ABSTRACT
Fatigue cracking is currently one of the main causes of damage to offshore jacket structures in the North Sea. As these cracks are found during in-service inspection programmes, the operator of the installation must decide whether to repair, monitor and/or assess the significance of the defect. Since the fatigue design of tubular joints is based on the stress-endurance approach, which cannot be applied to existing defects, the most common course of action is repair. However, these repairs are not always necessary since the remaining life of the joint may be significant. This paper outlines the use of the fracture mechanics approach which allows the remaining life of cracked tubular joints to be calculated. Fatigue crack growth calculations were carried out using this approach on a Veritec Y-joint and the results were found to compare well with experimental measurements.
