Failure Mode Based Optimization of Durability and ... · Project Risk Assessment Prepara-tion RA Main Session RA Minutes / Report Work with RA Document RA Review RA Review Minutes

October 2006 | Page 1Reliability Presentation – SAE Meeting, Reno, NV

Failure Mode BasedOptimization of Durability and Reliability Validation Programs

SAE Ground Vehicle Reliability Committee Presentation

Dr. Klaus Denkmayr

Reno, October 23rd, 2006


Content

AVL‘s Reliability Engineering Process

The Load Matrix – Failure Mode based Optimizationof Validation Programs

Conclusions


Content



Conclusions


Who is AVL?

Privately owned company

(Owner: Prof List and family)

Turnover:1984: ~40 million €

2006: ~500 million €

Staff:1984: ~560

2006: ~3500

Average R&D spending10 % of turnover

AVL AdvancedSimulation Technologies

AVLInstrumentationand Test Systems

AVLPowertrain Engineering

Engineering

Simulation

Testing


AustriaAustria (HQ)(HQ)

CroatiaCroatia

CzechCzech RepublicRepublic

FranceFrance

GermanyGermany

SloveniaSlovenia

SpainSpain

SwedenSweden

United KingdomUnited Kingdom

HungaryHungaryPolandPoland

BelgiumBelgium

SwitzerlandSwitzerland

TurkeyTurkeyItalyItaly

BrazilBrazil

ArgentinaArgentina

MexicoMexico

CaliforniaCalifornia

MichiganMichigan

AVL Establishments

ChinaChina

JapanJapan

KoreaKorea

RussiaRussia

ThailandThailand IndonesiaIndonesiaMalaysiaMalaysia

TaiwanTaiwanIndiaIndia

IranIran


A Reliability Engineering Approach for Powertrain Development

Reliability Engineering

CustomerService

Design & Development

Testing

ProductionEngineering

QualityAssurance

AVL’s Reliability Engineering ...

Is focused on failure-free products in the field

Includes a range of methods,

Risk management

Field and test data analysis

Statistical methods

Validation optimisation

Is a comprehensive process throughout product development


The Reliability Engineering ProcessThe Reliability Engineering Process

RA & FMEA

Reliability Charts

Warranty Cost Prediction

StatisticalAnalysis

Reliability Allocation

ConceptPhase

Production ValidationPreproduction Development (Gen 2)

Prototype Development (Gen 1)

Development time

Volume Prod.

Concern System

Load Matrix

DoE / Robustness

May 2006 | Page 8

Project Risk Assessment

Prepara-tion

RA Main

Session

RA Minutes /Report

Work withRA

Document

RAReview

RAReviewMinutes

To get a quick, clear and unbiased view on project risksTo be able to act upon critical risks in an appropriate way

How?The risks not to reach the project targets are rated.Assessment is done similar to FMEA. Scoring system, facilitator, interdisciplinary team.Technical, organisational, financial, and legal / contractualrisks are covered.Generation of an action plan.


Robustness / DoE Techniques

Benefits

Optimized, robust design and testingReduction of test effortInsight into „load space“ and damaging parameters

Application of DoE (Design of Experiments) and relatedstatistical methods

Definition of variants of reference duty cycles

Derivation of load variations for especially critical components / failure modes

problem definition test plan conduction of tests analysis



Benefits

Gives an instant overview of the whole system and on reliability-criticalparts

Provides reliability targets for as an input for supplier technical specs

Serves as a basis for life cycle cost models

The system is modelled reliability-wise as a block diagram

Reliability values (eg, B10 and RF) areallocated to each subsystem

Values are derived from similarprojects, prototypes, FMEAs and fielddata.

exhaust systemRF target = 0.05

cylinder head assemblyRF target = 0.04

crank trainRF target = 0.01

crank caseRF target = 0.01

injection systemRF target = 0.05

add-on partsRF target = 0.04

engineRF target = 0.2

(simplified model)


