Fine Modeling And Dynamic Response Analysis Of Wind Power Generation Structure Considering Blades

The supply of traditional fossil energy in the world is tight,and environmental problems are prominent.The development and utilization of clean energy,such as wind energy,has attracted more and more attention from all over the world.In recent years,megawatt wind turbines have been widely used.More and more research has been done on wind power generation structure.The first step of wind power structure design and analysis is to establish a reasonable wind turbine model.Wind turbines are composed of coupling components.Their internal structure is complex and their external shape is special.When the static and dynamic analysis of wind turbines is carried out with different fineness finite element models,the accuracy and efficiency of calculation are different.In view of this,in the performance analysis of wind power generation structure,it is more meaningful to select the appropriate finite element model of wind power generation structure for different analysis purposes.Behind the vigorous development of the wind power industry,the damage accidents of wind turbines in various regions also occur from time to time.The reasons behind the accident are analyzed.Part of them is the resonance of the wind power structure during its operation,which causes the damage of the wind turbine.Therefore,the dynamic characteristics of the wind power structure deserve attention.It has been found that dynamic stiffening caused by blade rotation can change its own dynamic characteristics,while the speed range of blade can reach 8r/min-20r/min when wind power structure works.Another factor affecting the dynamic characteristics of wind power generation structure is the interaction between foundation and structure.China has a vast territory,and the construction sites of wind farms vary greatly.Therefore,it is necessary to analyze the influence of soil-structure interaction on the dynamic characteristics of wind power generation structure according to different site types.Another part of the cause of fan failure is that the fan bears large external loads.With the worsening of severe sandstorms in recent years,the damage caused by sandstorms to wind power generation structures occurs from time to time.Sandstorms erode buildings seriously,and their load effect is obviously greater than that under net wind load.Although wind-sand hazards have obvious wind erosion effects on buildings,there is a lack of in-depth study on the dynamic response analysis of wind-sand loads on wind power generation structures and the hazards caused by wind-sand loads.In the past,most of the dynamic response analysis of wind power generation structure only focused on wind load,not sand load.Wind power generation structure has strong sensitivity to wind load.With the increase of sand storm load intensity,the influence of wind-sand coupling effect on wind power generation structure will gradually increase.In view of the problems exposed by the above wind power industry,the main contents of the text research are as follows.Firstly,based on the 2WM three-blade horizontal-axis wind turbine commonly used in wind farms,seven finite element models of wind power generation structures with different fineness are established by using ANSYS,a large-scale generalpurpose finite element software.According to the established wind turbine structure model,the seismic response analysis of wind power generation structure is taken as an example,and the response results of each model are obtained,respectively,from deformation,internal force and response.Four aspects of force and stress concentration in detail are analyzed to calculate the results of each model.The results show that the upper structure has little influence on the deformation of the wind turbine tower,and the lower-order beam element can still get better simulation results.For the section shear force and section bending moment at the bottom of the tower,the results obtained by the finite element model of the whole machine are more accurate,and the higher-order solid element should be used in the selection of the elements;the section of the tower tube obtained without considering the blades,hub and engine room should be considered.The force dispersion is large,and the shell element can simulate the stress of the section of the tower tube better;the upper structure such as the blade engine room has a great influence on the local stress concentration of the portal,and the multi-scale model of the local solid element of the portal of the tower shell element can simulate the stress concentration of the portal well.Secondly,the dynamic characteristics of wind power generation structure are analyzed.Considering the influence of blade rotation rigidization and soil-structure interaction on the dynamic characteristics of wind power generation structure,the dynamic characteristics of wind power generation structure under different blade rotation speed,different site types and different site types are studied,and its frequency variation law is studied.Campbell diagram is used to analyze the resonance characteristics of wind power generation structure under the above conditions.The results show that the increase of blade speed increases the natural frequencies of wind turbines,and the coupling deformation between tower barrel and blade accelerates the frequency growth.Considering the soil-structure interaction,the frequency of wind turbines decreases,and the softer the site soil,the smaller the frequency of wind turbines.When the two conditions work together,the blade rotation only affects the first frequency,and affects the higher frequency.Very little,and the frequency of wind turbines decreases;when the blades rotate,the resonance point of wind turbines does not occur in 1P frequency conversion,and the resonance point of first order frequency in 3P frequency conversion is 14 r/min.In addition,wind turbine generates resonance points in different sites,and the resonance frequencies of three types of soils are farthest from the rated frequency conversion.Finally,the dynamic responses of wind power generation structures under different wind loads and wind sand loads are compared and analyzed.The dynamic responses of wind power generation structures under different wind loads and wind sand loads are analyzed and studied under three conditions,i.e.,wind turbine blades,wind turbine blades rotation and soil-structure interaction.The results show that for three finite element models with different fineness,wind generation under wind-sand loads is considered.