Study On Structural Strength For Variable Gauge Wheelset Of High-speed EMU

With the double promotion of the science,technology and globalization,economic and cultural exchanges between countries and regions are increasing with years.Meantime,the situation has greatly stimulated the transnational and trans-regional cargo and passenger transport.Due to characteristics of large capacity,low cost,low energy consumption,environmental protection,safety and rapidness,railway transportation has become the first choice of transportation between internation and regions.For a long time,various countries and regions have adopted different gauge due to political,economic,military and technological considerations,resulting in a large number of different gauge railways in the world,which has greatly hindered the improvement of the efficiency of railway international intermodal transport.To realize railway intermodal transport between different gauges,variable gauge bogie has been invented.At the beginning of this paper,the existing solutions for different gauges combined railway transport are introduced,the advantages of variable gauge bogie technology are compared and analyzed,and then the domestic and foreign development status of research on variable gauge bogie technology is analyzed,In consideration of the prominent position of structural strength reliability in train safety design,the fatigue strength of the key component of the variable gauge bogie—the variable gauge wheelset is studied.In this paper,the variable gauge wheelset including the axle and sliding sleeve of a certain type of high-speed EMU with variable gauge bogie is taken as the research object,Because of the adaption of spline between the axle and the sliding sleeve for torque transmissions,the spline fit strength was also studied.Firstly,by sorting out and summarizing the existing research methods of axle,sliding sleeve and spline strength,a suitable strength assessment method is selected.Then,according to the analysis of load transfer relation of the variable gauge mechanism,a suitable finite element method is constructed to simulate the stress and evaluate the strength.A complete finite element model of variable gauge wheelset was built on the ANSYS platform.Based on the European standard EN13104,the structural stress of the axle under 1435 mm gauge and 1520 mm gauge was simulated and the fatigue strength was evaluated.Based on the European standard and the domestic standard,the interference fit tightness of the sliding sleeve was checked,the contact pressure distribution under different interference ratios and the influence of rotating speed on the contact pressure were analyzed,the structural stress simulation of the sliding sleeve was conducted based on standard UIC 510-5 wheel fatigue load,and the fatigue strength was evaluated.Based on standard GB/T 17855-2017,the spline fit strength of involute spline was evaluated.In consideration of three possible misalignment positions in the assembly of spline pairs,an accurate finite element model of spline pairs was constructed in order to study the influence of misalignment on spline tooth mating.Through the analysis of axle fatigue strength,sliding sleeve fatigue strength,interference fit of wheel-sleeve,clearance-fit spine joints and the influence of assembly misalignment on key tooth fit,the paper reveals the weak area of the variable gauge wheelset and the stress characteristics of the fit area,which can provide theoretical support for the subsequent structural design.