Multibody dynamics modelling of the freight train bogie system

Previous work in the railway technology laboratory at Virginia Polytechnic Institute and State University (Virginia Tech) focused on better capturing the dynamics of the friction wedge, modelled using three-dimensional rigid body dynamics with unilateral contact conditions. The current study extends the previous work to a half-bogie model treated as an application of multibody dynamics with unilateral contact to model the friction wedge interactions with the bolster and the sideframe. The half-bogie model was derived using MATLAB and functions as a three dimensional, dynamic, and multibody dynamics model comprised of four rigid bodies: a bolster, two friction wedges, and a sideframe assembly. This expanded model allows each wedge four degrees of freedom: vertical displacement, longitudinal displacement (between the bolster and sideframe), pitch (rotation around the lateral axis), and yaw (rotation around the vertical axis). The bolster and the sideframe are constrained to have only the vertical degree of freedom. The geometry of these bodies can be adjusted for various simulation scenarios. The bolster can be initialised with a pre-defined yaw (rotation around the vertical axis) and the sideframe may be initialised with a pre-defined pitch/toe (rotation around the lateral axis). The results of the multibody dynamics in half-bogie model simulation are shown in comparison with results from NUCARS^®, an industry standard in train-modelling software, for similar inputs.     

快速公交系统票制票价敏感性分析

快速公交（BRT）因其快速、便捷、高效等优良品质被许多城市采用，近年来，在世界各地发展迅猛。票制票价作为BRT系统的重要组成部分也受到了关注。介绍国际国内城市的BRT票制票价情况，对票制票价的敏感性进行分析。从昆明市的实际情况出发，结合公众意愿调查数据，分析居民公交费用支出对居民收入、出行时耗、舒适度以及拥挤收费的影响情况，为昆明市BRT系统的改造与提升提供基础支撑。     

某铸造和采石作业生产性粉尘的粒子结构和元素分析

调查研究某铸造作业和采石作业生产性粉尘成分的元素含量。用扫描电子显微镜和X射线能量色散仪测定某铸造作业翻砂车间、造型车矧、清砂车间和某采白作业生产性粉尘粒子的结构及各元素的百分含鼙。随着铸造用的砂粒结构向多面结构改变，其粉尘中各元素的百分舍最也随浇铸、高温发生改变，氧、硅、硫逐渐减少，铝、钙、铁逐渐增多，牛产性粉尘的粒子结构和元素成分发生变化。     

转K1型转向架组装工艺

介绍了转K1型转向架的结构特点和关键技术参数,着重分析了侧架导框的加工、侧架与支撑座板的组焊和转向架的组装工艺等。     

考虑疲劳强度和减轻质量的转向架构架设计

用有限元法对各种载荷工况下的转向架构架进行了疲劳分析,利用人工神经网络和遗传算法最大程度地减轻了转向架构架的质量.     

"肋骨冷弯加工机器人"的研制

从弦线测量法控制原理、大地式检测装置、"肋骨冷弯加工机器人"信息集成系统、加工数据预处理、智能控制方法、自动冲印号料装置诸方面,较为详尽地介绍了最近研制成功的、国际首创的"肋骨冷弯加工机器人"。该"肋骨冷弯加工机器人"业已成功地应用于造船生产。     

横系梁对双肢薄壁高墩刚构桥稳定性的影响分析

研究目的：高墩桥梁稳定性一直是影响桥梁结构安全的关键因素，如何在保证桥梁外形美观、结构受力合理的情况下提高高墩桥梁的稳定性，是工程技术人员一直在探讨的问题。本文以京承三期清水河2^#桥为工程背景，采用三维有限元分析软件SAP2000对双肢薄壁高墩刚构桥进行空间稳定性分析，并对比分析在有无横系梁的情况下最大悬臂施工阶段和成桥阶段桥梁的稳定性。研究结论：初步得出了墩间横系梁对双肢薄壁高墩桥梁稳定性的影响：墩间横系梁主要对顺桥向的桥梁稳定性贡献较大，对桥梁横向稳定性基本上没有影响；随着墩问横系梁数量的增加，对稳定性的贡献也趋于稳定。恰当地设置横系梁能有效地提高双肢薄壁高墩刚构桥梁的稳定性，但随着横系梁数量的增加稳定性提高并不明显。     

沉井结构在大型原水泵房中的应用及研究

在长江取水工程中,取水口的高度会对通航及河床稳定有直接的影响,因此在设计中一般会尽量降低取水口标高,这将会导致与之相连的原水泵房的埋深通常都比较深.在这种情况下,沉井施工工艺将比传统的基坑支护更有优势.通过具体的工程实例,阐述了沉井结构如何以带框架(或中隔墙)下沉的形式应用于较大型原水泵房,并对沉井在下沉阶段、水下封底阶段、顶管施工阶段及使用阶段中的稳定性及受力进行分析研究,为同类工程提供借鉴.     

K形、KT形圆钢管桁架节点试验及力学性能分析

在对750k V格构式变电构架K形、KT形圆钢管桁架节点足尺试验研究的基础上,采用ABAQUS软件对优化的钢管节点进行有限元数值分析,考察减小连接板厚度以后K形、KT形钢管节点的受力性能和承载力、连接板应力分布及变形等指标。结果表明:在设计荷载作用下节点没有明显变化,处于弹性状态;超加载阶段,试件局部进入塑性,但分布面积较小,区域不连通,节点整体受力稳定。有限元分析的连接板应力分布及变形趋势与试验结果吻合较好。     

Investigating the influence of soil properties on railway traffic vibration using a numerical model

This paper presents the influence of dynamic and geometrical soil parameters on the propagation of ground vibrations induced by external loads. The proposed approach is based on a three-dimensional model, focusing on realistic excitation sources like impulse loads and moving railway vehicles. For the latter, a complete vehicle/track model is developed. The simulation is performed in time domain, offering an interesting approach, compared with classic cyclic analyses. The ground is modelled initially as an elastic homogeneous half-space and additionally as a layered half-space. First, the effect of homogeneous soil properties on ground vibration is analysed. Soil stratification is then taken into account, using various configurations. Analysis reveals that as receiver distance increases ground wave reflection in a layered ground plays an important role in the reduction of ground surface motion. This effect is magnified when the phase velocity wavelength becomes large compared with the depth of the surface layer.