To study the mechanical characteristics and live load effect of the ultra-wide steel box girder of the cable-stayed rail-cum-road bridge, based on the study of the ultra-wide steel box girder section of Yibin Lingang Yangtze River Bridge with a width of 63.9 m, a model of the composite structure with a scale of 1∶10 was designed and constructed for static load model tests and finite element analysis, where the mechanical characteristics, longitudinal and transverse normal stress distribution and beam deformation characteristics of the ultra-wide steel box girder were investigated under the dead load condition, road vehicle load condition, railway train load condition and combination of different live load conditions. The results show that the box girder of the bridge has a significant lateral bending force behavior, with the girder body exhibiting the mechanical properties and deformation characteristics of a shoulder-supported girder under the live load conditions. The middle box shows the mechanical characteristics of a simply supported beam with positive bending moment under the load of the railway train, while the side boxes of the beam show the mechanical characteristics of the cantilever beam with a negative bending moment under the load of the road vehicles, pedestrians and non-motor vehicles, showing reasonable design of the cross-section of the girder body, clear live load action mechanism, and clear force transmission of the middle and side box structures. The research results provide important reference and design basis for the design and construction of ultra-wide steel box girders, and provide guidance for the design of similar bridges.

为了提高超导电动磁悬浮列车的乘坐舒适性,建立由三辆车体与四台转向架铰接式组成的14自由度超导电动磁悬浮列车垂向-俯仰动力学模型,以轨道随机不平顺时间序列作为激励,通过研究车体垂向速度和垂向加速度的耦合作用规律,提出改进天棚阻尼半主动控制方法.通过建立仿真模型,对比分析天棚阻尼和改进天棚阻尼两种半主动控制方法应用于超导电动磁悬浮车辆次级悬挂的减振效果.结果表明,在改进天棚阻尼控制作用下,编组车辆中间车体质心处的垂向加速度和俯仰加速度的均方根值相比被动控制分别降低19.77％和17.34％;在获得相同减振效果的前提下,相较于天棚阻尼半主动控制方法,改进天棚阻尼控制半主动方法作用下输出控制力的峰值减小12.8％,因此改进天棚阻尼控制方法控制效果更佳,减振效率更高,更适用于车辆振动的控制.

该文提出一种等效模拟零磁通式电动悬浮的系统,阐述系统的工作原理和结构组成,并结合有限元仿真与实验测试对系统的电磁力特性进行分析.建立系统的三维有限元模型,研究了线圈运动速度、磁体垂向与横向偏移、线圈极距对系统性能的影响规律.研制样机并进行实验测试,测试了不同工况下悬浮力的变化情况,并与仿真结果进行对比分析,证明了有限元模型的准确性与可靠性.另外,实验样机实现了磁体的起浮,为零磁通式电动悬浮在轨道交通的应用与设计提供了理论依据.

钢-混凝土组合结构是土木工程中一种主要组合结构,能充分发挥混凝土和钢材的性能,可作为一种可持续发展的桥梁结构.近年来,随着绿色建造以及可持续建造理念的普及,钢-混组合结构桥梁在公路、铁路桥梁中所占比例逐步提高,学者们从多个方面开展了对钢-混组合结构桥梁的科学研究和工程应用.为了促进对该结构更加全面、深入的研究,指导钢-混凝组合结构在桥梁建设中更切合实际的应用与推广,对2019年度钢-混组合结构整体力学行为、钢-混组合结构剪力键、钢-UHPC组合结构、钢管混凝土结构及波形钢腹板-混凝土组合结构5个方面的最新研究进行梳理与总结,并对未来钢-混组合结构研究热点和方向进行展望.

为提高燃气调压器用指挥器的性能检测精度与效率、降低检测人员劳动强度,设计了一款基于STM32的燃气调压器指挥器的性能检测系统.该系自动调节指挥器进口压力,采用差压法实现了指挥器密封性的快速检测,利用开发的HMI界面进行人机交互和测试操作.试验结果表明,该系统工作稳定可靠,检测精度与效率高,降低了检测人员工作强度和失误率,已用于实际生产.

In order to improve the testing precision and efficiency of gas regulator, a performance testing system was designed.In this system, PLC was applied to regulate the pressure and flow in the pipeline.The static characteristic test of the regulator was realized.Differential pressure method was used to realize the rapid and dry detection of the regulator's tightness.The HMI interface was developed based on force control configuration software for human-computer interaction and testing operation.This system had good human-computer interaction, high detection accuracy and efficiency, which had been used in practical production.

通过建立三种不同的承台与管桩连接方式的有限元模型,对其力学行为进行有限元分析和研究.正常使用阶段分析了承台混凝土、填芯混凝土的应力;承载力阶段分析了结构的承载力和延性.有限元分析结果表明:在正常使用阶段,就应力水平而言,采用套筒连接方式优于管桩顶面端板上焊接锚固钢筋和管桩内放置插筋并浇灌填芯混凝土的连接方式.在承载力阶段,管桩内放置插筋并浇灌填芯混凝土连接方式的结构延性、耗能能力、变形能力比另外两种连接方式提高4%;套筒连接方式的承载能力比管桩内放置插筋并浇灌填芯混凝土连接方式提高16%.

