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Mohammad Sadegh Mobin PhD Candidate in Engineering Management Department of Industrial Engineering and Engineering Management Western New England University Springfield, MA PhD advisor: Dr. Zhaojun (Steven) Li 2017 Reliability Modeling and Optimization of New Product Development Process [email protected]

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Page 1: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Mohammad Sadegh MobinPhD Candidate in Engineering Management

Department of Industrial Engineering and Engineering ManagementWestern New England University

Springfield, MA

PhD advisor: Dr. Zhaojun (Steven) Li

2017

Reliability Modeling and Optimization of New Product Development Process

[email protected]

Page 2: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

1

Reliability Modeling and Optimization of New Product Development Process

Part 1: Reliability Growth Planning (RGP) Modeling and Optimization Part 2: Verification and Validation (V&V) Activities Planning and Optimization

Overview

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Page 3: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Continuous

Product

DevelopmentHigh % of

total

revenue

Consumer needs

changes

Marketing

environment

changes

To stay ahead of

Competition

Changing

technology

Not to lose

market share

2

New Product Development (NPD)

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Page 4: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

3

Prototype/pilot (Build components/

system)Prototype test

(Test components/ System)

Production phase Field

performance

Verification &Validation

(System and process V&V)

Business case(new idea)

Concept design(System requirement

identification)

Detail design(Component requirement

identification)

New Product Development (NPD)

Planning

Product/Process design & development

Product/Process V&V Production

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Page 5: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

NPD ChallengesNPD programs are often plagued with:

Cost overruns, Schedule delays, and Quality issues.

Product Company Issues Year Source

787

DreamlinerBoeing Co Delay due to a structural flaw 2009

The Wall Street

Journal

Chevy Volt General Motors Cost overrun during design 2009 CNN Money

The

Honda/GE

HF120

turbofan

engine

Honda

Design issues: An unanticipated test

program glitch. A part of the gearbox

failed during the test. Rebuild the

engine and begin the test again.

2013 Flying

F-35

United Technologies

Corp.’s Pratt and Whitney

unit

Delays in delivering engines. Quality

flaws and technical issues. Systemic

issues and manufacturing quality

escapes.

2014

Defence-

aerospace.com

Bloomberg Business

SikorskyUS Marine Corps'

(USMC's)

A failure in the main gear box and need

for redesign of the component.

Problems with wiring and hydraulics

systems. Budget constraints.

2015 HIS Jane’s 360

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Page 6: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

5

NASA’s main projects that faced

cost and time overrun:

The International Space Station.

Prime contract had grown: 25%

(from $783M to $986M, the 3rd increase in 2

years).

The NASA Ares-I launch system.

Cost overrun: 43%

(from $28 billion original estimate to $40 billion)

The Department of Defense (DoD)

The set of 96 major new weapon system

development programs (2000-2010) have:

an average development cost growth of

42%,

an average delay of 22 months.

“50% of the DOD’s NPD programs faced cost

overrun”.

“80% experienced an increase in unit costs from

initial estimates”.

NPD Challenges

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Page 7: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Reliability Management Process

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Page 8: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Objective

Improve the NPD process by reducing:

Time to market delay (Scheduling)

Cost overrun (Budgeting)

Quality flaws (Reliable product)

Model and optimize the NPD reliability process in terms of

cost, time, and product reliability

Proposing a model to improve the reliability growth planning (RGP).

Providing a quantitative model to improve product V&V activities planning.

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Page 9: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Part1: RGP

Multi-Objective and Multi-Stage Reliability Growth Planning

(MO-MS-RGP)

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Page 10: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Test Time

MT

BF

(D

ays)

1.000

10.00

100.0

1000

Initial MTBF:

3 days

Achieved

MTBF:

70.0 days

Reliability goal = 73

390 Days

A single stage Reliability Growth Plan

One RG plan can be:

390 Days,

Required test units

Required test time

Total cost: $50k

Objective of RGP: To determine the number of test units, test time, and cost to maximize the reliability growth.

