Dynamic analysis of a pantograph-catenary system using absolute nodal coordinates

The dynamic interaction between the catenary and the pantographs of high-speed trains is a very important factor that affects the stable electric power supply. In order to design a reliable current collection system, a multibody simulation model can provide an efficient and economical method to analyze the dynamic behavior of the catenary and pantograph. In this article, a dynamic analysis method for a pantograph-catenary system for a high-speed train is presented, employing absolute nodal coordinates and rigid body reference coordinates. The highly flexible catenary is modeled using a nonlinear continuous beam element, which is based on an absolute nodal coordinate formulation. The pantograph is modeled as a rigid multibody system. The analysis results are compared with experimental data obtained from a running high-speed train. In addition, using a derived system equation of motion, the calculation method for the dynamic stress in the catenary conductor is presented. This study may have significance in providing an example that a structural and multibody dynamics model can be unified into one numerical system.     

半主动悬挂的横向和垂向阻尼系数对车辆动力学性能的影响

利用天棚控制原理和SIMPACK动力学软件建立了具有二系横向和垂向半主动悬挂车辆模型,分析在不同的半主动悬挂横向和垂向阻尼系数下,车体平稳性指标、构架加速度、轮对冲角和磨耗指数的变化情况,结果表明动力学性能之间存在多处相互矛盾的地方,在选择半主动悬挂横向和垂向阻尼系数时应合理安排,充分协调相互矛盾的动力学性能.     

On the dense water spreading off the Ross Sea shelf (Southern Ocean)

In this study, current meter and hydrological data obtained during the X Italian Expedition in the Ross Sea (CLIMA Project) are analyzed. Our data show a nice agreement with previous data referring to the water masses present in this area and their dynamics. Here, they are used to further analyze the mixing and deepening processes of Deep Ice Shelf Water (DISW) over the northern shelf break of the Ross Sea. In more detail, our work is focused on the elementary mechanisms that are the most efficient in removing dense water from the shelf: either classical mixing effects or density currents that interact with some topographic irregularity in order to drop to deeper levels, or also the variability of the Antarctic Circumpolar Current (ACC) which, in its meandering, can push the dense water off the shelf, thus interrupting its geostrophic flow. We also discuss in detail the (partial) evidence of dramatic interactions of the dense water with bottom particulate, of geological or biological origin, thus generating impulsive or quasi-steady density-turbidity currents. This complex interaction allows one to consider bottom particular and dense water as a unique self-interacting system. In synthesis, this is a first tentative analysis of the effect of bottom particulate on the dense water dynamics in the Ross Sea.     

碎石路基压实连续控制的试验研究

结合碎石路基工程实例,介绍压实连续控制的动力学方法的应用试验研究,分别从压路机性能参数、压实程度、压实均匀性等方面进行了实时监测与控制,达到了预期的目的,得出了原位试验结果与动态评价指标之间为正向关系的结论,进一步验证了理论分析的结果,为实际应用提供了必要的依据。     

SS7E机车与SS7E模块化机车动力学性能比较与分析

基于机车车辆一轨道耦合动力学理论，运用TTISIM动力学仿真软件系统，分析SS7E机车与SS7E模块化机车在弹性结构轨道上的整车动力学性能，并进行了详细的对比分析。研究结果表明：SS7E模块化机车与SS7E机车相比运行稳定性略优，曲线通过时的安全性能相当，直线运行平稳性十分接近。     

轮/轨接触几何参数对高速客车动力学性能的影响

为研究轮轨关系对高速铁路车辆动力学性能的影响,选择中国车轮踏面LMA与钢轨断面CHN60、日本新干线圆弧车轮踏面JP-ARC与钢轨断面JIS60和欧洲标准车轮踏面S1002与钢轨断面UIC60,应用AD-AMS/Rail软件,考虑轮对内侧距从1 353 mm变化到1 360 mm的情况,计算分析高速客车的临界速度、脱轨系数、车辆运行平稳性以及车辆稳态曲线通过的轮轨磨耗指数。车辆动力学仿真计算中均采用基于先锋号客车基本参数建立的车辆动力学模型。分析轮轨几何参数对高速车辆运行平稳性和稳定性的影响,结果表明:增大轮对内侧距可以改善舒适性,减小磨耗,提高临界速度。     

电力机车电子控制柜瞬态故障检测装置

介绍了一种新型的电力机车电子控制柜瞬态故障检测装置，阐述了装置工作的基本原理，并对关键的技术问题进行了分析，提出了解决方法。文章提出了一些新的检测概念，如快通道、慢通道、前史、后史等，在机车故障检测技术方面作了一些新的探讨与尝试。     

锚泊设备陆上性能测试系统的研制

在分析锚泊设备动静态综合性能及其性能试验所需的张力表现的基础上,提出了锚泊设备动静态张力负载仿真的策略。阐述了在陆地上通过模式控制的液压拖动系统仿真实际锚泊负载环境的途径,对系统的主要参数和结构布置进行了说明。锚泊设备陆上性能测试系统通过实时试验数据采集、仿真过程控制和在线性能分析等关键环节,实现了对锚泊设备的动静态性能的高效率的测试。     

平面假设条件下基于运动方程的飞机航迹仿真

在大地平面假设条件下，建立运动方程和仿真模型，利用MATLAB对运动方程的解算进行讨论，完成对飞机六自由度和飞机实时坐标的求解。其求解过程和结果对飞机飞行航迹的实时仿真具有较高的参考价值。     

Total dynamic response of a PSS vehicle negotiating asymmetric road excitations

A planar suspension system (PSS) is a novel automobile suspension system in which an individual spring–damper strut is implemented in both the vertical and longitudinal directions, respectively. The wheels in a vehicle with such a suspension system can move back and forth relative to the chassis. When a PSS vehicle experiences asymmetric road excitations, the relative longitudinal motion of wheels with respect to the chassis in two sides of the same axle are not identical, and thus the two wheels at one axle will not be aligned in the same axis. The total dynamic responses, including those of the bounce, pitch and the roll of the PSS vehicle, to the asymmetric road excitation may exhibit different characteristics from those of a conventional vehicle. This paper presents an investigation into the comprehensive dynamic behaviour of a vehicle with the PSS, in such a road condition, on both the straight and curved roads. The study was carried out using an 18 DOF full-car model incorporating a radial-spring tyre–ground contact model and a 2D tyre–ground dynamic friction model. Results demonstrate that the total dynamic behaviour of a PSS vehicle is generally comparable with that of the conventional vehicle, while PSS exhibits significant improvement in absorbing the impact forces along the longitudinal direction when compared to the conventional suspension system. The PSS vehicle is found to be more stable than the conventional vehicle in terms of the directional performance against the disturbance of the road potholes on a straight line manoeuvre, while exhibiting a very similar handling performance on a curved line.