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791.
In this paper a conventional low volume maritime terminal equipped with straddle carriers is compared against an advanced automatic stacking crane/automatic guided vehicle alternative. For both configurations a convenient layout was designed, a reasonable level of service (common for both terminals) was adopted, and the required amount of equipment was determined using computer simulation. The results indicate that the total cost per container and the area requirements do not differ considerably between the two configurations although there exist differences in the investment capital and the personnel required. 相似文献
792.
Road Surface Correction o f Tire Test Data 总被引:1,自引:0,他引:1
P. Van Der Jagt A.W. Parsons 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1996,25(2):147-165
Most tire data used for vehicle simulations is measured on laboratory test facilities. An investigation showed that the frictional properties of these laboratory machines can be quite different from actual road conditions. This paper describes a method to correct laboratory tire test data to be more like road data in order to achieve a higher degree of correlation between instrumented test- and simulation results. 相似文献
793.
The Stationary Motion of a One-Axle Vehicle Along a Circular Curve with Real Rail and Wheel Profiles
P. Arrus A. D. de Pater P. Meyers 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2002,37(1):29-58
In this paper, we present a theory on the stationary motion of a one-axle railway vehicle along a circular curve in the presence of single- or double-point contact. The rail and the wheel profiles may be either stylized or real and as an example we take the profile combination UIC60 1:40 S1002. The mathematical model of the system is based on De Pater's first-order theory [1]. The geometrical contact problem between wheel and rail is solved by using a modified Newton-Raphson procedure. Both the cases with and without friction are considered. When friction is present, the non-linear Kalker creep law [6, 7] is used to describe the physical contact. For various values of the friction coefficient, the cant angle and the curvature of the track, the contact forces are presented as functions of the velocity parameter C v = V 2 / V 2 eq , where V is the velocity of the vehicle and V eq is the equilibrium velocity of the frictionless case. For the case of stylized profiles in which both the wheel treads and the wheel flanges are conical, and the rail cross sections are circular, we have determined the velocity range with single point contact in dependence on the friction coefficient, the conicity of the tread, the curvature of the track and the cant angle. 相似文献
794.
Information from various sources, but most specifically from the YORKSHARE car-sharing schemes, is brought together in an analysis of public reaction to, and participation in, a car-sharing scheme with centralised matching of applicants. The importance of various attributes of the sites, of the individuals and of the scheme organisation are assessed and conclusions are drawn.The motivation of individual participants is analysed and is seen to vary from one person to another depending to some extent on their circumstances, but the universal importance of some features, notably cost savings, is revealed. 相似文献
795.
W.X. Wu B.V. Brickle J.H. Smith R.K. Luo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1998,30(3):229-236
A model for the numerical simulation of vehicle/track interaction and stick-slip vibration is presented. A finite element model is developed to calculate vertical contact forces. These forces are then coupled through the contact patch into a non-linear time-domain model by which the stick-slip vibration behaviour of a wheel-rail system is analysed. The investigation suggests that stick-slip vibration may occur if a vehicle which has a maligned or an initial 'wind-up' wheeiset meets a vertical irregularity or contaminants on the track. 相似文献
796.
J. Castillo A. P rez De La Blanca J. A. Cabrera A. Sim n 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2006,44(3):207-221
An optical tire contact pressure test bench developed by the IMMa group is described. The measurement system is based on the frustration of total internal reflection (FTIR) of light. The test bench allows performing normal pressure distribution and patch contact shape measurements on passenger car tires. The system is based on the use of a laterally illuminated glass on which the tire leans. Between them a plastic interphase is located that will cause the FTIR of light. A video camera catches the formed shining image through the glass. The brightness level in each pixel of the image can be related to the existing normal pressure. The study of the contact patch provided by the bench makes it possible to characterize tire behaviour under different loading states, inflation pressure, tire defects and toe and camber angles. The bench incorporates a computerized load and control system of the tire operation parameters, an image acquisition module and a data acquisition system that allow monitoring and acting on the experimental variables of interest in the tests such as load on the tire and environmental conditions. A supporting mechanical system incorporated to the bench allows providing the tire with variable toe and camber angles. From the images obtained with this system, the maximum normal pressure points, total force, size and shape of the patch can be determined, which are related to the tire-use conditions. As an application example, results that show the patch size and shape under different load and tire inflation pressures are presented. A further application, which is the use of the system for the detection and study of defective tires is also presented. 相似文献
797.
岳阳 《变流技术与电力牵引》2005,(2):15-18
为使用超导磁体(SCM)的磁悬浮运输系统开发不需接触地面的车上电源,对减少环境污染(噪声和废气的排放)是非常重要的.文章提出了将线性发电机(LG)并入现有SCM以提高输出功率、改善功率因数和测量系统的可行性,并在山梨磁悬浮试验线进行了试验.装在转向架左侧的线性发电机,在400km/h和500km/h的速度范围内,能为磁悬浮车辆提供25kW的电力.分析和运行试验测量的结果有良好的相关性.因此可望将线性发电机投入实际应用. 相似文献
798.
The rapidly changing complexity of the Global War on Terrorism has changed the approach to equipping forward-deployed military forces. Combatant Commanders conducting operations now require timely materiel solutions to enhance mission capabilities and reduce the risk for individual soldiers. To address this challenge, the US Army established the Rapid Equipping Force to assess emerging requirements, to propose solutions to those requirements, and to implement those solutions in an expedient time frame. Unfortunately, the REF lacks a consistent analytical methodology for assessing alternative materiel solutions. To address the need for a human systems integration (HSI) analysis method, the authors developed an Assessment-Based Rapid Acquisition HSI Analysis Method (ABRAHAM) capable of generating tailored surveys and evaluating these surveys for unacceptable risks to soldiers. To validate ABRAHAM's concept and content, ABRAHAM was showcased in three Department of Defense settings: the Human Factors Engineering Technical Advisory Group, the REF, and the US Marine Corps' Operational Test and Evaluation Activity. The ABRAHAM appears to fill a gap in the current library of HSI tools. Based on the feedback provided during the product showcases, there is sufficient interest and technological maturity to further develop ABRAHAM to serve both the traditional and rapid acquisition processes. 相似文献
799.
800.
Governments of all persuasions are increasingly seeking the participation of the private sector in the supply of transport facilities and services. Private sector participation in the financing, construction, operation and maintenance of infrastructure is considered a serious option in a number of countries in the search for ways of providing much needed investment which would otherwise be deferred. This paper considers some economic and financial problems in the private sector provision of major road infrastructure within urban areas. The main issues are attaching prices (i.e. tolls) to the provision of the service, the value of government rights which are being given up either permanently or temporarily, and the identification required by the promoters of the cost of capital which is essential information in establishing the risk. Broader environmental and equity issues are not addressed. If the approach to establishing a private presence in a previously public supply context is handled properly from the outset, the benefits can be significant. Contrarily however, the prospects could be quite undesirable if badly managed, despite the presence of an extended public purse.requests for offprints 相似文献