Another RGP can be:

490 Days,

Test units and test time

Total cost $70k490 Days

8

Reliability Growth Planning (RGP)

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Page 11: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Duane Model (1964)

o An empirical model, based on the learning curve,

o Also known as power law model

o Duane model in terms of cumulative failure rate:

𝒍𝒏 𝑪 𝒕 = 𝜹 − 𝜶 𝒍𝒏 𝒕

𝐶 𝑡 : The average failure rate 𝐶 𝑡 = 𝑁(𝑡)/𝑡

𝑁 𝑡 : The cumulative number of failures up to time 𝑡 during the reliability growth

testing.

𝛿, 𝛼 > 0 , 𝛼 is known as growth rate

Duane Reliability Growth Model

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Page 12: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Motivation for Multi-Stage RGP

An example of multi-stage NPD plan

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Page 13: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Challenges for multi-stage RGP in early product development stage:

1. How to allocate test units and time to individual stage.

2. How to determine the proportion of new technology introduction in each stage

The schematic of multi-stage reliability growth planning

11

Multi-Stage Reliability Growth Planning

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Page 14: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

RGP Literature Review

Significant contribution: Multi-objective & Multi-stage RGP

Author

Early

design

stage

Field (test)

stage

Single

objective

Multi

objective

Single -

stage

Multi-

stage

Duane (1964) [1] No Yes Yes No Yes No Crow (1974) [2] No Yes Yes No Yes No Lloyd (1986) [3] No Yes Yes No Yes No Robinson and Dietrich (1987) [4] No Yes Yes No Yes No Coit (1998) [5] No Yes Yes No Yes No Walls & Quigley (1999) [6] Yes No Yes No Yes No Walls & Quigley (2001) [7] No Yes Yes No Yes No Quigley and Walls (2003) [8] No Yes Yes No Yes No Krasich et al. (2004) [9] Yes No Yes No Yes No Johnston et al. (2006) [10] Yes No Yes No Yes No Jin and Wang. (2009) [11] No Yes No Yes Yes No Jin et al. (2010) [12] No Yes Yes No Yes No Jin et al. (2013) [13] No Yes Yes No Yes No Jin and Li (2016) [14] Yes Yes Yes No Yes No Jackson (2016) [15] No Yes Yes No Yes No Li et al (2016) [16] Yes No No Yes No Yes

Author

Early

design

stage

Field (test)

stage

Single

objective

Multi

objective

Single -

stage

Multi-

stage

Duane (1964) [1] No Yes Yes No Yes No Crow (1974) [2] No Yes Yes No Yes No Lloyd (1986) [3] No Yes Yes No Yes No Robinson and Dietrich (1987) [4] No Yes Yes No Yes No Coit (1998) [5] No Yes Yes No Yes No Walls & Quigley (1999) [6] Yes No Yes No Yes No Walls & Quigley (2001) [7] No Yes Yes No Yes No Quigley and Walls (2003) [8] No Yes Yes No Yes No Krasich et al. (2004) [9] Yes No Yes No Yes No Johnston et al. (2006) [10] Yes No Yes No Yes No Jin and Wang. (2009) [11] No Yes No Yes Yes No Jin et al. (2010) [12] No Yes Yes No Yes No Jin et al. (2013) [13] No Yes Yes No Yes No Jin and Li (2016) [14] Yes Yes Yes No Yes No Jackson (2016) [15] No Yes Yes No Yes No Li et al (2016) [16] Yes No No Yes No Yes

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Page 15: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Proposed MO-MS-RGP Model

Objectives :

1. Minimize failure rate at the final stage

2. Minimize total development time

3. Minimize total test cost

Decision

variables:

1- Number of test units for each

subsystem in each stage

2- Test time for each subsystem

in each stage

1- Total product test

time

2- Number of available

test units in each

development stage

Constraints:

Stage 1 Stage 2 Stage 3

Initial

MTBF

(stage 1)

Initial

MTBF

(stage 2)

Initial

MTBF

(stage 3)

