船舶搁浅模糊故障树的灰色模糊关联分析

为解决应用传统故障树方法分析船舶搁浅事故时带有不可避免的灰色性和模糊性的问题,在分析船舶操纵性搁浅故障树的基础上,对底事件发生概率进行模糊化,建立船舶搁浅模糊故障树。引入灰色模糊关联分析方法,对模糊故障树进行定性和定量分析,根据故障树的最小割集、底事件的结构概率重要度和模糊重要度,计算各故障模式与顶事件的关联度,关联度越大,说明其对顶事件发生的影响越大。最后,综合考虑各底事件在关联度较大的最小割集中的分布情况及其模糊重要度情况,找出对顶事件发生的影响较大的底事件和故障模式,为降低顶事件发生概率制定相关风险控制措施提供参考依据。     

基于模糊推理的故障树分析方法及其应用

提出了一种基于模糊推理系统的故障树分析方法.针对故障树的底事件发生概率存在一定的不确定性,在以往研究基础上,采用模糊数表示底事件的发生概率,同时,由于故障树分析中原因事件和结果事件之间的因果关系可能存在一定的不确定性,将模糊推理系统应用于故障树分析之中,根据原因事件和结果事件之间不同的逻辑关系,采用了不同的推理算法,并且推理算法保证了推理结果的正规性.船舶设备故障分析的计算实例表明所述分析方法具有可行性,总之,该研究为系统可靠性分析提供了一种新方法.     

搁浅及碰撞事件概率的计算

为了定量描述船舶航行的风险，必须对船舶碰撞及搁浅事件建立合理的评判准则。这意味着必须对这些事件的概率以及造成的后果作出分析和评判。本文概述了一种可用于估计船舶－船舶，船舶－海洋平台碰撞以及船舶搁浅概率的方法，此方法的好处是，通过对碰撞和搁浅相对频率的估计，可在不同的航线以及不同的驾船操作规程之间进行比较。     

船舶下水安全性评估的模糊故障树方法

建立了基于模糊故障树分析的安全性评估模型，提出船舶下水从最小割集、顶事件发生的概率模糊数及基本事件的模糊重要度三个方面进行分析的安全性评估方法。介绍模糊故障树基本原理，并以某4300PCTC船纵向滑道下水过程中某一顶事件的模糊故障树分析为例，作概要阐述。     

基于模糊故障树方法的钻井平台井喷概率计算

基于模糊理论,提出了一种定量风险评估方法——模糊故障树方法。查阅历史数据库或者借助专家判断,给出故障树模型中各基本事件发生可能性的模糊数表示。考虑到不同专家意见之间可能存在的差异,给出了处理专家意见的运算法则及确定专家权重的理论方法。以半潜式钻井平台发生井喷为顶事件,构建了故障树模型,依据给出的模糊故障树理论模型,计算得到半潜式平台在钻进或固井过程中发生井喷的概率。     

基于模糊综合评判的船舶搁浅风险预测

为了提高船舶搁浅风险预测准确性,针对当前船舶搁浅风险预测方法存在一些难题,设计了基于模糊综合评判的船舶搁浅风险预测方法。首先对船舶搁浅风险预测现状进行分析,并建立船舶搁浅风险预测指标,然后采用模糊综合评判确定船舶搁浅风险预测指标权重,建立船舶搁浅风险预测模型,最后进行船舶搁浅风险预测仿真测试。结果表明,本文方法可以合理设置船舶搁浅风险预测指标的权重,可以描述每一种指标对船舶搁浅风险预测结果影响的程度,获得高精度的船舶搁浅风险预测结果,误差小于当前其他船舶搁浅风险预测方法。     

船舶在狭水道水域利用ARPA雷达准确转向的方法

狭水道中船舶转向发生碰撞或搁浅的概率较大，利用ARPA雷达来确定转向时机，控制船舶航行在安全的预定航线上，是避免船舶发生碰撞或搁浅的有效途径。     

基于首次穿越理论的船舶搁浅风险计算

为研究长江中游航道水位变化对船舶通航安全的影响,根据随机振动的首次穿越理论建立水位变化下船舶搁浅风险定量计算模型,实现不同水位下长江中游航道船舶搁浅风险的定量计算。利用航道水位、船舶吃水及富余水深三者间的动态关系,分析水位变化对允许船舶最大吃水及船舶搁浅概率的影响。利用船舶运动模型推导波浪载荷下船舶升沉运动的位移响应,同时根据首次穿越理论构建船舶首次穿越失效(搁浅)模型。运用Simulink仿真工具箱,根据船舶首次穿越失效模型计算得到不同水位下船舶的搁浅风险。利用该方法计算长江中游典型船舶在不同水位下的搁浅风险,结果表明该方法不仅能量化水位变化下船舶的搁浅风险,还可确定不同船舶搁浅概率对应的水位临界值。     

