9/16/2003

ESD.36J System & Project Management

Instructor(s)

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Lecture 4

Design Structure Matrix: Iteration Models

©2003 Steven D. Eppinger

http://www.dsmweb.org

Prof. Steven D. Eppinger

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- Today’s Topics

Iteration ModelsPlanned vs. UnplannedSequential vs. Parallel

Product Development Process Analysis using DSMIndustrial ExamplesComparing alternative processes

Process Improvement using DSM“Design Modes”Work Transformation ModelCost and Schedule Simulation

Introduce HW2

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Semiconductor Development Example1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1 Set customer target • x x •2 Estimate sales volumes x • x x •3 Establish pricing direction x • x •4 Schedule project timeline • x5 Development methods x • x x x x6 Macro targets/constraints x x • x x x x7 Financial analysis x x x x x •8 Develop program map x • x9 Create initial QFD matrix x x x x •

10 Set technical requirements x x x x • x11 Write customer specification x x x x x • O O O O O O O O12 High-level modeling x x x x • x x x13 Write target specification x x x x x x x x x • x x14 Develop test plan x x x x x • x15 Develop validation plan x x x x • 16 Build base prototype x x x x x x •17 Functional modeling x x x x x • x x x x x x x x O O O O O O O O O O18 Develop product modules x x x x x x x x x • O19 Lay out integration x x x x x x x x x •20 Integration modeling x x x x x x x • x x x21 Random testing x x • x x x22 Develop test parameters x x x x x x x • x x x23 Finalize schematics x x x x x • x x O O O O O24 Validation simulation x x x x x x x • x x25 Reliability modeling x x x x x • x26 Complete product layout x x x x x • x x27 Continuity verification x x x x x x •28 Design rule check x x x •29 Design package x x x x x • O O O O O O O30 Generate masks x x x x • x O31 Verify masks in fab x x x •32 Run wafers x • x O33 Sort wafers x •34 Create test programs x •35 Debug products x x x x x • O O O O O O O36 Package products x x x •37 Functionality testing x x x •38 Send samples to customers x x x x •39 Feedback from customers x •40 Verify sample functionality x •41 Approve packaged products x x x x •42 Environmental validation x x x x •43 Complete product validation x x x x x •44 Develop tech. publications x x • x x45 Develop service courses x x • x46 Determine marketing name x x x x x • x47 Licensing strategy x x x •48 Create demonstration x x x x x x •49 Confirm quality goals x x x x x •50 Life testing x x x • x x51 Infant mortality testing x x x x • x52 Mfg. process stabilization x x x • O O53 Develop field support plan x x •54 Thermal testing x x x •55 Confirm process standards x • x x56 Confirm package standards x x x x x • x57 Final certification x x x x x x x x x x x •58 Volume production x x x • x59 Prepare distribution network x x x x x x x x •60 Deliver product to customers x x x x x x x x x •

x = Information Flows = Planned Iterations O = Unplanned Iterations • = Generational Learning

Concurrent Activity Blocks

Potential Iterations

Generational Learning

Sequential Activities

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- Two Types of Iteration

Planned IterationCaused by needs to “get it right the first time.”We know where these iterations occur, but not necessarily how much.Planned iterations should be facilitated by good design methods, tools, and coordination.

Unplanned IterationCaused by errors and/or unforeseen problems.We generally cannot predict which unplanned iterations will occur.Unplanned iterations should be minimizedusing risk management methods.

