Damage Tolerance Evaluation of Cracked Tubular Joints Subjected to Fatigue Loading

Abstract:

This paper presents methodologies for damage tolerance evaluation of tubular T- and Y-joints by using linear elastic fracture mechanics (LEFM) principles. The damage tolerance evaluation is in terms of crack growth analysis and remaining life prediction of tubular joints. Stress intensity factor (SIF) for T-butt plates which can be used for computation of SIF for tubular joints has been evaluated as per BS: 7910. It is observed from the literature that the expressions given in BS: 7910 for computation of SIF have not been used for remaining life prediction of tubular joints. In this paper, these expressions have been used for analytical prediction of remaining life of tubular T- and Y- joints subjected to constant amplitude loading (CAL) and variable amplitude loading (VAL). Wheeler residual stress model has been employed to represent the retardation effects due to tensile overloads. It is observed that remaining life predicted for T- and Y-joints under CAL are found to be in good agreement with those of experimental values reported in the literature. In the case of VAL, it is observed that crack growth retardation increases with increase of OLR resulting in higher predicted remaining life. It has also been observed that the predicted remaining life is influenced by the number of OLs and occurrence of OL. Early occurrence of OL causes the higher remaining life compared to later OLs.

• Periodical: Key Engineering Materials (Volumes 452-453)
• Pages: 653-656
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.452-453.653
• Online since: November 2010
• Authors: A. Rama Chandra Murthy, G.S. Palani, Nagesh R. Iyer
• Keywords: Constant Amplitude Loading, Damage Tolerant Design, Offshore Structures, Remaining Life, Stress Intensity Factor (SIF), Tubular Joints, Variable Amplitude Loading

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