弹性平底结构入水冲击压力及船舶总体强度研究与分析
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ຫໍສະໝຸດ IV上海交通大学硕士学位论文
英文摘要
analysis procedure of finite element which can be used to calculate strength of ships with large open. What’s more, the paper can be a reference for ship structure strength calculation according to the rules of loyd’s register. The result of the paper can be a guide for the design and strength analysis of other large container vessels.
与船首波(Bow wave)拍击船首而形成 4 湿甲板砰击 Wetdeck slamming 水面抬升的幅度大于双体船湿甲板的高度
此现象将会出现 其中最典型的就是船舶的首尾底部砰击 船舶在海面上航行 若遭遇到大的风 浪 首尾会因船体剧烈的纵摇和升沉运动而露出水面 从而出现首尾快速入水的现 象 此时船体结构可能遭受巨大的流体砰击作用力而出现过大的变形或破损 由于砰击载荷作用而发生的沉船事故屡见不鲜[2] 如 1969 至 1970 年间 由于 砰击载荷的作用 Boliver-maru 和 California-maru 突然从船中断裂导致严重的沉船 事故 1980 至 1981 年间 在北太平洋上也发生了多起同样的沉船事故 特别是 Onomichi-maru 一艘载重量 66874 吨的散货船 当时正满载着煤矿前往日本 在 beaufort 海域遭遇到 8 级海浪 两小时过后 前甲板由于强烈的激振而脱离下沉
2 当结构质量不变时 随着底部平板厚度的不断增加 弹性平底结 构在入水过程中所受到的冲击压力峰值也不断增加
3 当冲击速度为中低速时 弯曲刚度相同的弹性平底结构所受到的 冲击压力峰值基本相同 当冲击速度为高速时 上述结论将不成立
与此同时 本文还利用正交实验分析了底部平板各个参数对于冲击 压力峰值影响的程度 冲击速度最大 平板厚度次之 弹性模量最小
1
上海交通大学硕士学位论文
第一章 绪论
By means of orthogonal experiments, the paper has an investigation about some plate parameters which have an effect on impact pressure peak. The result is that impact velocity has the greatest effect, plate thickness takes second place and elastic modulus has a least effect.
The first part of the paper is to study impact pressure peak of an elastic flat-bottom structure. The paper builds up a 2-d finite element model of an elastic flat-bottom structure with the software MSC/Patran&Dytran. Through simulating the coupling of structure air media and water, the paper has a research about process of water entry of structure. The paper deals with two problem: structure elastic problem and air cushion problem. The deformation of an elastic structure has a great effect on liquid field, so the coupling of solid-liquid is taken into account. In addition, impact pressure of flat-bottom structure is caused by air cushion and it is difficult to describe it on theory. So the paper builds up a systemic finite element model, considering the coupling of structure air media and water.
图 １－１ 船舶砰击的四种类型
Figure 1-1 Types of slamming impact of a ship
1 底部砰击 Bottom slamming 常发生于露出水面的结构底部重新进入水面 的情况
2 艏外飘砰击 Bow flare slamming 较高速度的艏外飘冲击水面而产生 3 破波冲击 Breaking wave impact 运动速度较小时 入射波(incident wave)
The second part of the paper calculates structural strength of a 5618TEU container vessel. Using of the method of finite element analysis of the entire ship hull, the paper sets up a finite element model of 5618 TEU container vessel by software MSC/Patran&Nastran. According to rules and regulations for the classification of ships of loyd’s register, the loadings are computed and constrains are confirmed. Stress and deformation of structure on difference conditions are calculated finally. The paper introduces method and
上海交通大学 硕士学位论文 弹性平底结构入水冲击压力及船舶总体强度研究与分析 姓名：肖熙 申请学位级别：硕士 专业：船舶与海洋结构物设计制造 指导教师：夏斌
20050101
上海交通大学硕士学位论文
中文摘要
量的减小而减小的 并且随着冲击速度的不断增大 减小的程度也在不 断增大 但是结构的冲击周期基本上不变
关键词 弹性平底结构 冲击压力 集装箱船 总体强度
II
上海交通大学硕士学位论文
英文摘要
THE STUDY OF IMPACT PRESSURE PEAK OF ELASTIC
FLAT-BOTTOM STRUCTURE AND THE ANALYSIS
OF SHIP STRUCTURE STRENGHTH
ABSTRACT
Slamming (Impact) is a water-entry-rapidly phenomenon induced by heave and pitch of ship hull, when a ship encounters heavy wave on the sea. Because of the large response to high impact pressure, it is necessary to have a study of hydrodynamic loading and deformation of water-entry structure, which has two advantages. One is to predict the damage of structure; the other is to supply some instructions to ship maneuverability and ship design
III
上海交通大学硕士学位论文
英文摘要
The effects of some elastic parameters to peak impact pressure are discussed and some conclusions are drawn.
a) Impact pressure peak of elastic flat bottom structure water entry reduces with elastic modulus decreasing. When impact velocity is higher, the reduction is larger, but impact period almost is not changed.
