GRACAT: software for grounding and collision risk analysis

From 1998 to 2000 an integrated software package for grounding and collision analysis was developed at the Technical University of Denmark within the project: Information technology for increased safety and efficiency in ship design and operation. The cost of the software development was 6 man-years. The software provides a toolbox for a multitude of analyses related to collision and grounding accidents. The software consists of three basic analysis modules and one risk mitigation module: (1) frequency, (2) damage, and (3) consequence. These modules can be used individually or in series and the analyses can be performed in deterministic or probabilistic mode. Finally, in the mitigation module risk profiles for the calculated consequences can be calculated and compared to alternative solutions by assignment of a cost function to the consequences. Thus, the possible analyses range from a deterministic crash analysis to a comparative risk analysis of two vessels operating on a specified route where the result is the probability density functions for the cost of oil outflow in a given area per year for the two vessels. In this paper, we describe the basic modelling principles and the capabilities of the software package. The software package can be downloaded for research purposes from www.ish.dtu.dk/GRACAT.     

碰撞事故下油船泄漏的定量风险评估

针对目前船舶与海洋工程领域的风险评估大多为一些描述性的定性分析,难以确定风险发生的频率以及风险发生后的区域的状况,本文依据P.T.Pedersen研究船舶碰撞概率的计算方法,以某一区域为例,计算并分析了该区域的船舶碰撞事故发生概率;运用由挪威船级社(DNV)开发的NEPTUNE软件对油品特性进行了分析,并模拟了某一油船发生泄漏的油膜范围,预测了由泄漏所引发的火灾及爆炸事故的损害区域,这对油船上设备的合理布置及舱室设计工作具有一定的参考意义.     

Simplified method for quasi-static collision assessment of a damaged tanker side panel

The paper presents a simplified analytical method to examine the energy absorbing mechanisms of intact and damaged small-scale stiffened plate specimens, quasi-statically punched at the mid-span by a rigid wedge indenter. The specimens scaled from a tanker side panel are limited by one span between web frames and stringers. The influence of the initial damage on the impact response is based on the plastic behaviour of an intact specimen. The initial damage is provoked at one-quarter from the support by the same indenter that, afterwards, punches the specimen at the mid-span. In practice, initial imperfections of this type could be due to minor incidents during ship service operation, such as collision of ships with floating objects. To validate the proposed simplified method, experiments and numerical simulations are conducted. The experimentally obtained force-displacement responses and shapes of the deformation show good agreement with the simulations performed by the explicit LS-DYNA finite element solver. The analytical method derives expressions to estimate the energy dissipated by the intact and the damaged specimens based on the plastic deformation mechanisms, assuming that both the plate and stiffener structural components absorb the incident energy through the rotation of the plastic hinges at the point of contact and at the supports and the membrane tension over the plastically deforming region between the loading and the supports.     

碰撞、搁浅破坏下油船风险评估研究综述

综述了碰撞和搁浅破坏下油船风险评估的研究现状,分析和总结了研究的方法和流程,指出了碰撞和搁浅破坏下油船风险评估的研究热点和发展趋势。     

海上溢油事故及其防范

对近年来世界海运溢油事故现状以及其所产生的危害进行了具体的阐述,分析事故产生的原因、防范的现状及存在的问题,提出了防范措施.     

Review and application of ship collision and grounding analysis procedures

It is the purpose of the paper to present a review of prediction and analysis tools for collision and grounding analyses and to outline a probabilistic procedure for which these tools can be used by the maritime industry to develop performance based rules to reduce the risk associated with human, environmental and economic costs of collision and grounding events. The main goal of collision and grounding research should be to identify the most economic risk control options associated with prevention and mitigation of collision and grounding events.     

穿梭油轮与浮筒碰撞的有限元仿真分析

穿梭油轮靠近浮筒时,如果出现人为失误或者机械失效,穿梭油轮可能会与浮筒发生碰撞。由于穿梭油轮质量很大,其与浮筒碰撞危害不容忽视。本文采用非线性有限元软件ANSYS/LS-DYNA,对穿梭油轮与浮筒的碰撞进行研究,计算出70 000 t穿梭油轮分别以侧向和正向方式碰撞浮筒的情形下,能量转换,结构损伤程度和撞击力的数据,分析了碰撞的危害性。本文的研究成果对穿梭油轮与浮筒碰撞的风险评估具有实用价值。     

浅析"7.20"碰撞事故的成因与预防

自由裁量权的概念及分类自由裁量权是指国家行政机关在法律、法规规定的原则和范围内有选择余地的处置权力。这些自由裁量权是从法学意义上说的。它是行政机关及其工作人员在行政执法活动中客观存在的,由法律、法规授予的职权。根据现行行政法律、法规的规定,可将自由裁量权归纳为以下几种:     

"丰达油"轮碰撞特大险情救助及启示

载运4727吨航空煤油的成品油船“丰达油”轮与它船发生碰撞后机舱进水失去动力且造成船舶倾斜,为使难船尽快脱险,防止其沉没而造成海域污染,有关方面采取了应急拖带、海上过驳卸货等一系列措施,取得较好的实际效果。     

液货晃荡对双壳油船碰撞性能的影响研究

利用ANSYS/LS-DYNA分析载货情形下的双壳油船发生碰撞导致舱内液货发生晃荡时,晃荡载荷对舷侧结构碰撞性能的影响,并将所得结果与空载状态下的碰撞事故进行比对,发现液体晃荡对碰撞性能的影响主要体现在当撞击船接触到被撞击船内壳时,舱内液体动能较大,对碰撞性能产生显著影响,舱内液货能有效吸收撞击船的撞击能量,使得撞击速度快速下降,同时由于舱内液货与舱壁之间的耦合作用,使得碰撞力增大,导致内壳受损更为严重,造成内壳提前破裂。     

Elements of risk analysis for collision and grounding of a RoRo passenger ferry

Newly developed software was applied to study the effects of damages due to collision and grounding. The annual risk of collision and grounding was computed for an example RoRo passenger ferry. Collision frequency was evaluated for a specified route taking into account traffic data. Grounding frequency was calculated for an artificial obstacle located close to the traffic route. The consequences of collision and grounding scenarios were estimated by introducing damage criteria that link the calculated distribution of damage size and damage location to monetary units. Loss of human life and reputation was not considered. It was shown that the main part of the calculated annual risk is caused by capsize of the vessel after severe damage.     

