DEVELOPMENT OF 12MW CROSS-SHAPED SEMI-SUBMERSIBLE FLOATING OFFSHORE WIND TURBINE

We are developing cross-shaped semi-submersible floating structure composed of simple and lean stiffened plate structure. In this paper, we introduce the features and development studies of our 12MW semi-submersible floating offshore wind turbine. First, we introduce the main features of it. Second, we introduce the tank test of it, the purpose of which is verifying the behavior under the condition only wave load is applied. As a result of tank test, we verified motion response which is calculated by numerical calculation tool based on potential theory is well reasonable. Third, we introduce the initial structural analysis, the purpose of it is to decide initial scantling. Finally, we introduce the coupled analysis of our 12MW semi-submersible floating offshore wind turbine. Concerning the model of coupled analysis, we verified it from the several points of view. We verified the motion response of it under the condition that only wave load is applied. Compared to the result of numerical calculation and tank test, we confirmed motion response of coupled analysis model is valid. We also confirmed the natural frequency of the whole structure and the displacement due to both rigid motion and elastic deformation are reasonable compared to the result of FEM analysis. Then, we performed the coupled analysis under the condition that both wave load and wind load are applied considering the effect of turbine's operation.