Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture, in cases where there is a large degree of stable-tearing crack extension during the fracture process. This type of steady-state fracture resistance takes place when the CTOA in a material reaches a critical value, as typically occurs in low-constraint configurations. Our current research has applied the CTOA concept as an alternative or an addition to the Charpy V-notch and the drop weight tear test (DWTT) fracture energy in pipeline characterization. A test technique for direct measurement of CTOA was developed, using a modified double cantilever beam (MDCB) specimen. A digital camera and image analysis software are used to record the progression of the crack tip and to estimate CTOA using the crack edges adjacent to the crack tip. A steady-state CTOA has been successfully measured on five different strength grades of gas pipeline steel (four low strength grades and one high strength grade: X100). In addition, two-dimensional finite element models (2D FEMs) are used to demonstrate the sequence of the fracture process and the deformation mechanisms involved. The CTOA measurements and models are correlated and agree well.
Skip Nav Destination
2006 International Pipeline Conference
September 25–29, 2006
Calgary, Alberta, Canada
Conference Sponsors:
- Pipeline Division
ISBN:
0-7918-4263-0
PROCEEDINGS PAPER
Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels Available to Purchase
Ph. P. Darcis,
Ph. P. Darcis
NIST, Materials Reliability Division, Gaithersburg, MD
Search for other works by this author on:
G. Kohn,
G. Kohn
NIST, Materials Reliability Division, Boulder, CO
Search for other works by this author on:
A. Bussiba,
A. Bussiba
NIST, Materials Reliability Division, Boulder, CO
Search for other works by this author on:
J. D. McColskey,
J. D. McColskey
NIST, Materials Reliability Division, Boulder, CO
Search for other works by this author on:
C. N. McCowan,
C. N. McCowan
NIST, Materials Reliability Division, Boulder, CO
Search for other works by this author on:
R. Fields,
R. Fields
NIST, Metallurgy Division, Gaithersburg, MD
Search for other works by this author on:
J. Merritt
J. Merritt
DOT/PHMSA, Washington, DC
Search for other works by this author on:
Ph. P. Darcis
NIST, Materials Reliability Division, Gaithersburg, MD
G. Kohn
NIST, Materials Reliability Division, Boulder, CO
A. Bussiba
NIST, Materials Reliability Division, Boulder, CO
J. D. McColskey
NIST, Materials Reliability Division, Boulder, CO
C. N. McCowan
NIST, Materials Reliability Division, Boulder, CO
R. Fields
NIST, Metallurgy Division, Gaithersburg, MD
R. Smith
DOT/PHMSA, Washington, DC
J. Merritt
DOT/PHMSA, Washington, DC
Paper No:
IPC2006-10172, pp. 159-168; 10 pages
Published Online:
October 2, 2008
Citation
Darcis, PP, Kohn, G, Bussiba, A, McColskey, JD, McCowan, CN, Fields, R, Smith, R, & Merritt, J. "Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels." Proceedings of the 2006 International Pipeline Conference. Volume 3: Materials and Joining; Pipeline Automation and Measurement; Risk and Reliability, Parts A and B. Calgary, Alberta, Canada. September 25–29, 2006. pp. 159-168. ASME. https://doi.org/10.1115/IPC2006-10172
Download citation file:
17
Views
Related Articles
Interaction of Hydrogen Transport and Material Elastoplasticity in Pipeline Steels
J. Pressure Vessel Technol (August,2009)
Steady-State Crack Propagation in Pressurized Pipelines
J. Pressure Vessel Technol (February,1977)
Failure of Locally Buckled Pipelines
J. Pressure Vessel Technol (May,2007)
Related Chapters
Applications for Operation
Pipeline System Automation and Control
A 3D Cohesive Modelling Approach for Hydrogen Embrittlement in Welded Joints of X70 Pipeline Steel
International Hydrogen Conference (IHC 2012): Hydrogen-Materials Interactions
DEVELOPMENTS IN STRAIN-BASED FRACTURE ASSESSMENTS - A PERSPECTIVE
Pipeline Integrity Management Under Geohazard Conditions (PIMG)