Fatigue Life And Reliability Evaluation Of Chute On The Floor Of High-Speed Train Underframe

The rapidly developing Chinese high-speed train technology has become a bright card of China on the international stage.With the development of high-speed train,people put forward more and more demands on the train body structure.Although the lightweight of the vehicle body can reduce the weight of the vehicle body,it may also lead to the decrease of the strength,stiffness and fatigue performance of the vehicle body.Generally speaking,the static strength will be checked at the design stage of the vehicle body,and the vehicle body may suffer fatigue damage due to the action of cyclic vibration load in the process of operation.Therefore,the e valuation of fatigue life and fatigue reliability of key parts of the vehicle body is particularly important.The research object of this paper is Aluminum alloy floor chute of high-speed train underframe.By the experiment of fatigue limit of structure,the P-S-N curve of the floor chute structure is fitted out,combined with the fatigue cumulative damage theory to evaluate the floor chute hanging structure fatigue life.The reliability of the floor chute suspension system is evaluated based on the load multiple action model and the order statistics principle.The main research work of this paper includes:(1)Pro/E software was used to establish a 3D model of underfram floor and floor chute specimens for static analysis.By comparing the stress and stress distribution of underfram floor and floor chute specimens under the same load,the strength conversion relationship between floor chute specimens and floor chute specimens was determined.(2)Design the up-and-down fatigue test scheme of floor chute,and complete the fatigue strength test.The fatigue limit of floor chute was calculated by pairing method and Dixonmude method.(3)Fitting the probability density function of random load distribution according to the whole-process measured load data,compiling the eight-stage load spectrum,using the linear fatigue cumulative damage theory,predicting the fatigue life of the floor chute suspension structure,and evaluating its fatigue durability.(4)Considering the influence of strength gradually degenerating with the increase of loading times,the reliability model of floor chute with a single hanging point is established;Based on the theory of order statistics,the reliability model of floor chute system with single equipment and multiple hanging points is established.Finally,according to the reliability model of the tandem system,the reliability model of the floor chute system is established.