The effect of plastic constraint on the initiation of ductile tears in shipbuilding structural steels

In this paper, the effect of plastic constraint on the initiation of ductile tears in four different shipbuilding structural steels has been experimentally studied by measuring the J-integral and crack opening displacement COD at initiation in three-point bend specimens with deep and shallow notches. Experimental results of seven groups of different strength alloy steels show that both Si and Ji values of ductile tear from the shallow crack specimens which have less constraint flow field are significantly higher than those of deeply notched specimens. Slip-line-field analysis shows that, for shallow crack, the hydrostatic stress is lower than that from standard deeply cracked bend specimen, which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structural defects, especially if initiation values of COD and J-integral are used.     

天津滨海快轨车辆设计与制造

就天津滨海线高品质车辆的要求、设计和制造过程以及主要技术创新点进行分析和介绍。     

铁路运输企业间收益合理分配的数学模型

利用多人合作对策模型解决铁路运输企业间收益的合理分配，在特征函数的基础上，根据铁路运作生产的特点，引入势指标的概念反映不同联盟的“势力”。     

泥质粉砂岩点荷强度与单轴抗压强度对比研究

对抚州泥质粉砂岩的点荷载强度与岩石单轴抗压强度进行对比研究,结果表明,两者之间存在良好的线性相关性,并建立了显著线性相关的关系式。同时分析表明,现有的经验公式在推广应用时存在局限性,宜慎用。     

哈尔滨地铁一号线的客流预测

本文根据轨道交通客流预测的实际特点,应用修正后的四阶段模型对哈尔滨市地铁一号线的客流进行了预测,并得出预测结果。通过分析,证明了四阶段预测方法的可行性及合理性。     

浅议如何科学构建公路执法绩效评价指标体系

绩效评价是未来我国政府治理同时也是交通部门加强内部监督的一种重要方式,而绩效评价能否对公路执法发挥有效的导向和促进作用,关键在于是否有一套科学合理的评价指标体系.文章在政府绩效评估基本理论的指导下,结合实际,对科学合理地构建公路执法绩效评价指标体系进行了初浅探索,提出了必须把握四项原则,处理好三个关系,设计了6项评价内容和28项具体指标.     

哈尔滨市地铁一号线的客流预测

本文根据轨道交通客流预测的实际特点,应用修正后的四阶段模型对哈尔滨市地铁一号线的客流进行了预测,并得出预测结果.通过分析,证明了四阶段预测方法的可行性及合理性.     

Belief and fuzzy theories for driving behavior assessment in case of accident scenarios

The estimation of the overspeed risk before the accident is among the main goals of this paper. The proposed method uses the Energy Equivalent Speed (EES) to assess the severity of an eventual accident. However, the driver behavior evaluation should take into account the parameters related to the Driver, the Vehicle and the Environment (DVE) system. For this purpose, this paper considers a two-level strategy to predict the global risk of an event using the Dempster-Shafer Theory (DST) and the Fuzzy Theory (FT). This paper presents two methods to develop the Expert Model-based Basic Probability Assignment (EM based BPA), which is the most important task in the DST. The first one is based on the accident statistics and the second method deals with the relationship between the Fuzzy and Belief measurements. The experimental data is collected by one driver using our test vehicle and a Micro-intelligent Black Box (Micro-iBB) to collect the driving data. The sensitivity of the developed models is analysed. Our main evaluation concerns the Usage Based Insurance (UBI) applications based on the driving behavior. So, the obtained masses over the defined referential subsets in the DST are used as a score to compute the driver’s insurance premium.     

基于Richards-BP模型的地表沉降特征预测模型研究

地下开采引起的地表沉降大致呈S形发展,最终趋于稳定状态,这能够运用生长曲线Richards函数进行预测分析。同时,又因为测量和外界存在不确定性和随机性,使得地表沉降也具有动态的特征。针对地下岩矿开采矿区地表沉降曲线与Richards预测模型曲线的相似性,分析了Richards模型在地表沉降预测中的适用性,提出通过Richards生长曲线模型预测矿区地表沉降的趋势性变形部分,利用BP神经网络模型降低地表沉降的随机性影响部分,提高模型预测效果。计算结果证明了其在地表沉降预测中的适用性和可行性。     

草根加筋土的室内直剪试验研究

以庆阳黄土为研究对象,对加筋土的剪切试验研究现状进行了综述,通过室内直剪试验研究了草根加筋土的应力-应变及强度特性,探讨了草根加筋土抗剪强度指标的变化规律。试验结果表明,草根加筋土的强度和抵抗变形的能力较素土有显著的增强,加筋后土样的抗剪强度增强,内摩擦角φ提高幅度不大,而粘聚力c提高幅度较大。