THG2A型高压隔离开关的改进

分析THG2A型高压隔离开关使用中存在的一些不足之处,并针对其不足进行了绝缘子、轴组装等结构的改进。     

津滨轻轨桥梁徐变监测与分析

对津滨轻轨预应力混凝土箱梁的混凝土徐变发展规律进行长期的现场监测。在分析现场观测结果的基础上 ,总结混凝土徐变发展的规律 ,利用理论计算对混凝土徐变系数进行曲线拟合 ,得到比规范中规定的更小的徐变系数 ,并将此徐变系数应用于津滨轻轨其他类型桥梁的徐变预测中     

轮对摇头运动对轮轨滚动接触蠕滑率／力的影响

用数值分析方法分析了单轮对的摇头运动对其左右轮轨滚动接触斑上蠕滑率／力的影响。在轮轨滚动接触蠕滑率／力关系分析方面，利用了Ｋａｌｋｅｒ的三维弹性体非赫兹滚动接触计算模型。通过分析计算可知，轮对摇头角运动参量是影响轮轮之间横向蠕滑力的主要因素。     

考虑轮对弹性的轮轨接触点算法

研究轮对动力学相关问题时要考虑轮对的弹性变形,本文在传统迹线法的基础上发展一种考虑轮对弹性的轮轨接触点计算方法。该方法通过计算滚动圆上的点和该点在轨道上的投影点的法向矢量确定可能接触点,形成接触迹线,根据迹线和轨道型面的垂向最小距离确定最终的接触点。利用该方法,本文建立单轮对刚柔耦合系统动力学方程来求解轮轨接触点,并通过刚性轮对与弹性轮对的计算结果对比,讨论轮对弹性变形对接触点位置和轮轨蠕滑率的影响。结果表明,该方法可有效解决考虑轮对弹性的轮轨接触计算问题。     

基于光纤传感技术的混凝土支撑轴力监测及数据分析

支撑轴力作为地铁深基坑施工监测的主要监测项目,是考察基坑自身安全状况的重要指标。针对目前混凝土支撑轴力监测值与实际情况差异较大的问题,分析造成混凝土支撑轴力监测值偏大的原因。利用光纤传感技术,在混凝土支撑纵向主筋肋槽上胶粘封装光纤光栅传感器(FBG),通过监测钢筋的应变推算出支撑梁的内力。在现有计算公式的基础上提出考虑混凝土收缩、徐变、应力应变关系非线性影响的轴力修正公式,对监测数据进行修正。以某市地铁深基坑为例,验证了光纤传感轴力监测技术及轴力修正公式的有效性。结果显示,FBG与钢筋计轴力曲线变化趋势一致,FBG考虑了温度补偿,监测值较钢筋计更加稳定;对轴力监测值进行修正,修正后的轴力值约为修正前的1/3,结果更加符合实际。     

Modelling the effects of friction modifiers on rail corrugation in cornering

A proposed solution to the problem of rail corrugation on curves of urban lines is the use of friction modifiers. Recent experimental research indicates this approach can be effective. This paper makes use of two theoretical models to study the effects of friction modifiers on corrugation in cornering. The first one is a nonlinear time-domain model that predicts corrugation growth from a series of simulated passes of a bogie. The second one is a frequency domain model of wheel–rail interaction, linearised about a steady cornering state, estimated from the nonlinear model. Both models predict reduction of growth of corrugation due to the use of friction modifiers. Friction modifiers can alter the steady cornering state to one with somewhat lower creeps and much lower tractions. Major reductions in corrugation growth rate have been shown to occur if a wheel can be prevented from reaching a state of full sliding when subject to oscillating creeps caused by existing rail corrugation.     

Research into the problem of wheel tread spalling caused by wheelset longitudinal vibration

This study mainly focuses on the mechanism of wheel tread spalling through wheelset longitudinal vibration that has been often neglected. Analysis of two actual cases of the wheel tread spalling problem leads to the conclusion that the wheel tread spalling is closely related to the wheelset longitudinal vibration in some locomotives, and many of these problems can be reasonably explained if the wheelset longitudinal vibration is considered. For better understanding of some abnormal wheel spalling problems, the formations of the wheelset longitudinal vibration and the wheel/rail contact parameters were analysed in the initial wheel tread spalling. With the preliminary analytical results, the wheelset longitudinal dynamic behaviour, the characteristics of wheel/rail contact and the mechanics in the condition of the wheelset longitudinal vibration were further studied quantitatively. The results showed that the wheelset longitudinal vibration changed not only the limit of these parameters and the position of principal stress, but also the direction of the principal stress on the surface of wheel/rail contact patch. It is likely that the significant stress changes provoke too much stress on the surface of wheel/rail contact patch, cause fatigue in wheel/rail contact patch and eventually lead to wheel tread spalling. The results of these studies suggest that the suppression of the wheelset longitudinal vibration extends wheel/rail life and the addition of a vertical damper with an ahead angle provides a possible solution to the wheel spalling problem.     

非赫兹接触轮轨蠕滑力数表TPLR的研究

本文介绍了直线轨道上单轮对运动状态蠕滑率和蠕滑力关系律数表的编制方法。数表中轮轨蠕滑率／力计算模型是非赫兹型的。     

无缝线路流变问题初探

本文通过对无缝线路（简称ＣＷＲ）力学特性的介绍，引入了流变力学理论。系统地介绍了该理论同其它经典力学理论间的不同。详细论述了ＣＷＲ中存在着的流变现象，从而提出了ＣＷＲ理论研究必须将流变因素考虑进去的问题。     

Influence of creep forces on the risk of derailment of railway vehicles

The derailment mechanism in a railway vehicle is a complex mechanical phenomenon which has been, and still is, the subject of intense research activity due to the serious consequences it can entail. Since Nadal deduced his well-known formula, many researchers have put forward alternative equations which all attempt to move closer to the data obtained experimentally. This paper provides a summary of the best known and draws up a new formulation based on the theoretical 3-D study of creep forces emerging from the contact patch of the wheel likely to derail. It also provides an in-depth analysis of the role played by spin creepage, including its effect on obtaining theoretical derailment limits, which are more realistic than those obtained using Nadal's formula. Finally, a new derailment criterion is proposed. This new criterion leads to less conservative values than Nadal's equation for zero yaw angles. When the yaw angle is high enough, the results obtained are coincident with those predicted by Nadal's equation.