武汉站高速列车对管帘天花结构振动影响研究

以武汉站实际工程为背景,推导了列车所引起的振动对车站装饰管帘天花结构的影响。通过分析得到了屋盖网架结构与管帘天花结构的动力响应的极值、变形分布规律以及频谱特性,并根据计算结果提出了减振措施。     

浅谈铁路客车空调故障的分析和处理

对空调装置各部分正常工作工况进行了说明,对空调装置故障按系统进行了分类,对空调装置的故障进行了分析,并对故障进行说明制定了处理方案,以保证铁路客车空调的顺利运行。     

车载晃车的原因分析及整治

阐述了车载添乘仪晃车管理和处理要求,通过分析线路晃车产生的原因和处所,提出了线路晃车整治方法,并总结了偏差整治中的注意事项,实践证明,车载添乘仪的运用提高了工作效率,保证了列车的安全、平稳运行。     

合理选用管接头

管接头是液压和气动系统中不可缺少的辅助元件。本介绍了几种常用管接头的结构，性能特点及在主机上的典型应用。     

轨道刚度对路轨系统及饱和地基动力响应的影响

研究了轨道刚度对高速移动列车荷载作用下铁路系统动力响应的影响。将钢轨简化为无限长弹性Euler梁,将枕木简化为连续质量块,同时考虑道渣层的影响。由Fourier变换求解多孔饱和固体的动力基本方程,在Fourier变换域内,联立铁路系统和下卧土体的动力方程,求解列车荷载作用下钢轨位移、加速度、土体位移、孔压表达式。利用数值积分方法对表达式进行Fourier逆变换,得到钢轨位移、加速度、孔压在时域内的表达式。算例中主要讨论了荷载移动速度和轨道刚度对钢轨速度、加速度及土体孔压的影响。结果表明,轨道刚度在低速情况下对路轨系统和土体动力响应有影响较小,但在高速情况下对路轨系统和土体动力响应影响很大。     

可液化砂土地铁列车振动作用下沉降特性分析

地层的不均匀以及一些特殊地层的存在,对列车振动荷载作用下的长期差异沉降具有较为显著的影响,直接影响到地铁列车营运期的长期安全问题。以佛山地铁2号线为例,通过数值模拟的方法对加固前与加固后可液化砂土层中的结构受力与地层沉降进行了具体分析,研究结果表明列车振动荷载对结构和地层整体影响较小,产生的位移较小。在列车长期循环振动荷载作用下,隧道会产生长期的沉降,沉降量初期发展较快、后期发展缓慢。对可液化地层进行注浆加固可以显著减少隧道沉降量。     

虹桥枢纽磁浮—地铁—站屋耦合振动研究策略

结合虹桥综合交通枢纽磁浮站屋结构一体化设计研究课题,本文介绍了大型综合交通枢纽站中的磁浮列车与地铁—站屋耦合振动的研究策略和技术路线。通过理论分析与试验结果对比表明：在目前的研究水平下,该研究策略和技术路线是可行的。     

Full-scale measurements for evaluation of coal dust release from train wagons with two different shelter covers

The paper describes a full-scale study performed to evaluate the amount of coal dust released by eolian erosion from partly covered train wagons over runs of 350 km. The experimental setup designed for this study is described along with the effectiveness assessment of two types of dust collectors. Airflow statistics are reported for the region immediately above the top level of the wagons. Visualisation tests for the fugitive dust indicate that most of it leaves each wagon primarily through the rear end. The releases from the partly covered wagons are compared against those from the uncovered wagons, to assess the performance of the covers in what concerns the reduction of fugitive dust. The amounts of dust collected after being treated through an error analysis yields an estimate for the total amount of coal released from each wagon under consideration.The uncertainties resulting from a full-scale study based on actual operating conditions were taken into account and the major contribution of this study is toward the quantification of the fugitive dust release, which seems to have been overlooked in studies appearing in the open literature. The value of less than 0.001% of the 60 tons net load of coal for partly covered wagons, using a 95% confidence interval, over a particular 350 km run, may be representative of many other similar situations. This value tends to be lower than the values usually quoted in different contexts, and primarily within environmental impact assessments.     

