Study On Wind-induced Vibration And Response Design Of Wind Turbine Tower

Since the 21 st century,with the increasing greenhouse effect and global energy stress,All countries begin focusing on promoting clean energy development.Following the new situation in the world,China’s wind power industry is developing rapidly which installed capacity has become the largest one in the world.The scale of wind power in China will be further expanded to achieve "carbon peak" and "carbon neutralization".In recent years,extreme weather occurs frequently,which make a huge challenges to the wind power industry.As the basis of electric energy conversion,ensuring wind power tower’s safe and stable operation is of great significance to the development of wind power industry.Wind power tower is a typical thin-walled high-rise structure,and the stroke load is the most serious in the natural environment.The wind in nature is a non-stationary random process,which means both wind speed and direction change with time.Thus,actual wind vibration response of wind power tower is complex.This paper takes a built cone-table wind power tower as the research object,carries on the equivalent static analysis to study its failure mode and discusses the most unfavorable working conditions.Wind load time history is obtained by simulating wind speed time history,and wind vibration response in natural environment of wind power tower is studied.According to the failure mode,a wind resistant design method is proposed to improve the wind load carrying capacity of wind power tower.The specific research work of this paper is as follows:（1）ANSYS software is used for finite element analysis of wind power tower,and the most adverse working condition is judged by applying load.The failure mode of wind turbine tower was studied from three aspects of strength,deflection and stability by combining theoretical calculation and simulation results,and the accuracy of the model is verified.The analysis results show that the wind blowing vertically from the direct rear to the wind power tower is the most unfavorable working condition,and the failure mode of the wind power tower is plastic instability,and the failure position is near the junction of the second and third towers of the tower.（2）Time history analysis of wind vibration response of wind power tower is developed.Firstly,the modal analysis of wind turbine tower is carried out and its dynamic characteristics are given.Based on Davenport wind speed spectrum and linear filtering method,the instantaneous wind speed time history was simulated considering the spatial correlation coefficient,and the wind speed time history was converted into wind load time history.The wind vibration response of wind power tower was analyzed,and the tower failure process was observed through nonlinear analysis.The study shows that due to the influence of fluctuating wind,dynamic analysis of maximum stress and displacement of the top of the tower should be greater than the results of static analysis,and with the increase of wind speed,wind vibration response are increasingly noticeable,wind power tower under wind load local yield failure happen first,material mechanical properties change,plastic strain under wind load has the plastic instability increases until the tower collapsed.（3）Aiming at the failure mode of wind power tower,two wind resistance design methods of external supported steel pipe rod and internal stiffener and external supporting steel pipe rod are put forward,and the feasibility is judged preliminarily.Quantum particle swarm optimization（QPSO）and Workbench were used to optimize the design methods respectively,and the wind resistance effect of the two methods was evaluated.The results show that both of the two wind resistance designs can improve the wind resistance of wind power generation,and the higher the wind speed,the more obvious the wind resistance effect.Besides,the wind resistance design scheme with internal stiffeners and external steel pipe rods is better for improving the bearing capacity of the tower tube.Under 30m/s wind speed,the maximum stress of wind resistance design supported by external steel pipe bar is decreases by 19.27%,and the maximum horizontal displacement of tower top is decreases by 35.04%.In addition,the combined wind resistance design reduces the maximum stress by 33.03% and the maximum horizontal displacement by 46.11%.In summary,the combination of internal and external wind resistance design can ensure the safety and stability of the wind power tower structure under the wind speed of 50m/s.