舰载激光武器及其发展趋势分析

舰载高能激光武器作为一种新概念武器,以其响应速度快、机动性好、打击精度高、发射成本低等优点受到了各国海军的关注。文章分析了舰载激光武器的组成及特点,介绍了英、俄、美等国舰载激光器的发展状况,从技术角度,阐述了舰载激光武器的发展趋势。     

海关通关工作流程优化方案

为提高海关通关工作效率,应用关键路径和排队论的思想,对海关通关工作流程进行优化,首先建立抽象数学模型,然后通过实例验证该优化方案的可行性和合理性。     

轨道交通车辆制动用中继阀的可靠性

通过耐久性试验评估轨道交通车辆制动系统用中继阀的可靠性．结果表明,中继阀的故障服从形状参数m=3．43的威布尔分布,故障率随试验循环次数增加而递增．主要故障模式是V型圈和复位弹簧的疲劳破坏．     

基于挠度及索力监测的斜拉索损伤敏感性分析

由于斜拉索的锈蚀断丝等损伤必然导致索力及结构内力状态的改变,主梁的挠度也将随之发生变化,本文以一座独塔斜拉桥为例,从主梁挠度及索力的监测方法出发,以拉索损伤的敏感性分析为手段,探讨基于主梁挠度及索力监测的斜拉索损伤识别的方法及其适用性.     

筑路机械租赁合同签订应注意的问题

对公路工程施工中租赁双方合同条款订立、机械租赁的计费方法、租金结算、机械运输、维修、合同责任、机械租赁的优越性进行了介绍,并给出了租用过程中遇到问题的解决方法以及采取的防范措施,可以为类似工程的施工单位提供借鉴。     

高墩大跨径刚构桥悬臂施工稳定性分析

以沪蓉西高速公路龙潭河特大桥为工程背景,采用桥梁专用有限元软件建立桥梁的有限元模型,通过分析得到了桥梁典型工况下的一阶失稳特征值和失稳模态,探讨了悬臂施工高墩桥梁结构体系变化及系梁设置对稳定性的影响.     

矩形断面综合管廊线缆舱通风阻力系数数值仿真研究

为探究城市综合管廊通风阻力影响因素和计算方法,通过调研综合管廊通风系统设计和交通隧道通风阻力的相关研究成果,得到综合管廊线缆舱单位长度通风阻力系数的计算公式。建立综合管廊线缆舱三维数值模型,利用ANSYS FLUENT软件并采用标准双方程模型对通风障碍物比例约为15%的综合管廊线缆舱室内部支架、线缆和热效应对通风的阻力影响进行模拟。分析得到： 1)相较于内部无支架、线缆的综合管廊线缆舱,有支架、线缆时对通风阻力影响极大; 2）随着通风风速的增大,综合管廊线缆舱通风阻力逐渐增大,而通风阻力系数减小,且逐渐趋于稳定; 3）进口空气温度、线缆发热及舱内温度产生的热效应对通风的阻力效应有一定的影响,且随着进风温度增大,通风阻力和通风阻力系数逐渐降低。     

Modeling and forecasting household energy consumption and related CO2 emissions integrating UrbanSim and transportation models: an Atlanta BeltLine case study

Reducing energy consumption and controlling greenhouse gas emissions are key challenges for urban residents. Because urban areas are complex and dynamic, affected by many driving factors in terms of growth, development, and demographics, urban planners and policy makers need a sophisticated understanding of how residential lifestyle, transportation behavior, land-use changes, and land-use policies affect residential energy consumption and associated CO₂ emissions. This study presents an approach to modeling and simulating future household energy consumption and CO₂ emissions over a 30-year planning period, using an energy-consumption regression approach based on the UrbanSim model. Outputs from UrbanSim for a baseline scenario are compared with those from a no-transportation-demand model and an Atlanta BeltLine scenario. The results indicate that incorporation of a travel demand model can make the simulation more reasonable and that the BeltLine project holds potential for curbing energy consumption and CO₂ emissions.     

汽车轻量化铝合金轮毂设计

文章通过对现有的铸造铝合金轮毂进行减重,得到最优化的锻造铝合金轮毂结构,借助有限元模拟软件对轻量化的轮毂结构进行性能评价,达成满足性能目标要求的最优的轮毂结构.     

Aeronumeric optimal design of a wing-in-ground-effect craft

An optimization technique was used to generate a wing-in-ground-effect (WIG) configuration which can achieve the maximum lift and satisfy the height stability criteria within the design constraints. For the analysis of the aerodynamic coefficients, the vortex lattice method (VLM) was applied with the inviscid and potential flow approximations. The sequential quadratic programming (SQP) method, which is a nonlinear optimization method, was employed as an optimization tool. The lift and moment coefficients, including the stability analysis computed by VLM, were compared with the experimental results of a medium-sized WIG, and a good correlation was found between them. In addition, the optimization tool was validated by finding the optimal position of the side wing attached on the WIG craft. Then, various optimum examples are shown, with generation of the wing section, the determination of the planform configuration, the aspect ratio, and the position of the tail wing within the design constraints. It was shown that the present optimization tool can be used effectively for the optimal design of a WIG craft.