Numerical Analysis Of Wheel/Rail Contact Stress

The behaviour of high-speed wheel/rail rolling contacts is basic and complex problem in railway systems. An analysis of the relevant contact stresses is the basis of studies on the performance of wheel/rail interactions. This is also the theoretical basis for further studies to analyze and compute wheel running characteristics andsurface damage. So, it is important for improving the safety and reducing the cost of railway transportation.Analysis of Wheel/Rail rolling contact stress is the base for the study on the performances of Wheel/Rail, such as rolling contact fatigue, Wheel/Rail noise and derailment. The relationship of Wheel/Rail is the base for the study on corrugation, rolling contact fatigue, dynamical coupling and analysis of vibration of vehicle/rail system. So it is significant for improving the security and economy of railway transportation to analyze and compute the wheel/rail contact stress.In this dissertation, the effects of case parameters, material characteristics and inclusion in rail head on the distribution of elastic-plastic stress in rail head are simulated by using commercialized software ANSYS, taking into account the real geometry and boundary conditions of wheel and rail.The effects of case parameters on the distribution of elastic-plastic stress hi railhead are analyzed including lateral displacement, gross rail load on axle and constrained conditions of rail bottom. The dissertation obtains relationships between these case parameters and the elastic-plastic stress field in railhead, and analyzes the effects of these case parameters on the distributions of elastic-plastic stress in railhead.The influences of material characteristics including Young's modulus and Poisson's ratio are analyzed in the dissertation. The analyses show that Young's modulus and Poisson's ratio influences greatly maximum shear stress and have less effect on the maximum equivalent stress.Inclusion has great influences on the distribution of elastic- plastic stress in railhead. The calculation indicates that the maximum shear stress around inclusion is 1.2-1.7 times of that without inclusion, which has a harmful effect on the fatigue endurance of rail.All the above work is the base of studying the behaviour of high-speed wheel/rail rolling contacts, which is helpful to realize the dynamics simulation of wheel/rail rolling contact, and further reveals the mechanics of rail corrugation formation.