【作者】 李慧；

【导师】 甘浪雄；

【作者基本信息】 武汉理工大学 ， 交通信息工程及控制， 2017， 硕士

【摘要】 船舶在海上航行可能会由于操纵不当、机械故障、不良环境因素或其他不可抗因素而导致发生碰撞、搁浅等危险事故,统计数据显示,上述危险事故中,船舶碰撞事故发生频率较高。目前学者们基于船舶碰撞的研究对象主要集中在船首垂直撞击船中,研究内容主要集中在碰撞损伤、耐撞性结构优化、碰撞机理方面,但针对不同态势不同区间段的整船碰撞以及碰撞后的风险研究相对较少。船舶一旦发生碰撞,可能会造成严重的后果,如人员伤亡、货物损失和环境污染等,因此,如何最大程度地降低碰撞损伤和损失是急需研究的重点。为了减少船舶碰撞损伤和损失,船舶在实际航行中,若碰撞不可避免时,驾驶员应尽量选择合适的碰撞区间和态势(包括速度和角度)。因此,研究船舶碰撞危险区间及不同态势下的损伤具有十分重要的意义。本文基于有限元仿真技术展开研究,结合风险评价方法及改进后的BP-GA(Back Propagation-Genetic Algorithm)算法,以两艘10000吨级单舷侧结构散货船为研究对象,首先,探讨船舶碰撞损伤的影响因素;其次,界定船舶碰撞的危险区间段,以期指导船舶驾驶员应急避碰整体策略;再次,通过建立综合指标,确定船舶碰撞的临界速度及角度;最后,提出减少碰撞损伤的建议,指导船舶驾驶员应急操纵,减少和降低碰撞事故中船体结构损伤及碰撞导致的各类风险。本文在以下方面开展了相关研究工作:(1)整船有限元模型建立。以两艘10000吨级散货船为对象,依据船舶型线图、典型横剖面图、结构图等,利用有限元分析软件MSC.Patran建立船体结构有限元模型,并进行参数设置,如材料、接触、边界条件等;(2)船舶碰撞损伤程度影响因素探讨。建立局部舱段碰撞模型,针对球鼻首结构撞击船中舷侧舱段,设计多个数值仿真试验工况,根据舱段损伤结果探讨影响船舶碰撞损伤程度的因素;(3)船舶碰撞损伤危险区间界定。将被撞船划分为“船首球鼻首段”、“船中货舱段”和“船尾机舱段”三个区间段,从各区间段有限元仿真结果及碰撞风险评价两个方面对危险区间分别进行界定,最终综合确定最危险的碰撞区间段;(4)船舶碰撞损伤临界态势研究。以不同的速度、角度设计多个数值仿真试验工况,基于MSC.Dytran对最危险的区间段进行有限元仿真分析,确定船尾段结构未破裂时刻的速度范围和角度范围。为了更准确地确定临界速度和角度值,以船尾段结构未破裂,同时碰撞能量损失最小、撞深(变形尺寸)最小等建立综合指标,利用正交设计、改进后的BP-GA算法,最终确定其临界速度和角度值;(5)减小船舶碰撞损伤的建议。针对两艘10000吨级散货船的碰撞,从应急操纵以及结构优化设计两方面进行探究,提出减小碰撞损伤的建议。更多还原

【Abstract】 Collision,stranding and other dangerous accidents will happen due to inappropriate operation,machine breakdown,unfavorable environment and unavoidable factors when ships sail on the sea.Statistics show that ship collision has ranked highest among all these accidents.Until now,scholars have been focused on the collision of ship whose bow hits vertically the side amidships.They have mainly studied on collision damage,structural crashworthiness optimization and collision mechanism,but rarely on the collision of the whole ship under different situations and sections.What’s more,there is no study on the risk after collision.Once collision happens,it may result in casualties of people,loss of fortune and environment pollution,etc.Thus,how to reduce as much low collision damage and loss as possible is the most important thing.If collision is unavoidable in reality,in order to lower the damage and loss,the ship operator should adjust to the proper collision area and situation(including speed and angle).In this case,it is of significance to study the dangerous zone of ship collision and damage under different situations.Based on the finite element simulation,combined with risk evaluation method and the improved BP-GA(back propagation-genetic algorithm),the thesis takes two 10,000 DWT single-hull side structural bulk carriers as the research objects,first studies the factors that influence the degree of collision damage;then defines the dangerous zone of the ship collision which guides the ship operator to avoid more serious collision;and determines the critical velocity and angle of the ship collision by establishing the comprehensive index.At the end of it,suggestions about how to reduce the structure damage of collision and collision risk in an emergency are given to the ship operator.The related researches of this thesis are as follows:(1)Establishment of finite element model of whole ship.Taking two bulk carriers whose capacities are both 10,000 DWT as objects,the finite element models of ships are established by using finite element analysis software MSC.Patran according to the ship line drawing,typical cross-section drawing and structure drawing;based on the model,parameters such as materials,contact,boundary conditions,etc are set.(2)Discussion on factors affecting ship collision damage.Based on the situation that the bow hits the side amidships,several numerical simulation conditions are designed and the factors influencing the collision damage according to the damage results are discussed.(3)Definition of the danger zone of ship collision damage.The collision zone is divided into three sections: "the bulb-bow section of the bow","the cargo hold section amidships" and "the cabin section of the stern".The degrees of danger for the collision zones are defined respectively according to infinite element simulation of different zones and evaluation of collision risk.After comparing all the results,the most dangerous collision zone is determined.(4)Research on critical situation of ship collision.Several numerical simulation conditions including different speeds and angles are designed firstly.Then,the finite element simulation of the most dangerous zone is analyzed by MSC.Dytran and the velocity range and angle range are determined when the stern structure is unbroken.In order to get more accurate values of the critical velocity and angle,based on the situation that the stern structure is unbroken,the collision energy loss is smallest and the depth of collision(deformation dimension)is smallest,its final critical velocity and angle values are determined by using the orthogonal design and BP-GA algorithm.(5)Recommendations for reducing ship damage.Based on the analysis of the collision of two 10,000 DWT bulk carriers,the suggestions are given for reducing collision damage on the discussion from the two prospects of the emergency operation and structural optimization design.更多还原