变截面圆端形沉井框架内力计算与施工方法分析

基于变截面圆端形沉井框架结构及荷载作用的对称性,使内力计算得到简化,在计算方法的研究上取得了实用和简便的效果,并提出解决沉井施工中技术难题等措施。     

客运专线双线变四线连续梁挂篮控制关键技术

挂篮施工是指浇筑较大跨径的悬臂结构时,采用吊篮方法,分段安装预应力筋、管道、模板,并分段浇筑梁段混凝土的施工方法。以韩江双线特大桥为研究对象,结合该桥为双线变四线道岔连续梁的渐变特点,详细介绍了多桁架菱形挂篮的施工关键技术,为同类工程提供借鉴。     

基于HGANN的全方位推进器运动学正解研究

针对潜器全方位推进器的调距机构运动学位置正解求解高度非线性、计算速度慢、准确率低的特点，提出了一种改进的混合编码遗传神经网络算法（HGANN）。算法兼具了遗传算法的全局寻优能力和神经网络对于非线性映射的强大逼近能力，同时由于采用了二进制和浮点数混合编码方案及3层的染色体结构对遗传神经网络算法进行了改进，优化了网络结构和权值矢量，解决了遗传神经网络算法计算过程中短基因组实际交叉、变异机会过小的问题，使后代种群具有更好的多样性，结合Solis＆wets算子生成后代的方法丰富了遗传搜索空间，加快了收敛速度。仿真结果表明，HGANN算法有效地加快了遗传算法的收敛速度，提高了调距机构的位姿精度。     

浅析变动成本法的应用

随着市场经济的发展，现代企业制度的完善，传统的完全成本法越来越不能满足企业管理层决策的需要。通过阐述变动成本法的涵义及在我国理论界推行变动成本法的三种形式，并进行例证分析，初探变动成本法在实际中的应用。     

无级变速传动系统综合控制仿真与试验

基于无级变速传动系统动力学仿真模型与自适应模糊控制策略,综合考虑后备功率、动力传动系损失和CVT速比变化响应滞后的影响,提出了τ算法、发动机转矩补偿和发动机转速补偿3种控制方法,并分别对采用这3种控制方法时的动力性与燃油经济性进行仿真分析.结果表明,相对于常规控制,采用这3种综合控制方法后动力性基本保持不变,而经济性则分别提高了约2.9%-3.5%.     

无限长板带对位荷载下的有效分布宽度计算和应力分析方法

无限长板带对位荷载下的应力分布的研究有助于进一步理解和解决长条形板式结构（如带外伸横梁的桥梁结构等）的横向计算简化问题。其等效加载模式（平面应力问题）也对应于条形基础下的下卧刚性层的软土地基受力问题（平面应变问题）。通过理论分析采用复变函数法得到无限长板带对位荷载下的应力计算公式，然后导出该理论解的有效宽度简化计算方法，与理论解的误差控制在5%以内，为进一步工程应用做理论准备。     

Carpooling problem: A new mathematical model,branch-and-bound,and heuristic beam search algorithm

Carpooling is an environmentally friendly transportation system. It can efficaciously help resolve a variety of societal concerns of the urban areas, ranging from traffic congestion to environmental pollution. In this paper, we propose a new mathematical model to solve the carpooling problem. The model simultaneously minimizes the costs of travel times, the vehicle use, and the vehicle delays. An exact solution method based on Branch-and-Bound (B&B) algorithm is proposed to efficiently obtain the optimal solution of the problem. In order to find the near-optimal solutions for large-scale problems, a heuristic beam search algorithm is introduced, which is based on the partial relaxation of some fathoming criteria applied in our proposed B&B. The computational experiments are conducted, based upon the transportation network of Isfahan city, Iran. The results demonstrate the great capability of the proposed exact solution method in terms of both computational solving time required and the number of the evaluated nodes, in comparison with CPLEX software package. The findings of this research can be applied to solve the carpooling problem compatible to the real-life situations.     

Introducing a new semi-active engine mount using force controlled variable stiffness

This work introduces a new concept in designing semi-active engine mounts. Engine mounts are under continuous development to provide better and more cost-effective engine vibration control. Passive engine mounts do not provide satisfactory solution. Available semi-active and active mounts provide better solutions but they are more complex and expensive. The variable stiffness engine mount (VSEM) is a semi-active engine mount with a simple ON–OFF control strategy. However, unlike available semi-active engine mounts that work based on damping change, the VSEM works based on the static stiffness change by using a new fast response force controlled variable spring. The VSEM is an improved version of the vibration mount introduced by the authors in their previous work. The results showed significant performance improvements over a passive rubber mount. The VSEM also provides better vibration control than a hydromount at idle speed. Low hysteresis and the ability to be modelled by a linear model in low-frequency are the advantages of the VSEM over the vibration isolator introduced earlier and available hydromounts. These specifications facilitate the use of VSEM in the automotive industry, however, further evaluation and developments are needed for this purpose.     

考虑重力影响的含空洞地层浅埋隧道围岩应力及位移解析解

为了明确地层空洞对浅埋隧道施工引起的地层应力和位移的影响，建立了含空洞地层浅埋圆形隧道围岩应力和位移解析模型，该模型既能考虑隧道开挖边界上的重力释放过程，又能考虑隧道与空洞的相互作用。采用复变函数法和Schwarz交替法对模型进行了理论求解，并将该模型解析解与有限元数值解进行了对比分析，两者吻合较好。基于所建立的解析模型，分析了应力释放系数、空洞位置及尺寸对地层应力和变形的影响规律。结果表明：随着应力释放系数和空洞尺寸的增大以及空洞与隧道间距的减小，空洞影响效应逐渐增大；空洞位于隧道拱顶时影响最为显著，空洞位于隧道斜上方时影响次之；空洞导致圆心连线两侧0°~5°范围内的隧道洞周环向应力减小，两侧5°~45°范围内的环向应力增大；空洞导致靠其一侧的隧道收缩变形增大，其中圆心连线位置上的隧道收缩变形增长最为显著；而地表最大差异沉降位于空洞正上方处。研究成果对含空洞地层浅埋隧道施工引起的围岩变形和应力预测具有重要的理论意义和应用价值。     

高速公路生成建模与实证研究

高速公路的空间形态是城际交通服务水平的重要体现,高速路网的形成和扩 张蕴含着丰富的科学问题.为了探究高速公路的生成机制,本文以微观上路段的动态生成替代宏观上路网的全局规划,在局部的路段生长过程中引入生长规则,采用最短路确定 生长节点,构建非线性规划模型,并运用一维搜索算法进行求解确定路段的生长方向,进而构建出高速公路生成模型.模型再现了高速路网的生长过程及涌现特征,如共用路段、 枢纽节点.通过对比实际和仿真的树状结构高速路网,以及分析相关统计数据,结果表明, 该高速公路生成模型能较好地描述和解释实际路网形成的内在机理和宏观现象.