磁浮交通线的轨道梁结构及动力特性

介绍了磁浮交通线轨道梁的一般结构特性,包括轨道梁下部结构、上部结构、结构材料、结构荷载等,探讨影响轨道梁设计的轨道梁不平顺和轨道梁刚度的研究方法,以便为轨道梁的设计提供参考。     

Construction of a stochastic model of track geometry irregularities and validation through experimental measurements of dynamic loading

This paper describes the construction of a stochastic model of urban railway track geometry irregularities, based on experimental data. The considered irregularities are track gauge, superelevation, horizontal and vertical curvatures. They are modelled as random fields whose statistical properties are extracted from a large set of on-track measurements of the geometry of an urban railway network. About 300–1000 terms are used in the Karhunen–Loève/Polynomial Chaos expansions to represent the random fields with appropriate accuracy. The construction of the random fields is then validated by comparing on-track measurements of the contact forces and numerical dynamics simulations for different operational conditions (train velocity and car load) and horizontal layouts (alignment, curve). The dynamics simulations are performed both with and without randomly generated geometrical irregularities for the track. The power spectrum densities obtained from the dynamics simulations with the model of geometrical irregularities compare extremely well with those obtained from the experimental contact forces. Without irregularities, the spectrum is 10–50?dB too low.     

高速铁路路基-地基系统振动响应分析

推导了有砟轨道-路基-地基系统在轮轨接触点处的柔度矩阵,建立了考虑轨道不平顺的车辆-有砟轨道-路基-层状地基垂向耦合振动解析模型。通过算例分析了单台TGV高速动车引起的路堤本体-地基系统振动,得到路堤本体表面的垂向位移,研究了列车速度、轨道不平顺、基床刚度和路堤土体刚度对路堤本体振动的影响。研究结果表明:路堤本体垂向位移主要由移动列车轴荷载引起;随着列车速度的提高,路堤振动的"波动性"明显增加;基床刚度和路堤土体刚度对路堤振动影响显著,可通过增大基床和路堤土体刚度来减小高速列车引起的路基振动。     

嵌入式轨道钢轨焊接不平顺安全限值研究

为调查嵌入式轨道的槽型轨焊接不平顺的安全控制限值及焊接不平顺现代对有轨电车及嵌入式轨道动力作用的影响,建立现代有轨电车/嵌入式轨道耦合动力学模型。计算模型中,现代有轨电车简化为多刚体动力系统,嵌入式槽型轨被视为连续弹性支承基础上的Timoshenko梁,整体道床用三维实体有限元单元模拟,钢轨填充材料用三维粘弹性弹簧-阻尼单元模拟,嵌入式道床板底部的致密混凝土底座及路基简化为等效的弹簧-阻尼单元。基于动力学仿真计算,以GB5599-1985规定的车辆动力学性能指标为评定准则,对槽型轨焊接不平顺的安全限值进行详细分析。计算结果表明,对于短波波长小于0.2 m的焊接不平顺,1 m范围内槽型轨轨顶面容差的建议控制限值为0.2 mm;对于短波波长大于0.2 m的焊接不平顺,1 m范围内槽型轨轨顶面容差的建议控制限值为0.3 mm。     

高低不平顺条件下高速铁路桥-隧过渡段路基的动力特性

基于D'Alembert原理的能量弱变分和整体Lagrange格式,建立了无碴轨道桥-隧过渡段半无限三维空间动力有限元计算模型,结合高速车辆振动的几何不平顺条件,采用一与不平顺管理标准相应的激振力来模拟列车高速移动的竖向动荷载.通过数值分析,研究了高速移动荷载和不平顺条件下桥-隧过渡段路基的动态响应,揭示了几何竖向上"凸"或下"凹"不平顺等因素对其路基变形、动应力及加速度的影响规律,并与部分实测资料进行了对比,证实了计算模型的正确性.合理选择"超高"填筑过渡段,能减小过渡段路基动态响应,其研究结果为高速铁路过渡段的设计与施工提供了重要基础.     

基于扩展卡尔曼滤波的轨道垂向不平顺估计

轨道不平顺是影响列车平稳性和舒适度的关键因素,因此及时掌握线路状态对保证列车的运行安全具有重要意义。针对采用单个惯性量较难达到对不同波段不平顺的检测,通过观测多个惯性量,运用扩展卡尔曼滤波解决非线性离散系统的最优估计原理,根据车辆轨道耦合状态空间方程计算递推雅克比矩阵,并结合线性观测方程得到最优状态估计,实现轨道不平顺估计。在Matlab平台下,进行了实测轨道不平顺激励作用下的仿真,将仿真得到的观测值采用本文提出的方法进行轨道垂向不平顺估计,结果表明该算法具有很好的精确性。     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part II: simulation and analysis

In this paper, the semi-active suspension system for railway vehicles based on the controlled (MR) fluid dampers is investigated, and compared with the passive on and passive off suspension systems. The lateral, yaw, and roll accelerations of the car body, trucks, and wheelsets of a full-scale railway vehicle integrated with four MR dampers in the secondary suspension systems, which are in the closed and open loops respectively, are simulated under the random and periodical track irregularities using the established governing equations of the railway vehicle and the modelled track irregularities in Part I of this paper. The simulation results indicate that (1) the semi-active controlled MR damper-based suspension system for railway vehicles is effective and beneficial as compared with the passive on and passive off modes, and (2) while the car body accelerations of the railway vehicle integrated with semi-active controlled MR dampers can be significantly reduced relative to the passive on and passive off ones, the accelerations of the trucks and wheelsets could be increased to some extent. However, the increase in the accelerations of the trucks and wheelsets is insignificant.     

Effect of vehicle vibration environment of high-speed train on dynamic performance of axle box bearing

In this study, we developed a comprehensive three-dimensional vehicle–track coupled dynamics model considering the traction drive system and axle box bearing. In this model, dynamic interactions between the axle box bearing and other components, such as the wheelset and bogie frame, are considered based on a detailed analysis of the structural properties and working mechanism of the axle box bearing. A few complicated dynamic excitations, such as the time-varying mesh stiffness of gears, time-varying stiffness of bearing, bearing gaps and track irregularities, are considered. Then, the dynamic responses of the vehicle–track system are demonstrated via numerical simulations based on the established dynamics model. The results indicate that the traction drive system and track irregularities can significantly influence the dynamic interactions of the axle box bearing. The necessity of considering the excitation caused by gear meshing and track irregularities when assessing the dynamic performance of the axle box bearing is demonstrated.     

南京长江大桥的轨道几何状态变化规律的分析

位于京沪线上的南京长江大桥系该线贯通大江南北的主要咽喉.由于其轨道结构的差异,相应的轨道几何状态变化是不一样的.本文采用不平顺幅值和功率谱相对比的方法,综合分析大桥在重载快速行车条件下的轨道几何状态变化规律,为合理制定相应的养修标准提供了技术支持.