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-Design Iteration

Product development is fundamentally iterative —yet iterations are hidden. Iteration is the repetition of tasks due to the availability of new information.

changes in input information (upstream)update of shared assumptions (concurrent)discovery of errors (downstream)

Engineering activities are repeated to improve product quality and/or to reduce cost.To understand and accelerate iterations requires

visibility of iterative information flowsunderstanding of the inherent process coupling

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-Instrument Cluster Development

Faster Design ProcessFewer planned iterationsPlanned revision cycleNo unplanned iterations

Slower Design ProcessSeveral planned iterationsUsually one unplanned iteration

• •Casing Design • X X Casing Design • XWiring Layout X • X Lighting Details X •Lighting Details X X • Wiring Layout X X •Tooling X X X • Soft Prototype X X X •Hard Prototype X • Testing X •Testing X • Revision X •

• Hard Tooling X X X X X •• •

SupplierDelco

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- Two Iteration Styles

Sequential IterationOne activity is executed at a time.Models assume that probabilities determine the next actions.Signal Flow Graph Model

Parallel IterationSeveral activities are executed at a time.Models assume that rework is created for other coupled activities.Work Transformation Model

A

B

C

B

A

C

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-Stamping Die Development Process

PanelDesign

DieDesign

ManufacturabilityEvaluation

PrototypeDie

ProductionDie

SurfaceModeling

PanelData

VerificationData

SurfaceData

Analysis Results

SurfaceData

SurfaceDataAnalysis

ResultsDie

Geometry DieGeometry

VerificationData

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Signal Flow Graph Model:Stamping Die Development

1 432 5 6

7

8 9 10

Init. Surf.Modeling

Final Surf.Modeling

0.75 z2 z2

z20.25

z1

z0.25 1

z10.1

z30.9

z7Finish0.5

Start

0.75z2

z0 . 5

z3z3

Final Mfg.Eval.

Prelim. Mfg.Eval.-1

Prelim. Mfg.Eval.-2

DieDesign-1

DieDesign-2

DieDesign-3

1

pzt

durationprobability

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Computed Distribution ofDie Development Timing

.10

.20

1 0 2 0 3 0 4 0 5 0 6 0 7 0

.05

.25

.15

0time (days)

probability

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-Comparing Alternative PD Processes

Application:Jet Engine Development

Volvo Aero Corp.

Evaluation of Design Process Alternatives using Signal Flow Graphs

O. Isaksson, S. Keski-Seppälä, S.D. EppingerJournal of Engineering Design, Sept. 2000.

CB+C

C

Process A – No CFD analysisProcess B – Use CFD in evaluationProcess C – Use CFD in design + eval.

B+C

Rework(to be avoided)

Proceed

Design 1

Eval+Test

Design 2

Eval+Test

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-Comparing Alternative PD Processes

E[LT]C

Process A – No CFD analysisProcess B – Use CFD in evaluationProcess C – Use CFD in design + eval.

Prob

abili

ty o

f Com

plet

ion

Completion Time (days)300 400 500 600 700 800

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

E[LT]B E[LT]A

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-Brake System Design Example

**** **

**X **X **

X X **X **X **

X **X X **X X X **X X **X X **

X **X X X **X X **

X X X **X X X **

X X X X **X X X **

X X **X X X **X ** X

X **X X XX X X **

X X **X X ** XX X X **X X X X X **X X X X X **X X X X X X **

X X X X X **X X X X X ** X X

X XX X X X X ** X X X XX XX X X X X ** X X X XX XX X X X X ** X X X

X X X X X ** X X X X X XX X X X **

X X X X ** X XX X X X X ** X XX X X X X ** X

X X X X X ** XX X X X X ** X

X ** XX XX X X X X X X X ** X X X

X X X X X X ** X X XX X X X X X X ** X X

X X X X X ** XX X X X X ** X X X

X ** X XX ** X

X X X X X X X X X **X X X X XX X X X X X ** X X XX X X X X X ** X X

X X X X X ** XX X X X X X X ** X X X X X

X X X X X X X X X X X ** XX X X XX X X X X X X X X ** X X

X X X X X **X X X X X X X **

X X **X X X X X **

X X X X X X X X **X X X X X X X X X **

X X XX X X X **X X X**X X X X X XX ** X

X X X X X X **X X **X X **

X X **X XX X X **X XX X X X X X X X **

X X X X **X X X **X X X X X **

X X X X **X X **X X **

X X X X X X X X X **X X X X X X **

X X X X X **X X X **

X X X X X X X **X X X X X **

X X **X XX X X X X X X X **X XX X X X X X X X X **X XX X X X X X X X **X X X X X X X X X **X X X X X X X X **X X X X X X X X **

