斗轮堆取料机行走电机的变频器调速设计

斗轮堆取料机是大型散货港口连续装卸系统的核心工具。本文介绍了斗轮机行走电机的变频器调速方法,降低了维护量,拥有较强的故障诊断功能,能够提高系统的可靠性,同时也可以降低生产经济成本。     

半刚性基层沥青路面轮组系数研究

大量半刚性基层路面结构运营未达到设计要求,主要原因是轴载换算存在不足。为了研究轴载换算中轮组系数的值,使用Apbi计算软件,考虑面层厚度、面层模量、基层模量的不同,计算弯沉与应力,根据推导而得的轮组系数公式计算得到轮组系数,结果表明：面层厚度、面层模量、基层模量对轮组系数的影响不大,但计算结果与规范相差较远。通过计算得出与规范不同的轮组系数,可为轴载换算的修正提供参考数据。     

车辆-高架桥耦合系统竖向振动分析车辆轨道新模型

针对CRTS Ⅱ型无砟轨道-桥梁轨道结构的特点,建立了列车-无砟轨道-桥梁耦合振动新模型。整个系统离散成一个多节点的轨道单元和具有二系悬挂的动轮单元,基于有限元方法和Lagrange方程,建立列车-无砟轨道-桥梁时变系统竖向振动方程。该模型具有程序编制容易、计算效率高的特点。作为应用实例,计算得出了两车通过时随机不平顺条件下轨道桥梁结构的动力特性,说明新模型正确可行。     

考虑材料非线性和辐辋过盈装配的车轮径向疲劳特性研究

首先建立了汽车钢制车轮的三维有限元模型,考虑材料非线性和轮辐与轮辋间过盈装配的影响,通过仿真计算得到其在径向载荷作用下的应力分布.接着采用以偏应力张量第三不变量来判断材料塑性变形拉压类型的方法进行车轮应力分析.,并根据危险区域的Mises应力值计算车轮疲劳寿命.最后,对上述仿真和计算结果进行了试验验证,结果表明了有限元模型和分析方法的正确性,为车轮结构的进一步轻量化设计奠定基础.     

TBM盘形滚刀磨损与滚刀滑动距离关系研究

盘形滚刀磨损是制约TBM掘进效率和施工成本的重要因素。为研究滚刀滑动对滚刀磨损的影响,提出了"一次侵入位移"的概念,应用质点的运动合成原理推导出了考虑滚刀刀刃宽度影响的一次侵入位移及滚刀滑动距离的计算公式,研究一次侵入位移的影响因素以及滚刀磨损与滑动距离的关系,基于上述研究分析秦岭隧道TB880E型TBM滚刀滑动磨损系数分布规律。研究表明:1)滚刀破岩过程中,刀刃相对开挖面岩石除滚动外,还产生相对滑动;2)中心区域滚刀侧向位移分量最大,滚刀磨损以剪切破岩和滑动磨损为主,中心区域以外滚刀沿掘进方向位移分量最大,滚刀磨损以碾压破岩和滚动磨损为主;3)应进一步综合考虑滚刀破岩量、滑动距离以及二次磨损等因素对滚刀磨损的影响。     

High-speed trains subject to abrupt braking

The dynamic response of high-speed train subject to braking is investigated using the moving element method. Possible sliding of wheels over the rails is accounted for. The train is modelled as a 15-DOF system comprising of a car body, two bogies and four wheels interconnected by spring-damping units. The rail is modelled as a Euler–Bernoulli beam resting on a two-parameter elastic damped foundation. The interaction between the moving train and track-foundation is accounted for through the normal and tangential wheel–rail contact forces. The effects of braking torque, wheel–rail contact condition, initial train speed and severity of railhead roughness on the dynamic response of the high-speed train are investigated. For a given initial train speed and track irregularity, the study revealed that there is an optimal braking torque that would result in the smallest braking distance with no occurrence of wheel sliding, representing a good compromise between train instability and safety.     

Single wheel hub motor failures and their impact on vehicle and driver behaviour

This research work studies the impact of single wheel hub motor failures on the dynamic behaviour of electric vehicles and the corresponding driver reactions. An experimental study in a moving-base driving simulator is conducted to analyse the influence of single wheel hub motor failures for motorway speeds. Driver reaction times are derived from the measured data and discussed in their experimental context. The failure is rated objectively on the dynamic behaviour of the vehicle and compared to the subjective evaluation. Findings indicate that critical traffic situations impairing traffic safety can occur for motorway speeds. Clear counteractions by the drivers had to be taken.     

Partial-profilogram reconstruction method to measure the geometric parameters of wheels in dynamic condition

The present work poses a method for the measurement of geometric parameters of rail wheels in a dynamic condition, by reconstructing the profilogram from a portion of the wheel surface wear with artificial vision. The suggested procedure can work with a two-dimensional laser displacement transducer or by processing a sole image from a single camera with a structured light source. These two procedures require fewer devices and simpler implementation processes and allow the use of mathematical algorithms that demand less information processing, thus generating more accurate results. Railway operators may implement this method to perform predictive maintenance to their rolling stock at a fraction of the regular cost; thus achieving better precision, availability, maintenance performance and improving safety. Results were compared to those given by commercial equipment, showing similar precision but a better cost–benefit relation.     

120km/h大功率交流传动内燃机车的粘着控制

简单介绍了120 km/h大功率交流传动内燃机车的基本性能,对该车的新型粘着控制方法及原理进行了推导演示,给出其粘着控制的实测数据波形.结果表明该粘着控制算法可以切实有效地提高机车牵引性能,减少机车空转/滑行现象.