Evaluation of stress intensity factor solutions for offshore tubular joints
- Billington Osborne-Moss Engineering Limited, Maidenhead (United Kingdom)
Stress intensity factor (SIF) solutions for weld toe defects in offshore tubular joints are key input parameters in both fatigue and fracture assessments. This paper provides a review and comparisons of available Mk and SIF equations which may be applied in the assessment of weld toe defects in tubular joints. The comparisons, covering surface semi-elliptical weld toe cracks of various depths and of an aspect ratio (a/c) equal to 0.2, include evaluation of Mk estimates associated with a typical weld geometry and SIF estimates for saddle chordside cracks in a range of axially loaded T joints. The study indicates that the most reliable SIF equations for the cracks and T joints considered are those of Rhee et al for a/T {ge} 0.2, and the plate-based SIF equations of Newman and Raju in conjunction with appropriate Mk solutions for a/T < 0.2. In addition, the present study indicates that accounting for load shedding using the moment release model results in underestimating the SIF for the cases considered, in comparison with solutions based on 3D FE data, by approximately 16% for a/T = 0.5 and by up to 30% for a/T = 0.8. However, consideration of load shedding is necessary if the excessive conservatism associated with plate-based SIF solutions is to be avoided. The concept behind the moment release model is sound and simple but, the model requires further validation and calibration.
- OSTI ID:
- 403646
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1492-0
- Country of Publication:
- United States
- Language:
- English
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