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Correlation between experiment and FEM analysis for inelastic strain of catalytic converter
3DEXPERIENCE CONFERENCE GERMANY 2019DESIGN, MODELING & SIMULATION
Satoshi ISHIKAWA, IDAJ Co., Ltd., Kobe
Junko HISHINUMA, YUTAKA GIKEN CO.,LTD. TOCHIGI R&D CENTER
Agenda
1. Introduction
2. Verification Strategy
3. Material Correlation
4. Results
5. Summary
3DEXPERIENCE Conference Germany 2019
Introduction
3
What is Converter ?
A catalytic converter is a device used in the exhaust system to convert toxic gases and
pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants.
HOT-END
Clean Gas
3DEXPERIENCE Conference Germany 2019
Lineup
Direct Under Model middle and large size
set onto cylinder head directly
high performance
Underfloor Model combined with exhaust
manifolds or direct under model
catalyst is set onto the
underfloor
Direct Under for Diesel special model for diesel engine
black smoke, PM
Introduction
4
3DEXPERIENCE Conference Germany 2019
Introduction
5
Converter is important component for environmental preservation.
Converter suffers large vibration from engine and high temperature cycles.
MAIN PURPOSE
Estimation of fatigue life cycle
We need to acquire precise inelastic strain by Abaqus/Standard analysis model
under the high temperature cycles
Agenda
1. Introduction
2. Verification Strategy
3. Material Correlation
4. Results
5. Summary
3DEXPERIENCE Conference Germany 2019
Verification Strategy
7
start from simple Test Piece to construct the fundamental model under high temperature cycle
thermal stress analysis
Target : inelastic strain error within 10%
Simplified test Piece 1 (Cone shape) Simplified test Piece 2 (Valve case) Real model Converter Fr Port
Aim fundamental Material Parameter Wide range stress-strain relation test with real part
Model
3DEXPERIENCE Conference Germany 2019
Verification Strategy
8
start from simple Test Piece to construct the fundamental model under high temperature cycle
thermal stress analysis
Target : inelastic strain error within 10%
Simplified test Piece 1 (Cone shape) Simplified test Piece 2 (Valve case) Real model Converter Fr Port
Aim fundamental Material Parameter Wide range stress-strain relation test with real part
Model
However, the error between experimental
test and analysis result was large even in
simple test piece1, particularly, in the plastic
strain.
Agenda
1. Introduction
2. Verification Strategy
3. Material Correlation
4. Results
5. Summary
3DEXPERIENCE Conference Germany 2019
Difference between Tensile test piece and Cone Test Piece
10
Check Items
Tensile Test
Piece
Cone Test
Piece
Assessment Effect
StructureShape Plane plate Pressed
Residual Stress and Work Hardening by Press
working Exist
Welding None With Residual Stress by welding Exist
Point at
measurement
strain
measurePlane area Corner R measure the correct strain direction None
Conditions
Load
conditionDirect Load Thermal Stress
Using correct temperature distribution from CFD
Using temperature dependent material
Good correlation within elastic range
None
Phenomena
Time
Strain rate
0.45%/min0.2％/hr(mean) no effect of strain rate None
first trial material parameters real model material parameters
3DEXPERIENCE Conference Germany 2019
Product Condition
11
Real operation
Catalytic converter suffers thermal cycle like annealing process.
Question
Does the residual stress disappear with annealing process?
Does the mechanical characteristic change by annealing process?
Confirmation
We investigate the effect of annealing process and take the material correlation.
3DEXPERIENCE Conference Germany 2019
The way of confirmation of Annealing process
12
1. Study the parameters of annealing process
• parameter study of preservation time and temperature
2. Inspect the material composition
a. investigate the dissipation of Residual Stress
b. measure the Vickers hardness
c. observe the grain size number
3. Optimize the stress-strain curve after annealing
• modify the s-s curve
Time
Tem
pera
ture
Cooling
Preservation time
before annealing
after annealingapply to Abaqus
Strain
Str
ess
3. modify s-s curve
1. Study Annealing process parameter
3DEXPERIENCE Conference Germany 2019
Temperature preserve time
Top Surface
Latitude ①
Bottom Surface
Latitude②
Longitudinal
direction③
None thermal
treatment- -121 124 -4
650℃ 4hr -36 48 -14
700℃
10hr -7 42 -2
25hr -9 14 -2
100hr -4 35 0
800℃
10hr -1 12 3
20hr -2 13 2
100hr -1 47 2
①
② ③
-140
-120
-100
-80
-60
-40
-20
0
0 50 100 150
Resid
ual Str
ess
MPa
Preserve time hr
Top Surface Latitude ①
700℃
800℃
650℃
None Thermal treatment 0
20
40
60
80
100
120
140
0 50 100 150
Resid
ual Str
ess
MPa
Preserve time hr
Bottom Surface Latitude ②
700℃
800℃
650℃
None Thermal treatment
Findings
• The condition of 10hr and 20hr with
800ºC reduced the residual stress.
