In this study, a simplified empirical model for fatigue analysis of top-tensioned risers due to vortex-induced vibration (VIV) in a nonuniform current is presented. Compared with previous studies on this subject, this model is able to take into account the main intrinsic nature of VIV for low mass ratio structures in lock-in regions, added mass, and nonlinear fluid damping. Based on the simplified model, a closed-form solution of fatigue damage is suggested for the case of a riser with uniform mass and cross-section oscillating in a uniform flow. Fatigue damage characteristics of the top-tensioned risers due to VIV are investigated to determine the effects of various ocean conditions and riser dimensions on fatigue damage.
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Recommended Practice DNV-RP-C203, 2005, “
Fatigue Design of Offshore Steel Structures
,” DNV.Copyright © 2011
by American Society of Mechanical Engineers
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