Influence Of Bolt Connection Model On Fatigue Analysis And Optimization Of Wide Track Straddle Type Monorail Bogie Frame

Compared with subway,straddle monorail train has the characteristics of strong climbing ability,small turning radius and low cost.As an important part of the train,the research on bogie is very important.Traditional bogies,running wheels side by side,no differential.The tire wear is serious and needs to be changed frequently.In this mode,it is difficult to disassemble and repair the running wheel.Our research team and Qingdao Sifang jointly developed the wide track straddle type monorail bogies.Compared with the traditional straddle type monorail bogies,the advantages of the wide track straddle type monorail bogies are that the length of the stabilizing wheel legs is saved,the distance between the car body and the rail surface is reduced,the running tires are easy to disassemble and assemble,and the maintenance efficiency is high.At the same time,the structural characteristics of wide track straddle type monorail bogies are very different from the existing bogies,which are based on the frame structure of bolt connection.In order to ensure the reliability and safety of wide track straddle type monorail bogies,the fatigue life of wide track straddle type monorail bogies must be well predicted.Therefore,in order to improve the quality of fatigue life analysis of wide track bogie frame,the static strength analysis,modal analysis,fatigue strength analysis and comprehensive comparison of different bolt modeling methods of wide track straddle type monorail bogie frame are carried out,and the fatigue optimization analysis of weld and bolt is also carried out.The main contents and achievements of this paper are as follows(1)Firstly,the basic theory of fatigue life analysis is introduced in detail,which lays a foundation for the analysis and optimization of the fatigue life of the bogie frame and the bolt.(2)The frame structure of wide track straddle type monorail bogies is modeled by finite element method with different bolt modeling methods,and the load cases and boundary conditions are formulated according to relevant standards.The static strength of wide track bogies with different bolt modeling methods is analyzed respectively.The calculation results show that the maximum stress of wide track Bogies with different bolt modeling methods under each working condition is less than 0 The material yield limit,in which the stress value is the largest in the locked rotor condition,and the static strength meets the requirements.The static strength analysis results of wide track bogies with different bolt modeling methods are analyzed and compared.(3)The modal analysis of wide track bogies with different bolt modeling methods is carried out under two working conditions.The analysis results show that the dynamic characteristics of the bogies are reasonable.The first-order constraint modal frequencies of bogies with different bolt modeling methods are far away from the excitation frequency,which avoids the resonance between the bogie frame and the track beam.The modal analysis results of wide track bogies with different bolt modeling methods are analyzed and compared.(4)This paper describes the method of obtaining the measured load spectrum and simulated load spectrum.Considering the experimental conditions and cost,the load time history of guide wheel,running wheel and air spring of wide track straddle type monorail bogie frame is obtained by multi-body dynamics simulation.Then,according to the calculation needs,the fatigue analysis is analyzed and extracted,and the fatigue life is analyzed by using the load spectrum.Based on the basic theory of linear cumulative damage,the bogie frames with different bolt modeling methods are analyzed The results show that the life of wide track bogie frame with different bolt modeling methods can meet the requirements.The fatigue analysis results of wide track bogie frame with different bolt modeling methods are analyzed and compared.(5)The weakest weld position of fatigue strength of wide track bogie frame is redefined by different weld structure,and the influence of different weld structure on weld fatigue life analysis of wide track bogie frame is studied,which provides reference value for practical engineering.(6)Aiming at the bolt fatigue optimization of wide track bogie frame,two methods of bolt manufacturing process and bolt preload are studied respectively to optimize the bolt fatigue.The method of bolt manufacturing process is shot peening to introduce residual compressive stress on the surface of components,so as to improve the fatigue life of bolts.The optimal preload range is obtained by hyperstudy calculation,and the corresponding bolt fatigue life under the preload is calculated.At the same time,the corresponding bolt fatigue life under different preloads is calculated to verify the rationality of the preload.