Size Optimization process of an Exhaust...

Size Optimization process of an Exhaust System

Mauricio Monteagudo G.R&D Exhaust Durability ManagerFaurecia R&D Center, France.

2nd European Hyperworks Technology Conference

2008 Strasbourg, France.

2nd Hyperworks Technology Conference Strasbourg, France. Property of Faurecia - duplication prohibited

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2

Content

� Introducing Faurecia

� Aim

� Virtual Durability Product Development

� Brief review= Low Frequency Analysis ?!

� Problem description

� Size Optimization

� Summary & Conclusions

Introducing Faurecia

4

Exhaust systemn°1 in Europen°2 worldwide

Door panel / Modulesn°1 in Europen°1 worldwide

Instrument panel / Cockpitn°1 in Europen°1 worldwide

Front endn°1 in Europe n°2 worldwide

Seating n°2 in Europen°3 worldwide

Acoustic packagen°3 in Europe

Faurecia is an expert in 6 major modules

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International ESPG footprint

ASIA5 Plants1 Customer office2 D&D centers

NORTH AMERICA6 Production plants3 JIT1 D&D center

EUROPE9 Production plants

10 JIT1 R&D center3 D&D centers

South Africa

Brazil

Argentina

MexicoChina

Korea

Japan

USA

ROW3 Plants1 JIT

Plants

R&D Center

D&D Center

Customer Office

www.faurecia.com


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Aim

� Applying Size Optimization (modification of properties) approach to:

� NVH

� Decrease Hanger Forces

� Early selection of decoupling elements dynamic characteristics

� Durability

� Bending Moments at the I/O volumes

� Stress values vs. worst resonant frequencies

� Lightweight if loads are lower thanks to the more efficient decoupling values.

�Time

� Global virtual durability development to optimize the dynamic behavior of Exhaust Systems.

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Virtual Durability Development


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9

Overview of Exhaust System

Cold EndAcoustic

Hot EndEmission control

Structural integrityDurability


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10

Vehicle LevelVehicle Level

System System LevelLevel

Fatigue Life DesignFatigue Life Design

Very Low Frequency Very Low Frequency [Road & Engine loads]

~ 0-20 Hz

nn Engine BenchEngine Bench

nn Electrodynamics BenchElectrodynamics BenchSubsystem LevelSubsystem Level

nn UniUni (Bi)(Bi)--axial Force axial Force LoadingLoading Bench Bench

Component Component

LevelLevel

Low FrequencyLow Frequency[Engine load]

~ 20–250 Hz

nn Exhaust System Exhaust System Key Life Test

Complete

Exhaust

Validation

SOR

Virtual Durability Development


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11

Brief review = Low Frequency Analysis

� To evaluate the reacting forces at each hanging point that could induce Structure Borne Noise in the Vehicle or NVH

� To compute the bending moments, at inlet/outlet of volumes.

� To evaluate the stress map for each measuring points for worst resonant Frequencies tuning the structural experimental damping

Flex Coupling

Bending moment at the I/O of volumes

Isolators

Hanger Force

CS

DynamicStaticK

zK

yK

xK

Kz

Ky

Kx

*

&

θ

θ

θ

CS

DynamicStaticK

Kz

Ky

Kx

*&

Rotation speed - rpm

Am

plit

ude m

1k 6.5k6k5k4k3k2k0

40µ

30µ

20µ

10µ

Culasse X- Order: 1.5 RMS15-Jul-08 09:07:53




Worst Resonant Frequencies

Engine Excitation Load


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12

RF3

0

10

20

30

40

50

60

30 50 70 90 110 130 150

Frequency (Hz)

Fo

rce (

N)

AVD

AVG

ARD

ARG

CDC

Z directionRF3

0

2

4

6

8

10

12

14

16

30 50 70 90 110 130 150

Frequency (Hz)

Fo

rce (

N)

AVD

AVG

ARD

ARG

CDC

Z direction

Without Flex With Flex

� know-how to isolate engine vibrations using standard decoupling elements (Flex coupling & Isolators)

Problem description

Today

� To know the most accurate linear dynamic stiffness values by optimization loops to evaluate the reacting forces at each hanging point that could induce NVH