磁浮列车对某枢纽磁浮站屋荷载作用特性研究

结合虹桥综合交通枢纽磁浮站屋结构一体化设计研究,介绍了磁浮列车与考虑轨道梁间耦合振动的研究成果,磁浮列车的动力荷载特性的理论分析结果与磁浮试验对比表明：该研究方法是可行的。     

Fluid filling of a membrane tube with self-weight

The filling of a membrane tube with self-weight by a fluid is studied theoretically for the first time. The fundamental problem depends on two non-dimensional parameters, $\beta$ and $\gamma$ which represent the importance of internal pressure and membrane self-weight respectively. The nonlinear equations are solved by an efficient numerical integration method. It is found that membrane self-weight has considerable effect on the tube geometry and the tension of the membrane at low filling pressures.     

谈给水管材管路系统的类型及管材合理选用

针对给水管材管路系统的合理选用问题，通过多年的工作实践，从冷水管路系统和热水管路系统两方面对常见的管材作了分析比较，为给排水工程技术人员合理选用管材提供了参考。     

着火列车制动进站过程烟气扩散特性模拟

为探究火灾列车制动驶向地下车站进行救援时的烟气扩散特性，采用理论分析和数值模拟的方法研究在不同控制烟气措施下，火灾列车减速至停止过程中烟气在车站轨行区及站台层的扩散规律，以及车站防灾通风系统受到的影响。结果表明：火灾列车制动进站时受移动火源与活塞风两大特性影响，烟气在上下游表现出明显的不均匀、不对称分布规律；屏蔽门虽能有效阻止烟气蔓延至站台层，但同时会增大轨行区活塞风速，增加烟气蔓延速度，不利于安全疏散；受活塞风影响，轨行区排烟效率下降了14%，轨行区各排烟阀火灾中下游排烟效率更高。     

The influence of train properties on railway ground vibrations

This paper uses a sensitivity analysis to quantify the dominant train properties (mass and spacing of wheels and bogies) that contribute to ground-borne vibration generation, with the aim of reducing the complexity of train–track numerical models. This research is significant because ground-borne vibration from railways is a growing problem, particularly in urban areas. Despite this fact, attempting to predict vibration levels is complex because there are many variables that contribute to the overall dynamic response. Therefore, a deterministic approach is commonly used, that ignores many of these variables. Thus, this paper identifies the variables that can be ignored, while highlighting those that are highly influential on vibration generation. For this purpose, a previously validated 2.5D finite elements-boundary elements approach is used to simulate dynamic train–track interaction. It is computed many times for a variety of modelling variables to investigate the effect of each on the ground-borne vibration levels in the far field. It is found that increases in unsprung mass of the train causes a large increase in vibration levels. Furthermore, changes in wheel/bogie spacing and semi-sprung mass are found to have a minimal effect on vibration generation.     

巨型框架-核心筒结构地震剪力分布特征分析

目前,我国在巨型框架-核心筒结构体系的工程设计中主要参照现行规范对于普通框架-核心筒结构的相关规定执行。然而,巨型框架-核心筒结构与普通框架-核心筒结构的受力特点及规律有所不同,针对巨型框架-核心筒结构与普通框架-核心筒结构的框架剪力分布特征的对比研究有待完善,而且我国现行规范也缺乏对巨型框架-核心筒结构中框架剪力的调整规定。因此,通过典型普通框架-剪力墙与巨型框架-剪力墙平面模型算例的静力分析及典型巨型框架-核心筒结构算例的弹塑性动力时程分析,考察了地震作用下楼层剪力在结构各竖向构件之间的分布规律。结果表明：地震作用下巨型框架-核心筒结构中的框架楼层剪力分布规律与普通框架-核心筒结构有明显区别;巨型框架柱与次框架柱的楼层剪力分布规律存在明显差异;规范中规定的框架剪力调整方法不能直接应用于巨型框架-核心筒结构。结合分析得到的剪力分布规律及已有的工程经验,针对巨型框架-核心筒结构中框架剪力调整方案进行讨论并给出相关建议。     

广州市大北枢纽站设计探讨

现代交通建筑随着中国的现代化建设的进程、交通行业的发展、城市之间经贸往来和流动人口的增长已经在悄然地发生变化,许多旧式汽车客运站已经不能满足当前客流日益增长的需求,本文通过介绍广州市大北枢纽站的设计,总结现代汽车站设计的新思路,提出新的见解。     

