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931.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(4):285-303
Based on Chinese No. 12 high speed, single-way swing nose rail concrete sleeper turnout, a comprehensive vehicle/turnout system coupling dynamic model has been established in this paper, and the lateral and vertical dynamic characteristics of vehicle/turnout systems have been simulated while the car passes through the turnout zone on divergence. These dynamic characteristics show that the lateral impact and vibration of the systems caused by the wheel/rail contact and irregularity are very intensive, especially at the switch zone and nose area of the turnout, and the lateral dynamics of the turnout system, such as lateral stability, vibrating responses, impacting and the allowable passing velocity force between the wheelsets and the switch rails are much more complicated than that of the vertical ones. 相似文献
932.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(2):301-320
This work describes an analytical approach to determine what degree of accuracy is required in the definition of the rail vehicle models used for dynamic simulations. This way it would be possible to know in advance how the results of simulations may be altered due to the existence of errors in the creation of rolling stock models, whilst also identifying their critical parameters. This would make it possible to maximise the time available to enhance dynamic analysis and focus efforts on factors that are strictly necessary. In particular, the parameters related both to the track quality and to the rolling contact were considered in this study. With this aim, a sensitivity analysis was performed to assess their influence on the vehicle dynamic behaviour. To do this, 72 dynamic simulations were performed modifying, one at a time, the track quality, the wheel–rail friction coefficient and the equivalent conicity of both new and worn wheels. Three values were assigned to each parameter, and two wear states were considered for each type of wheel, one for new wheels and another one for reprofiled wheels. After processing the results of these simulations, it was concluded that all the parameters considered show very high influence, though the friction coefficient shows the highest influence. Therefore, it is recommended to undertake any future simulation job with measured track geometry and track irregularities, measured wheel profiles and normative values of the wheel–rail friction coefficient. 相似文献
933.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(3):460-480
Braking dynamics plays an essential role in ensuring the comfort and running safety of trains. Due to the complexity of the phenomena involved and the presence of dry friction, studies have been carried out by numerical methods using smoothening. Based on the non-smooth dynamics framework, in the present paper, an efficient and comprehensive alternative model is defined. Set-valued friction of Coulomb's law type is accounted for and motion equations are formulated as a differential inclusion. Some of the fundamental issues of contact dynamics are briefly reviewed. Static friction forces which arise in buffers are computed in a very intuitive and efficient manner, using an original method involving generalised inverses of matrices. The corresponding algorithm is described. Numerical integration is done by an event-driven algorithm. Indeterminate system configurations can be appropriately handled. The number of vehicles on which tests have been carried out ranged from 5 to 50. Comparison with the smoothening method reveals significant differences. Computational efficiency is dramatically improved. Computation speed can rise by a few orders of magnitude. Specific phenomena such as stick–slip or persistent longitudinal forces can be evidenced. Computed values of the system states differ substantially. In addition to this, any wagon connection model can be embedded. 相似文献
934.
绕船体自由表面流的数值模拟 总被引:16,自引:3,他引:13
本文采用RANS方程和VOF算法数值模拟了系列60粘性自由面流动,比较了幂指数律,二阶迎风,QUICK格式对计算结果的影响,详细给出了波形,阻力,伴流等的计算结果,与试验及其它计算结果比较显示本文的计算方法具有较好的计算精度,可用于船型性能分析和优化。 相似文献
935.
Dynamic analysis of multibodies system with a floating base for rolling of ro-ro ship caused by wave and slip of heavy load 总被引:2,自引:0,他引:2
SHEN Qing LI Yue and CHEN Xu-jun The Engineering Institute of Engineer Corps PLA University of Science Technology Nanjing China 《船舶与海洋工程学报》2003,2(2):17-24
Common effect of wave and slip of internal heavy load will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibodies System with a floating base is composed of ro-ro ship and slipping heavy load. This paper takes the rolling angle of the ship and the transverse displacement of the heavy load on desk as two freedoms. Making use of analysis of apparent gravitation and apparent buoyaney, the wave rolling moment is derived. By use of dynamic method of multibodies system with a floating base, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the ship and displacement response of the slipping heavy load under common effect of synchro-slipping heavy loads and wave. 相似文献
936.
车辆--轨道耦合动力学仿真软件TTISIM及其试验验证 总被引:11,自引:3,他引:8
TTISIM仿真软件采用现代车辆—轨道耦合动力学理论,全面考虑轨道结构参振影响及动态轮轨空间接触几何关系。结合近年来国内有关提速、脱轨、新型机车车辆动力学现场试验,对TTISIM软件进行了系统的分析验证。结果表明,用该仿真软件计算的结果与试验测量结果吻合良好,说明该仿真软件可以用来分析研究各种铁道机车车辆在不同状态线路上运行时的动力学性能。 相似文献
937.
938.
J.M. Huthnance 《Journal of Marine Systems》1997,12(1-4)
The EC MAST project PROFILE (Processes in Regions of Freshwater Influence, ROFIs) aims to develop process understanding and tested numerical models for ROFIs. This includes the role of physical processes controlling water-property distributions, suspended sediments controlling the availability of light, nutrients and phytoplankton growth. The project comprises: (1) construction of a 3D nearshore model, with high resolution (1 h and one km approx.) and a framework coupling modules for hydrodynamics (tides, effects of winds and waves, currents, temperature, salinity, turbulence and diffusivity), sediments, plankton, nutrients and oxygen, (2) investigation of methods to include ROFI model detail in coarser shelf-wide models, (3) specific tests of model components against measurements, (4) tests of model calculations against measurements in contrasted ROFIs, (5) systematic observations suitable for these model tests (time-series over a seasonal cycle for dynamics and intermittency, good vertical resolution and spatial surveys) of the contrasted Rhine, Clyde and Thermaikos Bay ROFIs, complementing earlier measurements in the ROFI areas of the Rhine, German Bight and Po, (6) interpretation and comparison of the contrasted ROFIs' behaviour, (7) a defined set of observations, model code and output suitable for subsequent integration and promulgation as test data and a nearshore model for wider use. 相似文献
939.
运用SIMPACK多体动力学分析软件对某型地铁拖车进行了动力学建模和分析,显示该车具有良好的动力学性能,能够满足运行的要求。 相似文献
940.