Except above, the paper has a simulation analysis of a falling object experiment. Impact pressure measured is the same with those calculated, which indicates the method used in the paper has some veracities and reliabilities at certain extent.
KEY WORDS elastic flat-bottom structure, impact pressure, container vessel, structural strength
V
上海交通大学硕士学位论文
第一章 绪 论
第一章 绪论
§１．１ 引言
结构物冲击入水问题的研究 在军事和民用上都有着广泛而现实的工程背景 船舶与水面或波浪的相对运动所导致的砰击问题可大致分为四类[1] 如图 1-1 所示
b) Impact pressure peak increases, when plate thickness is added, with structure mass invariableness.
c) Impact pressure peak of same flexural rigidity plate is the same, when impact velocity is low. But when impact velocity is high, the conclusion is not right.
除此之外 本文还对一落体实验进行了仿真计算 落体所受到的冲 击压力的测量值与仿真计算值在一定的入水速度范围 3m/s 6m/s 之 内相差不大 说明本文所采用的数值计算方法还是具有一定的准确性和 可靠度
本文的第二部分进行的是 5618TEU 集装箱船全船三维有限元结构 总体强度计算 主要利用全船有限元结构分析方法 采用大型通用有限 元软件 MSC.Pastran&Nastran 对一艘 5618TEU 集装箱船舶进行全船有限 元建模,根据英国劳氏船级社入级规范提拱的公式进行载荷计算和边界 条件的确定 得到在不同工况下结构的应力与变形并按照规范提供的许 用应力进行了强度校核 本文对全船有限元分析方法与过程进行了详细 的阐述 因此对于诸如集装箱船此类大开口船舶的整船有限元分析有一 定的指导意义 而且对于根据英国劳氏船级社入级规范所进行的其它船 舶强度计算也有一定的参考作用 另外 本文所得到的全船有限元分析 的结果对大型集装箱船舶的设计与开发研究也有一定的借鉴价值
英文摘要
analysis procedure of finite element which can be used to calculate strength of ships with large open. What’s more, the paper can be a reference for ship structure strength calculation according to the rules of loyd’s register. The result of the paper can be a guide for the design and strength analysis of other large container vessels.
与船首波(Bow wave)拍击船首而形成 4 湿甲板砰击 Wetdeck slamming 水面抬升的幅度大于双体船湿甲板的高度
此现象将会出现 其中最典型的就是船舶的首尾底部砰击 船舶在海面上航行 若遭遇到大的风 浪 首尾会因船体剧烈的纵摇和升沉运动而露出水面 从而出现首尾快速入水的现 象 此时船体结构可能遭受巨大的流体砰击作用力而出现过大的变形或破损 由于砰击载荷作用而发生的沉船事故屡见不鲜[2] 如 1969 至 1970 年间 由于 砰击载荷的作用 Boliver-maru 和 California-maru 突然从船中断裂导致严重的沉船 事故 1980 至 1981 年间 在北太平洋上也发生了多起同样的沉船事故 特别是 Onomichi-maru 一艘载重量 66874 吨的散货船 当时正满载着煤矿前往日本 在 beaufort 海域遭遇到 8 级海浪 两小时过后 前甲板由于强烈的激振而脱离下沉
2 当结构质量不变时 随着底部平板厚度的不断增加 弹性平底结 构在入水过程中所受到的冲击压力峰值也不断增加
3 当冲击速度为中低速时 弯曲刚度相同的弹性平底结构所受到的 冲击压力峰值基本相同 当冲击速度为高速时 上述结论将不成立
与此同时 本文还利用正交实验分析了底部平板各个参数对于冲击 压力峰值影响的程度 冲击速度最大 平板厚度次之 弹性模量最小
1
上海交通大学硕士学位论文
第一章 绪论
By means of orthogonal experiments, the paper has an investigation about some plate parameters which have an effect on impact pressure peak. The result is that impact velocity has the greatest effect, plate thickness takes second place and elastic modulus has a least effect.
