This paper presents an experimental study of fatigue crack initiation and growth in tubular T-joints, simulating the extreme case of those used for offshore platforms. The crack locations and profiles were recorded and fractographic examinations were carried out to reveal the mechanisms of crack initiation, growth, and crack closure. The relationships between crack length/depth and the numbers of fatigue cycle were analyzed using the Paris equation. During testing, the static strain responses at selected gage locations were also recorded. The variations in the static strains caused by the formation and growth of cracks were correlated with fatigue cycles by a characteristic equation. These results and correlations are useful for understanding the fatigue damage process and for monitoring the development of such damage in tubular T-joints of offshore structures.

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