膨胀岩土地层盾构隧道结构力学行为研究

文章在提出膨胀接触压力概念的基础上,采用接触单元对膨胀接触压力和膨胀力的关系进行了研究,得出了膨胀接触压力与膨胀岩土分布、厚度、结构及地层刚度等的关系;同时对膨胀岩土地层中盾构隧道"荷载-结构"模式外荷载及"梁-弹簧"模型的特点进行了分析;并将其分析结果直接应用到成都地铁2号线膨胀岩土地层盾构隧道的结构分析中,得出了盾构隧道在不同膨胀岩土层、膨胀力、埋深和拼装方式条件下的结构内力值,对隧道结构设计起到了指导作用。     

农村公路水泥混凝土路面结构设计中影响因素分析

计算分析了交通量、土基模量、基层模量、基层厚度变化对水泥混凝土路面板厚度影响,通过计算分析可知,通过调整土基模量或基层厚度来减小水泥混凝土路面板的厚度效果不明显,可适当增大基层强度,减小水泥混凝土路面板的厚度。     

基于尺寸精度的铝合金减震器塔结构设计及优化

铝合金作为一种优质轻量化材料在轻量化车身上的应用越来越广泛,为了确保铝合金零部件的使用功能和性能,设计人员在设计前期就需要对零部件的精度进行设计分析和优化。文章基于一种压铸铝合金减震器塔的零部件,首先对该铝合金零部件精度进行分析摸底并识别出影响该铝合金零部件精度的两个关键要素,再分别针对两个关键要素进行优化设计,重点一是优化加强筋结构,以增加减震器塔本体的刚度和抗变形能力,另外是增加热处理工艺中夹具支撑块结构,通过外力支撑来增加抗变形能力。结果表明:合理的加强筋布置能有效提升减震器塔本体的刚度、强度和尺寸精度;热处理时需设计专用支撑夹具,且支撑夹具要保证所有重要安装面的支撑,避免铝合金减震器塔局部出现悬臂,通过外力支撑来防止变形。     

Intermodal Transit System Coordination

In urban areas where transit demand is widely spread, passengers may be served by an intermodal transit system, consisting of a rail transit line (or a bus rapid transit route) and a number of feeder routes connecting at different transfer stations. In such a system, passengers may need one or more transfers to complete their journey. Therefore, scheduling vehicles operating in the system with special attention to reduce transfer time can contribute significantly to service quality improvements. Schedule synchronization may significantly reduce transfer delays at transfer stations where various routes interconnect. Since vehicle arrivals are stochastic, slack time allowances in vehicle schedules may be desirable to reduce the probability of missed connections. An objective total cost function, including supplier and user costs, is formulated for optimizing the coordination of a general intermodal transit network. A four-stage procedure is developed for determining the optimal coordination status among routes at every transfer station. Considering stochastic feeder vehicle arrivals at transfer stations, the slack times of coordinated routes are optimized, by balancing the savings from transfer delays and additional cost from slack delays and operating costs. The model thus developed is used to optimize the coordination of an intermodal transit network, while the impact of a range of factors on coordination (e.g., demand, standard deviation of vehicle arrival times, etc) is examined.     

Mathematical properties and constraints representation for bottom-up approaches to the evaluation of GHG mitigation policies

Bottom-up models, including MARKAL, MESSAGE and AIM, are widely used when analyzing the effect of greenhouse gas (GHG) abatement policies. These bottom-up models are mostly formulated as a linear programming (LP) optimization model to find both the minimal cost combination of abatement technologies and energy flows while satisfying demands. It is not unusual that the bottom-up modeling involves a great number of technical, industrial, socioeconomic and environmental constraints. Investigating representative constraints needed for analyzing GHG abatement policies, this study proposes how to implement these constraints in bottom-up modeling.     

内外温差对明挖隧道主体结构内力的影响研究

明挖隧道内外温差会使其衬砌结构产生附加应力,严重时会使隧道轴线方向的衬砌产生环向裂缝。通过对温度进行现场监测,获得工程实际内外温差,对其规律进行简要分析并将其作为有限元计算的温度边界条件;采用ANSYS进行有限元计算,考虑明挖隧道主体结构修建完成和回填完成两个阶段,对隧道内部温度低于外部温度、隧道内部温度高于外部温度以及无温差3种工况进行分析,得出温差对隧道结构应力的影响规律。     

Prioritization of failure risk in subsea flexible pipes via data envelopment analysis

Risk-based inspection is nowadays the predominant approach to structural integrity assurance in complex engineering systems, such as those designed for and operated in deepwater environments. One of the major tasks in risk-based planning is risk ranking of the components comprising an engineering system. In this paper, a mathematical model based on data envelopment analysis is developed for this purpose, whereby two types of weights are employed: subjective judgmental weights which are provided as input, and objective which constitute the output of the model. The use of the mathematical model is illustrated in a real world system of subsea flexible pipes, which operational in the south Atlantic Shelf off the Southeast Coast of Brazil.     

用模糊逻辑实现动力定位船舶的艏向寻优

由于各种环境因素随时间不断变化，船舶作为动力定位作业时，最优艏向也是不断变化的，所以艏向寻优是动力定位的关键技术之一，本文用模糊逻辑实现艏向寻优，其优点是，不依赖于环境要素的测量值和数学模型，寻优与控制相结合，反应快，准确程度高。     

辽宁省高速公路管理局收费中心系统改造分析

简要说明辽宁高速公路中心收费系统升级改造方向,结合辽宁高速公路收费系统现状,提出适合辽宁高速公路中心系统升级的解决方案.