由於台灣位於太平洋颱風多發地區，離岸風機場址設計條件應包含颱風事件之考量。本研究針對套管式離岸風機於極端環境條件下進行極限負載分析以及支撐結構最佳化設計。為探究離岸場址之環境特性，本研究選用新竹浮標測站與外埔潮位測站之實測資料作為初步分析之依據，並分別參考IEC 61400-3與GL Tropical Cyclone Technical Note規範之要求決定出外部條件與設計負載組合。氣動力負載計算方面，分別採用美國國家再生能源實驗室(NREL)所開發之Turbsim與FAST v8軟體來模擬隨機紊流風場以及分析NREL 5-MW離岸參考風機之動力反應。水動力負載則採用Morison’s equation來計算波浪與海流於支撐結構之作用力，其中流體粒子速度與加速度依據Stream function wave theory與Second-order kinematics model計算求得。經由有限元素分析後，討論規範中各設計負載組合之極限負載結果與各支撐桿件之受力情形，並依據API RP 2A-LRFD鋼結構設計規範進行支撐結構最佳化設計，計算出支撐結構所需之總用鋼量，可作為工程造價估算之參考。電腦輔助分析程式由 朱聖浩教授研究團隊所開發，分析程式與研究成果皆為公開資源。

Since there is high risk of typhoons for structural damage in Taiwan, the offshore site design conditions shall include the occurrence of typhoons. The objective of this thesis was to carry out ultimate load analysis and optimum design of a jacket-type support structure of an offshore wind turbine under extreme environmental conditions. To study the environmental characteristics of the offshore wind turbine site, we chose the environmental data measured at Hsinchu buoy station and Waipu tide station as the basis of preliminary analysis. The external conditions and the design load cases to be considered in this study were based on the requirements of IEC 61400-3 or GL Tropical Cyclone Technical Note. In the calculation of aerodynamic loads, TurbSim and FAST v8 software provided by National Renewable Energy Laboratory (NREL) were used to simulate stochastic inflow turbulence and to analyze the dynamic response of the NREL 5-MW offshore wind turbine, respectively. For hydrodynamic loads, the Morison’s equation was used to calculate the wave and current induced loads on the support structure, where fluid particle velocity and acceleration were obtained by using the stream function wave theory and the second-order kinematics model. After the finite element analysis, the results of the ultimate loads acting on the support structure for each design load case were discussed. Finally, we conducted the optimum design of the jacket-type support structure for evaluating total design steel weights by using the API RP 2A-LRFD standard, and the results may be used as the basis of construction cost estimation. Note that the computer programs developed by the research team of Shen-Haw Ju are open and free to use.

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