A Variable Free Control Characteristic Vehicle

A variable characteristic car (VCC) has been developed at Melbourne University for driverlvehicle handling research. The vehicle is unusual in that it has facilities for varying both its fixed control and free control dynamic characteristics over wide ranges. In this paper the servo systems used to effect these changes are described. The calibration methods used to relate the vehicle response characteristics to the variable servo settings are detailed. Sample calibration results are given for the fixed control parameters steering ratio, yaw response time and stability factor. Calibration of the free control parameters is also described and results are given for the steering torque gradient, and the time-to-peak and percentage overshoot of the steering wheel motion in response to a step input of torque.     

机构法结合遗传算法优化拱桥设计

对结构工程师来说,设计优化正变得日益重要。该文描述了一种结合机构法和遗传算法进行整体化设计优化的方法。前种方法是当前英国交通部采用的一种主要的计算拱的工具;后者是强有力的数值函数优化方法。文中显示了英国肯特Teston桥和一系列其它样本设计优化的试算结果及相关的算法有效性数据。建议本方法为涉及现存桥梁的评估、维护和修理及新拱桥设计的结构工程师的设计辅助工具。     

21世纪的美国交通

就美国交通的基本情况、发展模式、交通工具的选择和新技术的应用、智能交通系统及私有化和外包等诸多方面进行了深入的探讨，对美国交通的发展趋势做出了详尽而有理有据的预测，这样的综合介绍无疑会使我国的交通规划与发展颇受裨益。     

Simulation model for the study of overhead rail current collector systems dynamics, focused on the design of a new conductor rail

Overhead rigid conductor arrangements for current collection for railway traction have some advantages compared to other, more conventional, energy supply systems. They are simple, robust and easily maintained, not to mention their flexibility as to the required height for installation, which makes them particularly suitable for use in subway infrastructures. Nevertheless, due to the increasing speeds of new vehicles running on modern subway lines, a more efficient design is required for this kind of system.

In this paper, the authors present a dynamic analysis of overhead conductor rail systems focused on the design of a new conductor profile with a dynamic behaviour superior to that of the system currently in use. This means that either an increase in running speed can be attained, which at present does not exceed 110 km/h, or an increase in the distance between the rigid catenary supports with the ensuing saving in installation costs.

This study has been carried out using simulation techniques. The ANSYS programme has been used for the finite element modelling and the SIMPACK programme for the elastic multibody systems analysis.     

台湾隧道衬砌异状类别之探讨

以台湾隧道为背景,搜集整理1990年代以来安全检测作业调查所得的异状,并纳入相关报导中早期隧道的破坏案例,继而区分不同的异状及其类别,并探讨采用砖(石)砌、混凝土与钢筋混凝土等不同的衬砌材料以及不同构筑方式之隧道所发生的异状形态.     

隧道工程止漏树脂灌浆技术

隧道沿线经常遭遇断层、剪裂带、卵砾石层、有害气体、软弱地盘及河床下施工等问题,为克服此种困难地质,除了加强支撑措施之外,另外必须采取各种辅助工法才能顺利通过,其中止漏树脂灌浆材料能发挥止水(气)效果与固结功能,增强开挖面自立时间与稳定性.本文首先针对止漏树脂灌浆材料之特性作一概略说明,接着列举多项止漏树脂灌浆技术在台湾隧道工程之应用实例,包括:1)止气灌浆;2)修补衬砌;3)河床下浅覆盖开挖;4)止水灌浆.     

Physically Realisable Feedback Controls for a Fully Active Preview Suspension Applied to a Half-Car Model

An optimal preview type active suspension with feedback control based on easily measured relative displacements, velocities and accelerations is proposed. Measurements relative to the road, except by the preview sensor, are not required and the front and rear spring rates are quite arbitrary. Also, state estimators or observers are unnecessary and as a practical alternative the body accelerometers may be replaced by load cells. The effects of preview on the performance, for a theoretical step type road input and an analogous random road input, are described. The definition of the optimum preview function, and its consequent effects on performance, receives attention and an example is given.