基于相对差商法的大型油船中剖面结构优化

基于DNV规范对大型油船中剖面结构进行了优化设计.针对采用DNV规范进行油船结构设计的特点,确定了作为设计变量的构件尺寸与相邻同类构件尺寸之间的关系,进而建立了较为精细的优化模型,以增强优化效果和实用性.优化方法采用相对差商法,并作了若干改进.算例显示优化后纵向构件总重量减轻了5.54%,表明所建的优化模型和改进的相对差商法在大型油船结构优化方面具有良好的有效性.     

Elastic Modulus Limit of Support Layer in Twin-Block Ballastless Track Based on Train Load Effect

The support layer is an important component of twin-block ballastless track. The modulus of the support layer is an important design parameter and must be carefully solved. We studied the bending stress and deformation of track slab and support layer due to train load using the beam-plate finite element model on elastic foundation. The results show that support layer type has great impact on both support layer deformation and the stress on subgrade, but has little impact on the bending stress of either track slab or support layer. The continuous support layer type, and articulated support layer type with shear transfer device at their ends, are recommended. In order to keep the stress in the support layer less than that in track slab, the modulus of the continuous, unit, and articulated types of support layer (in unit twin-block ballastless track), and the support layer in continuous twin-block ballastless track, should not be larger than 15, 22, 20.5 and 5 GPa, respectively. In addition, the modulus of the unit-type support layer should not be more than 20 GPa, to ensure the step in support layer remains less than 1 mm.     

梁式桥地震设防应注意的问题

对常规梁桥下部结构、上部结构、梁体及支座在地震作用下的结构反应进行了论述,并对采取的相应梁桥抗震设防措施进行了归纳总结,对梁桥的设计施工有一定的参考借鉴意义。     

基于DEA方法的车辆管理信息资源配置效率评价

随着信息资源在人类社会各个领域中发挥的作用日益显著,信息资源的合理配置问题得到各国政府和学术界的普遍重视,信息资源配置效率是衡量信息资源有效利用程度的重要标准。采用数据包络分析（DEA）方法对车辆管理信息资源配置效率进行评价,并根据评价结果对车辆管理信息资源配置中的投入产出进行调整,以实现车辆管理信息资源的有效配置。     

基于车流特征分区算法的地磁传感器单节点车速估计

地磁车辆检测器是近年来兴起的新型交通流信息检测技术,而利用单节点检测数据完成车速估计是该技术研究的重点之一. 本文首先对地磁车辆检测技术予以简要介绍,然后基于对道路车辆车长分布规律的分析,在合理假设的前提下,提出了车流特征分区的车速估计算法. 该算法充分考虑实际应用中各类车型组成情况,应用最大类间方差法实现大型车与小型车的分类,基于城市道路小型车居多且车长分布集中的特点,仅利用小型车通过时间检测数据完成对平均车速的估计. 最后,选取实际路段开展试验,并基于Matlab平台对该算法进行了验证. 结果表明,本文提出的车流特征分区算法稳定性好,平均准确率达到85％以上.     

浅谈沥青路面病害的处理

为保证道路的畅通、安全、舒适以减少养护费用,应对坑槽及时处理。对坑槽处理的材料和施工工艺进行了介绍,并分析了其寿命周期费用。     

山区公路路线设计经验

结合鹤大国家高速公路七台河—鸡西段扩建工程七台河至鸡西段辅道的设计实践,提出山区公路路线设计之浅见。对山区公路路线设计中线形标准、曲线间最小直线长度、超高值、缓和曲线长度与超高过渡段等进行了分析与探讨。     

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公交优先是提高城市中心区道路设施利用效率、改善交通环境的有效方法,确定中心区合理干道网密度是满足公交运行、提高运输效率的重要内容. 本文在分析城市中心区交通需求特征和公共交通发展要求的基础上,提出了从宏观系统层、设施、运输组织和交通管理四个方面分析中心区道路网密度影响因素,并探讨了公交优先下公共交通与道路网的关系,考虑公交线网布设和运行的要求,并以公交站点覆盖率和最佳公交线网密度两个主要指标为导向,研究并提出了中心区干道网合理密度和间距推荐值. 该研究提出的干道网密度能够较好地满足中心区公交运行,落实公交优先.     

Safety Evaluation for Freeway Exit Ramp Based on Speed Consistency

Speed differential has direct relationship with road safety. Conventional speed consistency measures draw sample data from independent population that follows a normal distribution. These methods may fall into ecological fallacy and overestimate the safety level of road elements. After deducing the relationship between the difference in operating speed ΔV₈₅ and85(ΔV), the 85^th percentile value of individual speed reduction, this paper recommends 85(ΔV) and speed reduction rate 85(ΔV)R is used to evaluate ramp safety. Point speeds of individual vehicle at freeway diverge area, upper ramp, and lower ramp are collected by radar guns. Safety performance of 37 exit ramps are appraised using three different measures, namely, ΔV₈₅, 85(ΔV), and 85(ΔV)R. The results show that 85(ΔV) is 1.42 to 2.02 times of ΔV₈₅, and that the evaluation result of 85(ΔV)R is between the other two. The measure 85(ΔV)R considers not only individual speed but also the base speed on upstream element, which avoid the pitfalls of ecological fallacy and overestimation possessed by conventional measures. It is a safer and reasonable measure that should be adopted in practice.     

浅谈如何做好一体化教学实施

本文就目前高职院校一体化教学在具体实施中存在的问题进行了分析,并结合高职院校的实际情况,对如何搞好一体化教学工作进行了探讨。