船载精矿倾覆事故成因及其控制

为避免船载精矿倾覆事故的发生,此文对精矿易流态化危险特性进行了分析,并应用系统安全工程评价方法着重分析了由于货物、船舶、天气和船公司不安全运营等因素造成船舶倾覆事故发生的原因,并有针对性的提出了安全措施来预防和控制此类倾覆事故的发生。     

油船货泵舱爆燃事故分析

油船货泵舱爆燃事故作为船舶主要风险之一,一旦发生往往引起巨大的财产、人员损失和环境损害。为保证船舶安全运营,开展油船货泵舱爆燃事故研究迫在眉睫。油船货泵舱爆燃事故风险因素辨识事故树分析法(FaultTree Analysis,FTA)是一种从结果到原因的逆向分析法。将事故结果确定为顶部事件,然后找出导致事故后果的直接因素和间接因素,把所有因素运用逻辑关系绘制成一个树形结构,进而对事故进行定性或定量分析。     

浅谈船长在船舶保险商务中的应对

船舶运营过程中难免会发生一些事故或产生一些纠纷,处理这些事故及纠纷必将涉及到一些保险及法律上的实务。文章简要介绍船舶保险的一些重要知识,尤其在事故或纠纷发生后,船长应应对的船舶保险商务事宜。     

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。     

以“COSCO BUSAN”轮事件论提升我国水上交通公共管理水平

通过分析评估发生在美国旧金山船舶碰撞大桥事故的应急处置、事故和污染调查以及后续处置等一系列措施,对比我国目前现存的水上事件应急体制、机制和程序,以及在我国发生类似事件的处置情况。     

人为失误与船舶引航事故的预防

船舶引航事故中的主要原因是人为失误,在分析该原因及其相关的失误链与事件链和不同种类失误的基础上,全面认识人为因素与引航事故的关系,注意调节引航员生理与心理状态和及时识别并破断引航中的失误链与事故链的角度,就预防船舶引航事故的发生进行了论述,并提出了一些设想与建议。     

船舶无损检测开启新纪元

有关资料显示．近年来我国发生的多起新建船舶断裂事故．主要原因之一就是焊接缺陷。2007年的6月-10月．鄱阳湖区和赣江发生了7起船舶断裂沉没事故,其中船龄最短的“健鸿”号船投入运营才10来天。经对事故船舶勘验、查证、分析和计算证实,除钢质结构差、造船工艺不合理等原因外,焊角尺寸过小、夹渣、咬边,吹偏、未融合、未焊透等严重焊接缺陷．是这些短命船舶的最致命杀手。     

基于“浴盆”曲线的海事预防分析

船舶海上交通事故是随机事件,很难预测,但事故发生也有其规律,掌握了事故规律就有可能控制和预防事故。通过"浴盆"曲线分析"人"和"机"两因素与海事之间的内在联系,旨在认识海事发生的规律,有效减少发生海事的风险,预防海事的发生。     

基于VISSIM软件的船舶交通流仿真可行性探讨

随着我国经济的高速发展,运输船舶日益增多,发生船舶碰撞事故的可能性逐渐加大。为了保证船舶航行安全,减少船舶碰撞事件和水域污染事故,近年来,人们一直在尝试利用计算机仿真技术来研究船舶交通流控制问题。本文利用VISSIM软件模拟公路交通流并期望通过此方法对船舶交通流的模拟进行可行性探讨,优化船舶交通流控制,避免船舶碰撞的发生。     

论船舶防碰撞整治措施

文章通过对船舶碰撞事故的分析,提出防止船舶碰撞事故发生的安全措施,有助于减少船舶碰撞事故的发生。     

台湾海峡水域搁浅事故的方差分析

船舶搁浅事故造成的经济损失和海洋环境污染是台湾海峡水域主要危害之一.为减少搁浅事故的发生,使台湾海峡水域的船舶航行更安全、海洋环境更清洁,以台湾海峡水域搁浅事故为例,在统计分析船舶搁浅事故特征的基础上,选用方差分析法对搁浅事故因素相关性和差异性进行了系统的分析.提出了台湾海峡水域搁浅事故中人为因素所占比例最高,水深不足...     

