微气泡减阻的二相湍流边界层模型计算

利用边界层中注入微气泡来降低固体壁面摩擦阻力是一项有实用价值且有待进一步研究的减阻技术.本文以含微气泡的湍流边界层为研究对象,以气液二相流理论为基础,对二相湍流边界层控制方程进行了详细讨论,并利用差分网格法进行了求解,计算结果表明微气泡具有明显的减阻效果.最后对影响减阻效果的因素进行了分析,指出了今后的研究方向.     

基于胎-梁耦合的湿滑跨座式单轨梁面抗滑性能研究

为了确保跨座式单轨车辆在不同工况下的行车安全,针对跨座式单轨车辆在雨天、冰雪、潮湿环境下的运行状态进行研究。基于流-固耦合算法(CEL)和有限元方法构建耦合关联的轮胎-梁面模型,在此基础上研究不同积水深度、不同行车速度条件下,轮轨垂向力和轮轨应力等参数的变化情况,解析水膜厚度与轮轨垂向力以及轮胎应力之间的关系。研究结果表明：接触参数数值变化受到梁面抗滑性能影响,这是引发行车安全问题的主要诱因。车辆轮胎接触垂向力随着梁面积水厚度的增加快速降低,从而引起车轮漂移、瞬间打滑现象。研究成果可为跨座式单轨制定行车安全的保障措施提供理论依据。     

新型救生装置流场性能数值模拟研究

海洋事故的频发和传统的救生装置存在不能进行及时救援和易受环境影响的缺陷,使得救援十分困难,因此新型救生装置应运而生。本文通过对三体叉式和整体式两种不同线型的新型救生装置进行阻力性能的数值仿真,分析其在空载、搭载儿童、搭载成人和极限四种载重工况下不同速度（0.5m/s,1m/s,1.5m/s,2m/s）时的流场性能,对比两种救生装置的阻力性能,得出相较于A型三体叉式救生装置,B型整体式救生装置的侧体对装置的阻力性能影响更大,且搭载重量越大,其阻力先增后减;救生装置表面高压的分布区域会随速度变大而发生变化,由前体向侧体后移,高低压差是影响阻力大小的关键因素。本文的研究对新型救生装置的优化提供了一定的数据支撑。     

基于宏观断裂力学的CFRP薄壁结构耐撞性能研究及应用

为了研究碳纤维增强复合材料（Carbon Fibre Reinforced Plastics,CFRP）薄壁圆管在准静态轴向压溃过程的压溃失效形式和吸能特性,提出一种基于宏观断裂力学理论基础的本构模型。通过对比试验和仿真结果,发现比吸能和平均力误差均小于1%,这验证了宏观断裂力学分析方法的合理性。为了进一步研究复合材料在汽车前纵梁吸能部件中的应用,从耐撞性能和轻量化角度出发,对比了CFRP前纵梁和钢质前纵梁的仿真结果。结果表明,在相同前纵梁结构件中,CFRP前纵梁的能量吸收能力要大于钢质前纵梁的能量吸收能力。     

FPDB——参量图生成的特殊方法

CAD系统中,解决图形生成的参量化问题推动我国CAD技术的应用与发展的主要问题之一。本文介绍一种特征参量数据库(FPDB)的建立,探讨一种图形参量化生成的积极有效的方法。对于寻求图形参量化生成的量佳途径具有现实的意义。     

Towards a standardized European road network database

Many Driver Information Systems, especially those that provide location information and route guidance instruction, rely on some form of digital map data, i.e. data that represent the location and other properties of earth-bound objects. A deeperinformation analysis of the data needs of the systems reveals that many needs are very close to the demands that a human navigator makes on a classical paper map. But it also reveals some hidden needs, which relate to the fact that the current Driver Information Systems have only a very poor or no general knowledge. Gathering all these data, putting them into a database and keeping them up to date is an enormous task. Therefore it is very important to know whatsurveying and digitizing techniques are the most suitable for such data. This question is currently being investigated by two DRIVE projects, PANDORA and Task Force EDRM.To guarantee the efficiency of a road network database and to guarantee the exchangeability of traffic messages, a certainstandardization will be inevitable. One possibility is to standardize the finished article, i.e. the map data in the form in which they are represented on the medium used by the system itself (e.g. CD, coded beacon message). This is the solution that has been chosen in Japan, where a CD-ROM based standard has been defined. It is also the solution chosen by the European manufacturers of beacon-supported systems such as Autoguide and LISB, who have defined a standard for the road-vehicle communication link. Another possibility is to standardize the semi-manufactured article, i.e. the map data as they occur in a general purpose road database or in the datafiles produced by data suppliers. This solution has been chosen by Bosch and Philips and had led to their GDF, in which they define a standard data content, a data model and an exhange format for these files. If the systems are going to combine data coming from different sources, the need arises for standard reference numbers. This means that an organizational infrastructure will have to be set up to create and maintain such a reference numbering system. A road database that is kept up to date, represents a lot of money. It will be vitally important for such databases to be legally protected against copying activities.     

可维护性机车检修网络图的设计与实现

主要从数据库规划和程序设计两方面，介绍了一种基于Delphi6．0和SQL Server2000的检修网络图动态生成方法，实现了网络图的可维护性。     

单片机控制的绝缘电阻的测试

介绍了单片机控制的绝缘电阻的测试系统组成，硬件工作原理，软件结构及软件编制的特点，并提出了几点抗干扰措施。     

Study of algorithms of new slender ship theory of wave resistance

In this paper, Noblesse‘s New Slender-Ship Wave-Making Theory was investigated numerically. Detailed expressions of zeroth and 1st order wave resistance have been derived and calculation programs have also been compiled. In the single and double integral terms of Green function, the kernel function of wave resistance expression, special function expansion method and Chebyshev polynomials approach have been adopted respectively, which greatly simplify the calculation and increase the convergence speed.