Correlation between experiment and FEM analysis for ... · Simplified test Piece 1 (Cone shape)...

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

ishikawa.satoshi@idaj.co.jp

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

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ishikawa.satoshi@idaj.co.jp

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

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ishikawa.satoshi@idaj.co.jp

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

ishikawa.satoshi@idaj.co.jp

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

ishikawa.satoshi@idaj.co.jp

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

ishikawa.satoshi@idaj.co.jp

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

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ishikawa.satoshi@idaj.co.jp

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.

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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

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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

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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

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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.

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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

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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%

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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%

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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.

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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: ishikawa.satoshi@idaj.co.jp

Thank you for your kind attention

Vielen Dank für Ihre Aufmerksamkeit