1. Study the Annealing parameters on Cone Test Piece
2.a Inspect the dissipation of Residual Stress
3DEXPERIENCE Conference Germany 2019
2.b Measure the Vickers hardness
14
Measure the Hardness through the thickness every 0.1mm
Findings
The hardness was reduced by Annealing process and came to uniformity through the thickness.
Work Hardening was canceled also.
Thickness 2.0mm
outside inside
100
120
140
160
180
200
220
240
260
280
300
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Hard
ness
HV
熱処理なし
800℃-10Hr×2回
no thermal treatment
800ºC – 10hr two times
Max
Min
outside inside
3DEXPERIENCE Conference Germany 2019
2.c Observe the grain size number by metallographic microscope
15
no thermal treatment 800ºC 10hr 2times 800ºC 10hr 800ºC 100hr 700ºC 25hr
Magnification
25
Magnification
100
inside area
Magnification
100
center area
Magnification
100
outside area
板外 板内
metal flow
7.5
7.3
7.4
7.6
7.4
7.5
7.6
7.6
7.7
7.4
7.3
7.5
7.4
7.4
7.7
Findings
• The metal flow went out by Annealing process.
• There were no coarse grain.
3DEXPERIENCE Conference Germany 2019
3. Optimize the Stress-Strain curve
16
Tensile test piece with annealing process
Experimental curves do not show the initial yield stress clearly.
Principal optimized parameters are Elastic modulus and Yield Stress.
Proportional
limit
Stress
Resonance Young’s Modulus
(traditional using)
Total Strain
optimized
Yield stress
optimized
Young’s modulus●
real elastic strain
traditional
elastic strain
●
traditional plastic
strain
real plastic strain
analysis s-s curve
●
stre
ss
strain
Experimental s-s curve
20ºC
100ºC
200ºC
700ºC
900ºC
Agenda
1. Introduction
2. Verification Strategy
3. Material Correlation
4. Results
5. Summary
3DEXPERIENCE Conference Germany 2019
Simplified test Piece 1 (Cone shape)
18
Model includes real thickness
Verify three sections
Yield
StressUPPER SIDE LOWER
Experiment
(µST) -2518 -2981 -2260
AAbaqus -2810 -3114 -2513error (%) 11.6 4.5 11.2
BAbaqus -2666 -3001 -2413error (%) 5.9 0.7 6.8
CAbaqus -2979 -3644 -2461error (%) 18.3 22.3 8.9
UPPER
SIDE
LOWER
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
UPPPER SIDE LOWER
µst
rain
Experiment
Yield Stress A%
Yield Stress B%
Yield Stress C%
3DEXPERIENCE Conference Germany 2019
Simplified test Piece 2 (Valve case)
19
Verify seven points Yield
StressNo.1 No.2 No.3 No.4 No.5 No.6 No.7
Experiment
(µST)-7220 -7050 -3340 -2301 -2584 -3508 -2646
AAbaqus -8262 -7202 -3871 -2699 -2859 -3081 -2951error (%) 14.4 2.1 13.8 17.3 10.6 12.2 11.5
BAbaqus -6792 -6557 -3387 -2521 -2835 -3160 -2841error (%) 5.9 7.0 0.4 9.5 9.7 9.9 7.4
CAbaqus -6602 -6439 -3402 -2500 -2824 -3153 -2935error (%) 8.6 8.7 0.1 8.6 9.3 10.1 10.9
No.1 No.2
No.3
No.4
No.5
No.6
No.7-9000
-8000
-7000
-6000
-5000
-4000
-3000
-2000
-1000
0
No.1 No.2 No.3 No.4 No.5 No.6 No.7
µst
rain
Experiment
Yield Stress A%
Yield Stress B%
Yield Stress C%
3DEXPERIENCE Conference Germany 2019
Real model Converter Fr Port
20
Verify three points
No.1 No.2 No.3
Experiment
(µST)-1471 -2050 1687
Yield Stress B -1565 -2236 1839
error(%) 6.3 9.0 9.0
No.1No.2
No.3
The errors are within 10% even in the real model.
3DEXPERIENCE Conference Germany 2019
Summary
21
Summary
Annealing process erase the work hardening and residual stresses.
Redefinition of the stress-strain relation after the anneal.
All models include the real shape thickness.
We could get the precise inelastic strain by using Abaqus/Standard.
Future Work
Estimation of fatigue life cycle by using fe-safe
Plan of using Abaqus/Explicit on forming process for definition of precise
thickness
Inquiry
22
web: https://www.idaj.co.jp/
e-mail: [email protected]
Thank you for your kind attention
Vielen Dank für Ihre Aufmerksamkeit