X X X X X **X **

X XX X X X X X X **X X X X **

X X X X X X X X X **X X X X X X X X X X X X X **

X X X X X X X X X **X X X X **

105parameters

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Brake System Coupled Block

33 34 35 37 40 44 45 46 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 0433 Knuckle envelope & attach pts ** • •34 Pressure at rear wheel lock up ** x X • •35 Brake torque vs. skidpoint ** x x x x37 Line pressure vs. brake torque ** • x •40 Splash shield geometry—front • ** • • x x • x44 Drum envelope & attach pts • **45 Bearing envelope & attach pts • ** • •46 Splash shield geometry—rear • • ** • •48 Air flow under car/wheel space x x ** x49 Wheel material ** x50 Wheel design • ** •51 Tire type/material • ** •52 Vehicle deceleration rate X X X ** • x •53 Temperature at components x ** • x •54 Rotor cooling coeficient x x • ** x x55 Lining—rear vol and area x • ** x56 Rotor width x x ** x x •57 Pedal attach pts ** x •58 Dash deflection x ** x59 Pedal force (required) x ** • x X x •60 Lining material—rear • ** • x •61 Pedal mechanical advantage x ** x •62 Lining—front vol & swept area x x ** •63 Lining material—front x • ** X x x64 Booster reaction ratio • x x ** •65 Rotor diameter • • • • ** x •66 Rotor envelope & attach pts x **

104 Rotor material x • • • **

• Weakx MediumX Strong

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The Work Transformation Model(Parallel Iteration Model)

AssumptionsAll coupled tasks are attempted simultaneously.Off-diagonal elements correspond to fractions of each task’s work which must be repeated during subsequent iterations.Objective is to characterize the nature of design iteration.

work vector

work transformation matrix

ut +1 = Aut

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Work Transformation Model Mathematics

totalwork

eigenvectormatrix

scalingvector

work transformation equation

total work vector

eigenvalue decomposition

Total work is a scaling of the eigenvectors.

substitution

11 − λdiagonal matrix of terms

ut +1 = Aut

U = utt =0

∞

∑ = ( At

t =0

∞

∑ )u0

A = SΛS−1

U = S Λt

t =0

∞

∑⎛

⎝ ⎜ ⎞

⎠ ⎟ S−1u0

Λt

t =0

∞

∑⎛

⎝ ⎜ ⎞

⎠ ⎟ = (I − Λ)−1

U = S (I − Λ)−1S−1u0[ ]

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Brake System “Design Modes”

0 5 10 15 20 25 30

Rate of Convergence

Design Mode

slower

faster

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-Brake System “Design Modes”

ThermalDesign Mode

First SecondKnuckle envelope & attach pts 0.0157 0.1215Pressure at rear wheel lock up 0.4808 0.0075Brake torque vs. skidpoint 0.4254 0.0435Line pressure vs. brake torque 0.1979 0.0228Splash shield geometry—front 0.1109 0.8328Drum envelope & attach pts 0.0011 0.0141Bearing envelope & attach pts 0.0168 0.1356Splash shield geometry—rear 0.0143 0.0654Air flow under car/wheel space 0.0512 0.5824Wheel material 0.0057 0.0610Wheel design 0.0156 0.1051Tire type/material 0.0731 0.0177Vehicle deceleration rate 1.0000 0.0910Temperature at components 0.1641 0.3224Rotor cooling coefficient 0.1035 0.9598Lining—rear vol and area 0.1479 0.0166Rotor width 0.1043 1.0000Pedal attach pts 0.1843 0.1584Dash deflection 0.3510 0.2265Pedal force (required) 0.7818 0.2317Lining material—rear 0.1765 0.0587Pedal mechanical advantage 0.4193 0.1749Lining—front vol & swept area 0.1669 0.2052Lining material—front 0.4870 0.0417Booster reaction ratio 0.3502 0.0787Rotor diameter 0.1117 0.0463Rotor envelope & attach pts 0.0057 0.0705Rotor material 0.0757 0.3168

