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PRCI Report 212
- Characterization of Axial Flaws in Pipelines, with a Focus on Stress Corrosion Cracking
- Report / Survey by Pipeline Research Council International, 12/01/1997
- Publisher: PRCI
$248.00$495.00
L51807e
Battelle Memorial Institute
(e-book version) Need: At present, analysis to predict crack growth or to serve as failure criteria do not consider the effect of short, deep cracks or deep, banded arrays of cracks. However, such crack geometries have great practical significance because they are found near or along leak and rupture planes.
Benefit: This report presents the results of a series of projects that involved: (1) characterizing the behavior of crack colonies associated with stress-corrosion cracking (SCC); (2) developing failure criteria to provide safety without undue conservatism; and (3) developing criteria to characterize crack coalescence prior to SCC leaks. Analytical details are given for the various types of axial cracks, with a focus on short, deep cracks, patches of SCC cracks often found in field-digs, and deep, co-parallel cracks. All analyses were done in a fracture mechanics framework for use in developing criteria to ensure safety and assess the serviceability of natural gas transmission pipelines.
Result: Because this report discusses failure criteria to ensure safety and serviceability for cracks in SCC colonies, colonies are characterized in terms of what has been observed before pursuing analyses to characterize it. What has been observed is presented first. Key analysis results follow, along with some necessary definitions. Then, results characterizing interaction and coalescence are presented in terms of results for crack pairs. Finally, the viability of pairs solutions are discussed in light of results for crack arrays introduced to reflect the scope of cracking seen in SCC colonies. These data are then used to assess the validity of the criteria for failure and coalescence.
Battelle Memorial Institute
(e-book version) Need: At present, analysis to predict crack growth or to serve as failure criteria do not consider the effect of short, deep cracks or deep, banded arrays of cracks. However, such crack geometries have great practical significance because they are found near or along leak and rupture planes.
Benefit: This report presents the results of a series of projects that involved: (1) characterizing the behavior of crack colonies associated with stress-corrosion cracking (SCC); (2) developing failure criteria to provide safety without undue conservatism; and (3) developing criteria to characterize crack coalescence prior to SCC leaks. Analytical details are given for the various types of axial cracks, with a focus on short, deep cracks, patches of SCC cracks often found in field-digs, and deep, co-parallel cracks. All analyses were done in a fracture mechanics framework for use in developing criteria to ensure safety and assess the serviceability of natural gas transmission pipelines.
Result: Because this report discusses failure criteria to ensure safety and serviceability for cracks in SCC colonies, colonies are characterized in terms of what has been observed before pursuing analyses to characterize it. What has been observed is presented first. Key analysis results follow, along with some necessary definitions. Then, results characterizing interaction and coalescence are presented in terms of results for crack pairs. Finally, the viability of pairs solutions are discussed in light of results for crack arrays introduced to reflect the scope of cracking seen in SCC colonies. These data are then used to assess the validity of the criteria for failure and coalescence.