Correlation of fracture behavior in high pressure pipelines with axial flaws using constraint designed test specimens. Part II: 3-D effects on constraint

Author(s)

Silva‚ L.A.L. ; Cravero‚ S. ; Ruggieri‚ C.

• Document type: Journal article
• Source: ENGINEERING FRACTURE MECHANICS; v. 73, n. 15, p. 2123-2138, 2006.

Abstract

This study describes an extensive set of 3-D analyses conducted on conventional fracture specimens, including pin-loaded and clamped SE(T) specimens, and axially cracked pipes with varying crack configurations. The primary objective is to examine 3-D effects on the correlation of fracture behavior for the analyzed crack configurations using the J-Q methodology. An average measure of constraint over the crack front, as given by an average hydrostatic parameter, denoted Q(avg), is employed to replace the plane-strain measure of constraint, Q. Alternatively, a local measure of constraint evaluated at the mid-thickness region of the specimen, denoted Q(Z0), is also utilized. The analysis matrix considers 3-D numerical solutions for models of SE(T) fracture specimens with varying geometries (i.e., different crack depth to specimen width ratio, a/W, as well as different loading point distance, H) and test conditions (pin-loaded ends vs. clamped ends). The 3-D numerical models for the cracked pipes cover different crack depth to pipe wall thickness ratio, a/t, and a fixed crack depth to crack length ratio, a/c. The extensive 3-D numerical analyses presented here provide a representative set of solutions which provide further support for using constraint-designed SE(T) specimens in fracture assessments of pressurized pipes and cylindrical vessels. (c) 2006 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 03/02735-6 - Micromechanics and experimental methodology for defect and strutuctural integrity assessments of gas and oil transmission pipelines
• Grantee: Claudio Ruggieri
• Support Opportunities: Research Projects - Thematic Grants