Wheel/rail interface management in heavy haul railway operations—applying science and technology

The primary objective of the paper is to review science and technologies that have been developed by various scientists and engineers over the years and that have made it possible to push the limits within the wheel/rail interface in the heavy haul railway environment. After describing the wheel/rail stress-state and its consequences, preventative and corrective measures that can assist in optimising wheel and rail life, and thus reduce costs, are reviewed. The significant contribution of measurement and monitoring technologies to quantify the stress-state of the wheel/rail system is highlighted. Finally, a brief review of the fundamentals of contact mechanics, vehicle dynamics and wheel/rail interface analysis software is given.     

钢轨轨头三维应力有限元分析

应用有限元分析程序ANSYS5．5对60kg·m-1钢轨轨头接触应力和最大负弯矩截面的弯曲应力进行了分析计算，并给出在实际机车轮压作用下有关截面上的应力数值和分布规律，为今后研究钢轨轨头近表面区域缺陷的发展规律及预测伤损钢轨的使用寿命提供了依据。     

准双曲面齿轮有摩擦承载接触分析

本文推导了准双曲面齿轮有摩擦承载接触问题的数学规划解法，首先采用有限元方法计算工作齿面网格结点的柔度张量，并通过插值和叠加获得一对啮合齿在各接触位置上接触椭圆长轴离散点的综合柔度，然后结合齿面几何因素（包括齿面间隙，滑动系数，法矢和切矢对于转轴的矢径等）建立了接触问题的线性规划模型，采用载荷增量法求解了摩擦的接触变形过程，本文还以一对准双曲面齿轮为例，进行了整个啮合过程的承载接触分析。     

球笼式等速万向节接触应力分析与计算

球笼式等速万向节是前置前驱动轿车的关键部件之一，其性能和寿命与接触应力密切相关。对球笼式等速万向节的接触应力进行了分析，给出了计算方法，并对某一车型的ＢＪ７５型球笼式等速万向节进行了计算，结果表明内滚道接触应力大于外滚道，内滚道易于磨损。     

A simplified model of wheel/rail contact mechanics for non-Hertzian problems and its application in rail vehicle dynamic simulations

The presented model assumes semi-elliptical normal pressure distribution in the direction of rolling. The contact area is found by virtual penetration of wheel and rail. The normal pressure is calculated by satisfying contact conditions at the geometrical point of contact. The calculation is non-iterative, fast and completely reliable. It may be carried out on-line in MultiBody Systems (MBS) computer codes. The tests using the programme CONTACT by Kalker and experience from application in MBS codes show that the model is suitable for technical applications. The creep forces have been calculated with the FASTSIM algorithm, adapted for a non-elliptical contact area. Some applications in rail vehicle dynamics and wear simulation have been outlined.     

针对行人保护头部仿真分析中雨刮臂的接触设置研究

利用计算机进行有限元仿真分析,在汽车行人保护性能开发过程中有着广泛的应用。对于行人保护建模来说,风挡玻璃区域应按照实际情况对玻璃进行准确建模,然而对于风挡玻璃与雨刮器采用以往的接触设置,雨刮臂与玻璃产生穿透现象。因此为了解决穿透问题,准确模拟出其实际运动关系,对于雨刮臂与风挡玻璃之间的接触设置研究是非常有必要的。     

基于Bro的蠕虫检测系统设计及实现

在分析蠕虫传播机制基础上,基于入侵检测系统Bro的整体框架,以基于FCC（First Contact Connections,第一次连接）失败概率和重尾特性的蠕虫检测算法为核心,设计并实现了基于Bro的蠕虫检测系统。该系统对Bro的策略脚本解释器进行扩充,实现上述检测算法的策略脚本,将检测结果输出到共享内存,基于SNMP协议,将检测结果传送至监视端,方便用户对网络蠕虫的实时监视。该系统能够迅速准确地检测出网络上的蠕虫主机。     

汽车转向器齿条齿扇传动副的几何和啮合计算（续1）

为便于研究变厚渐开线齿轮在循环球齿条齿扇式转向器中的应用,文章介绍了变厚渐开线式齿扇在设计过程中相关参数的选择方法,并通过大量计算得到转向器变齿厚齿扇齿条传动参数匹配表方便设计师的查阅使用;还介绍了齿扇大端单边转角计算方法和齿条齿根圆角干涉验算方法,通过实例计算验算其正确性.结果表明,通过合理地选择变位系数、齿顶高及齿根高,可以确保齿扇大端面齿顶圆齿厚达到0.3～0.5个模数,大端截面重合度达到1.0.     

Understanding ship-grounding events

The paper presents a simple procedure to estimate the damage to a ship bottom and the associated seabed topology that results from a dynamic grounding event. The seabed is modeled as a rigid body and parameterized by a quadratic surface, i.e., a paraboloid, which can in principle model a wide range of seabed topologies. A nonlinear finite element program (LS-DYNA) is used to simulate the contact force versus the lateral penetration, from which the horizontal force component of powered grounding is estimated. The simplified procedure for analyzing dynamic and static grounding events is outlined. Simulations are performed for different ship speeds and for different initial levels of obstruction over the keel. It is shown that a static approach may replace the dynamic grounding simulation, thereby considerably reducing the computational work. The static approach allows for the quick estimation of the energy absorption during powered grounding, which is imperative for decision making during critical situations. The ultimate goal of the study is to provide a near real-time prediction of the risk of rupture of the cargo tanks and hull girder failure. Moreover, the residual strength of damaged ships is an important issue that is related to operations involved in the salvage of wrecked vessels, such as re-floatation and towing.     

基于直接积分法的弓网耦合系统动态性能仿真分析

针对提速铁路采用的弹性链型悬挂接触网及受电弓结构,建立包含承力索、辅助线、接触线和吊弦4个部件的接触网模型、以及简化为弹簧阻尼机构的受电弓模型。通过接触单元将接触网和受电弓直接耦合起来得到弓网系统的整体模型,进而构建弓网耦合系统的动力学平衡方程。采用直接积分法对建立的平衡方程进行求解,得到反映弓网系统动态性能的抬升位移、接触压力以及应力等数据。与先前研究的参考数据比对结果表明,采用接触单元和直接积分法分析弓网耦合系统的动态性能,切实可行。