en Offshore Hydrodynamic مقاله پژوهشي Research Paper <span lang="EN" style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">This study presents a systematic investigation into the influence of geometric parameters and structural characteristics on the dynamic response of a semi-submersible platform supporting a floating wind turbine, with an emphasis on identifying stable performance regimes rather than determining a single optimal configuration. The analyses initiated with preliminary linear evaluations and were subsequently complemented by nonlinear time-domain simulations. A comparison of these approaches demonstrates that while the linear model is useful for identifying general response trends, it fails to fully capture oscillation amplitudes or the coupling intensity among degrees of freedom, particularly under hydrodynamic nonlinearities and mooring system effects. Consequently, a realistic assessment of system behavior necessitates nonlinear analysis. The investigation focused primarily on surge, heave, and pitch motions, as sway, roll, and yaw contributed minimally to the global response. Results indicate that the vertical and rotational motions of the platform are governed not only by the heave plate geometry but also by its interaction with the offset column arrangement. Variations in heave plate diameter and thickness, in conjunction with the geometric configuration of the offset columns, alter the dynamic response by modifying the added mass, hydrodynamic damping, and the relative positions of the centers of gravity and buoyancy. Within the examined range, heave plate diameters of 24&ndash;30 m and thicknesses equivalent to 7&ndash;10.5% of the offset column height produced more stable responses without shifting natural frequencies toward resonance. Specifically, a diameter of approximately 28.5 m and a thickness of around 8% yielded balanced surge, heave, and pitch responses. However, comparable performance across adjacent configurations suggests a robust design envelope rather than a single unique optimum. Overall, the findings highlight the utility of evaluating geometric parameters within an integrated framework to elucidate the relationships between platform geometry, hydrodynamic coefficients, and the coupled dynamic response.</span></span><div style="text-align: justify;"></div> Floating offshore wind Turbines,Coupled Dynamics,Hull Form Effects,Time-Domain Solution Method,Response Amplitude Operation 1 19 http://ijmt.ir/browse.php?a_code=A-10-246-1&slc_lang=en&sid=1 Mohammad Javad Eslahi mj.eslahi@srbiau.ac.ir 10031947532846004544 10031947532846004544 No Department of Civil Engineering, SRBIAU saeid kazemi Saeid.kazemi@srbiau.ac.ir 10031947532846004545 10031947532846004545 Yes Department of Civil Engineering, SRBIAU Mojtaba Ezam ezam@srbiau.ac.ir 10031947532846004546 10031947532846004546 No Department of Physics Oceanography, SRBIAU madjid ghodsi hassanabad m.ghodsi@srbiau.ac.ir 10031947532846004547 10031947532846004547 No Department of Mechanical Engineering, SRBIAU