基于贝叶斯网络的内河搁浅船舶应急决策方法

为使内河搁浅船舶快速有效地进行应急处置,提出一种基于贝叶斯网络的应急处置决策方法,该方法具有直观性强、能定量分析各种应急方案和能处理不确定性信息等优点。通过对江苏海事局2009—2012年的搁浅船舶应急处置数据进行统计分析,获得搁浅船舶的应急处置方案和相对应的影响因素值。提出搁浅船舶的三层应急决策框架,即影响因素层、决策准则层和决策方案层。在该决策框架的基础上建立搁浅船舶应急处置模型,并介绍各决策层的因素及其含义;同时,利用条件概率表建立相互间的定量联系。以一艘在长江内运营的典型搁浅船舶为例进行案例验证,结果表明,提出的贝叶斯决策模型能很好地处理搁浅船舶的应急处置。     

船舶搁浅事故的防患与应急措施

随着海运事业的迅速发展,船舶的数量激增,船舶搁浅事故在海事中的比例达40%。为了减少船舶搁浅事故造成的损失以及预防船舶搁浅事故的发生,文章提出并探讨了船舶发生搁浅的原因,船舶搁浅应急措施,脱浅后的工作,船舶搁浅事故的预防措施。     

全国大型船舶搁浅应急处置研讨会在汕头召开

11月29日,由中国海上搜救中心组织、广东海事局承办的全国大型船舶搁浅应急处置研讨会在汕头召开。此次会议是我国举行的首次全国性的大型船舶搁浅应急处置研讨会议。交通运输部安全总监刘功臣,部海事局副局长、中国海上搜救中心主任翟久刚等领导以及沿海各直属海事局,救     

船舶搁浅应急处置船体固定方法

船舶搁浅是海上应急处置中相对常见的险情之一。船舶搁浅后船员需要根据当时的情况采取适当的船体固定方法以便船舶能够顺利脱浅。为此笔者介绍常见的船舶搁浅方式、常用的固定船体的方法，重点介绍固定船体的时间、方式等。     

浅析船舶搁浅和应急措施

船长及岸基管理人员充分认识到海上船舶突发搁浅的风险和危害,有利于提高对船舶搁浅的风险预控和应急处置能力,有利于杜绝及减少类似性质的事故发生,确保人员、船舶、货物和环境的安全。     

大型船舶单点触礁危险远距离应急预警研究

传统的预警方法受到检索区域大等影响,导致预警实时性较差,增加了事故的发生次数,为提高大型船舶单点触礁危险远距离应急预警实时性,设计一个大型船舶单点触礁危险远距离应急预警方法。首先对安全水深阈值设计,然后构建船舶搁浅触礁危险区域模型,最后以搁浅礁紧急危险区作为船舶紧急危险海图检索区,进行危险判断,以此完成大型船舶单点触礁危险远距离应急预警。实验结果表明,此次研究的预警方法较传统方法预警实时性好,准确性高。     

图说水运

正(1)苏北航务管理处启动低水位应急通航模式水位持续走低,船舶面临搁浅等安全风险。近日,苏北处召开苏北运河淮安段低水位应急通航专题会议,讨论低水位情况下,如何保障淮安船闸下游航段畅通,以及在可能出现的极端低水位情况下的应急措施,同时启动苏北运河低水位应急通航模式。(朱晓鸿)     

船舶搁浅的模糊概率计算

目前，计算船舶搁浅的概率时常采用故障树和事件树方法，以确定的概率数表示底事件的发生概率，这种方法的一个不利之处在于无法考虑基本事件发生概率的不确定性，所以无法了解船舶搁浅概率的不确定性，本文引入了合适的模糊数表示基本事件的发生概率，通过模糊计算算法得到了船舶搁浅的模糊概率，并进行了敏感分析，确定了减小船舶搁浅事故发生的措施，与其他方法的计算结果比较表明，本文采用的方法更有利于了解船舶搁浅的概率分布规律。     

