基于MATLAB和VB的船舶短时电压波动检测软件设计

针对船舶短时电压波动检测软件的设计实现,介绍了用VisualBasic和Matlab混合开发该软件的两种实用方法。方法结合了VB和Matlab的优点,具有软件实现简单,界面友好,数据分析功能强,可做到实时复杂分析等特点,而且有利于实现对船舶电能质量信号的分析。     

并联式混合动力环卫车电控系统可靠性研究

由于混合动力汽车添加了驱动电机、动力电池组、电机控制器、电池管理器、整车控制器等模块,使其电控系统更加复杂,电磁环境也更加苛刻,传统汽车电控系统设计难以保证其可靠性要求。本文以SX5256DH434PHEV型并联式混合动力环卫车为研究对象,应用分布式层次化控制策略,通过分析电控系统可靠性的影响因素(振动、电磁干扰、散热、防水),提出了并联式混合动力环卫车电控系统控制器与线束的布置方案;可靠性试验结果反映了电控系统设计的可行性和布置方案的合理性。     

基于虚拟激励法的轨道车辆垂向振动响应分析

针对传统的随机振动分析方法计算复杂、计算量大的问题,提出采用虚拟激励法求解轨道车辆的垂向振动响应,建立某型车辆的垂向动力学模型,求解车辆的垂向振动响应并验证模型的正确性.与传统求解方法的计算结果比较表明,虚拟激励法适合于求解车辆的垂向振动响应,并且计算简单.在频域内对车辆垂向振动响应的分析表明:随着车辆运行速度的提高,车体、前后转向架以及一位轮对的垂向加速度的功率谱密度和振动主频均增大,轮对的垂向振动经一系悬挂传到转向架,再经二系悬挂传到车体,其振动频率f降低,振动幅值迅速减小,传到车体上时振动已变得很弱;f＞5Hz时,车体、前后转向架和一位轮对垂向加速度的功率谱密度均随着一系阻尼器两端橡胶节点刚度与一系弹簧刚度比值的增大而增加,尤其是车体和前后转向架的垂向加速度的功率谱密度变化更为明显,因此降低橡胶节点的刚度有利于提高车辆运行的平稳性.     

沪昆高铁防灾系统改造与优化

通过统计告警分布,对高铁防灾设备电源类和网络类告警的原因、特点进行分析和判断,并给出处理和减少此两类告警的思路和实施方案。     

Numerical simulation of level ice impact on landing craft bow considering the transverse isotropy of Baltic Sea ice based on XFEM

Ice bending is a major failure mechanism of level ice when ships and marine structures interact with level ice. This paper aims to investigate the ice bending and ice load when level ice collides on ships and marine structures using numerical simulation method, and compare the numerical results with field test. The fracture of ice is simulated with extended finite element method (XFEM), and cohesive zone concept is used to describe the crack propagation. In order to consider the characteristics of S2 columnar ice, a transversely isotropic elastic material model is used for the ice bulk elements, and a transversely isotropic Tsai-Wu failure criterion is adopted to predict the initiation of cracks. A well-controlled field test of a landing craft bow colliding with level ice in Baltic Sea is simulated to verify the numerical scheme. The ice plate's continuous deformation, crack initiation and crack propagation at different impact velocities and angles are simulated and the results are discussed. In the simulation, the bending crack emerges at the midline of the top surface of ice plate, then propagates towards free boundary, and finally a circumferential crack forms. It is found that with the impact velocity increases, the bending load increases and the fracture size (perpendicular distance from the crack to the contact edge) decreases. And as the angle between the landing craft bow and vertical direction increases, the bending load and the fracture size decrease. The simulated results corresponds well with the field test. The competition between the circumferential crack and radial crack is also found in the simulation and will be discussed in this paper. The results show that this method well simulates the bending of level ice and predict the ice load, and provides a good approach for investigating the mechanism of different forms of level ice fracture.     

