列车—桥梁相互动力作用下轮对横向运动规律

Lateral Movement Regularity of Wheelset under Train-Bridge Dynamic Interaction

基于蠕滑理论,研究单个轮对在轨道方向不平顺激励下简化的轮对横向力和轮对横向运动微分方程,并得到轮对横向运动的解析解。分析表明,根据几何学推导的自由轮对蛇行运动解是上述轮对运动微分方程的齐次解,而轮对所经过的轨道方向不平顺是其特解。齐次解将因阻尼而很快衰减,而特解则决定了系统稳态响应特征。采用整车模型的动力仿真计算也表明在不发生蛇行失稳的正常运营车速下,轮对横向运动轨迹与轨道方向不平顺的趋势基本一致。按蠕滑理论得到的轮对蛇形波长与车速无关,这与蛇形波理论一致,但2种理论在蛇形波的波长和波幅的随机分布特性上还有差异。车桥耦合振动分析也表明轮对横向运动轨迹和轮对横向力主要受轨道不平顺的影响,而受桥梁振动的影响较小。

Based on wheel-rail creepage theory, the moving on track alignment irregularity is derived by differential equation of motion of a single wheelset neglecting some secondary components of the lateral forces acting on the wheelset. And then the analytical solution of lateral motion of the wheelset is obtained from the simplified differential equation of motion of the wheelset. The analytical solution indicates that free wheelset hunting motion solution is the homogeneous solution of the simplified equation of motion while track alignment irregularity under the wheelset is its particular solution. The homogeneous solution will decline due to damping, while the particular solution will determine the steady-state dynamic response of the wheelset. Numerical analyses using a whole vehicle also agree well with the analytical results with a single wheelset： the trace of any wheelset is almost consistent with the track alignment irregularity under the wheelset. According to the numerical results, the wave length of hunting motion of the wheelset is almost irrespective of train speed, which shows the consistency between creepage theory and hunting theory. However, there is difference between the creepage theory and hunting theory if the stochastic property of the wave length and the wave amplitude are concerned. In addition, train-bridge coupling vibration analyses show that the lateral motion and lateral force of the wheelsets are mainly affected by track irregularity while less influenced by normal vibration of the bridges.