船舶气囊下水工艺中气囊承载性能影响因素分析

根据气囊承载形状变化规律,基于目前通用的假设条件归纳出船舶气囊下水工艺中气囊承载能力计算模型,分析影响气囊承载力相关因素。发现气囊承载力与气囊初始压力和工作高度密切相关;通过模型分析,设定合适初始压力与降低工作高度可提高船舶气囊下水的安全性。研究成果可供船厂在制定合理的船舶气囊下水工艺方案时参考。     

长江下游口岸直水道通航风险分析与安全评价

针对拟实施的航道整治工程,基于口岸直水道实际情况,对照航道通航环境影响因子的危险度评价标准,选取各影响因子作为评价指标,分析其对口岸直水道的通航安全的影响并进行风险评价,得到相应的风险级别。     

On stress concentration factors for tubular Y- and T-Joints in frame structures

This paper is written as a result of some years experience with fatigue analysis of offshore jacket structures where the connections are made as tubular joints. The hot spot stresses at the tubular joints in such analysis are normally derived based on parametric equations for stress concentration factors. These stress concentration factors are normally related to the axial force in the brace. It is observed that the hot spot stresses at the crown positions of the tubular joint in some cases are significantly affected by the local loading on the chord and the bending moment in the chord. In order to use the existing formulae in these cases some engineering effort is required to derive correct hot spot stress. This work can be avoided by using the nominal stress in the chord as the basis for calculating the hot spot stress at the crown position instead of using the axial force in the brace as basis for the analysis. This also extends the validity of the equations for stress concentration factors for T- and Y- joints in design standards. The proposed modification makes it also simpler to include the effect of joint flexibility in a proper way. The basis for a proposed revision of the equations for stress concentration factors for these joints is presented in this paper. It is considered that this modification leads to minor changes of the computer code, but that it will save analysis work for engineers and reduce the possibility of calculating incorrect fatigue lives in tubular frame structures.     

重型绞吸式挖泥船挖掘中风化岩影响因素分析

针对目前国内外疏浚岩石理论及岩石疏挖工艺研究较少的现状,以重型绞吸式挖泥船在中风化岩石条件下的挖掘施工数据为基础,提出了疏浚岩体基本质量指标修正值[BQ]TH,并对中风化岩石性质与施工参数的相互影响因素进行分析。结果表明,绞刀切片厚度、绞刀转速、绞刀功率等施工参数与岩体基本质量指标修正值[BQ]TH的相关性较好,并拟合得出相应的经验公式,对挖岩工艺的改进具有指导意义。     

基于环境因素和基准化原理的信息资源配置研究

针对维修信息资源特点,以装备维修系统投入、产出为双目标,兼顾决策者偏好,引入环境背景值及针对多阶段过程的时间窗,建立装备维修信息资源优化配置DEA模型,并采用基准化思想评价资源配置效率。算例分析结果符合实际,最优结果和效率评价分析为决策者提供决策支持,利于提高装备维修保障效用,充分发挥装备维修资源作用。     

ANFIS model for assessing near-miss risk during tanker shipping voyages

Adaptive neuro-fuzzy inference system (ANFIS) was applied to predict the risk of near-miss incidents during tanker shipping voyages. Firstly, near-miss incidents recorded by a global tanker shipping management company were analysed. Four variables—type of operation, vessel’s location, on-board position, and harm potential were selected to train and predict the risk levels of near-miss incidents. The selected variables were found to be correlated with the observed frequency at three risk levels, namely low, medium and high. Gravity factor (GF) was calculated using the frequency of the categories in each variable and their associated risk levels. The calculated GF values and the risk levels of near-miss incidents were used as input values in the ANFIS model. Triangular, Trapezoidal and Gaussian membership functions were used. Subsequently, fuzzy logical theory and artificial neural networks were applied to train the data. Causal factors in terms of direct contributory factors, indirect contributory factors and root contributory factors to the near-miss incidents were analysed. Risk control measures were also proposed to improve safety during tanker shipping.     

舰船尾迹图像的对比度特征提取方法

根据舰船尾迹图像尾迹区与海水背景区存在明显对照的特性,提出用对比度参数作为尾迹图像质量评价指标,进而表征舰船尾迹光学信号特征强度.为有效评价尾迹图像质量,在改进对比度基本计算模型的基础上,充分考虑人的视觉特性,引入尾迹区与海水背景区的加权因子进行组合评价,将主观与客观评价方法有机结合起来,并通过专门研制的海上特征提取实验装置进行对比度特征提取实验分析.结果表明,对比度参数能较好地反映人眼对尾迹图像实际质量的主观视觉感受,更能体现尾迹图像处理应用的本质,且能定量可靠地描述舰船尾迹光学信号特征强度的变化规律.     

面向港口营运指标预测的影响因素二次筛选方法研究

港口规模、能力及生产活动相关营运指标的预测对于港口的建设和规划有着极其重要的意义,而预测的首要步骤就是对相关的海量社会经济影响因素进行分析筛选。以此为目标,文章提出了一种基于主成分分析(PCA)与t值检验相结合的二次筛选方法,在众多影响因素中,甄别出显著性关键因素,进而对港口相关营运指标进行预测。最后,以某港口吞吐量指标因素筛选及预测作为实例分析,为港口规划建设提供参考依据。     

高速公路养护维修作业区危险因素分析

国内高速公路养护维修作业区事故是交通管理部门亟待解决的一个问题。文中研究了国外高速公路养护维修作业区的事故规律,通过对国外文献中高速公路作业区事故危险因素分析法的综述,建立完善的作业区危险因素体系。结合事故数据,分析国内作业区事故特点,并有针对性地提出了安全管理对策。     

车载作用下土基永久变形机理及影响因素分析

论述了土基永久变形的发展机理及其危害性,并从内、外因两个方面分析了影响土基永久变形的重要因素,为利用室内重复荷载三轴试验研究路基土的永久变形特性提供了参考依据。