Dynamic Coupling Analysis of Semisubmersible Platform Float-over Method for Docking Case

In this paper, the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated. First, coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed. Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory. The results of the hydrodynamic analysis were highly consistent with the test findings, verifying the accuracy of the multifloating hydrodynamic coupling analysis, and key hydrodynamic parameters were solved for different water depths and the coupling effect. According to the obtained results, the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered. Furthermore, the coupled motion equation combined with viscous damping, fender system, and mooring system was established, and the hydrodynamics, floating body motion, and dynamic response of the fender system were analyzed. Motion analysis revealed good agreement among the surge, sway, and yaw motions of the two floating bodies. However, when the wave period reached 10 s, the motion of the two floating bodies showed severe shock, and a relative motion was also observed. Therefore, excessive constraints should be added between the two floating bodies during construction to ensure construction safety. The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°, 45°, and 90° were in good agreement, and the error was less than 5