Investigation on structural performance predictions of double-bottom tankers during shoal grounding accidents

An investigation is carried out in this paper for the predictions of structural performance of double-bottom tankers during ship grounding over the “shoal” type seabed obstacles. Hong and Amdahl developed a simplified analytical model for the unstiffened double bottom. This method is carefully studied, verified and then used as the first stage of our prediction. The second stage is concerned with stiffeners since stiffeners are indispensable components for double-bottom tankers. A prevailing way to handle is to smear stiffeners onto their attached plating known as the smeared thickness method. However, the effective ratio in this method is dubious in such shoal grounding accidents. Proper values of this parameter are determined in stage two, and then together with the method in stage one, constitute a reliable and efficient tool for structural performance predictions of double-bottom structures in shoal grounding accidents.A double-bottom tanker is chosen as object for the case study. Finite element models of the hold both stiffened and unstiffened are created for numerical simulations using the LS_DYNA software. Simulation cases cover a wide range of slope angles of the indenter and indentations. Numerical results show that Hong and Amdahl's model in stage one is capable of predicting energy dissipation with high precision but poor accuracy for grounding resistances, and a possible reason may be the neglect of vertical resistance. The updated smeared method proposed in stage two is also proved to be capable of grasping major characteristics of stiffeners. Results and conclusions drawn from this paper can be conveniently applied for assessments of the performance of ship double-bottom structures during shoal sliding grounding scenarios, and will benefit the application of accidental limit state design concept in the ship design stage.     

Verification of a simplified analytical method for predictions of ship groundings over large contact surfaces by numerical simulations

In this paper, a verification is presented of a simplified analytical method for the predictions from numerical simulations of structural performance during ship groundings over seabed obstacles with large contact surfaces and trapezoidal cross-section. This simplified analytical method was developed by Lin Hong and Jørgen Amdahl and calculates grounding characteristics, such as resistance and distortion energy, for double-bottomed ships in shoal grounding accidents. Two finite-element models are presented. One was built for a hold, and the other was built for a hold and a ship hull girder and also considers sectional properties, ship mass, added mass and the hydrodynamic restoring force. The verification was completed by comparing horizontal and vertical resistances and the distortion energy between seven numerical-simulation cases and a set of corresponding cases computed by a simplified analytical method. The results show that the resistances obtained by the simplified analytical method are close to the mean values of the resistance curves obtained by numerical simulations. The comparisons prove that the energy dissipation-prediction capability of the simplified analytical method is valuable. Thus, the simplified analytical method is feasible for assessing ship groundings over seabed obstacles with large contact surfaces and trapezoidal cross-section. Furthermore, studies of the influence of ship motion during groundings ascertained that ship motion affects structural performance characteristics. Resistances are lessened at the end of the grounding due to the reduction of indentations caused by heave and pitch motions of the ship hull girder. Finally, a new method for predicting the structural performance of the time-consuming complete-ship model by applying a combination of normal numerical simulations and ship-motion calculations is proposed and proven.     

Statistics and damage assessment of ship grounding

In this paper, general statistics of ship grounding incidents are considered and the damage extent distributions for Ro–Ro ships are presented from the results of a comprehensive damage data survey conducted using Lloyd's Register's damage database. Theoretical models and semi-empirical formulae based on parametric studies are used to study the damage extents of grounded ships. Two real life grounding accidents are assessed. One is a single hull VLCC grounded onto a single rock and the other is a cargo ship grounded onto multiple rocks. A simulation based on a simple multi-rock scenario has been conducted on a 304-m single hull tanker. Correlation is made between the present calculation method results, statistical results and IMO requirements. The paper concludes with the main findings from the study.     

