大型风力机叶片模态性能及振动分析

Modal and Vibration Analysis for the Large Wind Turbine Blade

为研究大型风力机叶片铺层参数对叶片动态性能的影响、防止叶片发生共振、减小叶片挠度、改善叶片结构力学性能和提高风力机安全性，建立了5MW风力机叶片的有限元模型，通过改变铺层材料和铺层角度实现不同的叶片结构，并对成型叶片进行了模态分析；采用CFD方法获得叶片表面载荷，分析不同风速下不同铺层结构叶片振动性能，结果表明：复合材料铺层角度能影响叶片固有频率，叶片低阶振型以挥舞和摆振为主，高阶模态出现扭转；增加0°铺层纤维比例可提高低阶固有频率，45°铺层能提高叶片抗扭能力；叶片振动位移沿叶片展向呈非线性增长，风速越大叶片挠度越大；碳纤维可有效提高叶片固有频率，减小叶片挠度。

In order to study the effect of blade parameters on the dynamic performance of large wind tur- bine blades, the finite element model of 5 MW wind turbine blade was established to prevent the reso- nance of the blade, reduce the deflection of the blade and improve the mechanical properties of the blade structure. The blade structure was realized by changing the laying material and the laying angle, and the corresponding modal analysis was carried out. The surface load of the blade was obtained by CFD method, and the vibration performance of different layer structure blades under different wind speed was analyzed. Result showed that the angle of the composite material can affect the natural frequency of the blade. The low-order vibration mode of the blade is mainly waving and vibrating, while the high-order mode is twis- ting. Increasing the ratio of 0° fiber can improve the low order natural frequency,and 45° laying can im- prove the blade torsion resistance. The blade vibration displacement increases nonlinearly along the blade orientation ,and the blade deflection increases with the wind speed. Carbon fiber can effectively improve the natural frequency of blade and reduce blade deflection.