Validation of a finite element procedure for obtaining stress intensity factors in doubly curved cracks in tubular joints

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:205414

Bowness, D; Lee, M M.K. ^[1]

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1. Univ. of Wales Swansea (United Kingdom). Dept. of Civil Engineering

Fatigue tests on tubular joints have shown that as a crack propagates through the chord wall, it curves under the weld toe. This produces, at the brace-chord intersection, a doubly curved semi-elliptical crack emanating from the weld toe. A doubly curved crack in a tubular joint is a very complex geometry which has proved to be difficult to model. In consequence, previous work on the evaluation of stress intensity factors in tubular joints adopted a simplified approach, ignoring the crack curvature under the weld toe. However, in the absence of benchmark solutions, the effect of any modelling approximation on accuracy is impossible to quantify. To address this problem and as part of the research on fatigue assessment methodologies, a technique which is able to accurately model doubly curved cracks in tubular T-joints has been developed at University of Wales, Swansea. This paper first summarizes the modelling sequence of the 3-D procedure and the way by which the stress intensities are evaluated. These are then followed by a full description of the validation of the numerical model which demonstrates its accuracy and reliability. The result of this work is a fully validated model having a doubly curved weld toe crack with a refined weld toe and crack tip mesh that has not been achieved in previous research.

• OSTI ID: 205414
• Report Number(s): CONF-950695--; ISBN 0-7918-1309-6
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CRACK PROPAGATION
FATIGUE
FRACTURE MECHANICS
MATERIALS TESTING
MATHEMATICAL MODELS
OFFSHORE PLATFORMS
STRESS INTENSITY FACTORS
WELDED JOINTS