潜艇事故概率的模型事件树分析

潜艇事故概率计算在潜艇风险分析过程中占有很重要的地位，可以为潜艇结构系统综合的风险分析提供基础。计算结果表明，采用模糊事件树方法有利于了解潜艇结构系统事故的规律。在统计资料不全的情况下，模糊事件树比传统的方法更具有分析优势。本文主要介绍了模糊事件树在潜艇事故概率中的应用。     

潜艇事故概率的模糊事件树分析

潜艇事故概率计算可以为潜艇结构系统综合风险分析提供基础。计算结果表明，采用模糊事件树方法有利于了解潜艇结构系统事故的规律。在统计资料不全的情况下，模糊事件树比传统方法更具优势。本文介绍了模糊事件树在潜艇事故概率分析中的应用。     

船舶消防系统失效模型的建立与分析

消防系统是保障船舶生命力的重要复杂系统。针对消防系统存在着失效不确定和失效路径模糊的问题,结合船舶的特点应用故障树建立了船舶消防系统失效模型。为了有效地避免故障树的计算量组合爆炸问题,采用二元决策图对该模型进行定性和定量分析。分析结果明确了系统失效路径,简便地得到了各失效因素的关键重要度,计算结果精确,并提出了相应措施来降低船舶消防系统失效的发生。     

基于贝叶斯网络方法对船舶搁浅概率的研究

针对船舶航行安全的薄弱环节,在故障树分析船舶搁浅事故成因的基础上,运用贝叶斯网络对事件之间的多态性和逻辑性进行了研究。得到了事件的后验概率值,分析了导致事故发生的薄弱环节,推理得出最可能引起事故发生的事件组合,结果与统计资料一致,为提高船舶运营的安全和运营管理提供了科学依据。     

基于模糊故障树的压载水系统可靠性分析

文中以船舶压载水系统为研究对象,建立压载水调驳不成功为顶事件,运用模糊集合理论建立的故障树,并进行了可靠性计算与分析。继而对压栽水系统进行优化,并对优化后的系统进行模糊计算。计算结果表明优化后的压栽水系统具有更高的可靠性。     

舰船海上纵向补给装置液压系统的模糊故障树分析

在建立舰船海上纵向补给装置液压系统故障树的基础上,对液压系统进行模糊故障树分析,采用参照函数为正态型的L-R模糊数来描述各底事件发生的概率,推导出液压系统不能正常工作顶事件发生的模糊概率及其隶属函数分布,为提高系统的可靠性、改进结构设计提供了理论依据.     

模糊专家系统的连锁失效方法及在船舶消防中的应用

本文提出了一种基于模糊专家系统的连锁性失效测评方法,建立了基于该系统的连锁性失效测评指标,该方法不同于以往故障树方法的静态性,具有实时动态性,根据不同的输入参数,能够给出不同的决策结果,更能满足实际的需要。文章以船舶火灾自动报警系统为例,对船舶火灾自动报警系统以舱室为单元进行模块化建模,考虑了温度、烟雾浓度、可燃气体浓度,舱室危险度尤其是舱室之间关联信息、报警时间和舱室着火温度三个对连锁失效起重要作用的影响因子,详细设计了模糊规则,确定连锁报警舱室,判定连锁报警等级,得到船舶舱室消防系统单元连锁性失效路径。仿真结果说明了该方法的准确性与有效性,表明测评结果的准确性。最后,通过和故障树方法对比阐述了该方法的优越性。     

Plate tearing and bottom damage in ship grounding

A theoretical method for plate tearing by a rigid wedge is developed in this paper. The studied model is an idealization of ship-grounding and collision damage. The analysis model postulates that the plate curls up into two curved surfaces behind the wedge tip and that the plate material ahead of the wedge is tensioned and ruptured due to the direct pushing. Based on a parametric study, a semi-empirical formula is proposed for determining grounding force in the event of a ship running onto rocks in a high-energy grounding. The bottom strengths of single hull structures and double hull structures in ship-grounding incidents are compared. Finally, simple formulae for determining damage resistance and the extent of damage in ship grounding, expressed in terms of the ship principal particulars, are developed.     

