Finite Element Simulation Research On High Strength Bolt Connection Of Wind Turbine

High-strength bolts are one of the most common parts in steel structures.Due to their high strength,good fatigue resistance,ability to withstand large external loads,and not easy to loosen in harsh working environments,they are compared with ordinary bolts.Has been more widely used in steel structure engineering.Similarly,in wind turbines,high-strength bolts are one of the indispensable components.In order to ensure the normal and safe operation of the entire wind turbine,it can meet the needs of wind power companies.Based on the basic theory of bolt connection,this thesis establishes a wind power generator tower bolt connection model,studies the mechanical properties of bolts,such as stress,displacement and fatigue,and designs pitch connection bolts and simulation analysis.The main research contents are as follows:(1)Briefly describe the connection strength theory between the high-strength bolts and the connected parts in the wind turbine,how to tighten the bolts and how to control the bolt preload,and analyze the applicable conditions and their respective advantages.Shortcomings,which can provide a suitable method for the calculation and installation of wind turbine tower bolts.At the same time,the concept of fatigue strength and its development history are introduced,and the principle of cumulative fatigue damage is compared and analyzed.(2)A simulation calculation model for the flange bolt connection of the wind turbine tower was established,and the high-strength bolts and their connections of the wind turbine under normal load conditions,ultimate load conditions,and equivalent fatigue load conditions were sequentially analyzed.Finite element analysis was carried out on the part.At the same time,the influence of bolt loosening on the stress,displacement and fatigue life of the bolt was considered and research was carried out.(3)Use the German standard VDI2230 engineering algorithm to conduct theoretical analysis on the high-strength bolts at the pitch bearing of the wind turbine.The main contents include the basic parameters of the high-strength bolts,bolt flexibility,minimum clamping force,load factor,and loss of preload.Check the strength of bolts under load,minimum and maximum preload,minimum screw-in depth,preload torque,assembly stress,working stress and alternating stress.The relationship between the bolt stress and the bending moment of the blade root flange is verified by simulation analysis.At the same time,the influence of excessive bending moment at the blade root flange on the bolt is analyzed.Finally,the research content and results of this project are summarized,and the issues to be studied in the next step are prospected to provide references for the flange bolt connection design,installation,and real-time monitoring and remote warning during operation of the wind turbine tower.