Full six degrees of freedom coupled dynamic simulation of ship collision and grounding accidents

By taking advantage of the user-defined load subroutine (loadud) and the user common subroutine (usercomm) in LS-DYNA, the authors proposed a new coupled approach for simultaneously calculating structural damage and the planar 3DOF ship motions in ship collisions. The coupled procedure aimed at predicting the detailed structural damage together with reasonable global ship motions. This paper extends the method to consider the full 6DOF ship motions; thus, ship collision as well as grounding accidents can be properly handled. This method is particularly useful for design purposes because the detailed ship hull profile is not needed.A traditional ship maneuvering model is used for the in-plane surge, sway and yaw degrees of freedom with a series of nondimensional coefficients determined from experiments. It is assumed that the out-of-plane degrees of freedom are not coupled with the in-plane ship motions, and there is no coupling among roll, pitch and heave motions. The implementation is verified through free decay tests, and the obtained natural periods show good agreement with theoretical results.Several collision and grounding cases are simulated in which a supply vessel crashes into rigid plates with different orientations. The effects of the roll motion, the heave and pitch motions and the full 6DOF motions are studied. The results are compared with those from a 6DOF decoupled method. Ship motions through the proposed method compare reasonably well with SIMO results. It is found that several consecutive impacts may occur in the simulation of one collision case due to the periodic motions. This is not taken into account in the decoupled method, which makes this method unconservative.     

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.     

Generalized F distribution model with random parameters for estimating property damage cost in maritime accidents

ABSTRACT

This study develops a generalized F distribution model with random parameters to estimate the ship property damage cost in maritime traffic accidents with 10 years’ shipping accident data in the Fujian waters. Model results show that sinking and capsizing can incur the largest property damage cost, followed by collisions, contact, grounding and fire/explosion. There is a smaller ship property damage cost when the ship is moored or docked. The poor visibility has the least impact on the increment of ship property damage cost. Results reveal that the bigger property damage cost is associated with maritime accidents occurring in the Straits/sea areas and under the strong wind/wave condition and nighttime periods. It is also found that the lookout failure exhibits a bigger effect than the operation error. These results are helpful for policy makers to make efficient strategies for reducing property damage cost in maritime accidents. The developed model is useful for insurance companies in determining the appropriate ship insurance rates.     

碰撞/搁浅事故中船体强桁材结构损伤机理解析预报方法研究

随着航运业的快速发展,海上航行的船舶越来越多.尽管人们做了许多努力避免海上意外事故的发生,但海难事故依然不可避免.为了降低上述事故造成的损失,需要在设计阶段快速并准确地预报船舶的结构耐撞性.本文以强桁材结构为研究对象,通过开展准静态冲压试验及相应的数值仿真,分析强桁材结构在面内冲压载荷作用下的变形机理,并基于试验与仿真所得到的结构变形特点,提出强桁材面内受压时的变形模式.以此为基础,运用塑性力学理论,推导出结构变形能、瞬时结构变形抗力及平均结构变形抗力的解析预报公式,并将计算结果与试验结果进行比较验证.研究得到的结构面内受压变形能和抗力解析计算公式,可以快速评估事故载荷下结构的响应情况,包括结构变形阻力及能量耗散,具有使用方便,计算速度快,计算结果相对可靠的优点,对船体耐撞结构设计及抗撞性能评估具有一定的指导意义.     

船舶搁浅于刚性斜坡数值仿真的模型化技术

显式非线性有限元分析已逐渐成为研究船舶搁浅问题的重要方法,但其模型化技术是实现数值仿真的关键。本文将搁浅船处理为可变形结构,用弹塑性材料模拟并进行整船建模,斜坡处理为刚体,用刚性材料模拟,船舶与斜坡之间定义为主从接触,船艏定义为自接触。通过仿真计算,获得并讨论了搁浅过程中的船体运动情况、搁浅接触力曲线、能量转化及船舶损伤变形情况。算例表明本文的模型化技术可以用于船舶搁浅的仿真计算。