桥上无砟轨道竖向动力特性分析

根据桥上CRTSⅡ型轨道结构形式,考虑高速列车与无砟轨道、桥梁之间的相互作用,建立基于新型车辆单元和无砟轨道-桥梁单元的车辆-无砟轨道-桥梁纵垂向耦合振动模型。运用有限元方法和Lagrange方程,分别推导车辆单元、无砟轨道-桥梁单元的刚度、质量和阻尼矩阵,建立有限元数值方程。考虑轨道平顺和轨道不平顺两种工况,求解有限元数值方程,分析梁端和跨中动力特性。计算结果表明,该模型及程序能够反映轨道结构的竖向振动响应。施加轨道不平顺,轮轨作用力增大了50%左右,梁端处钢轨的竖向加速度增加了6.5倍左右,跨中处从10 m/s~2增加到30 m/s~2。每种工况下,梁端和跨中处轨道结构的竖向位移、竖向加速度分别逐渐减小,梁端处轨道结构的振动及其位移变化都比跨中处大。

Analysis of Vertical Dynamic Characteristics for Ballastless Track on Bridge

According to the CRTS II slab track-bridge struc-ture,and considering the interaction between high-speed train, ballastless track and bridge,a longitudinal vertical coupled vi-bration model of vehicle-ballastless track -bridge is estab-lished based on new vehicle element and ballastless track-bridge element. Finite element method and Lagrange equation are used to derive stiffness,mass and damping matrix of new vehicle element and ballastless track-bridge element respec-tively,and establish the dynamical finite element equations. According to both track regularity and irregularity on the track structure,by solving finite element equations,the dynamic characteristics of the side and the mid of middle bridge are analyzed.Calculation result shows,the model and program can reflect the vertical vibration responses of track structure. On the condition of track irregularity,the wheel-rail interaction force will increase by 50%,and the vertical acceleration of the rail at side of the bridge increase by 6.5 times,with changes from 10 m/s2to 30 m/s2in the middle of bridge. Track struc-ture on the side of the bridge vibration and the displacement is relatively larger in each condition.