Study On Fatigue Life Assessment Of Five-module 100% Low Floor Tram Body

Compared with other urban rail transit,100% low floor tram has the advantages of low floor height,convenient for passengers to get on and off and no need to set up platform.Many rolling stock factories in China have developed low floor trams.However,due to the late start and lack of relevant industry standards,the research on fatigue life assessment method for low floor tram has certain engineering application value.The research object of this paper is an articulated 100% low floor tra m body.Based on reasonable assumptions,according to the stress characteristics of the body structure,the load of body interface is calculated by the method of module separation,and compared with the load which is calculated by the finite element method of the whole vehicle.This paper compared the current strength standards of railway vehicles from static strength load and fatigue strength load,analyzed the characteristics of each standard,and gave some suggestions on formulating the standards for low floor trams.Based on the absolute maximum principal stress criterion and projection criterion,the fatigue life of the weld and base metal of the car body is evaluated by fatigue limit method and cumulative damage method respectively.The relative relationship between the results of different evaluation methods is analyzed and the causes are explored.The results show that: for low floor trams,the modular separation method can greatly improve the speed of calculation feedback on the premise of guaranteeing the accuracy of calculation,which is conducive to the pre-design verification of car body structure;When formulating the strength standard for low floor trams,the static strength condition is recommended to consider the influence of wind load on the basis of EN 12663 and JIS E 7106 standard,and the fatigue condition is recommended to consider the torsional load of 40 kN·m on the basis of EN 12663 and VDV 152 standard;The fatigue limit method based on absolute maximum principal stress criterion is the most conservative evaluation method,while the cumulative damage method based on projection criterion is a relatively dangerous evaluation method.