Finite Element Stress Analysis of Composite Wind Blade Structure

• Main Authors: Cheng, You Cheng, 鄭有成
• Other Authors: Yeh, Meng Kao
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/73941104538403396693

碩士 === 國立清華大學 === 動力機械工程學系 === 103 === 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.