An experimental investigation of tubular T-joints under cyclic loads

This paper presents an experimental study of fatigue crack initiation and g rowth in tubular T-joints, simulating the extreme case of those used for of fshore platforms. The crack locations and profiles were recorded and fracto graphic examinations were carried out to reveal the mechanisms of crack ini tiation, growth, and crack closure. The relationships between crack length/ depth and the numbers of fatigue cycle were analyzed using the Paris equati on. During testing, the static strain responses at selected gage locations were also recorded. The variations in the static strains caused by the form ation and growth of cracks M-ere correlated with fatigue cycles by a charac teristic equation. These results and correlations are useful for understand ing the fatigue damage process and for monitoring the development of such d amage in tubular T-joints of offshore structures.