MTBF at the

end of stage 1

MTBF at the

end of stage 2

MTBF at the

end of stage 3

Test

time for

stage 1

Test

time for

stage 2

Total time

Reliability Goal

MT

BF

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Page 16: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

MS-MO-RGP Mathematical Modeling

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Page 17: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Proposed MO-MS-RGP Model

Min: 𝜆𝑛 = 𝑓 𝜆 𝑖−1, 𝜆 𝑛(𝑖), 𝛼𝑖 , 𝑇𝑖

Min: 𝜏 = 𝑖=1𝑛 𝜏𝑖 , 𝑖 = 1, … , 𝑛

Min: 𝐶 = 𝑖=1𝑛 𝐶𝑖 , 𝑖 = 1, … , 𝑛

s.t. 0 ≤ 𝜏 ≤ 𝜏𝑢

𝑁𝑙(𝑖) ≤ 𝑁𝑖 ≤ 𝑁𝑢(𝑖) , 𝑖 = 1, … , 𝑛

Decision variables:

• 𝑛𝑖𝑗• 𝑡𝑖𝑗

𝒇𝟏𝒇𝟐

𝒇𝟑 An optimal solution (RGP)

* Time (Yrs.)* Cost ($)* Reliability (MTBF (YRS.))* Number of test units for each sub-system in each stage* Planned testing time for each sub-system in stage

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Page 18: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Method 1: Creating a weighted composite objective function

Shortcomings: 1. Difficulties in determining appropriate utility functions (weights).

2. Objectives have different scale and cannot easily be added up.

Method 2: Consider one as main objective function and others as constraints

Shortcomings: 1. Difficulties in determining boundary values.

2. Defining boundaries may reduce the solution space.

Method 3: Multi-Objective Evolutionary Algorithms (MOEAs)

e.g., MOPSO, NSGA, etc.1. Simultaneously optimizing two or three (or more) conflicting objectives.

2. Effective methods in exploring feasible solutions and providing a population of approximately

optimal solutions (Pareto-optimal frontier).

3. Apply evolutionary operators, e.g., crossover and mutation to generate variety of new solutions.

Solution Methodologies

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Page 19: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Overview of the proposed solution methodology

Mathematical model:

• Objective functions

• Constraints

• Decision variables

A set of Pareto-

optimal solutions

Inputs

(Minimization objective functions)

Outputs

(Maximization objective functions)

Data

Envelopment

Analysis (DEA)

Multiple

Objectives

Evolutionary

Algorithm

Optimal

efficient

solutions

17

Proposed Solution Methodology

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Page 20: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Case Study Application of MS MO RGP for next generation dual engine development process

istage

Group description λijθ1

(%)

θ2(%)

θ3(%)

cij($1000)

mi αi Nl(i) Nu i

1Engine Block 1.38 100 0 0 600

2 0.4 4 8Turbocharger 0.03 100 0 0 45

2

Engine control 0.24 0 80 0 50

4 0.3 8 16Cooling System 0.02 0 100 0 30

Fuel System 0.20 0 80 0 40

Lubricating system 0.05 0 80 0 20

3

Engine control 0.24 0 0 20 12.5

3 0.2 6 20Fuel system 0.20 0 0 20 10

Lubricating system 0.05 0 0 20 5

Min: 𝜆𝑖=3 = 𝑓 𝜆 𝐼(𝑖−1), 𝜆 𝑛(𝑖), 𝛼𝑖 , 𝑇𝑖

Min: 𝑖=1𝑛 𝐶𝑖 = 𝐶1 + 𝐶2 + 𝐶3

Min: 𝜏 = 𝑖=1𝑛 𝜏𝑖 = 𝜏1 + 𝜏2 + 𝜏3

s.t. 0 ≤ 𝜏 ≤ 𝜏𝑢⟹ 0 ≤ 𝜏1 + 𝜏2 + 𝜏3 ≤ 3.54 ≤ 𝑛11 + 𝑛12 ≤ 88 ≤ 𝑛21 + 𝑛22 + 𝑛23 + 𝑛24 ≤ 166 ≤ 𝑛31 + 𝑛32 + 𝑛33 ≤ 20

