Róbert Beleznai Tibor Köves Péter Kavalyecz
25
2 nd Hungarian-Ukrainian Joint Conference on SAFETY-RELIABILITY AND RISK OF ENGINEERING PLANTS AND COMPONENTS ASSESSMENT OF SUB-CLAD FLAWS, J-INTEGRAL CALCULATION Róbert Beleznai Tibor Köves Péter Kavalyecz BAY-LOGI Bay Zoltán Foundation for Applied Research Institute for Logistic and Production Systems Kyiv 20 th September, 2007
description
BAY - LOGI. 2 nd Hungarian-Ukrainian Joint Conference on SAFETY-RELIABILITY AND RISK OF ENGINEERING PLANTS AND COMPONENTS ASSESSMENT OF SUB-CLAD FLAWS, J-INTEGRAL CALCULATION. Róbert Beleznai Tibor Köves Péter Kavalyecz. Bay Zoltán Foundation for Applied Research - PowerPoint PPT Presentation
Transcript of Róbert Beleznai Tibor Köves Péter Kavalyecz
2nd Hungarian-Ukrainian Joint Conferenceon SAFETY-RELIABILITY AND RISK OF
ENGINEERING PLANTS AND COMPONENTS
ASSESSMENT OF SUB-CLAD FLAWS, J-INTEGRAL CALCULATION
Róbert Beleznai
Tibor Köves
Péter Kavalyecz
BAY-LOGI
Bay Zoltán Foundation for Applied ResearchInstitute for Logistic and Production Systems
Kyiv20th September, 2007
2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007 2
CONTENT
• Test specimens– Crack type
– Crack dimensions
– Crack geometry
• Material properties• Residual stress• Validation of the model• Boundary condition• J-integral calculation
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Main objective of the work
WWER Cladded Reactor Pressure Vessel (WWER-440) J-integral calculation based on the report of the Nuclear Research Institute Rez plc, Division of Integrity and Technical Engineering.
Introduction
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Test specimen
• Specimen type: 4PB (40x85x670 mm)
Support(Reaction Force F/2)
670 mm
(Total)Applied Force F
Flaw Centreplane248 mm 57 mm
Support(Reaction Force F/2)
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Material properties
• WWER reactor pressure vessel steel with austenitic cladding
• Data arises from the report of the NRI
• True stress – true plastic strain curve was derived for the FE calculation
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BAY-LOGIMaterial propertiesAged base metal
860
880
900
920
940
960
980
1000
1020
1040
1060
0,00 0,01 0,02 0,03 0,04 0,05 0,06 0,07
True plastic strain, [-]
Tru
e st
ress
, [M
pa]
Aged cladding
0
100
200
300
400
500
600
700
800
900
1000
0 0,1 0,2 0,3 0,4 0,5
True plastic strain, [-]
Tru
e st
ress
, [M
Pa]
E=211 GPa=12.55*10-6
E=162 GPa=17.1*10-6
Poisson ratio: =0.3
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Crack types
• Two different crack lengths were analyzed• 1e2 and 1e4:
– crack length: 15 mm– upper crack tip located 3 mm under the fusion line of the
cladding– both crack tips are sharp
• 1e7: – crack length: 40 mm– upper crack tip located 3 mm under the fusion line of the
cladding– upper crack tip is sharp– lower crack tip is drilled out
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Crack dimensionsStraight crack front were considered in all case.
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1e21e2
Cladding thickness 10.8 mm
Upper crack front 69.81 mm
Lower crack front 55.88 mm
Crack length 13.93 mm
1e41e4
Cladding thickness 11.35 mm
Upper crack front 70.76 mm
Lower crack front 55.87 mm
Crack length 14.89 mm
1e71e7
Cladding thickness 11.25 mm
Upper crack front 70.63 mm
Lower crack front 30.78 mm
Crack length 39.85 mm
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Crack geometry BAY-LOGI
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Residual stress
• Residual stress arises from the difference of the thermal expansion coefficients
• Stress free temperature: Tsf=350°C
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Temperature-time curve
0
50
100
150
200
250
300
350
400
0 10 20 30 40 50
Time, [s]
Tem
per
atu
re, [
°C]
Load-time curve
0
0,2
0,4
0,6
0,8
1
0 10 20 30 40 50Time, [s]
Loa
d, [-
]
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Residual stressBAY-LOGI
Comp 11 of stress
Residual stress distribution
-200
-150
-100
-50
0
50
100
150
200
250
0 20 40 60 80
Distance from upper cladding surface, [mm]
Com
p 1
1 of
Str
ess,
[M
Pa]
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Residual stress BAY-LOGI
Residual stress distribution
-200
-150
-100
-50
0
50
100
150
200
0 20 40 60 80
Distance from upper cladding surface, [mm]
Com
p 3
3 of
Str
ess,
[M
Pa]
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Validation of the FE model
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FEM calculations results - stress variation over specimen width (in stress measurement position)
-150
-100
-50
0
50
100
150
200
250
0 10 20 30 40 50 60 70 80 90
Distance from upper cladding surface [mm]
[MP
a]
longitudinal transversal
NRI
The results of NRI and BZF are in very good correlation.
