基于轨道元的运动有限元分析

A Moving Finite Element Algorithm for the Adaptive Solution of Dynamic Behavior of Railway Track Structures

基于轨道纵向条带状分布的规则性结构,建立轨道元的运动有限元数值计算方法与轨道结构空间整体模型,分析钢轨与轨枕所采用的空间Timoshenko梁单元有限元控制方程的形成,阐述轨道元单元移动的数值计算过程和边界条件的处理方法。轨道元作为数学模型,从形式上表现为轨枕间距长度范围内的一段轨道截矩,涵盖一根轨枕及其相应钢轨、扣件、弹性垫层、道床与路基在内的动力学特性,应用列车前后适时"增加与缩减"一个(或多个)轨道元的方法,可进行无限长轨道结构的动态响应分析。理论计算与实测结果对比表明,所建基于轨道元的运动有限元模型及其程序能够反映轨道结构的振动特性及进行相应的动力性能分析。

Owing to the strip regularity of the track structure along its longitudinal direction,a special moving finite element method named ＂the track element＂ for the numerical solutions of railway track dynamics is developed based on the time-dependent algorithm of moving mesh and boundaries. Particularly, the finite element equations deduced from the theory of Timoshenko beam to represent rails and sleepers have been proposed. According to the efficient scheme of ＂the track element＂ which is a cut section as long as one tie-spacing and includes the dynamic characteristics concerning one sleeper as well as its corresponding rail, fastening, elastic pads, ballast and roadbed, the dynamic response of an infinitely long track can be investigated through ＂cutting and merging＂ timely one or more such ＂the track elements＂ in front of and behind the vehicle. The good correlation between the theoretical results and the experimental data obtained from an indoor full-scale railway track employed for model verification shows that the moving finite element procedure of ＂the track element＂ and its relevant numerical program can be used to analyze and reflect the railway track structure＇s dynamic behavior.