The first part of the paper is to study impact pressure peak of an elastic flat-bottom structure. The paper builds up a 2-d finite element model of an elastic flat-bottom structure with the software MSC/Patran&Dytran. Through simulating the coupling of structure air media and water, the paper has a research about process of water entry of structure. The paper deals with two problem: structure elastic problem and air cushion problem. The deformation of an elastic structure has a great effect on liquid field, so the coupling of solid-liquid is taken into account. In addition, impact pressure of flat-bottom structure is caused by air cushion and it is difficult to describe it on theory. So the paper builds up a systemic finite element model, considering the coupling of structure air media and water.
图 １－１ 船舶砰击的四种类型
Figure 1-1 Types of slamming impact of a ship
1 底部砰击 Bottom slamming 常发生于露出水面的结构底部重新进入水面 的情况
2 艏外飘砰击 Bow flare slamming 较高速度的艏外飘冲击水面而产生 3 破波冲击 Breaking wave impact 运动速度较小时 入射波(incident wave)
The second part of the paper calculates structural strength of a 5618TEU container vessel. Using of the method of finite element analysis of the entire ship hull, the paper sets up a finite element model of 5618 TEU container vessel by software MSC/Patran&Nastran. According to rules and regulations for the classification of ships of loyd’s register, the loadings are computed and constrains are confirmed. Stress and deformation of structure on difference conditions are calculated finally. The paper introduces method and
上海交通大学 硕士学位论文 弹性平底结构入水冲击压力及船舶总体强度研究与分析 姓名：肖熙 申请学位级别：硕士 专业：船舶与海洋结构物设计制造 指导教师：夏斌
20050101
上海交通大学硕士学位论文
中文摘要
量的减小而减小的 并且随着冲击速度的不断增大 减小的程度也在不 断增大 但是结构的冲击周期基本上不变
关键词 弹性平底结构 冲击压力 集装箱船 总体强度
II
上海交通大学硕士学位论文
英文摘要
THE STUDY OF IMPACT PRESSURE PEAK OF ELASTIC
FLAT-BOTTOM STRUCTURE AND THE ANALYSIS
OF SHIP STRUCTURE STRENGHTH
ABSTRACT
Slamming (Impact) is a water-entry-rapidly phenomenon induced by heave and pitch of ship hull, when a ship encounters heavy wave on the sea. Because of the large response to high impact pressure, it is necessary to have a study of hydrodynamic loading and deformation of water-entry structure, which has two advantages. One is to predict the damage of structure; the other is to supply some instructions to ship maneuverability and ship design
III
上海交通大学硕士学位论文
英文摘要
The effects of some elastic parameters to peak impact pressure are discussed and some conclusions are drawn.
a) Impact pressure peak of elastic flat bottom structure water entry reduces with elastic modulus decreasing. When impact velocity is higher, the reduction is larger, but impact period almost is not changed.
Except above, the paper has a simulation analysis of a falling object experiment. Impact pressure measured is the same with those calculated, which indicates the method used in the paper has some veracities and reliabilities at certain extent.
KEY WORDS elastic flat-bottom structure, impact pressure, container vessel, structural strength
V
上海交通大学硕士学位论文
第一章 绪 论
第一章 绪论
§１．１ 引言
结构物冲击入水问题的研究 在军事和民用上都有着广泛而现实的工程背景 船舶与水面或波浪的相对运动所导致的砰击问题可大致分为四类[1] 如图 1-1 所示
b) Impact pressure peak increases, when plate thickness is added, with structure mass invariableness.
c) Impact pressure peak of same flexural rigidity plate is the same, when impact velocity is low. But when impact velocity is high, the conclusion is not right.
除此之外 本文还对一落体实验进行了仿真计算 落体所受到的冲 击压力的测量值与仿真计算值在一定的入水速度范围 3m/s 6m/s 之 内相差不大 说明本文所采用的数值计算方法还是具有一定的准确性和 可靠度
本文的第二部分进行的是 5618TEU 集装箱船全船三维有限元结构 总体强度计算 主要利用全船有限元结构分析方法 采用大型通用有限 元软件 MSC.Pastran&Nastran 对一艘 5618TEU 集装箱船舶进行全船有限 元建模,根据英国劳氏船级社入级规范提拱的公式进行载荷计算和边界 条件的确定 得到在不同工况下结构的应力与变形并按照规范提供的许 用应力进行了强度校核 本文对全船有限元分析方法与过程进行了详细 的阐述 因此对于诸如集装箱船此类大开口船舶的整船有限元分析有一 定的指导意义 而且对于根据英国劳氏船级社入级规范所进行的其它船 舶强度计算也有一定的参考作用 另外 本文所得到的全船有限元分析 的结果对大型集装箱船舶的设计与开发研究也有一定的借鉴价值