Piping systems in power plant may experience combined bending-torsion loads in the presence of planar crack-like flaws. ASME Boiler and Pressure Vessel Code Section XI nonmandatory Appendix C provides flaw evaluation procedures for pipes with flaws. These are currently limited to straight pipes under pressure and bending loads and no provision is made for torsion loading. The working group on pipe flaw evaluation is developing guidance for including the torsion load within the existing solutions provided in the Appendix C for bending loading on a straight pipe under fully plastic fracture regime. This paper reports on the finite element limit load analyses performed on the straight pipe containing a circumferential planar crack-like flaw. Pipe diameters were ranging from 4 in. (100 mm) to 24 in. (600 mm) nominal diameter (OD) and R/t ranging from 6 to 40. For the purpose of nonmandatory Appendix C flaw evaluation, it is concluded that the torsion loads can be combined with bending loads using the root of the sum of the squares (RSS) method of Section III of the ASME Boiler Code, without any additional weighting on torsion.

References

References
1.
ASME Boiler and Pressure Vessel Code, Section XI
, Rules for Inservice Inspection of Nuclear Power Plant Components,
2010 Edition
,
The American Society of Mechanical Engineers
,
New York, NY
.
2.
RSE-M
, 1997,
Rules for in-Service Inspection of Nuclear Power Plant Components
,
3rd ed.
, addendum—October 2005,
AFCEN
,
Paris
.
3.
NUREG/CR-6299
, 1995, “
Effects of Toughness Anisotropy and Combined Tension, Torsion and Bending Loads on Fracture Behaviour on Ferritic Nuclear Pipe
,” Report No. NUREG/CR6299—BMI2184 for NRC.
4.
Li
,
Y.
,
Hasegawa
,
K.
,
Hoang
,
P.
, and
Bezensek
,
B.
, 2010, “
Prediction Method for Plastic Collapse of Pipes Subjected to Combined Bending and Torsion Moments
,” ASME PVP2010, Bellevue, WA, Paper No. PVP2010-25101.
5.
Li
,
Y.
,
Hasegawa
,
K.
,
Hoang
,
P.
, and
Bezensek
,
B.
, 2010, “
Effect of Pressure on Plastic Collapse Under the Combined Bending and Torsion Moments for Circumferentially Surface Cracked Pipes
,” ASME PVP2010, Bellevue, WA, Paper No. PVP2010-25102.
6.
ABAQUS Standard, Dassault Systems Simulia Corp., Providence, RI.
7.
Bezensek
,
B.
,
Hasegawa
,
K.
,
Li
,
Y.
, and
Hoang
,
P.
, 2010, “
Proposal for Inclusion of Torsion in Section XI Flaw Evaluation Procedures for Pipes Containing Surface Crack-Like Flaws
,” ASME PVP2010, Bellevue, WA, Paper No. PVP2010-25133.
You do not currently have access to this content.