Comparative Study On Kalker Simplification Theory And 3D Rolling Contact Theory Algorithm Applied To High-speed Wheel And Rail

In recent years,with the rapid development of high-speed railway in China,the running speed of EMUs has been increasing.The research on wheel-rail contact involved in the operation of EMUs is the key factor to improve the running performance,while the wheel-rail creep theory is often the focus of the study.At present,with the gradual improvement of wheel-rail creep theory,many scholars focus on the problems arising from the steady rolling condition of high-speed EMUs,and less on the transient rolling problems of wheels and rails under different conditions and creep phenomena caused by the high-speed operation of EMUs,mainly including the analysis and research of wheel-rail creep force and creep characteristics of contact zone.Accurate simulation of actual contact conditions and analysis of wheel-rail rolling creep characteristics are urgently needed in practical engineering applications.In this paper,a vehicle-track multi-body dynamic model is established by using the multi-body dynamic simulation software UM.Based on the wheel-rail rolling creep theory,the differences between FASTSIM algorithm and CONTACT algorithm in the dynamic forces of wheel-rail under straight line,curve and straight line and curve conditions with wind resistance taken into account are compared and analyzed.The results show that the creep force obtained by the vehicle running on the straight track is almost the same.There is little difference between the values calculated by FASTSIM algorithm and that calculated by CONTACT algorithm when running on the curve track,which reaches 10% to 15%.However,the creep force calculated by FASTSIM algorithm is different from that calculated by CONTACT algorithm when running under the bad working conditions such as large creep and considering wind resistance.There is a big error between the calculated value of slip force and that of CONTACT algorithm.Especially in the curve section after considering the wind resistance,the maximum difference of creep force is up to 25%.It can be concluded that CONTACT algorithm is more accurate than FASTSIM algorithm in calculating creep force under transient rolling conditions,and more suitable for evaluating the safety of train operation.