REDUCING CONSERVATISM IN THE VIV DESIGN OF STEEL CATENARY RISERS -A TIME DOMAIN APPROACH TO THE PREDICTION OF MODAL RESPONSE FOR THE VIV DESIGN OF DEEPWATER SCRS

摘要

Vortex induced vibration (VIV) assessment forms a critical part of the fatigue design of arnsteel catenary riser (SCR). The most widely used design approach to determining thernVIV response of an SCR is to combine modal frequencies, mode shapes and modalrncurvatures derived from finite element modal analysis software with semi-empiricalrnmethods of modal superposition to determine the fatigue effects of current-induced VIV.rnAs an alternative to the frequency domain modal analysis technique, while still remainingrnwithin the framework of a widely accepted approach to VIV analysis, this paperrnconsiders alternative time domain techniques as a means to avoiding unnecessaryrnconservatism associated with the frequency domain approach. Each of these twornmethods is evaluated and conclusions drawn on the relative merits of the time domainrnapproach.