在近代城市轨道交通的发展中,低地板轻轨车得到了快速发展.通过对其制动系统的分析和研究,阐述了低地板轻轨车的制动方式.介绍了磁流变液技术的原理及其在制动系统中的运用.以100％低地板轻轨车辆为例,在Simulink组件环境下建立磁流变液盘型制动器模型,分析了其性能特点,论述了磁流变液制动在低地板轻轨车上的运用前景.

介绍了中央导向胶轮轻轨车辆的主要特点及分类,并以法国Translohr型中央导轨胶轮车辆为例,分析了其导向特性,并展望了中央导向胶轮轻轨车辆在我国的运用前景.

The development and current status of rubber tire railway are presented,and the operational mode and classification of rubber tire railway are given.Taken rubber tire railway vehicles at home and abroad as examples,the development and application of rubber tire railway on urban mass transit are discussed,and the oldest rubber tire railway in China is introduced.On the basis of the comparison with traditional urban mass transit vehicle,the advantages and disadvantages of rubber tire railway are discussed,and the application prospect of rubber tire railway in China is elucidated.

In order to quickly design and analyze the fatigue strength of the wheel, parametric design of the wheel was designed based onVC++ and APDL. Professional wheel fatigue post-processing software was compiled by using of the hybrid programming of VC + + andMATLAB. The program could be transplanted between different computers without MATLAB software. The strength of worn wheel wasanalyzed in terms of UIC510-5 standard. The fatigue strength of worn wheel was analyzed by using four multi-axial fatigue evaluationmethods. The results showed: the distribute trend of the wheel’s safety factor was almost the same, but the minimum safety factor of differentmethods was different. The UIC method should be the optimal choice in the wheel fatigue strength assessment.

The development and current status of independent rotating wheels are presented,and the analysis of guiding mechanism is given.Taken the latest developed low floor mass transit vehicles abroad as examples,the application of independent rotating wheels on the current low floor mass transit vehicles is discussed.On the basis of the comparison with the mass transit vehicles that using traditional bogie to realize full-low floor,the development trend of low floor mass transit vehicle is elucidated,and the application prospect of low floor mass transit vehicle in china is discussed.

High speed independently rotating wheels bogies,the gauge-changeable bogies with independently rotating wheels and low floor LRV bogies with independently rotating wheels that developed in the past 100 years are described.The structure of powered bogies with independently rotating wheels of 100% low floor LRVs is analyzed according to the arrangement of the traction motor.The development and application prospect of independently rotating wheels in China are described.

The longitudinal,vertical and lateral coupling dynamics model for a certain type of multiple units(including 2 motor cars and one trailer) is set up with the SIMPACK software.With simulation of high speed operation and consideration of basic aerodynamics,the effects of longitudinal,vertical and lateral dampers between vehicles in high speed multiple units on the ride comfort indexes and acceleration,negotiation safety performance of the multiple units are discussed.The calculation result shows that installation of dampers between vehicles can make certain improvement on the dynamics performance of high speed multiple units.

The corrugated wear of sliding surfaces for wheel-rail was studied through simulating the contact stress of wheel and rail with pin-on-disk tester.The relationship between the friction-induced vibration and corrugated wear of sliding surfaces were analyzed through collecting the friction-induced vibration signals during testing,and profiles of worn scars of sliding surfaces after testing.The results show that friction-induced vibration can easily cause corrugated wear of sliding surfaces and the wavelength of corrugated wear is approximate to sliding speed multiplied by the period time of the friction-induced vibration.

The mechanism of a new air flotation equipment with an air water mixing chamber is explained. The removal efficiency of the equipment is determined under experimental conditions. For substances such as petroleum and suspended solids(SS), the removal efficiency is more than 95%. The experimental data are analyzed, and the relationship between the removal efficiency of the equipment and the rotational velocity is discussed. It is found that the removal efficiency increases with the rotational velocity before arriving at an optimal rotational velocity, and decreases over the optimal rotational velocity. Meanwhile, an empirical formula for evaluating the optimal rotational velocity is obtained.

The purpose of this paper is to study the wall jet in defined space during tunnel construction. For two dimensional wall jets in defined space, through a lot of experiments and theoretical analyses it is concluded that: (1) the flow field of wall jet in defined space can be categorized as the wall jet zone, the back flow zone and the eddy zone; (2) the boundary of a wall jet can be approximately regarded as a straight line and the angle of spread is 7.67 degrees; (3) the flow motions in the developing region and fully developed region of the flow are similar; and (4) along the distance, the maximum velocity of profile decays faster in defined space than that in half limitless space; and the length of the back flow zone in a defined space wall jet increases with the increase of the pipe flow. In this paper, the formula for calculating the length of the back flow zone is presented.