風機葉片為複合材料結構，主要為兩片強硬的外層，搭配加強肋結構結合而成。本研究以鋁合金作為3kW小型風機葉片之材料，以有限單元軟體分析風機空心葉片幾何外型，並加入一肋與三肋結構，另外改變葉片遠端翼型與近端翼型的面積比例，以Whiffle-tree方法來模擬風力負載施於風機葉片上，探討在不同之遠端與近端翼型面積比例之下，加強肋數目對於應力與最大位移之影響。結果顯示，使最大von Mises應力下降，增加加強肋數目之效果比增加遠端與近端翼型面積比例顯著；使最大y方向位移下降，增加遠端與近端翼型面積比例比增加加強肋數目顯著。
另外針對大型NREL 5MW葉片進行單向流固耦合分析，模擬風速於NREL葉片之風壓分布，並進行碳纖維布/環氧樹脂相關材料常數試驗，探討改變支撐結構與材料常數對於NREL葉片之應力與位移之影響。結果顯示，NREL葉片於攻角-90°時所承受之應力及位移量為最大，於攻角0°時所承受之應力及位移量為最小；使用箱型樑支撐結構可有效提升NREL葉片結構之剛性；碳纖維布/環氧樹脂與玻璃纖維/乙烯樹脂兩者材料在應力與位移分析結果相差不大，但碳纖維布/環氧樹脂密度低，可大幅減少葉片重量。

Wind blades are composite structure, which is mainly composed of two tough outer facesheets and with reinforcing spar structure in it. In this study, wind blades without spar, with one or three spars were analyzed using the finite element code ANSYS. The material of two facesheets and the reinforcing spar of 3kW wind blade are assumed to be aluminum alloy. The ratio of far and near airfoil was varied. The Whiffle-tree loading was adopted to simulate the wind load on the blade. The stress distribution and maximum deflection of the 3kW wind blade were evaluated. The results show that to reduce the maximum von Mises stress on the 3kW wind blade, increasing the number of reinforcing spar is better than increasing the ratio of far and near airfoil. In addition, to reduce the maximum deflection in the vertical direction, increasing the ratio of far and near airfoil is better than increasing the number of reinforcing spar.
For the large-scale wind blade, the One-way FSI was used to calculate the pressure distribution on the NREL 5MW wind blade. The carbon fiber sheet/epoxy experiment was conducted for the material constants. The stress distribution and maximum deflection of the 5MW wind blade were evaluated under different structural support and material constants conditions. The results show that the NREL wind blade has the maxium stress and deflection at the attack angle of -90°, while the NREL wind blade has the minium stress and deflection at the attack angle of 0°, and the rigidity of NREL wind blade is enhanced by spar-cap. The results in both stress and deflection analysis are similar in Carbon fiber sheet/epoxy and glass fiber/vinyl epoxy, while the Carbon fiber sheet/epoxy has the lower density, which can significantly reduce the weight of the NREL blade.

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