碳纳米管在汽车上的应用

碳纳米管具有独特的结构和优异的物理与力学性能,在众多领域有广阔的应用前景,在汽车上的应用也倍受关注。本文对碳纳米管在汽车上的已有应用及潜在的应用进行了综述,包括汽车新能源动力系统、轻量化结构材料、多功能复合材料等。     

马凌河大桥T梁施工简介

介绍了马凌河大桥T梁在支架上现浇横移及T梁在T梁上现浇横移的施工经验。     

湛江市规划管理(GIS)信息数据库设计

该文简要介绍湛江市规划管理地理信息数据库结构设计问题,包括数据库设计的目的和要求、数据处理与集成建库、数据库的管理等问题,并结合实际对数据库设计进行论述。     

汽车悬挂系统故障寻迹检测设备的设计方案

汽车悬挂系统故障维修工作中,某些故障需要在复杂路况下路试重现,给维修工作带来很多不便.为解决上述问题,设计方案中提供了一种可变振幅可倾斜动态模拟汽车路试的震动装置,采用这种装置可动态模拟汽车以不同车速以及行驶在各种路况.震动装置由型钢焊接成的框架,和框架上安装的两根滚筒,其中一根是无动力同心滚筒,另一根是可变偏心度的偏...     

预制沉箱表面缺陷的成因分析及其改善对策

沉箱预制是重力式码头的主要分项工程,其预制质量直接影响码头的整体质量。结合汕头港广澳一期工程沉箱重力式码头的施工监理实践,分析大型沉箱预制表观质量缺陷常出现的位置;实际使用的材料、施工环境、人员操作等因素对表观质量缺陷成因的影响;并介绍采取的对策和取得的效果。     

高速列车的稳定性

为了研究列车中各车辆在直线上和大半径圆曲线上的蛇行稳定性,建立了具有17个自由度的车辆系统非线性数学模型。模型中考虑了车钩力横向分力的作用,根据列车运行阻力确定各车辆(动车或拖车)的车钩力,其是列车速度和车辆在列车中位置的函数,列车编组共考虑了2M9T、3M8T和6M5T三种形式。应用牛顿一拉夫森达代法确定车辆系统的平衡位置,采用QR算法求解系统雅可比矩阵的特征值,并结合二分法搜索系统平衡位置失稳时的临界速度。通过计算得知,在直线上列车中各车辆的临界速度相差不大,但在曲线上有一定的差别,车辆在曲线上的临界速度要低于直线上的临界速度,曲线半径越小,其临界速度越低,因此进行曲线上的临界速度计算时,必须考虑车钩力的影响。     

Numerical solutions for a two-dimensional airfoil undergoing unsteady motion

Continuous vorticity panels are used to model general unsteady inviscid, incompressible, and two-dimensional flows. The geometry of the airfoil is approximated by series of short straight segments having endpoints that lie on the actual surface. A piecewise linear, continuous distribution of vorticity over the airfoil surface is used to generate disturbance flow. The no-penetration condition is imposed at the midpoint of each segment and at discrete times. The wake is simulated by a system of point vortices, which move at local fluid velocity. At each time step, a new wake panel with uniform vorticity distribution is attached to the trailing edge, and the condition of constant circulation around the airfoil and wake is imposed. A new expression for Kutta condition is developed to study (i) the effect of thickness on the lift build-up of an impulsively started airfoil, (ii) the effects of reduced frequency and heave amplitude on the thrust production of flapping airfoils, and (iii) the vortex-airfoil interaction. This work presents some hydrodynamic results for tidalstream turbine.     

Time-fuel synthetic optimal control of ship-borne special crane based on predictive average dynamic

Ship-bome special crane, a multi-joints and foldaway one, is important to study the most effective energy-saving ( i. e. synthetic time-fuel optimal) operation control mode. In this paper, by introducing weighted parameters, a time-fuel synthetic optimal criterion is obtained, and configuration of the optimal controller is verified. Furthermore, a predictive average dynamic method is put forward, and applied to treat nonlinearity and coupling of the crane. Finally, an optimal controller with feedback is designed. The validity of this approach is verified by simulation results.     

Analysis and experiment of a vessels shell cover in submarine structure

This paper aims to achieve analysis and experiment results that relate to mechanics capability and structural parameter of a special saddle shell of revolution. Theoretically speaking, the saddle shell of revolution consists of a toroidal shell and a spherical shell. The shells simultaneous equations can he solved with harmonious terms. Where, the fundamental equations can be solved by asymptotic exponential perturbation method. The equations of special solution can be solved by Hovozhilovs special solution. This new idea is from a study of some existing solutions of the toroidal shell. The results have heen proved by eompared with some experimental results. The experiments aims to study the effect caused by change of material parameter,or by change of different geometrie dimensions of the saddle shell,which include the ehange of thickness, the change of radius of shell, and the change of ribs. Finally, the accepted product of the saddle shell were reinforeed by a toroidal rib has been submitted.     

Kinematic and Kinetic Analysis for the Tilting Mechanism of Railway Passenger Cars

The kinematics and kinetics of the tilting mechanism of railway passenger cars are studied. The parameters of the mechanism are given. The motions of the actuator, the center of gravity of the carbody and the center of coupler are calculated. Finally, the maximum driving force, output power and velocity of the actuator are discussed in detail.