𝜏𝑢: 3.5 years

The effective work hours in each year: 2000 hours

The variable cost per hour: $2000

18 decision variables:

• 𝑛𝑖𝑗 (discrete)

• 𝑡𝑖𝑗 (continuous)

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Page 21: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Obtaining Pareto optimal frontier for RGP using NSGA-II

0.50.6

0.70.8

0.91

1.11.2

1.31.4

1.5

00.5

11.5

22.5

33.5

0

3000

6000

9000

12000

15000

f1(x): Failure rate of stage 3f

2(x): Projected total test time

f 3(x

): P

roje

cted

to

tal

test

co

st 1 = 0.4

2 = 0.3

3 = 0.2

n(1)

= 1.41

n(2)

= 0.51

n(3)

= 0.49

19

Optimal Solutions

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Page 22: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

DEA applications

0.50.6

0.70.8

0.91

1.11.2

1.31.4

1.5

00.5

11.5

22.5

33.5

0

3000

6000

9000

12000

15000

f1(x): Failure rate of stage 3f

2(x): Projected total test time

f 3(x

): P

roje

cted

to

tal

test

co

st CCR solutions

NSGA-II solutions

Inputs Output DEA Models

DMUs Time Cost Reliability CCR CCR BCC BCC

(Yrs.) ($) MTBF (Yrs.) (I-O) (O-O) (I-O) (O-O)

DMU 01 3.45 15.38 2.13 0 0 1* 1* DMU 02 0.79 4.56 0.79 0 0 1* 1* DMU 04 3.28 14.72 2.13 0 0 1* 1* DMU 07 0.82 4.67 0.83 0 0 1* 1* DMU 10 2.30 10.87 1.88 0 0 1* 1

DMU 15 0.88 4.91 0.89 1* 1* 1* 1* DMU 19 0.80 4.60 0.81 0 0 1* 1* DMU 26 3.23 14.53 2.10 0 0 0 1* DMU 31 2.66 12.31 1.96 0 0 0 1

DMU 34 1.76 8.57 1.58 0 0 1* 1*

DMU 36 2.57 11.96 1.94 0 0 0 1

DMU 38 2.25 10.68 1.86 0 0 1* 1* DMU 48 0.79 4.56 0.79 0 0 1* 1* DMU 51 2.22 10.56 1.86 0 0 1* 1* DMU 56 1.83 8.84 1.62 0 0 0 1*

DMU 58 2.29 10.84 1.87 0 0 0 1

DMU 67 1.86 8.95 1.64 0 0 0 1

DMU 69 1.78 8.65 1.60 0 0 1* 1*

DMU 70 2.55 11.88 1.94 0 0 1 1

DMU 86 1.20 6.20 1.18 1* 1* 1* 1*

DMU 87 1.86 8.94 1.63 0 0 0 1

DMU 96 1.22 6.27 1.20 1* 1* 1* 1*

DMU 98 1.21 6.23 1.19 1* 1* 1* 1*

20

Optimal Efficient Solutions

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Page 23: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

21

Conclusions and Future Research

Uncertainties in the variables of the RGP model:e.g. uncertainty in the failure rate, reliability growth, etc.

Component-level approach in RGP:e.g. provide number of test units and test time for each component in different sub-systems.

Application and comparison of other evolutionary algorithms:e.g. Multi-objective Particle Swarm Optimization (MOPSO).

Ongoing and Future Research:

Conclusion:

A new approach in reliability growth planning (RGP)

o Correlates multiple stages of developing a new product.o Considers multiple objectives of NPD process.o Determines test time and test units for each subsystem in each stageo Provides efficient and optimal RGP for implementation

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Page 24: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

[1] Duane J., Learning curve approach to reliability monitoring, IEEE Transactions on Aerospace, 2(2), 563-6, 1964.

