Application of Constraint Corrected J-R Curves to Fracture Analysis of Pipelines

[+] Author and Article Information
Xian-Kui Zhu

 Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201zhux@battelle.org

Brian N. Leis

 Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201

J. Pressure Vessel Technol 128(4), 581-589 (Dec 06, 2005) (9 pages) doi:10.1115/1.2349571 History: Received July 26, 2005; Revised December 06, 2005

Fracture properties of an API X80 pipeline steel have been developed using a set of single edge notched bend (SENB) and single edge notched tension (SENT) specimens with shallow and deep cracks to generate different crack-tip constraint levels. The test data show that the J-R curves for the X80 pipeline steel are strongly constraint dependent. To facilitate transfer of the experimental J-R curves to those for actual cracked components, like flawed pipeline, constraint corrected J-R curves are developed. The two-parameter J-A2 formulation is adopted to quantify constraint effect on the crack-tip fields and the J-R curves. The constraint parameter A2 is extracted by matching the J-A2 solution with finite element results for a specific crack configuration. A constraint corrected J-R curve is then formulated as a function of the constraint parameter A2 and crack extension Δa. A general method and procedure to transfer the experimentalJ-R curves from laboratory to actual cracked components are proposed. Using the test data of J-R curves for the SENB specimens, a mathematical expression representing a family of the J-R curves is constructed for the X80. It is shown that the predicted J-R curves developed in this paper agree well with experimental data for both SENB and SENT specimens. To demonstrate its application in assessing flaw instability, a pipeline with an axial surface crack is considered. For a crack depth of 50% of the wall thickness, the predicted J-R curve is found to be higher than that for the SENB specimen with the same crack length to width ratio. From this predicted J-R curve and crack driving force obtained by finite element analysis, the failure pressures of the pipeline at the crack initiation and instability are determined and discussed.

Copyright © 2006 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 8

Comparison of predicted and experimental J-R curves for SENB specimens

Grahic Jump Location
Figure 9

Comparison of predicted and experimental J-R curves for SENT specimens

Grahic Jump Location
Figure 10

Finite element mesh for 762×23mm2 pipe with an axial surface crack of a∕t=0.5

Grahic Jump Location
Figure 11

Distribution of the opening stress determined from the FEA and J-A2 solution along the distance from the crack tip

Grahic Jump Location
Figure 12

Predicted J-R curve for X80 pipe with a surface crack and compared with those for SENB specimens

Grahic Jump Location
Figure 13

Variation of J integral with internal pressure for the cracked pipe

Grahic Jump Location
Figure 1

True stress-strain curve of X80 pipeline steel

Grahic Jump Location
Figure 2

Experimental J-R curves for SENB specimens

Grahic Jump Location
Figure 3

Experimental J-R curves for SENT specimens

Grahic Jump Location
Figure 4

Typical finite element mesh for test specimens

Grahic Jump Location
Figure 5

Distribution of opening stress σθθ along the distance from the crack tip. Symbols are FEA results, lines are asymptotic solutions. (a)a∕W=0.24, (b)a∕W=0.42.

Grahic Jump Location
Figure 6

Variation of A2 with J for SENB specimens by (a) the J-A2 solution and (b) the modified J-A2 solution

Grahic Jump Location
Figure 7

Variations of J0.2mm and J1.0mm with constraint parameter A2 for SENB specimens




Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In