Stopping PerformanceDesign Mode

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-Turbine Blade Development Process

Process Improvement Simulations Using the Work Transformation Model

P. Cronemyr, A. Öhrwall Rönnbäck, S.D. Eppinger International Conference on Engineering Design

Munich, August 1999.

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Turbine Blade Development DSM

Existing Process: Different CAD Tools Proposed Process: Common CAD Tools

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- DSM (WTM) Analysis Results

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- Lessons Learned: IterationDevelopment is inherently iterative.An understanding of the coupling is essential.Not everything should be concurrent in concurrent engineering.Iteration results in improved quality.Iteration can be accelerated through:

information technology (faster iterations)coordination techniques (faster iterations)decreased coupling (fewer iterations)

There are two fundamental types of iteration:planned iterations (getting it right the first time)unplanned iterations (fixing it when it’s not right)

Mature processes have more planned and fewer unplanned iterations.

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DSM Simulation QuantifiesCost and Schedule Risk

Task-based project network model using DSM representationEffects modeled:

Probabilistic iteration and reworkLearning effectsStochastic task durations and costsResource constraintsOverlapping tasksRisk-based control of parallel rework

Discrete-event Monte-Carlo simulationLatin Hyper Cube samplingSimulation outputs:

Cost and schedule outcome distributions Budget and deadline risk factors

Two reference papers:“Product Development Process Modeling Using Advanced Simulation”, Soo-Haeng Cho and Steven D. Eppinger, ASME Design Theory and Methodology Conference, September 9-12, 2001.“Modeling Impacts on Cost and Schedule Risks in Product Development”, Tyson R. Browning and Steven D. Eppinger, Working Paper 2001.

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-UAV Concept Study DSM Inputs

Unmanned Aerial VehiclePreliminary Design Activities

Tasks, Durations, Learning Parameters

MIT Lean Aerospace Initiative

2 3 4 5 6 7 8 9 10 11 12 132 0.23 0.5 0.44 0.55 0.5 0.1 0.1 0.3 0.16 0.47 0.48 0.5 0.59 0.5 0.5 0.5

10 0.1 0.5 0.2 0.1 0.411 0.5 0.5 0.5 0.512 0.4 0.5 0.5 0.413 0.5 0.4

2 3 4 5 6 7 8 9 10 11 12 132 0.13 0.3 0.54 0.85 0.1 0.1 0.1 0.3 0.16 0.37 0.88 0.5 0.59 0.3 0.3 0.3

10 0.1 0.5 0.4 0.3 0.311 0.5 0.5 0.3 0.312 0.3 0.5 0.5 0.513 0.9 0.3

Exp. Duration Lear-ID Task Name Opt. Likely Pess. ning

1 Prepare UAV Preliminary DR&O 1.9 2.0 3.0 0.352 Create UAV Preliminary Design Confinguration 4.8 5.0 8.8 0.203 Prepare Surfaced Models & Internal Drawings 2.7 2.8 4.2 0.604 Perform Aerodynamics Analyses & Evaluation 9.0 10.0 12.5 0.335 Create Initial Structural Geometry 14.3 15.0 26.3 0.406 Prepare Structural Geometry & Notes for FEM 9.0 10.0 11.0 0.907 Develop Structural Design Conditions 7.2 8.0 10.0 0.358 Perform Weights & Intertias Analyses 4.8 5.0 8.8 1.009 Perform S&C Analyses & Evaluation 18.0 20.0 22.0 0.25

