Feasibility of Very Large Floating Structure as Offshore Wind Foundation: Effects of Hinge Numbers on Wave Loads and Induced Responses

Floating offshore wind is a rapidly growing technology that is attracting global interest. To date, most of the demonstrated concepts for offshore floating wind are based on a simple one turbine–one platform system, which might not be the most efficient approach for manufacturing, transportation, and onsite installation. Very large floating structures (VLFS), which allow for operation of multiple turbines, might be an effective alternative to traditional floating foundations. However, the large bending moment caused by waves is a major concern for a VLFS foundation. Adding hinges into the structure might help to alleviate the bending moment. Based on the discrete-module-beam-bending hydroelasticity method, the effects of hinge numbers on the bending moment will be investigated in detail and will be presented in this paper. Overall, the bending moment is reduced when the vertical displacement is increased by the addition of hinges, which indicates a compromise when choosing hinge numbers. In addition, a feasibility study for the application of the multihinged VLFS as a floating wind platform will be provided. It demonstrates that the existence of wind turbines might further reduce the wave-induced bending moment, but they enlarge the total bending moment by introducing a still water bending moment. The effect of wind turbines on the vertical displacement of the multihinged VLFS is insignificant.