Hydrodynamic response for flexible connectors of mobile offshore base at rough sea states

Abstract

Mobile offshore base (MOB) was treated as a research object, and a simplified algorithm was developed for determining the dynamic constraint forces on flexible connectors of MOB at rough sea states. The algorithm was adopted to calculate and analyze the fluctuation laws between dynamic constraint forces and different parameters. The wave loads on MOB structures were evaluated based on the revised Morison equation instead of potential flow theory, and the conventional computational methods were simplified. The numerical results of the simplified algorithm were compared to those of the algorithm based on potential flow theory for validating the correctness and reasonability of the simplified algorithm. The simplified algorithm was used to estimate the dynamic constraint forces on flexible connectors of MOB under different sea states, wave incident directions, and connector stiffness values. The results show as the wave angle increases, the dynamic constraint force decreases in the x direction, while increases first and then decreases in the y and z directions; the dynamic constraint force increases as the sea state increases, and shows a trend of linear increasing with the connector stiffness increasing; the dynamic forces on different connectors are well even in the same conditions. Key words: mobile offshore base (MOB), semi-submersible platform, flexible connector, dynamic constraint force, rough sea state