Assessment of VIV fatigue of subsea template jumper by using a time domain model

Book chapter, 2021

This paper addresses the application of a time domain model for Vortex-Induced Vibration (VIV) to assess the fatigue damage of subsea jumpers. The time domain model, capable of accounting for structural non-linearity and time-varying flow, was applied on a typical ’M’-shaped jumper model. Obtained results were compared against VIV motion data from experiments in the literature. Fatigue estimates were also compared to the DNVGL response model approach. Two models were investigated, with and without elbow elements in the bends. The reduced stiffness of the model including elbow elements improved the results of modal analysis and caused a shift in the mode shape order. VIV motion results were in good correlation with model test data. With several exceptions, the fatigue damage calculated using the DNVGL response model procedure was higher than obtained from the time domain model, as no mode competition is applied on non-straight pipes. For several load cases torsion stress was the largest stress component.