17000载重吨油船结构疲劳分析的快速估算方法(英文)

Fatigue cracks and fatigue damage have been important issues for ships and offshore structures for a long time.However,in the last decade,with the introduction of higher tensile steel in hull structures and increasingly large ship dimensions,the greater attention should be paid to fatigue problems.Most research focuses on how to more easily access the fatigue strength of ships.Also,the major classification societies have already released their fatigue assessment notes.However,due to the complexity of factors influencing fatigue performances,such as wave load and pressure from cargo,the combination of different stress components,stress on concentration of local structure details,means stress,and the corrosive environments,there are different specifications with varying classification societies,leading to the different results from different fatigue assessment methods.This paper established the Det Norske Veritas(DNV) classification notes "fatigue assessment of ship structures" that explains the process of fatigue assessment and simplified methods.Finally,a fatigue analysis was performed by use data of a real ship and the reliability of the result was assessed.     

有关油船设计的OCIMF规则

本文主要介绍OCIMF在油船设计中的一些建议和规则,便于设计人员在油船的设计中能方便地查阅和参考.     

Simplified analytical method for evaluating web girder crushing during ship collision and grounding

The paper presents a simplified analytical method to examine the crushing resistance of web girders subjected to local static or dynamic in-plane loads. A new theoretical model, inspired by existing simplified approaches, is developed to describe the progressive plastic deformation behaviour of web girders. It is of considerable practical importance to estimate the extent of structural deformation within ship web girders during collision and grounding accidents. In this paper, new formulae to evaluate this crushing force are proposed on the basis of a new folding deformation mode. The folding deformation of web girders is divided into two parts, plastic deformation and elastic buckling zones, which are not taken into account for in the existing models. Thus, the proposed formulae can well express the crushing deformation behaviour of the first and subsequent folds. They are validated with experimental results of web girder found in literature and actual numerical simulations performed by the explicit LS-DYNA finite element solver. The elastic buckling zone, which absorbs almost zero energy, is captured and confirmed by the numerical results. In addition, the analytical method derives expressions to estimate the average strain rate of the web girders during the impact process and evaluates the material strain rate sensitivity with the Cowper-Symonds constitutive model. These adopted formulae, validated with an existing drop weight impact test, can well capture the dynamic effect of web girders.     

油船斜撑杆结构理论计算分析

油船结构轻量化设计中,船体横向强框和横舱壁水平桁端部优化为类似斜撑杆的轻型结构,并在多型油船上进行了实船应用。然而,目前还没有相关规范和标准用来指导斜撑杆结构的设计。本文通过建立相关结构力学模型,得到斜撑杆结构的轴向载荷理论值,并验证相关力学模型及理论结果的有效性。最后对影响斜撑杆轴向载荷的主要因素进行了研究分析,能够为斜撑杆结构的优化设计提供一定的指导。     

由"安庆"号油轮爆炸事故引发的思考

此文介绍了一起油轮惰气系统风机间爆炸事故和原因分析,并提出几点提高油轮管理水平的建议。     

中国油运船队的战略选择——访大连远洋运输公司副总经理李玉平

目前,中国已成为全球第二大石油消费国和第三大石油进口国。进口原油中,有50%来自中东,22%来自非洲,12%来自东南亚。而且中国从这三个地区进口石油,不仅路途遥远,而且全部依赖海运。那么,如何才能建立起一支担负国家使命的油运船队?"国油国运"与油轮船队的国际化之间究竟是一种什么关系?大连远洋运输公司副总经理李玉平在接受本刊专访时,对此作了详细的阐释。     

关于油船评价体系的探讨

文章就如何综合评价油船展开了探讨,结合国标《海洋运输船舶主要性能水平评级》提出了新的观点,并就几型VLCC进行评价分析。     

油轮和干散货市场未来运价分析

未来而言，考虑到供求因素，我们认为油轮市场2007年～2008年均将出现同比下滑，但下跌幅度有限。从2009年开始，单壳船的逐渐拆解将支持运价回升，同时，我们预计2007年下半年的油轮运价有望出现季节性反弹；对于干散货市场，基于目前的订单量以及相对较老的运力结构，我们认为2007年～2009年的供求状况将使得运价维持高位，但在2007年，由于一些需求的结构性因素使得BDI指数一路创新高，保守估计，若这些结构性因素在2008年得到缓和，可能会导致2008年运价相比2007年略微回落。     

商船与渔船在中国沿海碰撞事故分析及避碰措施

中国的海岸线虽说很长，但由于其特殊的地理位置，致使大船航线集中．渔区集中并相互交叉。冬季的寒潮大风．春夏季的雾和每年多达20多个台风，都制约了航行和航线的选择。台风、大风过后大船恢复航行，渔船也突击出海，大雾天更是捕鱼的好时机。这一切最终加剧了航行风险，碰撞事故时有发生，其中又以大船与渔船碰撞居多。