High Wind Turbine Tower Multi-objective Structure Optimization Study

Wind turbines have a trend to be large-scale, tower is higher and higher, the tower top load is becoming heavier and heavier, the stability and strength of the tower has faced a growing threat and higher requirement. This paper build a two-level wind tower optimization model, get the tower optimized parameters and effect of the parameters on the stability and strength of tower. Then discussed the linear buckling, nonlinear buckling and engineering calculation of optimized tower model, Verify the optimization effect, provided a method for subsequent optimization of the tower. At last, Discuss the effect of different shear modulus of soil under different earthquake conditions on the dynamic response of tower, also provide a method to calculate the dynamic response under earthquake and give a guidance for tower optimization design.The main research work is as follows:(1) Established a two stage tower optimization model, for the first stage optimization, considering the roundness and eccentric connection defects though reliability analysis, and then calculate the model with the genetic algorithm(NSGA- Ⅱ) which based on the mechanism of elite and non-dominated sorting. In the second stage optimization, carry out the tower door optimization with the first stage optimization parameter and the effect of tower door parameter on stress concentration.(2) Linear buckling, nonlinear buckling and buckling engineering calculation are compared, got the tower wall thickness optimization and tower door optimization on the ability of tower flexing resistance, the complementary function of nonlinear buckling calculated with the finite element method(FEM) on the tower design and buckling of engineering calculation.(3) Study the tower top displacement and acceleration at the top, Von mises stress and shear stress, it is concluded that seismic conditions have much influence on the dynamic response of the tower, so earthquake conditions should be considered in the tower optimization and design. By applying different equivalent stiffness and damping on the tower, got the relationship between the soil shear modulus and dynamic response of the tower, put forward different earthquake conditions, the different interaction of the stiffness and damping between tower base and soil should be taken into consideration in the dynamic response analysis.