Study On Structural Dynamic Of Large Turbine Blade Of Sma Composite

The main form of wind energy is the wind power generation. The blade is the essential part in the wind turbine system.The structure and the intensity of the blade play a decisive role to the reliability of the wind turbine generator. Because of the superiority that the common metallic blade can not compare with, the composite blade becomes more and more popular in the wind turbine system. In this paper, the structural dynamics issues about the blade of SMA composite materials are studied.First of all, the main mechanic behavior of the SMA and the constitutive relational model is introduced in this paper, which describes its mechanic behavior.The curve on which the constrained recovery stress of the SMA and the content of the Martensite change with the temperature, are also given. On the basis of the free vibration equation of the composite wind turbine blades which is developed using the beam theory about the coupling of the bending and torsion, the natural vibration characteristics of the blade of composite sandwich material, which is made of the NiTi/graphite/epoxy resin are investigated. The vibration equation of the composite rotating blade is formulated according to the Lagrange equation. The lower-order natural vibration analysis model is also established, which couples the bending and torsion, in the generalized coordinates is also derived by the method of Galerkin. The numerical results show the effect of the composite ply sequences, the ply angle, SMA content, temperature and the rotational angular velocity on the natural frequency and vibration mode of the composite wind turbine blades.According to the classic section structural model and quasi steady flow aerodynamic model, the blade aeroelastic stable method is presented. And the eigenvalues under different wind speed are calculated, when the wind turbine blade rotates. The results are also compared with the results by Runge-Kutta method blade aeroelastic stability, agreement between results is verified.Finally, the natural vibration characteristics of composite wind turbine blade are it simulated by the ANSYS finite element analysis software.