浅谈搜救中心对船舶搁浅、触礁后的应急处置

从航行、停泊、作业的船舶,搜救中心接到船舶搁浅、触礁后的险情报告后,搜救中心及遇险船舶如何应急处置,并进出了自己的观点。应急处置得当,可以减少难船人命伤亡和财产损失,如处置不当,可能会放任险情、事故的态势的恶化,给人命和财产造成更大的损失。     

琼州海峡船舶安全航行风险分析及应对

琼州海峡是北部湾通往中国沿海各港口的交通要道,也是海南岛和雷州半岛之间水路交通的必经之路。常年船舶流量大,经常发生搁浅、碰撞等事故。本文从琼州海峡的航道特殊性出发,分析进出琼州海峡的注意事项及应急处置。     

Monitoring of ship damage condition during stranding

This study proposes a new procedure for the estimation of stranding forces and their contact positions. The method is based on the measurement of a few characteristic on-site parameters, i.e., the draughts and bending moments acting on a stranded ship. A procedure that estimates penetration into the ship bottom based on knowledge of the resistance versus penetration relationship is also presented. The seabed topology is parameterized by a paraboloid. This geometry can, in principle, characterize a wide range of obstructions, from sharp rocks to large shoals. Nonlinear finite element analysis is used to simulate various stranding situations and to generate the corresponding resistance versus penetration curves. The present method provides insight into the identification of real stranding scenarios in terms of the location of obstructions, their possible shapes and the corresponding resistance-penetration curves. The proposed methodology represents a first step towards a tool for quick decision making during salvage operations. The ultimate goal is to allow near real-time prediction of the risk of penetration into cargo tanks and hull girder failure. To demonstrate the effectiveness of the proposed method, it is applied to a simulated trial stranding scenario.     

Analysis of structural crashworthiness of double-hull ships in collision and grounding

A conceptual design framework for collision and grounding analysis is proposed to evaluate the crashworthiness of double-hull structures. This work attempts to simplify the input parameters needed for the analysis, which can be considered as a step towards a design-oriented procedure against collision and grounding. Four typical collision and grounding scenarios are considered: (1) side structure struck by a bulbous bow, (2) side structure struck by a straight bow, (3) bottom raking, (4) bottom stranding. The analyses of these scenarios are based on statistical data of striking ship dimensions, velocities, collision angles and locations, as well as seabed shapes and sizes, grounding depth and location. The evaluation of the damage extent considers the 50- and 90-percentile values from the statistics of collision and grounding accidents. The external dynamics and internal mechanics are combined to analyse systematically the ship structural damage and energy absorption under accidental loadings.     

有限水深中破损船舶的运动与波浪载荷研究

由于有限水深中船舶搁浅和触礁等严重破损事故频发,为了减少事故的发生,对有限水深中船舶破损后的运动及波浪载荷的研究显得十分必要。文章基于三维势流理论,引入有限水深自由面Green函数,在频域内使用奇点分布法对一艘首部破损进水的散货船在有限水深中的运动与波浪载荷展开了计算,并根据劳氏船级社规范做了短期预报。短期预报结果表明,该散货船破损进水后,船体所受垂向和水平波浪弯矩均比破损前有明显增加,且在较浅水深中变化更为显著。     

Behavior of a double hull in a variety of stranding or collision scenarios

A series of nine tests was conducted to investigate the behavior of a double hull in a variety of stranding or collision scenarios. Cones of five different nose radii were made to model accident scenarios ranging from grounding on a sharp rock to stranding on a relatively flat seabed or shoal, and collision with a sharp bulbous bow of a fast ship to collision with a large bow of a VLCC. Three sub-series were designed in which the cones pressed shell plating, main supporting members and intersections of main supporting members. The test results reveal that the nose radius and the location of penetration have a very strong influence on the behavior of a double hull. Therefore, careful definition of accident scenarios is of crucial importance to assess the strength of ship hulls in accidents, and it is necessary to base the assessment on probability of accidents. Characteristics of the response of structural members were identified and idealized as simple theoretical models. Analytical formulae were derived and discussed. Primary damage mechanisms include membrane stretching of shell panel, onset of rupture, crack propagation, folding of main supporting members, and crushing of intersections of main supporting members. The new plate punching model captures the phenomenon that the load-carrying capacity of a plate depends on the size of the striking object. The plate perforating model predicts the reduced strength of plates with cracks. It reflects the observed test phenomenon that loads do not drop to zero even after rupture occurs in shell plating. A simple analytical method was developed to calculate the global strength of a double hull. The method takes geometrical parameters of seabed rocks or bulbous bows into account, and can be used for a wide range of different accident scenarios. Calculations using this method compared satisfactorily with the test results. This method can be easily incorporated into a probability-based framework to properly assess structural performance for a variety of damage scenarios. Similar to the Wang et al. (J Ship Res 41 (1997) 241) paper on raking damage, which uses only four analytical models, this method also requires only a common calculator to carry out the calculations.     

