeloninclinePlane

Liquid Res. Pot. E.

h

F

Spring Other SpringsComp. GasF

20

An Old Competition

20 ftSt

art L

ine

6.25 ft

12.5 ft

21

Function Tree Diagram

Place Masson Target

Moveto

Target

Navigateto

Target

Brake onTarget

GeneratePower

TransmitPower

HitTarget

22

Going from concept to physical reality

Morphological Chart

Generate Power

Transmit Power

Brake on Target

Move to Target

Navigate to Target

Gravity Mouse Traps

Car Hit by Trap Rip Cord Effect Ramp Catapult

Friction String Break Anchor Rubber Stopper Weighted Skid

Equal Size Wheels Larger Front Wheels

Rolling Sliding Projectile Launch

23

Combining Solution Principles

Sub-Functions

\Solutions 1 2 j m

1 F1 S11 S12 S1j S1m2 F2 S21 S22 S2j S2m

i Fi Si2 Sij Sim

n Fn Sn1 Sn2 Snj Snm

Combination of Principles1 2Combination 1: S11 + S21 + … + Sn1Combination 1: S11 + S22 + … + Sn2

Sub-Functions

\Solutions

1

2

(

j

(

m

1

F1

S11

S12

S1j

S1m

2

F2

S21

S22

S2j

S2m

(

(

(

(

(

(

i

Fi

Si2

Sij

Sim

(

(

(

(

(

(

n

Fn

Sn1

Sn2

Snj

Snm

24

Summary – Function Tree

Elements• List critical functions and sub-functions• Sub-branches from a function or sub-function must

number 2 or greater• Do not specify specifications that are dependent on

design decisions, design choices come later!

Describing this figure in text• Describe the contents, not the tool itself!• What are critical functions?

See Ch. 3 in book for detail

25

Elements• Mechanisms for lowest level elements of

FT, match one-to-one• Diagrams to depict mechanisms• Labels to briefly name mechanisms

Describing this figure in text• Highlight key mechanisms/functions• Use a selection matrix to identify

mechanisms used in different designs• Use different mechanisms in designs

Summary – Morphological Chart

See Ch. 5 in book for detail

26

Identify design functions and sub-functions (Function Tree)

Identify solutions for different functions/sub-functions (Morphological Chart)

Combining individual solutions to generate conceptual alternatives

Learning Objectives

27

Other Morphological Chart Examples

28

Function Structure with Auxiliary Functions

Material Flow Main Function System Boundary

Signal Flow Auxiliary Function

Stamp Form

Length

Separate Offcuts

Check Quality

Count Squares

Combine in lots Pack DispatchMaterial

Send Signal to combine

squares into one lot

Supply packing material

Remove rejects

Remove offcuts

Function Block DiagramsExample: Packing of Carpet Squares

29

Example: Harvest Potatoes

Potatoes

Reject Potatoes

Leaves

Course Particles

Lift Sift Separate Separate Sort Collect

Change

Change

Change

Fine Particles

Potatoes inthe ground

E2

E1

E2

E2

I

Harvest PotatoesPotatoes inthe ground

Potatoes

Reject PotatoesLeavesSoil, etc.

I

E

30

Example: Harvest Potatoes

31

Example: Additive Manufacturing

Williams, C.B., Mistree, F. and Rosen, D.W. (2011), “A Functional Classification Framework for the Conceptual Design of Additive Manufacturing Technologies”, Journal of Mechanical Design, Vol. 133 No. 12, p. 121002.

32

Example: Additive Manufacturing

Williams, C.B., Mistree, F. and Rosen, D.W. (2011), “A Functional Classification Framework for the Conceptual Design of Additive Manufacturing Technologies”, Journal of Mechanical Design, Vol. 133 No. 12, p. 121002.

33

Example: Additive Manufacturing

Williams, C.B., Mistree, F. and Rosen, D.W. (2011), “A Functional Classification Framework for the Conceptual Design of Additive Manufacturing Technologies”, Journal of Mechanical Design, Vol. 133 No. 12, p. 121002.

34

Example: Additive Manufacturing

Williams, C.B., Mistree, F. and Rosen, D.W. (2011), “A Functional Classification Framework for the Conceptual Design of Additive Manufacturing Technologies”, Journal of Mechanical Design, Vol. 133 No. 12, p. 121002.