钢轨扣件失效对列车动态脱轨的影响

建立了非对称车辆/轨道耦合动力学模型,分析轨道扣件失效对车辆动态脱轨的影响,考虑离散轨枕支承对车辆/轨道耦合作用的影响,通过假设轨道系统刚度沿纵向分布发生突变来模拟扣件组失效状态,推导了考虑钢轨横向和垂向以及扭转运动的轮轨滚动接触蠕滑率计算公式,利用Hertz法向接触理论和沈氏蠕滑理论计算轮轨法向力及轮轨滚动接触蠕滑力,采用新型显式积分法求解车辆/轨道耦合动力学系统运动方程,通过数值分析计算,得到轮轨横垂向力之比、轮重减载率、脱轨危险状态的持续时间和轮对踏面上轮轨接触点位置的变化。连续5个钢轨扣件不同程度失效对列车动态脱轨的影响的数值模拟结果表明,如果失效因子从0.8增大到1.0,即钢轨扣件经历从接近完全松脱到完全松脱,钢轨扣件失效对列车动态脱轨影响呈指数规律。

Influence of Rail Fastener Failure on Vehicle Dynamic Derailment

In order to investigate the effect of disabled fastener system on railway vehicle derailment,a non-symmetrical vehicle-track coupling dynamics model was established.The abrupt change of track stiffness along the track was assumed to simulate the failure situation of rail fastener system.The effect of discrete sleeper support on the coupling dynamics of vehicle and track was taken into consideration.The creepage formulas of wheel/rail rolling contact were deduced,in which the lateral,vertical and torsional motions of rail were taken into account,the normal forces of wheel/rail were calculated by Hertzian contact theory,the creep forces of wheel/rail rolling contact were decided by the nonlinear creep theory of Shen.The motion equations of vehicle/track coupling system were solved with new explicit integration method.The effect of five seriate fasteners' system in different failure situations on railway vehicle derailment was analyzed and evaluated.The ratio of lateral force and vertical force on wheel and rail,wheel load reduction ratio,vehicle derailment time and the variations of contact points on wheel treads were computed.Numerical computation result indicates that when the failure index increases from 0.8 to 1.0,that is to say,rail fasteners experience a process from almost looseness to complete looseness,the influence of rail fastener failure on vehicle dynamic derailment shows an exponential rule.1 tab,8 figs,13 refs.