Finite Element Modeling And Analysis Of Static And Dynamic Characteristics Of Wind Turbine Tower

Wind energy as one of the new and renewable resources has shown well perspective of exploitation and utilization at present. Wind power is the main way of wind energy utilization. However, wind turbine generator system can be damaged by the complicated work environment, various loads and vibration caused by shear wind and puffs of wind. So it is of great important to analysis the static and dynamic characteristic of wind turbine tower.In this thesis, mechanical models of cylinder tower with variable cross-section were built based on structural character and mechanics character of a large-scale wind turbine tower. Based on the structural dynamics theory, the formations of the horizontal displacement of the top of tower, basic frequencies formula and the critical force of the tower which are taken mutually by the gravity of the wind wheel, cabin and tower are deduced. Specific parameters influence on the stability of whole machine was discussed. And the effect of load on the fatigue properties was studied Static and dynamic simulation analysis for the tower was investigated by FEM and using ANSYS software. Some main contents and conclusions are concluded as follows:1. The result of FEM is close to theoretical calculation result which verifies the accuracy of the finite element model. The opening which located at the bottom of the tower and the change of weight in each component located at the top of the tower caused by the blade angle have an impact on static strength. Therefore, in the process of mechanics analysis and design calculations the actual situation should be taken into account.2. Vibration characteristics and response of the tower are analyzed. Through the numerical simulation of several different models, the result shows that the foundation stiffness of head mass and stiffness had a greater influence on the natural frequency of the tower. The response of the tower at different frequencies and the deformation and stress of the structure corresponding to the peak frequency can be obtained through dynamic response analysis. The displacement, velocity and acceleration at different times are also calculated, which provide the foundation for optimization design of wind power.3. Buckling of the tower is analyzed. Using ANSYS software and solid element simulation of the flange in the tower junction, the results can reach a high accuracy; it can be applied to the application of general engineering which is more securer than the engineering calculations. For the opening tower, buckling may occur near the doorway. Thin cylindrical shell is imperfection sensitive structures, the impact of opening on the buckling should be considered. By adding structure of frame, the buckling strength of the tower will be increased.4. Fatigue analysis of the tower is analyzed. The coefficients of the fatigue life of the tower can be obtained; and the situation of the wind turbine tower life is tested and the fatigue strength of the tower are checked.