| With the continuous increase of the running speed and carrying capacity of high-speed EMU,Chinese rail transit has entered the stage of high-speed development.While the EMU brings us convenience,it is inevitable that there will be many dynamics problems in the service process.In order to make a deep analysis,this paper studies the dynamic performance of high-speed train in service and the evolution law of wheel profile wear by matching different wheel/rail tread from the perspective of wheel/rail nonlinear geometric contact.(1)In order to study the advantages and disadvantages of EMU running state under different wheel-rail tread matching,the wheel-rail contact matching characteristics and wheel-rail contact parameters,such as wheel-rail contact point,equivalent taper parameter,wheel diameter difference and some parameters representing the state of wheel-rail contact area,are described in detail.Meanwhile,based on the comparison of the existing wheel-rail contact geometrical nonlinear parameters,a new wheel-rail contact geometrical nonlinear parameter,the compound equivalent taper,was proposed based on the state parameters of wheel-rail contact region and wheel-rail contact equivalent taper,and was applied to the evaluation of vehicle dynamic performance.(2)The contour projection method was used to solve the wheel-rail contact geometry problems,and the position changes of wheel-rail contact points under four different wheel tread types of LMA,LMB,LMC and LMD matched with CHN60 rail were analyzed.The results show that the wheel-rail contact points are most evenly distributed in LMB.LMC distribution is the most concentrated,easy to form contact band concentration,resulting in reduced service life of wheelset.The shape of wheel tread of CRH3 EMU under different operating mileage was measured,and the geometric evolution law of wheel/rail contact of the worn wheel was analyzed.The results show that with the increase of vehicle mileage,the wheel-rail contact points tend to be concentrated,and the equivalent taper and wheel diameter difference increase.The wheel diameter difference decreases with the increase of wear when the wheelset transverse displacement is large.(3)The UM multi-body dynamics software was used to establish the CRH3 EMU dynamics model.The dynamic characteristics of EMU under different types of wheel tread are studied by using the model.The results show that the derailment coefficient is the most sensitive to wheel tread wear.With the increase of tread wear,the derailment coefficient decreases gradually,and the lateral safety of the vehicle also decreases,while the wheel weight reduction rate and vertical comfort indexes remain basically unchanged. |
PDF Full Text Request