Flexible Riser Local Fatigue Analysis Using Bflex

Atteris performed third party validation of a flexible riser system fatigue life assessment. The individual stress components, in particular the fatigue damage contribution of the contact and friction stress between the flexible pipe layers was assessed as part of the study. This understanding of the stress component contributions allowed optimisation and improvement to the predicted fatigue performance of the system.

Fatigue life is typically calculated as part of the detailed engineering and analysis performed by the flexible pipe vendor. Damage and fatigue life rely heavily on the use of representative SN curves and accurate armour layer stress prediction. Friction stress is usually the dominant component in fatigue conditions, which is highly dependent on contact stress between layers. BFLEX calculates contact stress around the circumference of the pipe as it bends, resulting in accurate friction and stress prediction. Through project work as well as extensive communication and training with BFlex developer SINTEF, Atteris has developed a deep understanding of cross section modelling and stress assessments.