中文摘要：

为研究单元板式无砟轨道扣件刚度整体及局部突变对行车安全的影响,指导扣件系统的养护维修,利用有限元方法和轮轨耦合系统动力学原理,建立车辆-轨道-路基系统垂向耦合动力学模型。研究扣件系统整体刚度突变和局部刚度突变对列车的振动特性和轮轨垂向作用力的影响规律。结果表明：扣件刚度从20 kN/mm增加到80 kN/mm时,轮对和转向架的振动加速度分别增加40.1%和28.2%,轮轨垂向力增加28.4%,车体变化不大;当局部扣件刚度突变时,车体、轮对、转向架的振动加速度和轮轨垂向力均较基本刚度（50 kN/mm）有所增大。扣件刚度整体突变以及局部突变均会对列车振动特性和轮轨垂向作用力产生不利的影响,建议及时对扣件系统进行养护检修,以保证行车的平稳性和安全性。

英文摘要：

To study the influence of the overall and local mutation of fastener stiffness of the unit slab track on the running safety and instruct the maintenance of fastener system,a dynamic computational model of vehicle-track-subgrade coupling system was built by means of finite element method and the wheel/rail system coupling dynamic theory.The effects of the overall and local mutation of fastener stiffness on vibration of vehicle and wheel-rail vertical force were studied.Results show that the vibration acceleration of wheel set and bogie increased by 40.1% and by 28.2% respectively,the wheel-rail vertical force increased by 28.4%,but the car-body changed a little when the fastener stiffness increased from 20kN/mm to 80kN/mm.The vibration acceleration of wheel set,bogie,car-body and the wheel-rail vertical force increased compared with the basic stiffness（50 kN/mm） when the fastener stiffness had local mutation.The overall and local mutation of fastener stiffness will have adverse effect on the vibration of vehicle and the wheel-rail vertical force,maintenance of the fastener in timely to ensure the running safety and stability of vehicle was recommended.