Abstract

In piping design analysis, the secondary stresses (displacement controlled) may have different design limits than primary stresses (load-controlled stresses). The current design limits for secondary stresses are based on elastic stress analysis. But realistically, a flaw in the piping system can cause nonlinear behavior due to the plasticity at the crack plane as well as in the adjacent uncracked-piping material. Hence, the actual stresses in a cracked piping system, which are elastic-plastic, are different than the design stresses, which are elastically calculated. To assess margins in the secondary stresses calculated using elastic stress analysis in pipe flaw evaluation, two parameters are defined in this paper. The first one is the secondary stress weighting factor (SSWF) on total stress, which is defined as the ratio of actual elastic-plastic stresses in a system to the elastic design stress. An alternative approach to applying margins on secondary stresses is to use a reduction factor only on stresses above the yield stress called plastic reduction factor (PRF). In this paper, a methodology developed to determine these factors for circumferential surface-cracked TP304 stainless steel pipes subjected to bending loads at ambient temperature is described. Four-point-bend tests are conducted on pipes with varying circumferential surface-crack lengths and depths. The moments and rotations needed for the pipe failure for different crack sizes are determined and compared to elastically calculated moments and rotations to establish margins.

References

1.
Wilkowski
,
G.
,
Scott
,
P.
,
Olson
,
R.
, and
Rudland
,
D.
,
2005
, “
Effect of Secondary Stresses on Pipe Fracture
,”
ASME
Paper No. PVP2005-71330.10.1115/PVP2005-71330
2.
R6 Revision 4,
2000
, “
Assessment of the Integrity of Structures Containing Defects
,” British Energy, BNFL, Magnox Generation, and AEA Technology, England, UK.
3.
Milne
,
I.
,
Ainsworth
,
R. A.
,
Dowling
,
A. R.
, and
Stewart
,
A. T.
,
1986
, “
Assessment of the Integrity of Structures Containing Defects
,” R/H/R6-Rev. 3, Published by Central Electric Generating Board, England, UK.
4.
Kanninen
,
M. F.
,
Broek
,
D.
,
Marshall
,
C. W.
,
Rybicki
,
E. F.
,
Sampath
,
S. G.
,
Simonen
,
F. A.
, and
Wilkowski
,
G. M.
,
1976
, “
Mechanical Fracture Predictions for Sensitized Stainless-Steel Piping With Circumferential Cracks
,” EPRI, US, Report No.
NP-192
.https://inis.iaea.org/search/search.aspx?orig_q=RN:12642181
5.
EPRI,
1986
, “
Evaluation of Flaws in Austenitic Steel Piping
,”
(Technical basis document for ASME IWB-3640 analysis procedure), prepared by Section XI Task Group for Piping Flaw Evaluation
, EPRI, US, Report No.
NP-4690-SR
.https://www.osti.gov/biblio/5539530-evaluation-flaws-austenitic-steel-piping
6.
Maricchiolo
,
C.
, and
Milella
,
P. P.
,
1989
, “
Fracture Behavior of Carbon Steel Pipes Containing Circumferential Cracks at Room Temperature and 300 C
,”
Nucl. Eng. Des.
,
111
(
1
), pp.
35
46
.10.1016/0029-5493(89)90277-X
7.
Sturm
,
D.
, and
Stoppler
,
W.
,
1987
, “
Forschungsvorhaben
,” Phänomenologische Behälterberstversuche–Traglast-und Bruchverhalten von Rohren mit Umfangsfehlern–150279, Abschlußbericht Phase II.
8.
Faidy
,
C.
,
Jamet
,
P.
, and
Bhandari
,
S.
,
1988
, “
Developments in Leak Before Break Approach in France
,” United States Nuclear Regulatory Commission, Washington, DC, pp. 69–82, Report No. NUREG/CP-0092.
9.
Kurihara
,
R.
,
Ueda
,
S.
, and
Sturm
,
D.
,
1988
, “
Estimation of the Ductile Unstable Fracture of Pipe With a Circumferential Surface Crack Subjected to Bending
,”
Nucl. Eng. Des.
,
106
(
2
), pp.
265
273
.10.1016/0029-5493(88)90283-X
10.
Shibata
,
K.
,
Yasuda
,
Y.
,
Onizawa
,
K.
, and
Miyazono
,
S.
,
1989
, “
Evaluation of JAERI's Ductile Fracture Test Results on Stainless Steel and Carbon Steel Piping
,”
Nucl. Eng. Des.
,
111
(
1
), pp.
135
146
.10.1016/0029-5493(89)90285-9
11.
Yagawa
,
G.
,
Takahashi
,
Y.
,
Kashima
,
K.
,
Hasegawa
,
K.
,
Saito
,
M.
,
Umemoto
,
T.
, and
Sasaki
,
N.
,
1984
, “
Stable Growth and Instability of Circumferential Cracks in Type 304 Stainless Steel Pipes Under Tensile Load
,”
ASME J. Pressure Vessel Technol.
,
106
(
4
), pp.
405
411
.10.1115/1.3264371
12.
Kalyanam
,
S.
,
Wilkowski
,
G.
,
Pothana
,
S.
,
Hioe
,
Y.
,
Sallaberry
,
C.
, and
Martin
,
J.
, ““
Apparent Net-Section-Collapse
” Methodology for Circumferential Surface Flaws in Piping,”
ASME
Paper No. PVP2017-65438.10.1115/PVP2017-65438
13.
Hioe
,
Y.
,
Kalyanam
,
S.
,
Wilkowski
,
G.
,
Pothana
,
S.
, and
Martin
,
J.
,
2017
, “
Fracture Toughness Variation With Flaw Depth in Various Specimen Geometries and Role of Constraint in Material Fracture Resistance
,”
ASME
Paper No. PVP 2017-65441.PVP2017-65441
14.
Krishnaswamy
,
P.
,
Scott
,
P.
,
Mohan
,
R.
,
Rahman
,
S.
,
Choi
,
Y. H.
,
Brust
,
F.
,
Kilinski
,
T.
,
Francini
,
R.
,
Ghadiali
,
N.
,
Marschall
,
C.
, and
Wilkowski
,
G.
,
1995
, “
Fracture Behavior of Short Circumferentially Surface-Cracked Pipe
,” United States Nuclear Regulatory Commission, Washington, DC, Report No.
NUREG/CR-6298
. https://inis.iaea.org/collection/NCLCollectionStore/_Public/27/031/27031852.pdf
15.
Scott
,
P. M.
, and
Ahmad
,
J. A.
,
1972
, “
Experimental and Analytical Assessment of Circumferentially Surface-Cracked Pipes Under Bending
,” United States Nuclear Regulatory Commission, Washington, DC, Report No.
NUREG/CR-4872
.https://inis.iaea.org/search/search.aspx?orig_q=RN:19002017
16.
Uddin
,
M.
,
2017
, “
Modeling of Pipe System Behavior With Circumferential Surface Crack for Secondary Stress Margin Assessment
,”
ASME
Paper No. PVP 2017-66037.10.1115/PVP 2017-66037
You do not currently have access to this content.