列车荷载作用下路轨系统及饱和弹性半空间上覆盖土层的动力响应

用解析法研究了移动列车荷载作用下下卧成层地基的路轨系统的动力响应问题。将整个系统分为上覆路轨系统和下卧土体。对于路轨系统,将钢轨简化为无限长弹性Euler梁,将枕木简化为连续质量块,同时考虑由Cosserat模型描述的道渣层。在实际工程中,地下水位往往位于地表以下几米处,因此将下卧土体考虑为成层土,其中,上层为弹性介质,下层为由Biot波动方程描述的饱和弹性半空间。在Fourier变换域内,联立铁路系统和下卧土体的动力方程,求解列车荷载作用下钢轨位移、加速度,土体位移、加速度,孔压表达式。利用数值积分方法对表达式进行Fourier逆变换,得到钢轨位移、加速度,土体位移、加速度,孔压在时域内的表达式。着重研究了弹性层厚度、密度、刚度和道渣层质量对钢轨动力响应的影响。计算结果表明,在低速情况下,这些参数对钢轨动力响应影响都很有限,但在高速情况下,这些参数对钢轨动力响应的影响都很大。     

Optimum seismic design of steel framed‐tube and tube‐in‐tube tall buildings

The relatively large number of structural elements and the variety of design code requirements complicate the design process of tall buildings. This process is exacerbated when the target is to obtain the seismic code‐compliant optimal design with minimum weight. The present paper aims at providing a practical methodology for the optimal design of steel tall building structures considering the constraints imposed by typical building codes. The applicability of the proposed approach is demonstrated through the determination of the optimal seismic design for 20‐, 40‐, and 60‐story buildings with a framed tube as well as a tube‐in‐tube system. Such a design gives rise to a basis for the fair comparison of the behavior of the framed tube with that of the tube‐in‐tube system under applied loads. The optimal weight of the buildings with the tube‐in‐tube system turns out to be slightly less than that of the buildings with the conventional framed‐tube system.     

Performance characteristics of a two-stage transcritical N2O refrigeration cycle with vortex tube

ABSTRACT

The thermodynamic analysis has been presented in this article using nitrous oxide as the refrigerant in a two-stage transcritical cycle with the vortex tube (TSTCVT) instead of the expansion valve and its results are compared with the two-stage transcritical cycle with the expansion valve (TSTCEV). The evaporator and the gas cooler temperature ranges in both the cycles have been considered between ?55°C to 5°C and 35°C to 60°C for the analysis. Gas cooler and intercooler pressures are simultaneously optimised to obtain the maximum cooling coefficient of performance (COP). The COP of the TSTCVT improves by 1.97–27.19% in comparison to TSTCEV. A decrease in evaporator temperature and an increase in gas cooler exit temperature reduce the COP of TSTCVT. The comparison of refrigerants N₂O and CO₂ in TSTCVT shows that N₂O exhibits higher cooling COP, higher second law of efficiency and lower optimum gas cooler pressure under the considered operating conditions.     

浅谈钢管混凝土的特点和应用

从承载能力、抗震性能、制作施工、耐火性能等方面介绍了钢管混凝土的特点,结合实例列举了钢管混凝土结构的运用,基于钢管混凝土的特殊优点,使得其在工程界广泛应用。     

基于Timoshenko梁理论的车辆荷载下沉管隧道振动预测

考虑车辆荷载影响,将沉管隧道管节等效为置于黏弹性地基上的Timoshenko梁,改进传统柔性接头等效模型,考虑接头阻尼作用,建立沉管隧道管节动力响应计算模型。依据Timoshenko梁理论,推导管节竖向振动微分方程,采用数值方法对管节位移响应进行求解。依托宁波甬江沉管隧道工程,分析车辆荷载下沉管隧道管节中点和端部的竖向位移响应情况,计算接头两端最大竖向位移差,并进行单因素影响分析。研究结果表明:江中段管节竖向位移较岸边段大,管节中点竖向位移较管节端部大,最大竖向位移达到3.7 mm;各接头参数相同的情况下,岸边接头的竖向位移差较中间接头大,最大竖向位移差达到1 mm;地基分布弹簧系数、接头刚度和车速对管节竖向位移幅值影响较大,而在安全车距范围内,车流密度对管节竖向位移幅值影响不大。