[2] Crow L.H.. Reliability analysis for complex, repairable systems. In Reliability and Biometry, ed. By F. Proschan

and R. J. Serfing, Eds: SIAM, 379-410,1974.

[3] Lloyd D.K., Forecasting reliability growth. Quality and Reliability Engineering International, 2(1),19-23. 1986

[4] Robinson D.G. and Dietrich D., A new nonparametric growth model. IEEE Transactions on Reliability, 36(4),411-8,

1987.

[5] Coit D.W., Economic allocation of test times for subsystem-level reliability growth testing. IIE transactions, 30(12),

1143-51, 1998.

[6] Walls L, Quigley J. Learning to improve reliability during system development. European Journal of Operation

Research, 119(2), 495-509, 1999.

[7] Walls L, Quigley J. Building prior distributions to support bayesian reliability growth modelling using expert

judgement. Reliability Engineering and System Safety, 74(2), 117-28. 2001.

[8] Quigley J. and Walls L., Confidence intervals for reliability-growth models with small sample-sizes, IEEE

Transactions on Reliability, 52(2), 257-62, 2003.

[9] Krasich M., Quigley J., Walls L., Modeling reliability growth in the product design process, Proceedings of the

Annual Reliability and Maintainability Symposium (RAMS), 424-30, 2004.

[10] Johnston W., Quigley J., and Walls L., Optimal allocation of reliability tasks to mitigate faults during system

development, IMA Journal of Management Mathematics, 17(2), 159-69, 2006.

[11] Jin T, Wang H., A multi-objective decision making on reliability growth planning for in-service systems,

Proceedings of the IEEE International Conference on Systems, Man, and Cybernetics (SMC), 4677-83, 2009.

[12] Jin T., Liao H., and Kilari M., Reliability growth modeling for in-service electronic systems considering latent

failure modes, Microelectronics Reliability, 50(3), 324-31, 2010.

[13] Jin T., Yu Y., Huang H. Z., A multiphase decision model for system reliability growth with latent failures, IEEE

Transactions on Systems, Man and Cybernetics, 43(4), 958-966, 2013.

[14] Jin T., Li Z., Reliability growth planning for product-service integration, Proceedings of the Annual Reliability and

Maintainability Symposium (RAMS), 2016.

[15] Jackson C., Reliability growth and demonstration: the multi-phase reliability growth model (MPRGM),

Proceedings of the Annual Reliability and Maintainability Symposium (RAMS), 2016.

References

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Page 25: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

22

Journal Publicationso Mobin M., Li Z., Komaki M., A Multi-Objective Approach for Multi-Stage Reliability

Growth Planning by Considering the Timing of New Technologies Introduction,IEEE Transaction on Reliability, 66 (1), 97-110, 2017

o Li Z., Mobin M., Keyser T., Multi-objective and Multi-Stage Reliability GrowthPlanning in Early Product Development Stage, IEEE Transaction on Reliability,65(2), 769-781, 2016.

Conference Presentationso Mobin M. and Li. Z., An Integrated Reliability Growth Planning in the New Complex

Engineering Product Development, Accelerated Stress Testing and ReliabilityConference (ASTR 2016), Florida, USA.

o Mobin M. and Li Z., Multi-stage Reliability Growth Planning Using DynamicProgramming, The Institute for Operations Research and the ManagementSciences Annual Conference (INFORMS 2014), California, USA.

o Li Z., Mobin M., Pervaiz M., Keyser T., Multi-Objective and Multi-Stage ReliabilityGrowth Planning in Early Product Development Stage, Industrial and SystemsEngineering Research Conference (ISERC 2014), Montreal, Canada.

