The Design And Static Mechanical Propertie's Anlysis Of Prestressed Wind Turbine Tower

In order to improve the structural strength and stiffness,make full use of the material performance,and reduce the manufacturing cost of the tower in high-power wind power system,prestressed technology is introduced to the design of wind turbine tower structure.The two different types of prestressed wind turbine tower structure are designed,and the tower's mechanical properties is analyzed by experimental test and finite element analysis.The main research contents show as follows:Axial prestressed structure of wind turbine tower is designed to improve the axial stability by the coordination of the separator and the steel wire.Under different design conditions,the mechanical properties of axial prestressed tower is tested when it bears horizontal load.What's more,the tower which is variable thickness and approximate equal strength is designed.According to the structure type of hyperbolic paraboloid guyed tower and based on the traditional guyed tower,a new type of cable tower which is similar to prestressed spatial structure is designed.The influence of different parameters on the mechanical properties of the new tower is obtained by the finite element analysis.Research results show as follows:Due to the constraint of the separator,when each segment's stiffness of the axial prestressed wind turbine tower is relatively small,the stress in the middle of each segment increases significantly.With the increasing of the stiffness,the stress' s increment of middle section is weakened and the stress of tower is also gradually reduced.The type of variable thickness tower upon the foundation of axial prestresses tower is designed and its mechanical properties is simultaneously tested.Experimental results show that the mechanical properties of each segment is consistent with the regularities of distribution in equal thickness condition.Compared with ordinary single cylinder tower,the steel consumption of the new tower decreased sharply under the condition of same capacity.Compared with the traditional cable type wind turbine tower,the new type of cable tower has bigger structural stiffness,lower stress and displacement under the same load.The tower's structural stress and displacement decrease with the decreasing of the rope tow angle and fluctuate from decreasing to increasing with the increment of cable prestress.The optimal prestress should be the minimum value which could make the stiffness of each direction stability in the main tower.With the stronger structural stiffness of the new type cable tower,the second moment effect is obviously weakened.Meanwhile,the tower has better control effect on the stress and displacement when the mass load acts on the top of tower.With the increasing of tow layers and space coupling point,the tower's stress and displacement reduce further.The tower's bending deformation and structural stress of the upper part increase obviously with the increasing of cable prestress.The dangerous section of structure moves up from the upper cable joint of main tower to the supporting rod of top beam.The stability of the new cable tower improved greatly.The structure which is mainly suffered unstable failure can reduce the radius of the bottom rope and save area covered under the same bearing capacity.