The vibration of railwayballa st is a keyfact or to cause track geometrych ange and increase of track maintenance costs. So far the methods for analyzing and testing the vibration of the granular ballast havenot been well formed. In this paper, a five-parameter model for analysis of the ballast vibration isestablished based upon the hypothesis that the load-transmission from a sleeper to the ballast approximatelyco incides with the cone distribution. The concepts of shear stiffness and shear damping of the ballast are introduced in the model in order to consider the continuityof the interlocking ballast granules. A full-scale field experiment is carried out to measure the ballast acceleration excited bymoving trains. Theoretical simulation results agree well with the measured results. Hence the proposed ballast vibration model has been validated.

The effect of a scratch formed on the running surface of a curved rail, due to the slide of a locomotive wheel, on the formation and evolution of rail corrugation is investigated in detail with numerical methods when a wheelset is steadily and repeatedly curving. In the calculation we consider a combination of Kalker’s rolling contact theory with non-Hertzian to be modified, a linear frictional work model and a vertical dynamics model of railway vehicle coupled with a curved track. Also the influence of different speeds of wheelset curving through the scratch on the development of the corrugation is taken into account. The numerical results indicate that a scratch causes strong contact vibration between the wheel and rail, and initiation and development of rail corrugation under the condition of steady creepage occurring between the wheel and curved rail. The wave-length of the corrugation depends on the speed of wheelset curving and the natural frequencies of the track.

The effect of track irregularities on rail corrugation is investigated in detail with the numerical method when a wheelset is steadily curving.The irregularities considered in the analysis include initial running surface of rail with periodically varying and different wave length, stochastic roughness on the rail running surface, and vertical uneven support stiffness of the rail due to the discrete sleeper supports.The numerical method considers a combination of Kalker’s rolling contact theory with non-Hertzian to be modified, a linear frictional work model and a vertical dynamics model of railway vehicle coupled with a curved track. The model is also validated by an experiment with a full scale facility.The influence of different speeds of wheelset curving on the development of the corrugation is taken into account in the calculation.The numerical results indicate that (1) for existing of the initial corrugation of new rail with any wavelength the depth from the peak to trough of it decreases gradually with an increase of wheelset passage, but the initial corrugation evolved has a tendency to move in the rolling direction, (2) the amplitude of the initial stochastic roughness of new rail is gradually leveled out and but a corrugation with very small depth and a few fixed passing frequencies is initiated, the passing frequencies are the same as the natural frequencies of the track, and (3) the discrete rail supports by sleepers have a great influence on the formation of the corrugation.

基于系统工程思想，运用频域分析方法。对轨道结构随机振动特性进行仿真计算与分析，并结合铁路现场测试结果对理论计算结果进行试验验证。结果表明：钢轨振动能量主要集中在1300Hz附近，而中、低频率的振动主要体现为轨枕与道床的振动；在整个分析频域范围之内，仿真计算得到的轨道结构振动加速度功率谱密度与试验测试结果吻合较好，且轨道结构振动加速度平均值的计算与试验结果差异不大。

基于系统工程思想，运用机车车辆一轨道耦合动力学理论，对采取了强化技术对策后的山区铁路小半径曲线轨道的动力性能进行仿真计算，并与强化前轨道结构动力学性能进行了对比分析。分析结果表明：强化后轨道结构的轮轨动态相互作用力及轨枕支点压力均较强化前的相应值略大，但皆属相同安全合格等级；强化轨道结构位移大幅度降低，有效抑制轨道结构变形，增强线路稳定性，尤其是钢轨横向位移和轨距动态扩大量较强化前下降十分显著，前者仅约为后者的1/3左右；强化轨道也有利于降低轨下结构振动和减轻列车提速后对轨下基础的破坏。

