预压荷载、板下材质、螺栓扭矩和频率对扣件系统刚度特性影响研究

Study on the Influence of Preload,Under-plate Material,Bolt Torque and Frequency on the Stiffness Characteristics of Fastener System

为研究我国高速铁路广泛使用的福斯罗W300扣件系统刚度特性,利用MTS-25伺服液压疲劳测试试验机,结合该扣件在线路上的实际服役状态,在不同预压荷载、板下材质、弹条螺栓扭矩和频率4种工况下,对此扣件系统整体动静刚度特性进行探究。结果表明:(1)随着预压荷载增加,扣件系统静刚度随之增加,30 kN预压荷载下静刚度比无预压荷载下增加了44.3%;(2)不同铁垫板的板下材质也会影响静刚度,尼龙材料对应的扣件系统静刚度值分别是热塑性材料和聚氨酯材料的1.61倍和1.78倍;(3)弹条螺栓扭矩松弛状态比标准状态的动刚度减小了27.3%,而弹条螺栓扭矩过拧状态比标准状态的动刚度增加了5.0%;(4)扣件系统刚度的频变特性非常明显,在5~100 Hz范围内,80 Hz时扣件系统动刚度比5 Hz时增加了38%,超出了高速铁路扣件系统动刚度合理设计限值,直接影响扣件系统的弹性减振效果及轨道承轨台强度。

In order to study the stiffness characteristics of Vossloh W300 fastener system,which is widely used in high-speed railway in China,the MTS-25 servo hydraulic fatigue testing machine is used to study the dynamic and static stiffness characteristics of the fastener system under four working conditions of different preload,material under plate,clip bolt torque and frequency.The results show that:(1) With the increase of preload,the static stiffness of fastener system will also increase.The static stiffness under 30 kN preload is 44.3% higher than that without preload;(2) The static stiffness is also affected by the material under the plate,the static stiffness of nylon fastener system is 1.61 and 1.78 times higher than that of thermoplastic and polyurethane respectively;(3) Compared with the standard state,the dynamic stiffness of the clip bolt in the torque relaxation state is reduced by 27.3%,while the dynamic stiffness of the clip bolt in the torque in the over-tightening state is increased by 5.0%;(4) In the range of 5~100 Hz,the dynamic stiffness of the fastener system at 80 Hz is 38% higher than that at 5 Hz,which exceeds the reasonable design limit of the dynamic stiffness of the fastener system of high-speed railway and directly impacts the elastic vibration isolation of the fastener system and the strength of the railseat.