中文摘要：

研究目的是通过建立机车单轮对动力学简化模型,分析轮对纵向颤振的影响。首先对简化模型进行受力分析,在模型中加入轨道不平顺的前提下观察到轮对在某些速度下发生纵向颤振现象,根据此速度确定轮对发生纵向颤振的频率,并对纵向颤振的的频率进行分析,给出一个较为接近的频率判据。然后讨论纵向颤振与前进速度、粘着利用系数的关系,提出颤振危险速度的概念,并对颤振危险速度进行估测。在此基础上,研究纵向颤振对轮轨接触区受力的影响和轮轨接触斑处相对滑动的影响,发现轮轨接触区受力显著增加,特别是轮轨接触斑相对滑动特别严重,接触斑的粘着区不再存在。分析的结果将有益于今后机车车辆研究中更加关注纵向振动的影响。

英文摘要：

To analyze the influence of longitudinal flutter,a simplified single-wheelset dynamic-model of locomotives was established.First of all,the force of the model was analyzed.Then,the phenomenon of the wheelset longitudinal flutter at some speed was observed under the prerequisite of track irregularity.The flutter frequency was analyzed,and an approximate criterion for its determination was offered.Next,the relationship of the longitudinal flutter with the forward speed and the adhesion-utilization-coefficient was discussed.The concept of flutter critical speed was put forward,and the corresponding formula was given.On this basis,the influence of the longitudinal flutter on the force in the wheel-rail contact zone and relative sliding at the wheel-rail contact patch was studied.It was found that the force in the wheel-rail contact zone was increased significantly,the relative sliding in the wheel-rail contact patch became very serious,and the contact patch adhesive area disappeared.So,much attention to the influence of the rolling stock longitudinal vibration should be paid in future study.