A prediction model of the deepwater steel catenary riser VIV is proposed based on the forced oscillation test data,taking into account the riser-seafloor interaction for the cross-flow VIV-induced fatigue damage at touch-down point(TDP).The model will give more reasonable simulation of SCR response near TDP than the previous pinned truncation model.In the present model,the hysteretic riser-soil interaction model is simplified as the linear spring and damper to simulate the seafloor,and the damping is obtained according to the dissipative power during one periodic riser-soil interaction.In order to validate the model,the comparison with the field measurement and the results predicted by Shear7 program of a full-scale steel catenary riser is carried out.The main induced modes,mode frequencies and response amplitude are in a good agreement.Furthermore,the parametric studies are carried out to broaden the understanding of the fatigue damage sensitivity to the upper end in-plane offset and seabed characteristics.In addition,the fatigue stress comparison at TDP between the truncation riser model and the present full riser model shows that the existence of touch-down zones is very important for the fatigue damage assessment of steel catenary riser at TDP.