Related Publications and Presentations

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Page 26: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Section 2: V&V Planning

An Approach for Design Verification and Validation Planning and Optimization for New

Product Reliability Improvement

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Page 27: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Scheduling

Challenges

Cost optimization

Reliability improvement

Failures prioritization

V&V effectiveness

Process iteration

A schematic summary of V&V process during NPD for reliability improvement

Failure modes (𝑓𝑖, 𝑖 = 1,… , 𝑛) Criticality (𝐷𝑖, 𝑆𝑖, 𝑂𝑖), V&V activities (𝑣𝑗, 𝑗 = 1,… ,𝑚)

Duration (𝑡𝑗)

Effectiveness (𝜃𝑖𝑗 , 𝛾𝑖𝑗)

Design Failure Modes and

Effects Analysis (DFMEA)

V&V Execution

V&V planning

NO

23

V&V Process in NPD

Final product design

Product Reliability Estimation

Meets reliability

goal?

YES

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Page 28: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Literature Review

24

Models that

only focus on

product

requirements

and

configurations

o Quality Function Deployment (QFD) [19]

o Key Characteristics (KCs) [20]

o Design for X (DFX) [21]

Models that

only focus

on

scheduling

and

budgeting

o Project evaluation and review technique (PERT) [16]

o The general evaluation and review technique (GERT) [17]

o The dependency structure matrix (DSM) [18]

Scheduling

Cost optimization Reliability improvement

Failures prioritization

Process effectivenessProcess iteration

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Page 29: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Objective function and constraints:Objective: Maximize the product reliability improvement.

Constraints: 1: Limited budget; 2: Limited time; 3: Cover all failure modes; 4: Precedence constraints

25

Objective of V&V activities planning: To determine an optimal set of V&V activities to be implemented in the limited time and cost,

and optimizing reliability.

V&V Activities PlanA schematic view of the V&V planning

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Page 30: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Proposed Model for the V&V Planning

Objective: Maximize the product reliability improvement

Constraint 1: Total cost of performing V&V activities

Constraint 2: The critical failure coverage constraint

Constraint 3: Total V&V process time (makespan of V&V process )

Constraint 4: Precedence constraints for V&V activities

Subject to:

𝑴𝑨𝑿 𝑹𝑰𝑻𝒐𝒕𝒂𝒍 = 𝒊=𝟏

𝒏

𝑹𝑰𝒊 =

𝒊=𝟏

𝒏𝑹𝑷𝑵𝒊(𝒊𝒏𝒊𝒕𝒊𝒂𝒍)

𝑹𝑷𝑵𝒊(𝒏𝒆𝒘)

(𝒔𝒋 + 𝒕𝒋)𝒗𝒋 ≤ 𝒔𝒋′,∀ 𝒋 immediately preceding 𝒋′

𝑴𝒂𝒙𝒋=𝟏,..,𝒎; 𝒊=𝟏,…,𝒏

{(𝒔𝒋 + 𝒕𝒋) 𝒗𝒋 , ∀ 𝒊 = 𝟏,… , 𝒏} ≤ 𝑻

𝒋=𝟏

𝒎

𝒂𝒊𝒋 𝒗𝒋≥ 𝟏 , ∀ 𝒊 = 𝟏,… , 𝒏

𝒋=𝟏

𝒎

𝒄𝒋 𝒗𝒋 ≤ 𝑪

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𝑅𝑃𝑁𝑖 (𝑖𝑛𝑖𝑡𝑖𝑎𝑙) = 𝐷𝑖 (𝑖𝑛𝑖𝑡𝑖𝑎𝑙) ∗ 𝑂𝑖 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 ∗ 𝑆𝑖 (𝑖𝑛𝑖𝑡𝑖𝑎𝑙)

𝐷𝑖 (𝑛𝑒𝑤) = 𝐷𝑖 (𝑖𝑛𝑖𝑡𝑖𝑎𝑙) ∗

𝑗=1

𝑚

(1 − (𝜃𝑖𝑗 ∗ 𝑣𝑗))

o 𝑚 V&V activities 𝑣𝑗 (𝑗 = 1,… ,𝑚) and (𝑣𝑗 ∈ {0,1})

o 𝑛 failures (𝑖 = 1,… , 𝑛).

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Numerical Example A modified case study of power assembly design when developing a new next generation engine.

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o Total budget (𝐶) for performing the V&V activities is $470K. o Total time of implementing V&V process is 480 days.

