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Indexed by:Journal Papers

Date of Publication:2020-09-15

Journal:OCEAN ENGINEERING

Included Journals:SCIE

Volume:212

ISSN No.:0029-8018

Key Words:Tubular K-Joints; Structure stress; Multiaxial fatigue; Stress gradient; Experiment

Abstract:Tubular K-joints, frequently employed in offshore structures, are subjected to multiaxial stresses. It is difficult to accurately assess fatigue strength of tubular K-joints using the uniaxial fatigue theory. In this paper, a multiaxial fatigue life prediction method for tubular K-joints is proposed, which is based on an improved Zero Point Structure Stress (ZPSS) approach that accounts for the stress gradient in the thickness direction to quantify the structure stress at the weld toe of a tubular K-joint. The multiaxial fatigue life is predicted making use of the Modified Wohler Curve Method (MWCM) as the multiaxial damage criterion. It is found that the multiaxial fatigue estimation using the proposed method predicts the fatigue critical point well. Meanwhile, the estimated multiaxial fatigue lives are much closer to experimental lives, in comparison with the uniaxial fatigue estimation using the CIDECT specification.