Load Bearing Performance Analysis Of Suspension Spring Of High Speed Train Based On Simulation And Fatigue Test

Compression spring is widely used in the connection and suspension of equipment and devices under high-speed trains.As an important buffer connection part,the structural safety and performance stability have been widely concerned by researchers.It often happens that the spring loses its original function in the long-term use,among which the accumulated fatigue damage and elastic relaxation under the long-term compression and alternating load are the main failure forms,which have a serious impact on the safety and stability of the suspension structure.The driving motor of CRH5 emu in China is elastic suspended under the body by compression spring.The fatigue performance and elastic relaxation characteristics of the spring are closely related to the safety of the train driving device.It is of great significance to analyze the failure characteristics and bearing capacity of the suspension spring for the train operation and maintenance.This paper takes the suspension spring of traction motor of CRH5 EMU as the research object,based on simulation analysis and fatigue test,the stress characteristics of the spring are obtained,the fatigue and elastic relaxation properties of the spring are analyzed.The main research contents are as follows:(1)The spring design parameters were analyzed with reference to relevant design standards.The geometric model of the suspension spring was restored using a 3D scanning and reverse engineering system.Based on the geometric model,a finite element calculation model of the spring was established in ABAQUS;based on the coil spring force theory,the coordinate transformation program was designed.,A method of extracting the stress distribution of the specified section by subroutine extraction and MATLAB calculation is proposed.(2)The finite element simulation and static load test of the spring were carried out,the deformation state and stiffness characteristics of the spring under axial load and lateral load were analyzed;the vibration mode of the spring under the load of the motor was calculated;the force of the spring contact ring and the effective ring was analyzed To extract the calculated stress of the spring,use the coordinate transformation method to analyze the stress level of the maximum force section of the spring working ring and its distribution law and cause analysis along the geometry of the spring,and compare it with the contact stress to determine the maximum force.(3)According to the actual parameters of the train,a rigid-flexible multi-body dynamic model of a single train was established in SIMPACK,the dynamic simulation was carried out under the conditions of the actual railway conditions.The spring load response and the vibration characteristics and load distribution of the traction motor were obtained.Through the time domain and amplitude frequency analysis,the spring load and the motor vibration are analyzed and compared,time domain load obtained by the dynamic calculation is applied to the spring finite element model to realize the transient stress state analysis.(4)The strength of the spring design parameters is checked,the S-N curve of the spring structure is obtained from the material S-N curve through the correction coefficient method,the maximum stress load spectrum of the spring is counted by the rain flow counting method,and the spring fatigue damage is calculated based on the linear cumulative damage criterion.The fatigue test of the spring is carried out,and the results show that the equivalent damage of the fatigue test far exceeds the full-life service damage under the working load of the spring.Introduced the mechanism of elastic relaxation characteristics,analyzed the spring stiffness and deformation stability of the service spring design cycle loading test,and judged the lower limit of spring relaxation through the test results,The suspension parameters of the dynamic model were changed to simulate the drop of the spring stiffness,and its impact on the driving device was analyzed.The calculation results showed that the performance change caused by elastic relaxation did not affect the driving safety and stability.