| The subject comes from the project"3-8MW wind turbine gearbox flexible pin shaft deformation test bench".The flexible pin shaft is the key support and load sharing component in the wind turbine gearbox planetary gear transmission.Because the working performance of the flexible pin shaft is difficult to be measured and evaluated comprehensively,a wind turbine gearbox flexible pin shaft deformation test bench is designed to accurately test the working Performance of the flexible pin shaft.The test bench is a high-power loading equipment.As an important connecting part of the test bench,high-strength bolts play an important role in the working performance and safety performance of the test bench.In this paper,the high strength bolt of the test bench is taken as the research object.In view of the connection strength and fatigue life of high-strength bolt under the extreme load condition,the traditional bolt connection analysis method can not effectively analyze the connection opening and fatigue.In this paper,the static equivalent decomposition of bending shear load of bolt group is carried out,the engineering calculation of bolt is carried out by VDI2230 standard,establishing a finite element model of the high-strength bolt connection of the test bench,study the working performance of the bolt,and the influence of the preload and thrust load on the work performance of the test bench and the bolt,and conduct fatigue life and influencing factors of the bolt Analysis to improve the safety performance and service life of the test bench.The main research contents of the paper are as follows:(1)Considering the bending and shear load state of the high-strength bolt group,the static analysis of the bending and shear load of the bolt group is carried out.This paper analyzes the stress of bolt group under the condition of preload and limit load,decomposes the thrust load into equivalent thrust load and equivalent overturning moment according to the principle of equal force system to obtain the minimum preload and working tension of the bolt,The initial preload of the bolt is obtained according to the strength calculation method of the thread connection in the mechanical design.(2)According to the static analysis results of the high-strength bolt group of the test bench under bending and shear loading,a single bolt model of the dangerous position is established,and the engineering calculation and analysis of the dangerous position bolts are carried out based on the VDI2230 standard process.The results show that the preload of the bolts ensures that the connection will not separate and slide,and the bolts have high fatigue safety and life,which provides a theoretical basis for finite element simulation analysis.(3)The finite element model of the high-strength bolt connection of the test bench was established,and the simulation analysis of the test bench under 950KN preload and extreme load conditions,as well as the analysis of the influence of the preload and thrust load parameters on the work performance of the test bench and high-strength bolts.The results show that the 950KN preload meets the performance requirements of the test bench under extreme load conditions;the preload force has little effect on the displacement and deformation of the test bench.Excessive preload force will increase the bolt stress concentration;the thrust load is proportional to the displacement change of the test-bed,and has little influence on the stress concentration of the bolt.(4)Based on the finite element analysis results of the test bench,the fatigue life and influencing factors of the bolts were analyzed using the fatigue analysis software FE-SAFE.The results show that the life of bolts under 950KN preload and limit load conditions meets the design goal of 10~6times;compared with the thrust load,the fatigue life of bolts is more sensitive to the preload.when the bolt preload is 950KN,it can ensure that connection strength and fatigue life of bolts meet the design requirements. |
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