Study On The Mechanism Of The Beijing Metro Rail’s Abnormal Wear

As a way of passenger transport in city which can run in broad-scale and at high speed, subwa y develops faster and faster. In recent years, within the operation of Beijing new subway lines,some sections has a serious phenomenon of abnormal wear, especially at small radius curve. Generation of abnormal wear of the rail is very complex, involving track structure, match of t he wheel-rail materials, structure and parameters of vehicle bogie, friction coefficient, vehicle axle load, radius of curve lines and driving speed, etc. It is concluded through the comprehens ive study of the impact of each factor on the wear that grasping Wear mechanism systematical ly has great significance on reducing wheel-rail wear and improving the safety, economy and etc of subway running. For the mechanism of abnormal wear research of Beijing subway, we first mastered the wear status of Beijing subway lines and wheels through investigating. Then as the foundation of the vehicle/track system dynamics and based on the actual parameter of metro vehicle, we set up a complete vehicle/track dynamic model by using the application of MBD software SIMPACK. Many parameters which are radius curve, rail base slope, track support stiffness, line irregularity, wheelbase, axle load, train bogie suspension parameters and axle stiffness parameters have influence on dynamic index. It analyzed the impact of these parameters of vehicle and track on dynamics indexes which are wear number, lateral wheel-rail force, vertical wheel-rail force, wear power, attach angle in the condition that single factor changes. Again, used the MINIPROF rail measuring instrument, it got several geometric surfaces of different wear stage. Then according to the theory of elastic-plastic mechanics, finite element model and the software-ANSYS, it set up the finite element model of different wear stage of rail. And it analyzed the relationship between the wheel rail guiding force, the material and friction coefficient of wheel-rail contact surface, contact state of wheel and rail and the contact stress and distribution on wheel-rail contact spot. With the help of effective combination of field test and simulation experiment, a comprehensive assessment of the influence of various factors on the wear of rail has been done. By means of these analysis, not only conductive to a comprehensive understanding of the nature and characteristics of rail wear, but also to ensure effective maintenance in the future rail and reduce the cost of metro operation effectively. At the same time, it also provides the ideas and methods of systematic understanding metro’s wheel-rail system and researching on the problems on wheel and rail. Keywords: subway wheel-rail relationship, rail abnormal wear, dynamics analysis,finite...