The incidence matrix Cost and duration of each

V&V activity Initial detectability, occurrence, and

severity for each failure mode

(𝜃𝑖𝑗 , 𝛾𝑖𝑗): Risk reduction percentage in 𝐷𝑖 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 and 𝑂𝑖(𝑖𝑛𝑖𝑡𝑖𝑎𝑙)after conducting the V&V activity 𝑣𝑗 on the failure mode 𝑓𝑖

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Numerical Results

Decision variables (𝑣𝑗) and the starting time of each V&V activity

o The objective function value is obtained as: 𝑅𝐼𝑇𝑜𝑡𝑎𝑙 = 𝑖=125 𝐼𝐼𝑖 = 850.132.

o The reduction in total RPN is calculated as: 𝑆𝑢𝑚 𝑅𝑃𝑁 𝑖𝑛𝑖𝑡𝑖𝑎𝑙 – 𝑆𝑢𝑚 𝑅𝑃𝑁 𝑛𝑒𝑤 = 3635.907. o Total cost of implementing the selected six V&V activities is $454,000. o Total implementation time is obtained as 405 days.

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Summary of results

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Conclusions and Future Research

Uncertainties in the variables of the V&V planning model:e.g. uncertainty in the DFMEA results, such as failure detectability and occurrence, time and cost of V&V activities, effectiveness, etc.

Possible iteration of V&V activities:e.g. V&V activities can be iterated with different effectiveness levels.

Multi-objective optimization applications:e.g. considering time and cost minimization as objective functions.

Ongoing and Future Research:

Conclusion:

A new mathematical approach to plan V&V activities

o Reliability improvement optimizationo Time and cost constraintso Failure coverageo Effectiveness of V&V activitieso Sequencing of V&V activities

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[16] A.K. Bhattacharjee, S.D. Dhodapkar, and R.K. Shyamasundar, “PERTS: an environment for specification

and verification of reactive systems,” Reliability Engineering & System Safety, vol. 71, no.3, pp.299-310,

2001.

[17] W. Bernard, III. Taylor, and J. L. Moore, “R&D project planning with Q-GERT network modeling and

simulation,” Management Science, vol. 26, no. 1, pp. 44-59, 1980.

[18] S. D. Eppinger, D. E. Whitney, R. P. Smith, and D. A. Gebala, “A model-based method for organizing

tasks in product development,” Research in Engineering Design, vol. 6, no. 1, pp.1-13, 1994.

[19] D. Y. Kim, and P. Xirouchakis, “CO 2 DE: a decision support system for collaborative design,” Journal of

Engineering Design, vol. 21, no. 1, pp. 31-48, 2010.

[20] Y. M. Deng, G. A. Britton, and S. B. Tor, “Constraint-based functional design verification for conceptual

design,” Computer-Aided Design, vol. 32, no. 14, pp. 889-899, 2000.

[21] T.C. Kuo, S. H. Huang, and H.-C. Zhang, “Design for manufacture and design for ‘X’: concepts,

applications, and perspectives,” Computers & Industrial Engineering, vol. 41, no. 3, pp. 241-260, 2001.

References

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30

Journal Publicationso Mobin M., Li Z., V&V Activity Planning Modeling and Optimization During New

Product Development Stages, Reliability Engineering and System Safety, (UnderReview).

Conference Presentationso Mobin M., Li. Z. An Integrated Approach to Plan the Design Verification and

Validation (V&V) Activities for the New Product Reliability Improvement, 2017IEEE Symposium on Product Compliance Engineering, California, USA.

o Mobin M., Li Z., A Simulation-Optimization Approach to Optimize the DesignVerification and Validation Activities Planning for the New Product ReliabilityImprovement. INFORMS 2016.

Related Publications and Presentations

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Page 36: Reliability Modeling and Optimization of New Product ... · 1 Reliability Modeling and Optimization of New Product Development Process Part 1: Reliability Growth Planning (RGP) Modeling

Mohammad Sadegh Mobin (PhD Candidate),

Western New England University, Springfield, MA

Question & Comments

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