Reliability Charts -Reliability Improvement Monitoring

BenefitsShows current and historic values of reliability indices

Illustrates the rate of improvement of these indices

Provides a basis for prediction of the indices in the future

Monitoring technique - shows the durability and reliability status of an engine / powertrain / vehicle during product development

One chart is made for the system lifetime, another one for RepairFrequency or MTBF value (classical Reliability Growth Testing)

B10 Life

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1.Q.1999

2.Q.1999

3.Q.1999

4.Q.1999

1.Q.2000

2.Q.2000

3.Q.2000

4.Q.2000

1.Q.2001

2.Q.2001

3.Q.2001

4.Q.2001

actual B10 value(calculated)

prediction

hours

Repair Frequency (RF)

0,0

2,0

4,0

6,0

8,010,0

12,0

14,0

16,0

18,0

20,0

Q11999

Q21999

Q31999

Q41999

Q12000

Q22000

Q32000

Q4 2000

Q12001

Q22001

Q32001

Q42001

actual RF values

predicton

Remark.1) 3rd and 4th quarter 2000 reflect pilot and seriesproduction, respectively

target

target


Warranty Cost Models

Benefits

make the costs of un-reliability transparentshow the SOP riskcan be used as a basis for life cycle cost prediction

Warranty Cost Models

illustrate in which way warranty costs depend on the B10 and theMTBF/RF values of the product

reflect 100%-repair campaigns due to serial defects

require as input repaircosts and subsystemfailure distributions (fromfield data or esti-mated from protos)

109

87

65

43

21

1000 20003000 4000

50006000 7000

80009000

0,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

cost

s(m

illio

ncu

rren

cyun

its)

RF

B10

30,0-35,025,0-30,020,0-25,015,0-20,010,0-15,05,0-10,00,0-5,0

2 yrs to SOP:RF = 10

B10 = 2000 h

SOPRF = 2,5B10 = 6500 h

millioncurrency

units

1 yr to SOP:RF = 7,5B10 = 4500 h


The Reliability Engineering ProcessThe Reliability Engineering Process

RA & FMEA

Reliability Charts

Warranty Cost Prediction

StatisticalAnalysis


ConceptPhase

Production ValidationPreproduction Development (Gen 2)

Prototype Development (Gen 1)

Development time

Volume Prod.

Concern System

Load Matrix

DoE / Robustness


Content



Conclusions


The Load Matrix

The Load Matrix is ...

a methodology to optimise test & validationprograms systematically

The Load Matrix is applied to ...

optimise existing „traditio-nal“ durability & reliability validation programs

design optimal validationprograms for newsystems (eg, DPF)


Load Matrix Details

The Load Matrix ...is based on component and failure mode specific test acceleration factors

uses these specific acceleration factors as weightingfactors to compare test efficiency and life coverage

uses damage models tocalculate acceleration

The Load Matrix is used for ...minimising validation costs without jeopardizingproduct durability & reliability


Load Matrix Process

Selection of critical components and failuremodes (basis: FMEA, field data, etc.)

Definition of reliability targets for thesecritical parts / failure modes

Collection of validation steps, test durations, determination of test acceleration factors

Evaluation of validation program withrespect to reliability & durability,

weak point analysis


Selection of critical components & failure modes

FMEAs and FP sheets of new subsystems

Result: List of criticalcomponents and failure modes

Existing reliability field data(e.g, from previous engine)


An Important Tool: The FP Sheet

Identificationof damageparameters

Priorisation of critical failure

modes

Selection of damage model

FP (Failure Mode - Parameter) Sheet

= Extended FMEA with emphasis on parameters relevant for damaging and critical operating conditions

FMEA, Risk Analysis, Field Data, Experience


Example of an FP Sheet (shortened)


Example. Load Matrix Single Sheet for Cylinder Head High Cycle Fatigue

testsaccelerationfactors

equivalentmileage

number and duration


Example. Load Matrix Summary Sheet

Highlights existing durability risks of the validation program

Indicates to what extent the test program is adequate to demonstrate the target reliabilities

Derived actions to reduce risks include higher acceleration, new test procedure, calculation (e.g., FEM analysis), longer test time / mileage, customer fleets)


