Post on 04-May-2018
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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Content
� Introducing Faurecia
� Aim
� Virtual Durability Product Development
� Brief review= Low Frequency Analysis ?!
� Problem description
� Size Optimization
� Summary & Conclusions
Introducing Faurecia
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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
Aim
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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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Overview of Exhaust System
Cold EndAcoustic
Hot EndEmission control
Structural integrityDurability
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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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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
Culasse X- Order: 3.0 RMS15-Jul-08 09:07:53
Culasse X- Order: 1.5 RMS22-Jul-08 22:08:37
Culasse X- Order: 3.0 RMS22-Jul-08 22:08:37
Worst Resonant Frequencies
Engine Excitation Load
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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)
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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)
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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
mauricio.monteagudo@faurecia.com