Residual stress distribution
-200
-150
-100
-50
0
50
100
150
200
250
0 10 20 30 40 50 60 70 80 90
Distance from upper cladding surface, [mm]
Res
idu
al s
tres
s, [
MP
a]Longitudinal
Transversal
BZF
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Load-displacement curves BAY-LOGI
1E2
0
50
100
150
200
250
300
350
400
0 1 2 3 4 5 6Displacement, [mm]
For
ce, [
kN]
FEM result_BZF
Measurement_NRI
1E4
0
50
100
150
200
250
300
0 1 2 3 4Displacement, [mm]
For
ce, [
kN
]
FEM result_BZF
Measurement_NRI
1E7
0
50
100
150
200
250
0 1 2 3 4
Displacement, [mm]
For
ce,
[kN
]
FEM result_BZF
Measurement_NRI
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FE model
MSC.MARC 2005R3 code 3D model 20 nodes hexahedron elements J-integral calculation
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Specimen number
Number of elements
Number of nodes
1E2 3840 18593
1E4 4152 20017
1E7 4818 23134
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Boundary conditions
Only one quarter of the specimen was simulated.
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Total applied force2
Total applied force2
Symmetry condition
Specimen numberSpecimen number Total applied force [kN]Total applied force [kN]
1E2 259.7
1E4 339.4
1E7 205.5
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J-integral calculation
J-integral values along the crack front at max loading
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Straight crack frontStraight crack front
1E2
0
10
20
30
40
50
60
70
0 5 10 15 20 25Width of the specimen, [mm]
J-in
tegr
al, [
kJ/
m2 ]
Upper crack front straight
Lower crack front_straight
1E4
0
50
100
150
200
250
300
0 5 10 15 20 25Width of the specimen, [mm]
J-in
tegr
al, [
kJ/
m2 ]
Upper crack front straight
Lower crack front straight
1E7
0
50
100
150
200
250
300
0 5 10 15 20 25Width of the specimen, [mm]
J-in
tegr
al, [
kJ/
m2 ]
Upper crack front straight
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J-integral calculationJ-integral values history plot
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Straight crack frontStraight crack front
1E2 upper crack tip
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al,
[kJ/
m^
2]
1e2_side_straight
1e2_centre_straight
1E2 lower crack tip
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/m
^2]
1e2_side_straight
1e2_centre_straight
1E4 upper crack tip
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e4_side_straight
1e4_centre_straight
1E4 lower crack tip
0
20
40
60
80
100
120
140
160
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e4_side_straight
1e4_centre_straight
1E7 upper crack tip
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Time, [s]
J-i
nte
gra
l, [
kJ
/m^
2] 1e7_side_straight
1e7_centre_straight
1E2 lower crack tip
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/m
^2]
1e2_side_straight
1e2_centre_straight
1E7 upper crack tip
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/m
^2]
1e7_side_straight
1e7_centre_straight
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Real crack front BAY-LOGI
1E2
1E41E71E7
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J-integral along the crack front BAY-LOGI
Real crack frontReal crack front
1E2
0
10
20
30
40
50
60
70
0 10 20 30 40 50Width of the specimen, [mm]
J-in
tegr
al, [
kJ/
m2 ]
Upper crack front straightLower crack front_straightUpper crack front real Lower crack front real
1E4
0
50
100
150
200
250
300
0 10 20 30 40 50Width of the specimen, [mm]
J-in
tegr
al, [
kJ/
m2 ]
Upper crack front straight
Lower crack front straight
Upper crack front real
Lower crack front real
1E7
0
50
100
150
200
250
300
0 10 20 30 40 50Width of the specimen, [mm]
J-in
tegr
al, [
kJ/
m2 ]
Upper crack front straight
Upper crack front real
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J-integral history plot BAY-LOGI
Real crack frontReal crack front
J-integral values history plot1E2 upper crack tip
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e2_side_straight
1e2_centre_straight
1e2_side_real
1e2_centre_real
1E2 lower crack tip
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e2_side_straight
1e2_centre_straight
1e2_side_real
1e2_centre_real
1E4 upper crack tip
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e4_side_straight
1e4_centre_straight
1e4_side_real
1e4_centre_real
1E4 lower crack tip
-20
0
20
40
60
80
100
120
140
160
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e4_side_straight
1e4_centre_straight
1e4_side_real
1e4_centre_real
1E7 upper crack tip
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e7_side_straight
1e7_centre_straight
1e7_side_real
1e7_centre_real
1E2 lower crack tip
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Time, [s]
J-in
tegr
al, [
kJ/
m^
2]
1e2_side_straight
1e2_centre_straight
1e2_side_real
1e2_centre_real
1E7 upper crack tip
0
50
100
150
200
250
300
0 10 20 30 40 50 60
Time, [s]J-
inte
gral
, [k
J/m
^2]
1e7_side_straight
1e7_centre_straight
1e7_side_real
1e7_centre_real
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Conclusion
• In case of short straight and short real cracks the difference of the J-integral values is not significant.
• In case of deep crack more accurate J-integral value was resulted, if real crack front was modelled.
• Residual stress was considered, and this calculation is validated by NRI data.
• FE models were also validated by LLD curve of NRI.
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Possibilities for further investigations
• Weibull stress calculation based on the Beremin-model.
• T-stress calculation.
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Thank you for your kind attention!Thank you for your kind attention!
BAY-LOGI