Challenge

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Size Optimization


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Size Optimization

�To minimize hanger force in each direction < 10 N

�To keep lower stress map and bending moments < 100 N*m

� Engine behavior load (FRF) for critical Eigen values

� Temperature map loaded

� Damping values are fixed according experimental tuning

� Decoupling elements dynamic characteristics data base

CS

DynamicStaticK

zK

yK

xK

Kz

Ky

Kx

*

&

θ

θ

θ

CS

DynamicStaticK

Kz

Ky

Kx

*&

Target

Inputs

Potential design parameters

� Flex Coupling: Kx, Ky, Kz, Hx, Hy, Hz (6)

� Isolators: Kx, Ky, Kz (2x3 = 6)


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Size Optimization

1.2e+06

1.2e+06

225e+05

300 000

300 000

1500

Upper bound

1.2e+06800 000400 000K θz(Nmm/rad)

81 362800 000400 000Kθy(Nmm/rad)

225e+0515e+0675 e+05Kθx(Nmm/rad)

100 000200 000100 000Kz (N/mm)

300 000200 000100 000Ky (N/mm)

5001000500Kx (N/mm)

Optimized values

Initial values

Lower bound

Flex

12282012Kz (N/mm)

141482.4Ky (N/mm)

141482.4Kx (N/mm)

41414024Kz (N/mm)

1717164.8Kx (N/mm)

17

Upper bound

Rear Isolator

17164.8Ky (N/mm)

Optimized values

Initial values

Lower bound

Front Isolator

1st LoopRear isolator

Front isolator


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Size Optimization


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Size Optimization

1.6e+06

1.6e+06

30e+06

400 000

400 000

2000

Upper bound

1.6e+06800 00080 000K θz(Nmm/rad)

749 512800 00080 000Kθy(Nmm/rad)

30e+0615e+061.5e+06Kθx(Nmm/rad)

30 585200 00020 000Kz (N/mm)

400 000200 00020 000Ky (N/mm)

3511000100Kx (N/mm)

Optimized values

Initial values

Lower bound

Flex

240202Kz (N/mm)

91680.8Ky (N/mm)

141680.8Kx (N/mm)

1080404Kz (N/mm)

3232161.6Kx (N/mm)

32

Upper bound

Rear Isolator

5.5161.6Ky (N/mm)

Optimized values

Initial values

Lower bound

Front Isolator

2nd LoopRear isolator

Front isolator


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Size Optimization


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Size Optimization

2.97.314.57.13.718.22.8Von Mises stress (MPa)

134116.

5

11068.5614335Frequency (Hz)

With optimized values (1st loop)

5.91.510.75.35.66.94.8Von Mises stress (MPa)

141.5116.5

10969.5614334Frequency (Hz)

With initial values

Max Von Misses stress


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Size Optimization

0

20

40

60

80

100

120

140

0 50 100 150 200 250 300 350 400

Hz

N/m

m

Typical dynamic characteristics values (example)

+ Z Direction

Summary&

Conclusions


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� Size Optimization approach was developed for Exhaust Systems in Low

frequency domain.

� An case study was presented here and proved the Size Optimization approach

can predict Flex coupling and Isolators dynamic characteristics in the earliest virtual development stage.

� The compromise of decreasing hanger forces and keeping lower stress values

and bending moments is possible.

� The predicted results were correlated reasonably with observed results from Faurecia decoupling elements data base assuring the steadiness of results.

� Size Optimization is able to predict dynamic performance of exhaust which

enables to avoid the treat of presumptive dynamic stiffness values in order to reach the design targets applying advance mathematical tools like OptiStruct.

Summary & Conclusions


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References� Mauricio Monteagudo Galindo, Science and Technology Designing Exhaust Systems.

SAE 2003 Noise & Vibration Conference, 2003-01-1656.

� M. Monteagudo, J. Clavier, T. Lauwagie, J. Strobbe, E. Dascotte, Optimization of the

Dynamic Response of a Complete Exhaust System, ISMA2008

� OptiStruct, User’s Manual, version 8.

Thank you for your attention.

ContactMauricio Monteagudo Galindo

R&D Exhaust Durability Manager

Faurecia R&D / France.

Tel: +(33) 3 81 99 25 63

[email protected]

Size Optimization process of an Exhaust...

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