考虑时间效应下新旧桥基础差异沉降研究

在桥梁拓宽改造工程中,必然涉及新建桥梁和原有桥梁基础差异沉降及桥面板的开裂等问题。考虑沉降与时间的关系下,对桥梁基础沉降量计算方法进行了研究,计算出了旧桥的总沉降量及工后沉降结果,结合新建桥的实际情况提出相应处理办法。     

Kinematic design of double-wishbone suspension systems using a multiobjective optimisation approach

This paper is focused on the kinematic design of double-wishbone suspension systems in vehicles, which is tackled using a multiobjective dimensional synthesis technique. The synthesis goal is to optimise an RSSR–SS linkage, subject to some constraints involved in the dynamic behaviour of vehicles. The synthesis method is based on gradient determination using exact differentiation to obtain the elements in the Jacobian matrix. These characteristics make the method adapt well to the optimum design of vehicle suspension systems. The method is capable of handling equality and inequality constraints, thus, the usual ranges of values may be imposed on the functional parameters. The formulation presented is easy to implement and the solutions obtained demonstrate the accuracy and robustness of the method.     

摩托车自动驾驶仪的开发与应用

为适应国Ⅲ标准中对摩托车进行排放耐久试验的需要,结合国内车辆和使用实际情况,开发了能够自动操纵摩托车的自动驾驶仪。自动驾驶仪采用＂类驾驶员＂一体化结构,着力点、施力方式等可完全按照人的习惯进行设计,执行器的拟人化特点更为突出,执行器与车辆的匹配和配合非常合理,试验人员调整执行器更易于理解。     

基于数值模拟的木拱廊桥洪水响应分析

近年来,木拱廊桥抗洪防灾方面的研究多基于水毁案例的经验总结来提出宏观维护策略,缺乏对于洪水荷载与廊桥结构受力的量化分析。因此,提出了基于计算流体动力学(CFD)与有限元方法的木拱廊桥抗洪安全性能分析方法,研究不同洪水频率下的荷载分布规律,并对桥体拱架的洪水响应及结构安全进行量化评估,为木拱廊桥预防洪水和安全监控提供参考依据。结果表明:受洪水荷载的作用,杆件上的水平力沿水深方向呈线性分布,竖向力呈均匀分布;主拱结构产生形变,迎水面向河内挤压,背水面向两岸拉伸,上部结构朝水流方向倾斜;主拱上背水面的端平苗受拉力作用,易脱开节点导致桥面塌落,基础的摩擦系数和土体抗剪性能决定了支座的稳定,是影响廊桥整体结构抗洪安全性能的关键因素。     

接触网吊弦自动化生产线研究

吊弦是铁路接触网设备重要零部件,其主要作用是控制接触线高度,保证弓网关系安全和良好的受流质量,是控制接触线与机车受电弓接触稳定性关键结构。其多采用人工预配方式,无法对吊弦预配参数做到标准化,预配精度无法得到有效保障。本文结合铁路接触网施工现状,介绍一种接触网吊弦自动化生产线,通过伺服电机、光线传感器、PLC控制器等机构研制及优化,实现对接触网吊弦自动化预制,可量化预制参数,精准控制吊弦预配质量,显著提高吊弦预制工效,达到自动化、智能化预配管理目标,彻底替代传统人工吊弦预配模式,助力铁路智能化建设,具有重大意义。     

基于组合自动优化策略的水下机器人型线设计（英文）

In this paper, a hybrid automatic optimization strategy is proposed for the design of underwater robot lines. Isight is introduced as an integration platform. The construction of this platform is based on the user programming and several commercial software including UG6.0, GAMBIT2.4.6 and FLUENT12.0. An intelligent parameter optimization method, the particle swarm optimization, is incorporated into the platform. To verify the strategy proposed, a simulation is conducted on the underwater robot model 5470, which originates from the DTRC SUBOFF project. With the automatic optimization platform, the minimal resistance is taken as the optimization goal; the wet surface area as the constraint condition; the length of the fore-body, maximum body radius and after-body's minimum radius as the design variables. With the CFD calculation, the RANS equations and the standard turbulence model are used for direct numerical simulation. By analyses of the simulation results, it is concluded that the platform is of high efficiency and feasibility. Through the platform, a variety of schemes for the design of the lines are generated and the optimal solution is achieved. The combination of the intelligent optimization algorithm and the numerical simulation ensures a global optimal solution and improves the efficiency of the searching solutions.     

基于高性能平面二维水流数学模型的计算效率研究

针对高性能平面二维水流数学模型,分别开展了基于单机多核处理器(CPU)和显卡(GPU)的并行化研究,旨在提高模型计算效率。以长江下游福姜沙水道为例,对并行后模型的可靠性和计算效率进行评估,结果表明:采用两种并行模式后,模型计算结果与串行结果一致,可靠性好,且计算效率有所提高,特别是采用GPU并行模式后,模型计算效率提高6.7倍以上,大大缩短了模型计算周期。     

基于二次反馈的两级交换结构

为缓解FTSA(feedback-based two-stage switch architecture)对调度算法执行时间的限制,提出了一种基于二次反馈的两级交换结构DFTS(double-feedback-based two-stage switch architecture).该结构通过二次反馈和接力调度模式,以多反馈一次N位缓存信息的代价拓展了调度算法的时域空间(N为交换端口数).理论分析表明:在相同条件下,DFTS的时延性能与FTSA的理论性能是一致的.     

某重型货车空调系统对乘员舱热舒适性影响的分析与改进

应用计算流体力学软件Fluent对某重型货车空调系统和乘员舱中的气流进行数值仿真,其结果与试验对比,相差在5%以内.采用当量温度Teq,i作为评价指标,对乘员舱的热舒适性进行分析.结果表明,由于各风道风量分配不均匀,乘员舱内部气流组织不合理,致使热舒适性较差.对空调系统进行改进,增加前吹面风道风量比例后,乘员舱的热舒适...     

CFD敞水螺旋桨性能计算分析

根据螺旋桨的投影原理及其型值参数,建立螺旋桨的三维模型。基于计算流体动力学(CFD)理论和CFD商业软件进行研究,采用分区混合网格方案和动网格技术及旋转坐标(MRF)方法,结合RANS方程和RNG湍流模型对螺旋桨三维粘性流动进行数值模拟,得到该螺旋桨的推力及其转矩。经与试验结果比较分析,证实该方法能实现对螺旋桨的敞水粘性流场模拟,预报其敞水性能。