中文摘要：

研究目的：目前，轨道刚度变化对车辆一轨道耦合系统频率响应的影响规律尚不明确，本文基于车辆一轨道耦合动力学理论，以既有提速线路为例，从频率角度，研究轨道刚度变化对车辆一轨道耦合系统振动响应的影响。研究结论：（1）轨道刚度的变化，对车体、转向架的振动影响较小，对轮对及轨道结构的振动影响较大；轨道刚度的增大，对27Hz以下的低频振动基本无影响，27～70Hz之间的中低频振动略有降低，100Hz以上的中高频振动显著增大；（2）随扣件刚度的增大，轮轨力谱以及轮对、钢轨振动加速度谱的最大值均显著增大，且振动频率有向高频发展的趋势；（3）随道床刚度的增大，频率响应谱的最大值变化相对较小，轮轨力、轮对、钢轨和轨枕的振动频率向高频移动；（4）总体上看，扣件刚度对耦合系统振动响应的影响较大，在线路维修时应及时更换恶化的扣件系统，道床刚度变化的影响相对较小，其维修周期可适当延长；（5）该研究可指导轨道结构的优化设计以及轨道的养护维修。

英文摘要：

Research purposes： Track stiffness is an important parameter ior the design and maintenance ol railway track. However, the frequency- domain influence of track stiffness on the vehicle -track coupling system is still not clear. Based on the theories of vehicle -track coupling system dynamics, taking the existing speed -increase line as an example, this paper explores the frequency - domain influence of track stiffness on the vehicle - track coupling system. Research conclusions：The influence of track stiffness on the vehicle and bogie is little and it influences the wheel set and the track structure a lot. With the increase of track stiffness, the vibration response of vehicle - track coupling system goes stronger obviously in the medium - high frequency band of 100 Hz above, but the vibration response in the low and medium frequency band of 27 - 70 Hz gets a little weaker and it shows nearly no influence on the vibration response in the low frequency band of 27 Hz below. As the stiffness of fastener system increases, the maximum values of wheel -rail force spectrum, the wheel set acceleration spectrum and the rail vibration acceleration spectrum all increase considerably and the vibration frequency shows a tendency to occur a frequency shift towards high frequency band. The similar rule can be found in the research of the stiffness of ballast bed. Overall, in the frequency domain, the stiffness of fastener influences the vibration response of vehicle - track system greatly while the stiffness of ballast bed affects thevibration response of vehicle - track system relatively weaker, so deteriorative fasteners should be replaced in time while the maintenance cycle of ballast bed can be extended appropriately. The research can provide a good guidance for the optimization design of track structure and the track maintenance.