Numerical Evaluation of Fatigue Damage of the Deepwater Riser Induced by VIV Using Pseudo-excitation Method

摘要

The fatigue damage of a long flexible riser undergoing vortex-inducedvibration (VIV) in deepwater is numerically studied using pseudoexcitationmethod (PEM) in present paper. For evaluating the fluidstructureinteraction problem of vortex-induced vibration of bluffbodies at high Reynolds number, the strip theory approach is taken intoconsideration, and the discrete vortex method (DVM) is used tocalculate the vortex-induced vibration of each strip to obtain the loadspectrum for the calculation of pseudo-excitation, while the finitevolume method (FVM) is employed for evaluating the structuredynamics of a long flexible riser. The DVM model is validated by itscomparison with the experimental results. The vortex-induced vibrationis considered as a stationary random process. The response of riser tovortex induced excitation is calculated using pseudo-excitation method(PEM). The fatigue damage rate of the riser per year is evaluated andthe service life of the riser can be predicted based on the Palmgren-Miner Rule.