高能搁浅下双层底结构的损伤特性研究

船舶搁浅事故会引起船体破损、环境污染和人员伤亡等严重后果.研究船舶搁浅,不仅有利于海上生命安全、防止海洋污染,还可为船体结构的抗冲击设计及规范航运繁忙区域中船舶的航速、操作规程提供一定的依据.本文用数值仿真法研究了船舶高能搁浅中的内部力学问题,分析了典型双层底结构的损伤变形、受力和能量耗散等结果,提出了一种新式的抗搁浅YF双层底结构,并与原结构进行了比较.研究表明,损伤变形集中于结构与礁石相接触的区域,高能搁浅内部力学问题的研究可以主要考虑局部的船体结构;肋板的存在显著增加了船底结构的抗搁浅能力;高能搁浅过程中,由于垂直方向的接触力,礁石对双层底的垂向贯入量会略有减小;当纵桁远离搁浅区域时,它的吸能能力无法发挥,抗搁浅作用很弱;YF双层底结构比原结构具有更大的吸能能力和抗搁浅力.     

Understanding ship-grounding events

The paper presents a simple procedure to estimate the damage to a ship bottom and the associated seabed topology that results from a dynamic grounding event. The seabed is modeled as a rigid body and parameterized by a quadratic surface, i.e., a paraboloid, which can in principle model a wide range of seabed topologies. A nonlinear finite element program (LS-DYNA) is used to simulate the contact force versus the lateral penetration, from which the horizontal force component of powered grounding is estimated. The simplified procedure for analyzing dynamic and static grounding events is outlined. Simulations are performed for different ship speeds and for different initial levels of obstruction over the keel. It is shown that a static approach may replace the dynamic grounding simulation, thereby considerably reducing the computational work. The static approach allows for the quick estimation of the energy absorption during powered grounding, which is imperative for decision making during critical situations. The ultimate goal of the study is to provide a near real-time prediction of the risk of rupture of the cargo tanks and hull girder failure. Moreover, the residual strength of damaged ships is an important issue that is related to operations involved in the salvage of wrecked vessels, such as re-floatation and towing.     

波浪引起破损船的垂向运动和弯矩（英文）

The wave-induced vertical ship motions and bending moments of a double hull-oil tanker in realistic flooding conditions are studied. The scenarios investigated are represented by water ingress into the starboard ballast tanks for collision damage cases and both starboard and portside ballast tanks for grounding situations. Seakeeping computations are performed for eight damage scenarios and for the intact condition, each corresponding to different changes in displacement, trim, and heel. For each of the damage conditions, transfer functions of vertical motions and loads are calculated using a potential linear 3 D panel hydrodynamic code in the frequency domain that includes effect of the motion of the water in flooded tanks. A MATLAB code is developed to facilitate automated hydrodynamic simulation of many damage scenarios. Verification of seakeeping results is performed by comparing transfer functions with results of the previous study. Wave-induced vertical responses of damaged ship are then compared to those of intact ship using two spectral-based methods originating from uncertainty analysis of wave loads, which are convenient tools to assess consequences of damage on short-term ship responses. Generally, observed trend is that vertical wave-induced responses of damaged ship converge toward those of intact ship with increasing wave period. Fairly small differences between responses of asymmetrically damaged ship with respect to the symmetrical incoming wave directions are found. The results of the study are an efficient method for seakeeping assessment of damaged oil tankers and the framework for evaluating consequences of damage scenarios, heading angles, and sea conditions on seakeeping responses of damaged ships.The results can be used to decide if the intact ship model can be used instead of the damaged one for the emergency response procedure or for the risk assessment studies when modeling and computational time represent important limitations.     

纵向弯矩下材料随机特性对复合材料船体可靠性的影响

The effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials under longitudinal moment were extensively studied using reliability and sensitivity calculations of a composite ship hull which was sagging.The reliability indices and failure probabilities of the ship in three kinds of failure modes (buckling,material failure,and ultimate collapse) were calculated by the surface response method and JC method.The importance factors of random variables in stochastic models,such as the model errors in predicting the ultimate longitudinal strength of ship and the longitudinal bending moment that the ship withstands,as well as the stochastic characteristics of materials in the models used,were calculated.Then,the effects of these random variables,including the stochastic characteristics of materials on the reliability index and the failure probability of ships which were sagging,were discussed with their importance factors.The results show that the effects of stochastic characteristics of materials on the reliability of ship hulls made of composite materials should be considered during the reliability assessment of composite ships.Finally,some conclusions and recommendations were given for high-speed ship design and safety assessment.