Modal and Vibration Analysis for the Large Wind Turbine Blade

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.