Analysis Of Fatigue Performance Of Pantograph In Urban Rail Transit

With the rapid development of urban rail transit in China,the pantograph-catenary system has been widely used,which has greatly solved the problem of urban traffic congestion.At the same time,with the increase of train load and the mileage,the failure of the pantograph in the design life,such as flaw,cracks and so on,has led to the increase of train maintenance costs,and seriously affected the safety of train operation.So,to analyze the causes of crack in pantograph,research the fatigue property of pantograph and guarantee the stability of pantograph operation has great significance to the safe and efficient operation of urban rail transit train.In this paper,the widely used pantograph at the present stage of urban rail transit in China is the research object,through theoretical analysis,finite element calculation and pantograph stress test,the fatigue performance of pantograph is studied.First of all,the influence factors of dangerous parts’ stress of the pantograph is analyzed based on the geometric relationship of pantograph and its load.Secondly,surface characteristics,temperature and corrosion medium of pantograph is analyzed by using the fatigue theory to find out the influence brought to the fatigue life of pantograph.Thirdly,on the basis of theoretical analysis,the static analysis of pantograph under different working conditions is carried out by using ANSYS software,and the stress distribution and the location of the maximum stress of the pantograph under different working conditions are obtained,the modal analysis is used to determine the pantograph parts which is greatly influenced by the excitation frequency.Finally,the stress of the pantograph is tested by the pantograph experiment platform,based on the test results,the influence of the contact force between the pantograph and catenary,the vibration frequency and the height of the pantograph on the stress of the pantograph are analyzed,and the influence of the fatigue performance is analyzed.Through theoretical analysis,the greater of the load,the thinner of the component and the longer of the pantograph,the greater the stress of the pantograph’s dangerous part and the shorter the fatigue life;By using ANSYS software,the simulation results shows that the stress of the pantograph’s dangerous part is increased with the increase of the contact force,and decreases with the increase of the working height,and the modal analysis shows that the vibration amplitude of the pantograph frame and the pantograph bow is larger under the natural frequency;Through the static stress test of pantograph,it is verified that the stress on the pantograph frame has approximately linear with the working height,and decreases with the increase the working height;The dynamic test results shows that the stress of each component of the pantograph shows different trends in different excitation frequency range.When the excitation frequency is 1-8Hz,the stress of each component of the pantograph shows the same trend,but there is a big difference between the stress vibration amplitude of each component;when the excitation frequency is 8-20Hz,different components’ stress will present different change.When the excitation frequency is 12-13Hz or 17-20Hz,the vibration amplitude of the upper arm junction will be strengthened again,the lower arm junction still been relatively stable.Finally,the relationship between the fatigue life and the excitation frequency is derived from the test results.