Strength Analysis And Optimization Design Of Corbel Structure For Maglev Vehicle Suspending Bracket

In high-speed maglev transportation system,there is no mechanical contact between the track and the car body structure and the traction force is not restricted by the wheel-rail adhesion,as a result,it has the characteristics of higher economic running speed.High-speed maglev transportation can fill the speed gap between high-speed railway and air transportation and it is a research hotspot in the current new type of rail traffic domain.With the application speed of the existing high-speed maglev vehicle is concentrated at the speed level of 400-500 km/h,there is no high-speed maglev vehicle structure design standard and higher speed grade design data for reference,so it is necessary to carry on the research on the adaptability of the existing high-speed maglev vehicle at the speed of 600 km/h.Based on the analysis of load characteristics and force transmission path of suspension frame corbel structure of high speed maglev vehicle,the application load of suspension frame corbel structure of high speed maglev vehicle at speed level of 600 km/h is determined in this paper.Based on General principles of structural finite element analysis for mechanical products and the nonlinear finite element theory of bolt connection,the finite element modeling method of suspension frame corbel structure and bolt of high-speed maglev vehicle is studied,and the refined finite element model of the corbel structure is created adopting this method.In reference to EN-13749-2011 Railway ApplicationsMethods of Specifying Structural Requirements of Bogie Frames standard,UIC615-4-2003 Motive power units-bogie and running gear-Bogie frame structure strength tests standard and high-speed train and maglev vehicle existing research results,and using the high-speed Maglev vehicle dynamic simulation platform established by the research team,the main calculation load of the suspension frame corbel structure of high speed maglev vehicle at speed level of 600 km/h is extracted,and 5 main calculation working conditions are decided.Results of the strength analysis on corbel structure indicate that:Main components of the corbel structure(the main beam and longitudinal traction beam,bolts,upper and lower longitudinal beam between corbel)can satisfy the requirements of structural strength design under all load cases.Without considering the problem of excessive local stress at the loading position,the corbel can meet the operating requirements of structural strength under the load cases of the working condition No.3 and No.5.Under load case of working condition No.2,there is a local weak spot that exceeds the allowable stress value in the arc transition plate at the position of the lower longitudinal beam,and the weak position requires structural optimization.According to operating requirements of the high-speed maglev vehicle suspension frame corbel,based on free shape optimization method and sub-model technique,the weak position of the corbel is optimized using Opti-Struct.The optimized bracket structure is remodeled and analyzed by simulation,whose calculation results indicate that the maximum Von Mises stress on weak position of the corbel decreased from 227.384 MPa to 198.038 MPa,and safety coefficient improved from 1.03 to 1.19 after optimization,which satisfies the requirements of structural strength design.According to the high-speed maglev vehicle suspension frame lightweight design requirements,this paper chooses upper longitudinal beam which has strength allowance under the load case of working condition No.2 for topology optimization.Based on unit density optimization method and sub-model technique,reduction of material design is conducted on the longitudinal beam using Opti-Struct,and the weight is reduced by 9.01% on the basis of the original structure.Intensity check indicates that the maximum Von Mises stress at the optimized longitudinal beam is 160.79 MPa,and safety coefficient is 1.46,which satisfies the requirements of structure strength design.In conclusion,the structure optimization scheme is feasible for high-speed maglev vehicle suspension frame structure under requirements of structural strength design and lightweight design.The research results of this paper has great engineering value that it can be reference for the design of the suspension frame corbel structure of the engineering high-speed maglev vehicle at speed level of 600 km/h.The finite element modeling method,contact nonlinear finite element simulation technique and structural optimization method used in this paper are of certain academic value because they are applicable to the simulation analysis and optimization design of similar structures.