A comprehensive study of failure assessment diagrams for circumferentially surface-cracked austenitic stainless and ferritic steel pipes was conducted with the use of the finite element method (FEM). While the majority of the analyses were conducted using the line-spring/shell finite element method, some three-dimensional finite element analyses, conducted independently, are also reported in this paper. Comparison of the predictions of the line-spring/shell and three-dimensional analyses reinforce the validity of the former approach for surface-cracked pipes. The results indicated that the ASME Code Case N-494-2 applicable for ferritic steel piping appears reasonably conservative even for pipes with mean radius-to-wall thickness ratios of 20, whereas the results showed that the newly adopted Code Case N-494-3 for austenitic stainless steel piping requires a limit for pipe with mean radius-to-wall thickness ratios larger than 15. For consistency, the limitation of Rm/t ≤ 15 was incorporated in the approved final version of Code Case N-494-3, and was incorporated in Code Case N-494-2 as well. Because these Code cases are applicable only to Class 1 primary nuclear piping, which typically has values of Rm/t ≤ 15, this is not a significant limitation. It was also shown that the choice of definitions of membrane and bending stresses as well as the choice of F1 function values in calculating the elastic part of the J integral have a profound effect on the resulting FAD curves.

1.
ABAQUS, 1995, User Manual, Ver. 5.4, Hibbitt, Karlsson, and Sorenson, Pawtucket, RI.
2.
Ainsworth, R. A., “The Assessment of Defects in Structures of Strain Hardening Material,” Engineering Fracture Mechanics, Vol. 19, 1984.
3.
Akhurst, K. N., and Milne, I., 1983, “Failure Assessment Diagram and J Estimates: Validation for an Austenitic Steel,” International Journal of Pressure Vessel and Piping, Vol. 13.
4.
Bloom, J., and Malik, S. N., 1982, “A Procedure for the Assessment of Integrity of Structures Containing Defects,” EPRI Topical Report NP-2431.
5.
Bloom, J., 1983, “Validation of a Deformation Plasticity Failure Assessment Diagram Approach to Flaw Evaluation,” Elastic-Plastic Fracture: Second Symposium, Vol. II, ASTM STP 803.
6.
Bloom
J.
,
1995
, “
Deformation Plasticity Failure Assessment Diagram (DPFAD) for Materials with Non-Ramberg Osgood Stress-Strain Curves
,”
ASME JOURNAL OF PRESSURE VESSEL TECHNOLOGY
, Vol.
117
, pp.
346
356
.
7.
Krishnaswamy, P., Scott, P. M., Mohan, R., Rahman, S., Choi, Y. H., Brust, F. W., Kilinski, T., Francini, R., Ghadiali, N., Marschall, C., and Wilkowski, G., 1995, “Fracture Behavior of Short Circumferentially Surface-Cracked Pipe,” NUREG/CR-6298, U.S. Nuclear Regulatory Commission, Washington, DC.
8.
Kumar, V., German, M. D., and Shih, C. F., 1981, “An Engineering Approach for Elastic-Plastic Fracture Analysis,” EPRI Topical Report NP-1931, Electric Power Research Institute, Palo Alto, CA.
9.
Harrison, R. P., Loosemore, K., Milne, I., and Dowling, A. R., 1976, “Assessment of the Integrity of Structures Containing Defects,” CEGB Report No. R/H/6.
10.
Milne, I., Ainsworth, R. A., Dowling, A. R., and Stewart, A. T., 1987, “Assessment of the Integrity of Structures Containing Defects,” CEGB Report No. R/H/R6-Rev. 2 (validation).
11.
Mohan
R.
, “
Application of Line-Spring/Shell Model to Surface-Cracked Pipes and Elbows
,” Fatigue and Fracture, ed., K. K. Yoon, Vol. II,
ASME PVP
-Vol.
324
, pp.
46
65
,
1996
.
12.
Wilkowski, G., Ahmad, J., Barnes, C. R., Brust, F., Ghadiali, N., Guerrieri, D., Kramer, G., Landow, M., Marschall, C., Nakagaki, M., Olson, R., Papaspyropoulos, V., Rosenfeld, M., and Scott, P., 1988, “Degraded Piping Program—Phase II,” NUREG/CR-4082, Vol. 6, U.S. Nuclear Regulatory Commission, Washington, DC.
13.
Zahoor, A., 1990, Ductile Fracture Handbook, Vol. 2, EPRI Project 1757-69.
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