浅水中浮式栈桥单浮箱系泊系统及运动响应特性

基于三维势流理论,利用水动力分析软件AQWA对浅水中浮式栈桥单浮箱系泊系统及运动响应进行研究。对初步设计的多种系泊系统进行优选,并计算浮箱在最优系泊系统下的运动响应幅值算子RAO。结果表明:聚酯缆材料极易疲劳破坏,浅水中交叉型半张紧式锚链系泊表现出良好的系泊性能。浮箱的振幅响应算子RAO与波浪周期变化及波浪作用方向有不可分割的关系,当波浪入射角为120°~150°时,浮箱的纵荡及纵摇RAO较大。为保证较小的垂荡值,浮箱布置可沿入射波方向。为保证较小的首摇角,浮箱布置应避免与来浪呈120°的入射角。     

两种大型集装箱船绑扎桥结构强度的对比计算浅析

以大型集装箱船常见的剪力墙式绑扎桥和A型斜撑式绑扎桥为研究对象,基于通用大型有限元分析软件PATRAN/NASTRAN及CCS规范的相关要求,对两种绑扎桥的结构强度进行了对比计算分析。结果表明：两种型式的绑扎桥在结构强度方面相差不大,相比而言,剪力墙式绑扎桥略优于A型斜撑式。     

最首尾货舱直接强度评估研究

针对CSR-H关于最首尾货舱有限元分析在实际评估中可能存在的技术问题进行研究分析。通过理论分析与数值试验相结合对最首尾货舱有限元评估方法中的边界条件、力学模型、模型范围进行合理性评估,通过已建造船数值试验对最首尾货舱开展有限元直接强度评估。数值分析结果表明两端简支的边界条件能较好的模拟翘曲效应,模型范围对强度评估结果有影响。最首货舱离边界很近会导致甲板、外板的屈曲强度不满足要求。而CSR-H针对最尾货舱有限元中的剪力调整方法仍基于货舱中段,仅以货舱前后端壁剪力为目标值进行调整,这种剪力调整方法不适用于最尾货舱。     

基于支持向量回归机和粒子群算法的船舶操纵运动模型辨识

基于仿真的Z形试验数据,应用支持向量回归机对船舶操纵运动响应模型进行了机理建模,从核函数结构中得到了模型中的操纵性指数,并利用建立的响应模型进行了Z形试验的运动预报,同时引入粒子群算法对惩罚因子C值进行寻优,以减少惩罚因子C值选择的任意性对船舶操纵运动模型辨识精度产生的不利影响。通过将运动预报结果同仿真试验数据进行比较,验证了文中方法的有效性。     

畸形波作用下半潜平台运动响应研究

海洋结构物的水动力性能研究对于安全、经济的工程设计至关重要.近年来,由海浪巨大波浪引起的事故越来越多地见诸报道,因此,有必要深入研究波浪尤其是畸形波对结构物产生的载荷及运动响应.海上浮式平台的运动响应与系泊载荷密切相关,而文中的出发点正是研究在何种波浪条件下会引起平台的最大运动响应.通过对一座设计作业水深为500 m的半潜式平台进行频域计算,获得了平台在自由漂浮状态下的响应函数(RAO),并与实验数据进行了比较.通过时域模拟,获得了新年波和"三姐妹"波作用下的平台运动响应,研究了畸形波的存在对于平台运动的影响.此外,还研究了畸形波中最大波峰值及连续大波的出现间隔对平台垂荡和纵摇运动的影响,可为后续研究和工程设计提供参考.     

基于AQWA计算规则波中新型海工船的运动响应

本文应用三维势流理论的水动力软件AQWA分析一种新型工程船舶在波浪中的运动响应,新型船为改造的波兰中型集装箱船B-573,设计搭载Pram型艉和POD吊舱式推进系统的新型海工船.本文计算此船在规则波中不同浪向角条件下的六个自由度的频域和时域的运动响应,得到在不同浪向角下船体的响应振幅算子RAO,计算船舶顺浪下不同船速的垂荡RAO以及纵荡、垂荡和纵摇三个自由度的一阶、二阶波浪力,分析结果显示该新船型具有良好的耐波性.     

沉管隧道地震响应分析

文章采用田村重四郎和冈本舜三提出的沉埋隧道地震响应分析的数学模型,对南京长江越江隧道(沉管段)方案进行了地震响应的纵向受力分析。分析中采用了隧址处100年超越概率为2%的人工合成地震加速度,考虑了不同管段的联结方式和不同的计算参数,对初步设计中沉管段结构的安全性进行了论证,所提供的数据曾为设计单位所采纳[1]。     

Geometric design safety estimation based on tire–road side friction

A closed-loop drive–vehicle–road–environment system (DVRES) model was established using Adams/Car and Matlab/Simulink. Dynamic responses of lateral tire forces based on tire–road side friction and road geometric characteristics are used to investigate vehicle side slip for geometric design safety estimation. The root mean square, the maximum values of lateral tire forces, comfort limit on curves and vehicle trajectories are used to quantify the safety margin of side friction. The simulation results show that the safety margins of lateral tire forces for radius, operating speed and superelevation rate were 18.2%, 19.3% and 17.6%, respectively, to guarantee good vehicle lateral reliability and ride comfort, while lower speeds are optimal in wet and slippery roads. Finally, a case study was conducted to illustrate the analysis of road design safety, and on-site experiment testing further validated the accuracy and reliability of the closed-loop DVRES model.     

The accuracy of proxy responses in a stated choice setting: A re-examination and some controversial conclusions

Data is typically gathered from an individual respondent who represents the group or the household. This individual is often identified as the “primary decision maker” and is asked to provide responses as a proxy for the group given that the cost of interviewing each member individually is impractical and/or expensive. The collection of joint preferences is rarely undertaken, with the use of proxy responses not uncommon in travel behaviour research. Under such a framework, there exists an assumption that the primary decision maker has perfect knowledge of other group member preferences, and bargaining behaviour, and is able to synthesise this information when providing a response on their behalf. The validity of such an assumption however remains an open question, with recent research calling the reliability of proxy responses into account (Bateman and Munro, 2009). In this paper, using three models estimated in willingness to pay space, we examine the accuracy of proxy responses in a stated choice experiment. We find that there is overlap between a proxy response and the own preferences of the individual providing the proxy choice, but while the proxy responses fail to represent the full preference heterogeneity that exists in the actual choices made by individuals, the proxy responses in aggregate provide a suitable replacement for actual data, subject to a number of caveats.