Calculation of Acceleration Factor (simplified)

engine speed

h1(v)

h2(v) h3

(v)

h4(v)

h5(v)

Freq

uenc

y(o

rpro

babi

lity)

Test: Cyclic Load Test Vehicle (duty cycle)

engine speed

h1(c)

h2(c)

h3(c)

h4(c)

h5(c)

Freq

uenc

y(o

rpro

babi

lity)

Frequency Plot resultingfrom test procedure Frequency Plot resulting

from statistics and in-vehicle measurements

engine speed

d1

d2d3

d4

d5

rela

tive

dam

age

Damage profileresulting fromdamage modelcalculation

Relative damage per hour in CyclicLoad Test: DR

(c) = Σ hi(c) di

Relative damage per hour in vehicle(duty cycle): DR

(v) = Σ hi(v) di

identical

Acceleration Factor = DR(c) / DR

(v)

engine speed

d1

d2d3

d4

d5

rela

tive

dam

age

Damage profileresulting fromdamage modelcalculation


time

Data Processing w.r.t. to Damage

vehicleoperation

dataprocessing

acquisitionof damage

relatedparameters


Example of Damage Calculation (Matlab-based)


Classes of Damage Models

Class Method Example

A empirical model based damage is proportional to the on general experience number of actuations

B simplified physical model L = (C/P)m

for the lifetime of a ball bearing

C full physical model FE-Analysis + Damage Accumulation Modell Hypothesis + Actual material data


Example. Optimization of an Exhaust Aftertreatment System Validation Plan

Optimization

Reliability Durability

Ori-ginalPlan

Plan afterOptimi-zation


Risk analysis / System FMEA

Detailed FMEAs

Hardware

Detailed FMEAs

Software

DVP

for HardwareFunctional

Checks

FP Sheets for Hardware

Durability & Reliability

SVP

Software Validation

Plan

Software Reliability

Methodology

Load Matrix Test Program Optimisation

(test bed, components and vehicle durability & reliability tests)

Software Function Tests(SIL, HIL, vehicle

testing, etc.)

Hardware Functional

Tests

CONCEPT PHASE DESIGN / DEVELOPMENT PHASE

Load Matrix Monitoring, Reliability Growth,

Reliability Analysis and Prediction, Corrective

Actions

TEST / VALIDATION PHASE PRODUCTION

Warranty Data

Analysis, Early

Warning System

Load Matrix as Key Element of an Overall Risk Mimimisation Process


Content



Conclusions


Load Matrix Benefits

Failure mode based optimization of validation ...

Generates complete and balanced validation plans, including analysis, component testing, test bed tests, vehicle tests.

Shows how far durability and reliability targets can be demonstrated.

Helps to avoid unnecessary testing.

Supports the exchange and proper use of key information from allinvolved partners, including suppliers.

Supports optimised assessment procedures to make full use of allavailable information.

Helps in deciding on the benefits of additional validation steps.


Customer System TasksEuropean OEM HD Diesel Engine Setup of a warranty cost prediction model

Assessment of Validation ProgramEuropean OEM HD Diesel Engine Determination of sub-system specific acceleration

factors Validation program optimisation

Supplier Diesel Particle Filter Definition of a test program Definition of the LOAD MATRIX for Substrate, Mat

and CanningEuropean OEM DENOX System Definition and optimisation of a test programJapanese OEM SUV and LCV

TCI Diesel Engine Determination of the effect of a different vehicle

application (LCV instead of SUV) on engine life Definition of a durability test program

European OEM Rear Axle Setup of Load Matrix Assessment of current test program

European OEM Pass Car Gasoline Engine Comparison of two different validation programsEuropean OEM LCV and HD TCI Diesel

Engine Assessment of validation program for a DPF

application

A Selection of Recent Projects


Thank you for your attention!

Documents

Failure Mode Based Optimization of Durability and ... · Project Risk Assessment Prepara-tion RA Main Session RA Minutes / Report Work with RA Document RA Review RA Review Minutes