Comparison of the crashworthiness of various bottom and side structures

The purpose of this work is to compare the resistance with damage of various types of double bottom structures in a stranding event. The comparative analyses are made by use of a commercial, explicit finite element program. The ship bottom is loaded with a conical indenter with a rounded tip, which is forced laterally into the structures in different positions. The aim is to compare resistance forces, energy absorption and penetration with fracture for four different structures. Those four structures are: a conventional double bottom, a structure (presently protected through a patent) with hat-profiles stiffened bottom plating, a structure where all-steel sandwich panel is used as outer shell and a bottom structure stiffened exclusively with hat-profiles. The paper shows that it is indeed possible to elevate the crashworthiness of side and bottom structures with regards to the loading considered here without increasing the structural weight.     

X型船艉管冷却系统改造设计

我厂建造的X型船艉管冷却系统冷却水由主机机带海水泵冷却主机后提供,冷却、冲刷橡胶轴承后排出舱外.由于X型船受多泥沙、多海生物且频繁进出浅水港等航行环境的影响,泥沙等杂质易进入冷却系统,导致橡胶轴承烧损,轴系铜套被严重划伤.为了避免类似事故再次发生,通过总体分析故障原因,根据系统的理论计算,对艉管冷却系统进行改造设计,并通过实船试验进行验证,确保改造后系统具有良好的可靠性及安全性.     

船行波对双船系靠LNG泊位系泊稳定性的影响

双船系靠LNG泊位对系泊稳定性要求高,而目前尚无船行波对双船系靠泊稳定性影响的定量分析方法。结合工程实例,以Flory-Remery单船系泊船行波荷载计算方法为基础,结合双船系靠泊位的特点予以修正,利用数值分析软件定量分析船行波过程对双船系靠泊位系泊稳定性的动态影响。结果表明,典型系泊条件下,双船系靠泊位系泊倒缆受力及纵移运动量受船行波影响最大,当船行波与系泊船间距50 m时系泊稳定性不满足要求;当船行波与系泊船间距100 m时系泊稳定性满足要求;当船行波与系泊船间距150 m时系泊稳定性基本不受船行波影响。     

水位变动对三峡升船机船厢下游对接运行操作的影响

三峡升船机下游引航道具有水位波动大、变化快的特点。为减少水位变动对三峡升船机船厢下游对接运行操作的影响,采用最小二乘拟合的方法,建立船厢下游对接时船厢水深、船厢与下游偏差拟合数学表达式,得出结论：船厢下游对接时船厢水深、船厢与下游偏差是线性对应的。根据三峡升船机现阶段运行操作现状,结合船厢水深、船厢与下游偏差变化,提出船厢下游对接不同时段的运行操作应对策略,为三峡升船机运行操作提供经验。     

航行船舶在波浪中响应长期监测技术

船舶在运营中遭遇恶劣海况时结构可能会发生破坏,从而对船舶在海上航行的安全性产生严重影响.对航行船舶结构安全性的实时监测与评估是船舶设计研究人员非常关注的问题,它对船体结构的研究、设计和标准制定以及航行操作都有重要的意义.对研发成功的一套航行船舶在波浪中响应的长期监测系统(LOTEMS)及其在实船航行中的长期应用情况进行介绍和分析.该系统能对船体结构的总纵强度和局部强度、船舶6个自由度的运动模态以及船舶的加速度进行实时的跟踪测量和分析,可为船舶结构安全状态提供必要的警示信息,以便为船舶操作人员航行决策提供辅助依据.