Climate change modeling and the weather-related road accidents in Canada

The objective of this research is to study the impact of climate change on the hazardous weather-related road accidents in the New Brunswick, Canada. We develop an Exposure to Weather-Accident Severity (EWAS) index multiplying accident and weather severity. The Negative Binomial Regression and Poisson regression models are applied to estimate the spatial–temporal relationship between the EWAS index and weather-related explanatory variables of road accidents. The regression results show that the surface-weather condition, weather, driver’s gender, weather-driver’s age, weather-driver’s experience, and weather-vehicle’s age have strong positive correlation with the EWAS index, while the surface-road alignment and surface-road characteristics have negative relationship with the EWAS index. The climate change model also indicates that the number of accidents declines during snowy and freezing days—most people stay at home and those who travel extra cautious—accidents do occur. The study suggests that the Road Safety Strategy 2015 of the Transport Canada should take a holistic approach to help minimize the incidences of severe road accident during the normal as well as hazardous weather conditions.     

石灰桩融化岛状多年冻土的试验研究

针对岛状多年冻土区的新建工程和既有工程改扩建过程中面临的地基多年冻土稳定性问题,利用生石灰与水反应放热原理,采用预融技术对多年冻土地基进行处理,达到使冻土融化并固结沉降从而增强地基承载力的效果。在收集国内外工程中处理岛状多年冻土的主要方法和生石灰桩在处理地基的应用范围等相关资料的基础上,创新性开展石灰桩预融冻土地基室内模型试验研究,通过试验确定适用于融化高温岛状冻土且增强其地基承载力的石灰桩材料类型、材料配合比及施工工艺,并对其应用效果进行评价,形成在高温岛状冻土地区可以应用的一种新型成套石灰桩预融技术。     

一种VTS管理水平的评价方法

尝试利用系统工程、现代管理理论和模糊数学方法建立一种VTS管理水平的评价模型,以寻求能对我国已建成VTS的管理进行评价和改进的方法。     

港内拖轮协助操船仿真数学模型的研究

本文为研制高精度、多功能的船舶操纵模拟器和进行船舶操纵安全评价的需要，首次提出了拖轮流体动力和拖轮Ｚ型导管螺旋桨四象限推力系数的实用估算方程。在此基础上，建立了港内拖轮协助操船仿真的数学模型。最后介绍了在港口引航实践中的两个仿真应用例。     

Support condition monitoring of monopile-supported offshore wind turbines in layered soil based on model updating

Monopile-supported offshore wind turbines (OWTs) are dynamically sensitive structures whose fundamental frequencies may be close to those of environmental and turbine-related excitations. The changes in fundamental frequencies caused by pile-soil interaction (PSI) may result in unwanted resonance and serious O&M (Operation and Maintenance) issues, which have been identified as major challenges in the research field. Therefore, a novel model updating framework with an implicit objective function is proposed to monitor both the stiffness and damping variation of the OWT system based on the measured vibration characteristics, which is further verified by laboratory tests. In particular, layered soil was considered in the tests to simulate the practical soil conditions of Chinese seas. Different pile lengths were introduced to consider the long-term PSI effects for rigid piles and slender piles. The results showed that the variation in the fundamental frequency is significantly reduced in layered soil compared with the pure sand scenario. For the OWT systems in layered soil, the variation in foundation stiffness is negatively related to the burial depth under cyclic loading. The proposed model updating framework is proven reliable for support condition monitoring of OWT systems in complicated soil conditions.     

鳍与舭龙骨的水动力干扰

在水平循环水槽中进行了鳍与舭龙骨定常升力干扰的平板试验，给出了试验结果，并建议采用剩余升力系数的概念来评估舭龙骨的整流作用，据此确定舭龙骨的合理尺度和布置。     

一种新型一体化船用离心通风机的设计计算和试验验证

针对实船通风机尺寸大、安装困难的问题,本文提出了一种新型离心通风机结构。通过叶片、蜗壳和电机等通风机关键部件的一体化融合设计,大大降低了设备尺寸。数值计算和样机试验结果表明,在尺寸优化的情况下,新研离心通风机的性能达到了使用要求。该型一体化离心通风机结构能很好地解决船用电动离心通风机性能需求与尺寸要求之间的矛盾。     

水面舰艇编队对潜搜索效能评估模型

  目的  为提高搜索到目标潜艇的概率,更有效地开展水面舰艇编队搜潜行动,对舰艇应召搜潜路径规划问题进行研究。  方法  首先,构建基于隐式马尔科夫模型（HMM）框架的水面舰艇应召搜潜模型,设计两阶段启发式求解的方法,使搜潜命中概率期望值最大,利用进化算法（EA）,通过对种群内的个体进行交叉和变异操作,避免出现局部最优的问题,并与常规搜潜方法进行对比;然后,通过实验研究不同分割策略对路径优化的影响。  结果  单舰搜潜和多舰搜潜的仿真实验表明,采用所提方法能够获得最大化搜潜命中概率期望值以及最优搜潜路径。而分割次数的实验表明,合理的重新划分搜潜区域,有利于找到总体更优的搜潜路径。  结论  该模型能找到最优搜潜路径,有效提高水面舰艇编队搜潜效率。     

基于MPC的局部路径规划与路径跟踪控制研究

文章主要针对无人驾驶车辆在进行路径跟踪遇到障碍物时,需要局部重新规划出一条可行路径的问题,首先基于车辆点质量模型的MPC局部路径规划算法,得到满足车辆动力学约束并实现避障功能的局部路径,然后在二自由度车辆动力学模型的基础上基于MPC进行路径的跟踪,最后使用Simulink/Carsim进行联合仿真验证,结果表明基于该局部路径规划与路径跟踪算法能够可靠地规划出避开障碍物的局部路径,实现高速下的路径跟踪。     

Q500qE高性能钢工型梁极限承载力研究

为评估Q500qE高性能钢梁的塑性水平和安全储备,设计Q500qE高性能钢和Q345qD普通低合金钢全尺寸试验工型梁,通过模型试验和有限元分析方法进行极限承载力研究.结果表明:Q500qE高性能钢梁有较好的塑性,不会因为屈强比大而发生脆性破坏;Q500qE与Q345qD工型梁的荷载一位移曲线以及塑性发展过程类似,均没有出现明显的屈服平台;两者不同塑性发展阶段作用荷载与材料的名义屈服倚载的比值基本相等,说明Q500qE高性能钢梁有与Q345qD钢梁基本相同的安全储备.试验梁加载过程各关键作用荷载对应的挠度有限元计算结果与试验值基本一致,误差较小,表明本文有限元分析中选用的多线性随动强化模型模拟高性能钢的本构关系是合理的.