基于机车车辆—轨道耦合动力学理论，仿真计算典型的提速机车车辆通过不同曲线轨道时的轮轨动态横向相互作用性能指标，包括提速客货列车通过山区铁路小半径曲线强化轨道、160km·h-1提速客运列车及120km·h-1提速货运列车通过不同半径曲线轨道。根据现行动力学性能评定规范，对轮轨相互作用性能指标进行了综合评估分析。理论分析结果表明：提速后列车通过曲线轨道时轮轨横向动态相互作用加剧，动力性能指标的最大峰值均出现在圆曲线上，并且客运机车车辆的曲线通过性能接近，货车车辆的曲线通过性能要优于货运机车的性能。为了确保列车提速后的行车安全性，山区铁路的小半径曲线轨道须采取加强措施，提速客运列车以160km·h-1和提速货运列车以120km·h-1速度运行时的最小曲线半径分别取1400m和1000m。

考虑车轮与钢轨的运动特性及轮周牵引力，推导出机车在牵引状态下通过曲线时的轮轨蠕滑率计算公式，并对曲线通过时的轮轨横向动态相互作用特性进行仿真计算与分析；同时研究牵引力大小对转向架导向性能的影响，对比分析了机车牵引与惰行状态下的导向性能。理论仿真分析结果表明：牵引力可以改变轮轨纵向蠕滑力的大小和方向， 与惰行工况相比，牵引状态下的轮对导向力矩有所减小，轮对的自导向能力减弱，不利于曲线通过；提高牵引力，总轮轨蠕滑率将很快达到饱和状态，牵引力越大，轮轨纵向蠕滑力越大，两侧纵向蠕滑力差值越小，机车轮对自导向能力越差，轮对冲角增大，而轮轨横向蠕滑力越小；当牵引力增加到一定程度时，总轮轨蠕滑率超过极限状态，曲线通过时两侧轮径差太小而出现打滑和空转的现象。

为提高列车在提速区段的乘坐舒适性，借助于现场试验测试数据，运用车辆一轨道耦合动力学理论，通过轨道随机不平顺功率谱变换得到不同波长的不平顺，研究了线路不平顺波长对列车运行平稳性及乘坐舒适性的影响及规律。分析结果表明：提速机车以150km•hl速度在直线轨道上运行时，如果线路不平顺波长为1～20m，则车体振动主频主要集中在2.20～4.00Hz，避开了人体正常敏感频率，平稳性指标属优级；如果线路不平顺波长为20～30m，则车体振动主频降低至1.50Hz左右，正好处于人体敏感频率范围，乘坐舒适性大大降低，平稳性指标值增加了20%多；更长的波长(大于30m)对机车运行平稳性影响较小，指标与1～20m波长的相应值处于相同等级。可见，对于既有提速线路，必须严格控制不平顺的20～30m波长，虽然该波段的不平顺幅值很小，但对列车在提速区段车体横向振动影响甚大。

从轨道谱的功率谱密度、时间样本幅值及对动力学性能影响的角度，对比了秦沈线轨道谱和德国轨道谱。秦沈线无碴轨道谱密度介于德国高干扰谱和低干扰谱之间，其中高低谱与德国高干扰谱接近，在30～45m波长范围内方向谱优于德国低干扰谱。 秦沈线有碴谱和德国高干扰谱互有优劣，方向和高低谱的分界波长分别是20m和30m。从时间样本来看，秦沈线无碴谱方向不平顺与德国低干扰谱非常接近，明显小于高干扰谱；有碴谱方向不平顺度略小于德国高干扰谱，但明显大于低干扰谱；无碴谱和有碴谱的高低不平顺均介于德国低干扰和高干扰之间。引起轮重减载的可能性大小依次是秦沈线有碴谱、德国高干扰谱、秦沈线无碴谱和德国低干扰谱。导致车体振动大小依次是德国高干扰谱、秦沈线有碴谱、秦沈线无碴谱和德国低干扰谱。

TTISIM仿真软件采用现代车辆—轨道耦合动力学理论，全面考虑轨道结构参振影响及动态轮轨空间接触几何关系。结合近年来国内有关提速、脱轨、新型机车车辆动力学现场试验，对TTISIM软件进行了系统的分析验证。结果表明，用该仿真软件计算的结果与试验测量结果吻合良好，说明该仿真软件可以用来分析研究各种铁道机车车辆在不同状态线路上运行时的动力学性能。