Identification of emission hotspots in roundabouts corridors

This study describes a methodology to quantify and characterize the vehicular emissions of functionally interdependent roundabouts at a corridor level. Corridor segments include those upstream of each roundabout, the circulating area, downstream of the roundabout as well as midblock sub-segments between adjacent roundabouts. The main purpose of the study is to identify the locations along the corridors where emissions tend to be consistently high. These locations are termed “Emission Hotspots”. The methodology is applied to four existing roundabout corridors in San Diego (California) and Avon (Colorado) in the United States, and in Mealhada and Chaves (Portugal). An extensive sample of second-by-second speed traces is available for these four corridors with roundabouts.The analysis shows that when roundabouts are fairly spaced and have similar geometric design features, no significant differences are observed between emissions of roundabouts located in the corridor. In such cases, the downstream sub-segments are the emission hotspots both in absolute terms (overall contribution on total emissions is higher than 34%) and per unit distance (22% higher than the average corridor value). When roundabouts are unequally spaced the highest emissions hotspots (more than 9% above the average corridor value) are found at the circulating area sub-segments. The results also demonstrate that the entry deflection angle has a slight impact on the spatial distribution of emissions especially in the case of closely spaced roundabouts.     

DP2自升式平台环网电站关键技术研究

本文依托某采用环网电站技术的具有世界领先水平的DP2多功能自升式海洋平台实船项目，对这种非常规的动力定位系统的设计难点和要点进行剖析，重点介绍了平台环网电站在过载、短路等故障或扰动情况下的故障隔离和故障穿越技术，并列举了相应的解决方案，最后通过实船验证对该解决方案进行了论证和总结，供类似项目借鉴。     

Optimal development of alternative fuel station networks considering node capacity restrictions

A potential solution to reduce greenhouse gas (GHG) emissions in the transport sector is the use of alternative fuel vehicles (AFV). As global GHG emission standards have been in place for passenger cars for several years, infrastructure modelling for new AFV is an established topic. However, as the regulatory focus shifts towards heavy-duty vehicles (HDV), the market diffusion of AFV-HDV will increase as will planning the relevant AFV infrastructure for HDV. Existing modelling approaches need to be adapted, because the energy demand per individual refill increases significantly for HDV and there are regulatory as well as technical limitations for alternative fuel station (AFS) capacities at the same time. While the current research takes capacity restrictions for single stations into account, capacity limits for locations (i.e. nodes) – the places where refuelling stations are built such as highway entries, exits or intersections – are not yet considered. We extend existing models in this respect and introduce an optimal development for AFS considering (station) location capacity restrictions. The proposed method is applied to a case study of a potential fuel cell heavy-duty vehicle AFS network. We find that the location capacity limit has a major impact on the number of stations required, station utilization and station portfolio variety.     

柴油机增压器包覆层隔声性能试验分析及优化设计

提出一种船用增压器的包覆层结构,其内层为绝热材料和吸声材料,外层为金属薄片。采用统计能量法(SEA)建立该结构的中高频段隔声数值模型,开展包覆层的隔声试验,隔声量实测值与仿真结果吻合较好,能验证数值建模的有效性。对包覆层的吸声材料的厚度、密度和流阻等参数进行优化设计,利用正交试验法设计数值试验组,采用极差和方差分析法分析影响材料隔声性能的关键因素,得出最重要的影响因素是材料厚度,在选型设计中还应考虑密度和流阻因素。当安装厚度受限时,可通过改变密度和流阻值来提高材料的隔声量。     

基于GPS技术的实时拥挤收费系统

通过拥挤收费来缓解中心城市交通拥挤,是交通管理者探讨的一个热点,也出现了一些成功实施的案例。针对目前ERP系统的不足,本文利用ITS先进技术将拥挤收费与交通信息平台相结合,提出一个基于GPS技术的实时拥挤收费系统,描述了系统的工作流程与基本功能,并且建立起多车型多准则弹性需求下的拥挤收费费率优化双层规划模型。