10 Develop Freebody Diagrams & Applied Loads 9.5 10.0 17.5 0.5011 Establish Internal Load Distributions 14.3 15.0 26.3 0.7512 Evaluate Structural Strength, Stiffness, & Life 13.5 15.0 18.8 0.3013 Preliminary Manufacturing Planning & Analyses 30.0 32.5 36.0 0.2814 Prepare UAV Proposal 4.5 5.0 6.3 0.70

ID 1 2 3 4 5 6 7 8 9 10 11 12 13 1412 1 13 1 14 1 15 1 1 1 1 1 2 16 1 27 1 28 1 19 1 1 1

10 1 1 1 1 111 1 1 1 212 1 1 1 2 213 1 1 114 1 1 1 1 1 1 1 1 1 1 1 1 1

Precedence, Rework Probability, Impact

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-Simulated Schedule of UAV Preliminary Design Process(1 of 1000 simulation runs)

ID \ State D (w /o rew ork) D (w . rew ork) 1 2 3 4 6 7 8 9 10 11 12 13 20 211 2.0 2.02 5.9 5.93 2.9 3.84 8.9 8.95 17.0 19.2 0.5

6 9.0 10.1 2.27 10.3 10.38 7.7 11.59 20.2 21.710 16.3 18.711 15.5 23.8 3.9 0.6

12 14.8 16.7 3.713 34.7 34.714 5.0 5.0

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Results for UAV Preliminary Design Process

570 600 630 660 690 720 750 780 810 840

Cost ($k)

.0

.2

.4

.6

.8

1.0Target

120 126 132 138 144 150 156 162 168 174 180

Schedule (days)

0.0

0.2

0.4

0.6

0.8

1.0Target

COST:PC(un.) ≈ 24%

SCHEDULE:PS(un.) ≈ 91%

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Joint PDF of Paired [C, S] Samples

550600

650700

750800

850900

120130

140150

160170

180

Cost ($k)Schedule (days)

Insight: Bimodal PDF has similar cost but different schedule outcomes.

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550 600 650 700 750 800 850 900120

130

140

150

160

170

180

Cost ($k)

Sch

edul

e (d

ays)

Contour Plot View of Joint [C, S] PDF

Scheduletarget

Budget target

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Comparing Alternative UAV Development Processes

.4 .2.5 .4

.3 .5

.4 .5 .1 .1 .3 .1

.1 .4

.4 .4.5 .5

.4 .5 .5 .5

.1 .5 .2 .1 .4.5 .5 .5 .5

.4 .4 .5 .5 .4

.5 .5 .4

.3 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4

.4 .2.5 .4

.3 .5

.4 .5 .1 .1 .1 .3

.5 .5 .4

.1 .4

.4 .4.5 .5

.4 .5 .5 .5.1 .5 .2 .1 .4

.5 .5 .5 .5.4 .4 .5 .5 .4.3 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4 .4

Configuration 1 Config. 3

Mfg.Analysisactivitymovedupstream

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-Planning the UAV Development

Process

Plot of RC vs. RS for five process configurations shows trade-off possibilities.

Linear Scale

Cost Risk

1

3

2

45

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Lessons Learned: Cost and Schedule Simulation

Quantify cost and schedule uncertainty and risk

Compare alternative process configurations to reduce risk and choose more robust processes

Visualize simulated process in Gantt chart format

Explore sensitivities toProcess changesLearning curve effectsRework probabilities and impactsActivity costs and durationsControl policies

total duration

Process Robustness

cum

pro

b

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-MIT Design Structure Matrix

Web Site

http://www.DSMweb.org•Tutorial

•Publications

•Examples

•Software

•Contacts

•Events

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- Problematics DSM Software

Download from: http://www.problematics.comIf you would like to use the software for work at your company, you should obtain a separate registration number from Problematics.

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Questions and

Discussion