Comparisons of finite element J and KJ estimation scheme predictions for a surface cracked pipe under bending or tension

Book · Sun Dec 01 04:00:00 EST 1996

OSTI ID:403209

Gilles, P; Bois, C

In order to check the accuracy of the J crack driving force estimation schemes for large surface cracks in pipes, fully detailed Finite Element computations were conducted and the results were compared to those predicted by two different estimations schemes. The first scheme considered is the GE-EPRI approach, the other is the 1995 version of the KJ approach developed by Framatome for surface cracks in pipes and elbows under combined loadings. The objective of the paper is to compare the J values with the predictions and to discuss the observed differences. The interest of the present study is twofold: few comparisons have been made for large surface cracks in pipes and for a stress-strain law which differs from a Ramberg-Osgood law. The KJ scheme for circumferentially cracked pipes under combined loading is presented. Then this scheme is applied to the considered case. The comparison is limited to the deepest point but details are given for checking the applicability of the KJ scheme to the entire front. The main advantage of the new KJ estimation scheme is to propose a closed formula valid for any type of circumferential crack: penetrating of not, shallow or deep, short or large, even off-centered. The limitations of the scheme are identified and some suggestions are given for its improvement.

• OSTI ID: 403209
• Report Number(s): CONF-960706--; ISBN 0-7918-1770-9
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CALCULATION METHODS
COMPARATIVE EVALUATIONS
CRACKS
FINITE ELEMENT METHOD
FRACTURE MECHANICS
PIPES
STRESS ANALYSIS
SYSTEM FAILURE ANALYSIS
THEORETICAL DATA