Study On The Influence Of The Wheel Profile On Metro Vehicle Dynamics And Wear

With the rapid development of economy and the accelerating urbanization, metro, as a convenient, fast and environmentally friendly transport, plays an important role in improving efficiency of urban trips, reducing traffic congestion and other aspects. Compared with the big railway vehicles, operating speed of metro vehicle is lower, metrolines are underground, operation lines are fixed and the radius of curves is relatively smaller. These features of metro vehicle lead to its special wheel-rail relationship. In addition, several lines have already been built for 120km/h metro in urban rail transit system, the increase of speed will not only affect the smoothness of operation and its safety, but also affect the wear between wheel and rail. Therefore, the study of the influence of wheel profile on dynamics performence and wear of the metro vehicle at different speeds is significant, and it also provides a theoretical basis and technical support for the selection and maintenance of metro wheel profiles and curve lines design.This paper describes the development history of domestie metro vehicle and types of the metro vehicle in China, provides a brief description of the status of wheel-rail wear research at home and abroad. Based on the theory of multi-body system dynamics and simulation software SIMPACK, the dynamic model of metro vehicle is created by adopting the methods of basic assumptions and linear relationship treatments. We tried to simulate the 80km/h metro vehicles and the 120km/h metro vehicles respectively with LM wheel profiles and DIN5573 wheel profiles in the same condition, and gave the comparative analysis of the stability of their operation at different speeds, smoothness, curve negotiation and other dynamic performance. From the view point of geometrical realitionship of the wheel-rail contact, in this paper we compared the rolling radius difference, angular difference of the wheel-rail contact, equivalent taper of wheel set between LM wheel profiles and DIN5573 wheel profiles, and introduced the calculation model of the wheel-rail wear. Moreover, according to Heumann abrasion index and Elkins abrasion index, we have given the comparative analysis of the influence of different wheel profiles on wheel-rail wear passing straight and curve lines. In addition, we did a study of influence of technical parameters of curve lines,such as radius, superelevation and transition curve length, on dynamics performance and wear of metro vehicles, and gave simple calculation and analysis of curve lines parameters of 120km/h metro vehicle.The calculation results of the vehicle running performance show that the stability, smoothness, curve negotiation and other index of the 80km/h metro vehicle and the 120km/h metro vehicle respectively with LM wheel profiles and DIN5573 wheel profiles basicly meet requirements. Under the same condition, LM worn profile has a better curve passing performance, DIN5573 worn profile has better riding stability on the straight lines. From the view point of wear, just based on worn profiles and wear between lines, DIN5573 worn profile has less wheel-rail wear than LM worn profile on straight lines; however, wheel flange and wheel-rail contact will be taken into consideration on curve lines, LM worn profile has a better wear performance. Reasonably setting the technical parameters of curve lines can in different degrees improve the dynmics performance and reduce wear, such as increase the curve radius, set certain superelevation and increase transition curve length.The impact of different profiles on dynamics performane of metro vehicle and the impact of wheel-rail wear and selecting the technical parameters on operation performance are studied in this paper, and the theoretical basis is provided for selecting the profiles and curve parameters setting.