浅谈汽车电路图的识读方法与技巧

介绍汽车电路图的类型与特点;重点阐述汽车电路图的识读方法:灵活运用追溯法分析汽车的常规电路图,利用电路图的说明和图注作为指导去分析复杂电路和总线系统的电路,使电路图的识读水到渠成。     

Vehicle headway modeling and its inferences in macroscopic/microscopic traffic flow theory: A survey

Vehicle headway distribution models are widely used in traffic engineering fields, since they reflect the fundamental uncertainty in drivers' car-following maneuvers and meanwhile provide a concise way to describe the stochastic feature of traffic flows. This paper presents a systematic review of vehicle headway distribution studies in the last few decades. Since it is impossible to enumerate the merits and drawbacks of all of existing distribution models, we emphasize four advances of headway distribution modeling in this paper. First, we highlight the chronicle of key assumptions on the existing distribution models and explain why this evolution occurs. Second, we show that departure headways measured for interrupted flows on urban streets and headways measured for uninterrupted flows on freeways have common features and can be simulated by a unified microscopic car-following model. The interesting finding helps gather two kinds of headway distribution models under one umbrella. Third, we review different approaches that aim to link microscopic car-following models and mesoscopic vehicle headway distribution models. Fourth, we show that both the point scattering on the density-flow plot and the shape of traffic flow breakdown curve implicitly depend on the vehicular headway distribution. These findings reveal pervasive connections between macroscopic traffic flow models and mesoscopic headway distribution. All these new insights bring new vigor into vehicle headway studies and open research frontiers in this field.     

A kinematic wave approach to traffic statics and dynamics in a double-ring network

Recently there has been much interest in understanding macroscopic fundamental diagrams of stationary road networks. However, there lacks a systematic method to define and solve stationary states in a road network with complex junctions. In this study we propose a kinematic wave approach to defining, analyzing, and simulating static and dynamic traffic characteristics in a network of two ring roads connected by a 2 × 2 junction, which can be either an uninterrupted interchange or a signalized intersection. This study is enabled by recently developed macroscopic junction models of general junctions. With a junction model based on fair merging and first-in-first-out diverging rules, we first define and solve stationary states and then derive the macroscopic fundamental diagram (MFD) of a stationary uninterrupted network. We conclude that the flow-density relationship of the uninterrupted double-ring network is not unique for high average network densities (i.e., when one ring becomes congested) and unveil the existence of infinitely many stationary states that can arise with a zero-speed shockwave. From simulation results with a corresponding Cell Transmission Model, we verify that all stationary states in the MFD are stable and can be reached, but show that randomness in the retaining ratio of each ring drives the network to more symmetric traffic patterns and higher flow-rates. Furthermore we model a signalized intersection as two alternate diverge junctions and demonstrate that the signalized double-ring network can reach asymptotically periodic traffic patterns, which are therefore defined as “stationary” states in signalized networks. With simulations we show that the flow-density relation is well defined in such “stationary” states, and asymptotic traffic patterns can be impacted by signal cycle lengths and retaining ratios. But compared with uninterrupted interchanges, signalized intersections lead to more asymmetric traffic patterns, lower flow-rates, and even gridlocks when the average density is higher than half of the jam density. The results are consistent between this study and existing studies, but the network kinematic wave model, with appropriate junction models, is mathematically tractable and physically meaningful. It has offered a more complete picture regarding the number and type of stationary states, their stability, and MFD in freeway and signalized networks.     

东风牌EQ3208G型平头柴油自卸车线束图解

描述了东风牌EQ3208G型平头柴油自卸车线束的组成和布局,详细剖析了该车线束各个分支插接件和连接件的示意形状、对应电器位置及其线路的相关属性,并采用了新的线路表达方式,绘出了该车的电路原理图。     

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...     

三维实体有限元模型网格图的消隐问题

本文讨论三维实体有限元模型网格图的消隐问题。分析了它的数据结构、几何特征及图形表达等方面的特珠性,并对这类图形的计算机绘制计算方法作了初步探讨,提出了一些实用算法,并给出实例。      

基于眼图分析的数字滤波选取方法分析

在数字通信系统中,由于存在码间串扰而影响通信质量,如何减小码间串扰的影响是数字信号传输面临的一个问题。经过分析发现,在传输过程中选取合适的滤波器及其特征参数能够不同程度地减小码间串扰影响。通过对相同干扰条件下,数字基带经过不同的滤波器后形成的眼图进行分析,进而选取了适合传输的滤波器及其特征参数,用最佳传输滤波器的方法减小了码间串扰,从而提高了信号的传输质量。     

鱼骨图视野下提高炮兵旅作战效能的F-AHP评估

在一般情况下经常用F-AHP评判进行系统效能评估,定量的说明各种因素与最终结果的因果关系。文章引入了F-D（鱼骨图）方法的思想,对传统的F-AHP评判法进行了创新与改进,在F-AHP的基础上结合了F-D方法,通过F-D方法来弥补F-AHP中的主观性,已更加准确的找出其定性问题与定量结果的关系,得出更加精确的数据,使评估更加客观的反应真实,进而确定制约作战效能的因素,提出合理的意见,并进行实例研究。     

基于大数据的车门抖动解决方案

车门抖是指车门打开的瞬间,车门长时间的抖动,衰减过程较长.车门抖动给客户带来非常差的体验,影响对车身品质的整体评价.Z177车型量产过程中,突然出现右后门开门后窗框抖动的问题,持续了一段时间,一直没有彻底解决.此问题主要来自质量考核部门质量整车考核和客户考核抱怨,认为此问题会给客户带来非常差的感官体验,形成车身结构单薄...     

基于ANSYS二次开发的实体单元模型内力图的实现

当依据规范对结构承载能力极限状态和正常使用极限状态进行设计验算时,需掌握其内力状态.有限单元法对复杂结构进行内力分析有时需要采用空间实体单元,而ANSYS软件不能直接输出实体单元模型的内力图,需另行开发.文中介绍了利用软件后处理中的面操作,通过面积分和矩阵运算并编制APDL宏程序求实体单元模型内力图的方法.给出了4种不同截面形式的连续梁求内力图示例,并对实体单元模型的有限元解与采用三弯矩方程求得的理论解进行了比较.结果表明,文中所述方法可以方便地求得实体单元模型的内力图.