| The dual-mode vehicles can not only synthetically utilize the efficiency of rail transport and the flexibility of road transport,but also achieve the "door to door"multimodal transport to reduce the overall cost.Especially in the field of special transportation,with the rapid development of railway network and road network in recent years,the study of dual-mode conversion equipment has a wide market space and value of engineering application.Under the project "The Structure Design of Swing Arm Type Bogie",the paper,which is based on the existing six-axle road vehicle,mainly researches the basic braking device suitable for this bogie,and puts forward the general design scheme of the unit disc brake device,then carries out the brake distance calculation and the disc shaft interference fit strength analysis.Further,according to the structural characteristics and working condition of the brake disc,the boundary conditions of the temperature field by the finite element method are determined,and the thermal structure coupling calculation and fatigue strength evaluation of the brake disc are carried out.At the same time,considering the heat shrinkage effect due to the heat flow in the contact surface,use the analytical method to determine the contact thermal conductivity between the axle and brake disc interference fit surface.This new estimation method simplifies the establishment of the interference contact thermal conductivity model.Therefore,the paper is focused as followed:(1)The basic brake rigging was designed based on the general design scheme of the swing arm bogie,and uses SolidWorks to establish the 3D model.Especially in the selection of brake cylinder and the design of brake pad,brake pad bracket,brake lever and brake disc,these were described in detail.(2)The emergency braking for this brake device was calculated by using cumulative method to determine the braking ratio,braking time,braking distance and other parameters were.And calculating the interference fit between the brake disc and axle by the finite element method,the contact pressure and interference in the assembly process were obtained,which can provide the calculation data for the thermal boundary conditions of the brake disc.(3)Established a reasonable three-dimensional cyclic analysis model,then to calculate the heat flux on disc friction surface,convective heat transfer coefficient of each interface and radiative convective heat transfer coefficient according to the basic principle of thermodynamics.Moreover,according to the contact pressure of the interference fit analysis,considering the heat shrinkage effect of heat flux in the contact thin channel,then to estimate the contact heat conduction coefficient between the contact surface by using analytic method.(4)The brake disc' s transient temperature field was simulated by finite element analysis software ANSYS during emergency braking and after braking,and the stress analysis of brake disc was carried out by using sequentially thermal-structural coupling analysis with the node temperature being loaded on the brake disc under the pre-stress of the interference fit.Then curves of von Mises stress and time on several large stress regions were mainly discussed.The results show that the static strength of the brake disc meets the design requirements.(5)The fatigue strength was determined in six cases of the static strength transient analysis result by referencing the UIC ORE B12/RP17 test report.The maximum principal stress and direction,the minimum principal stress,the stress amplitude and mean stress were calculated by MATLAB,then the brake disc fatigue performance was evaluated in Goodman-Smith diagram. |
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