摩托车减震器总成静载荷特性分析

摩托车减震器总成从设计、工艺、制造、检测、试验到市场质量信息处理和分析等都和 静载荷特性有很大关联。减震器总成在设计时,外特性和静特性都要满足整车的要求,减震器静载 荷特性用来验证和考核该减震器总成是否满足整车设计要求。因此,摩托车设计时,减震器总成图 除给出装配尺寸和性能要求外,还应给出静栽荷特性。该项目应作为一个重要部分纳入到修订后 的行业技术标准中。     

无砟轨道桥梁桥面板ZK活载计算图示分析

为准确模拟高速铁路桥上无砟轨道结构传递ZK活载至桥面板上的荷载分布效应,采用Abaqus软件建立CRTSⅠ型双块式无砟轨道精细化数值分析模型,通过对底座板底面垂向应力等值线分布进行分析,开展高速铁路桥梁桥面板ZK活载计算图示的研究.研究表明,进行桥梁结构横向荷载计算或桥面板、桥面铺装等桥梁结构局部精细化受力分析时,在单...     

柔性吊桥的图解算法

柔性吊桥计算涉及到结构的几何非线性问题,它即是吊桥计算的基本内容,也对深入理解力学知识有一定帮助。本文阐述了运用力线图法图解计算柔性吊桥主索内力及线形,理论浅显,操作简便。     

Marginal cost congestion pricing based on the network fundamental diagram

Congestion pricing schemes have been traditionally derived based on analytical representations of travel demand and traffic flows, such as in bottleneck models. A major limitation of these models, especially when applied to urban networks, is the inconsistency with traffic dynamics and related phenomena such as hysteresis and the capacity drop. In this study we propose a new method to derive time-varying tolling schemes using the concept of the Network Fundamental Diagram (NFD). The adopted method is based on marginal cost pricing, while it also enables to account realistically for the dynamics of large and heterogeneous traffic networks. We derive two alternative cordon tolls using network-aggregated traffic flow conditions: a step toll that neglects the spatial distribution of traffic by simply associating the marginal costs of any decrease in production within the NFD to the surplus of traffic; and a step toll that explicitly accounts for how network performance is also influenced by the spatial variance in a 3D-NFD. This pricing framework is implemented in the agent-based simulation model MATSim and applied to a case study of the city of Zurich. The tolling schemes are compared with a uniform toll, and they highlight how the inhomogeneous distribution of traffic may compromise the effectiveness of cordon tolls.     

不同荷载图式作用下桥上无缝线路纵向力研究

2016年客货共线设计活载采用ZKH荷载图式代替了中-活载图式,其与ZK荷载图式存在明显差异,但两者作用下的无缝线路纵向力差异鲜有研究。建立有砟轨道单线简支梁线桥模型,对比分析了ZK,ZKH荷载图式作用下的无缝线路纵向力,研究了荷载图式变化对无缝线路纵向力的影响,并对建议的墩顶线刚度限值进行探讨。研究结果表明:ZK荷载图式作用下的无缝线路纵向力明显小于ZKH荷载图式,不同荷载图式引起的无缝线路纵向力差别受桥梁跨度影响不大,荷载图式作用下的无缝线路纵向力与图式竖向荷载基本呈线性关系。设计活载较大的线路对应的墩顶纵向线刚度限值也越大。     

考虑超级街区的城市路网边界控制策略研究

为缓解城市中心区交通拥堵状况,提出基于超级街区的路网多子区边界控制策略. 将城市区域路网划分为中心区、郊区及超级街区3个子区,结合宏观基本图(MFD)建立各子区交通流动态平衡方程;以中心区车辆出行完成率最高为目标,以边界收费费率和出、入口数量为控制变量,建立考虑车辆通道选择行为的路网多子区边界控制优化模型;并以实际路网数据为算例验证模型有效性.结果表明：边界控制策略下的中心区服务能力比无边界控制提高 7%;利用超级街区实现路网边界控制能够有效改善区域交通密度分布均衡性,提升路网服务效率;通过改变超级街区出、入口数量,实现边界控制兼备有效性和实践性.     

Empirics of multi-modal traffic networks – Using the 3D macroscopic fundamental diagram

Traffic is multi-modal in most cities. However, the impacts of different transport modes on traffic performance and on each other are unclear – especially at the network level. The recent extension of the macroscopic fundamental diagram (MFD) into the 3D-MFD offers a novel framework to address this gap at the urban scale. The 3D-MFD relates the network accumulation of cars and public transport vehicles to the network travel production, for either vehicles or passengers. No empirical 3D-MFD has been reported so far.In this paper, we present the first empirical estimate of a 3D-MFD at the urban scale. To this end, we use data from loop detectors and automatic vehicle location devices (AVL) of the public transport vehicles in the city of Zurich, Switzerland. We compare two different areas within the city, that differ in their topology and share of dedicated lanes for public transport. We propose a statistical model of the 3D-MFD, which estimates the effects of the vehicle accumulation on car and public transport speeds under multi-modal traffic conditions. The results quantify the effects of both, vehicles and passengers, and confirm that a greater share of dedicated lanes reduces the marginal effects of public transport vehicles on car speeds. Lastly, we derive a new application of the 3D-MFD by identifying the share of public transport users that maximizes the journey speeds in an urban network accounting for all motorized transport modes.     

网络化运营条件下的地铁乘务计划优化方法

随着城市轨道交通网络化运营程度的不断深入,乘务管理也需要不断适应线路结构、客流特征、列车方案、管理制度等因素的变化需求。乘务计划优化是一类综合考虑各类因素的多目标组合优化问题。对计划列车运行图、线路条件、乘务班制、劳动时间等乘务计划编制的关键因素进行分析,从编制条件和编制目标等方面研究了网络化运营条件下乘务计划的编制难点,从乘务班制、任务划分、网络统筹、编制的智能化和信息化等方面提出网络化运营条件下乘务计划编制优化的建议与方法。     

基于监控数据挖掘的运行图参数查定与修正方法

采用基于统计的异常数据处理方法对列车运行监控装置记录的海量列车运行实测数据进行处理,剔出其中的异常数据,设计数据补齐算法补齐缺失的数据;应用统计分析方法,在分析实测数据的集中趋势、离散程度、分布形态等规律和按照列车种类对数据进行时距分组的基础上,建立能够合理反映数据变化趋势的拟合曲线回归模型,用于参数的修正。运用给出的数据处理方法和拟合曲线回归模型开发出基于实测数据的运行图参数查定与修正系统。以大同—准格尔铁路为例进行验证,结果表明该方法及系统提高了参数的计算精度和查定效率,并且简便易行,可操作性强。