Research On Motion Stability Of Express Urban Rail Vehicles

With the continuous expansion of the urban economic circle,the scale of express rail vehicles continues to expand.And the subsequent problems of vehicle dynamics have become increasingly prominent.Wheel wear has caused the deterioration of the wheel-rail matching status of express urban rail vehicles,and the motion stability of vehicles has been reduced,which has seriously affected the riding performance of vehicles.Wheel lathing is the most direct way to solve this kind of problems,but the number of wheel lathing is limited.Frequent lathing will shorten the service life of the wheels and increase operating costs.In order to explore other effective solutions,this thesis studies and analyzes the dynamic problems of express urban rail vehicles under different wheel states,and mainly carries out the following work.(1)Based on the test data of the line dynamic test of operating express urban rail vehicles,the dynamic performance indexes of the vehicles are analyzed,and the vibration frequencies and vibration transmission relationships between the car body and the frame are analyzed.At the maximum operating speed of such vehicles,the lateral ride index exceeds the excellent level limit of 2.5,and the vertical ride index is not abnormal.Based on this,the core of the research is clearly the stability of the lateral motion of the vehicle running at a higher speed.(2)The hunting motion law and main influencing factors of free wheelset and flexible positioning bogie are studied in order to provide theoretical basis for the research on vehicle lateral motion stability.A Simpack multi-rigid-body dynamic simulation model of a certain metro vehicle with the maximum operating speed of 120 km/h was established.Combined with the measured profile of LM tread,the problem that the lateral ride index exceeds the standard in actual operation is reappeared.The causes of abnormal vehicle riding performance are analyzed from the aspects of car body suspension mode,wheel-rail matching state,vibration frequency and vibration transmission.(3)Two methods of optimizing suspension parameters and installing anti-yaw dampers based on the original vehicle are proposed to improve the lateral motion stability of the vehicle.Simulate and analyze the vehicle at different equivalent conicity,primary positioning stiffness,primary vertical stiffness and damping,secondary transverse stiffness and damping,secondary vertical stiffness and damping,anti-rolling torsion bar stiffness and anti-yaw damper.The dynamic performance is verified by rolling vibration test.Combined with the space vector mapping method,the differences between the wheel-wheel equivalent conicity and the wheelrail equivalent conicity is compared.Using the established metro vehicle dynamic model,the curve passing performance of the vehicle after installing anti-yaw dampers was simulated and predicted.