考虑航速的汽车滚装船.doc
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考虑航速的汽车滚装船,摘 要随着船舶尺度的大型化，高强度材料的应用以及新的结构形式的研发应用等因素，导致船舶疲劳问题日益突出，并成为船舶与海洋结构物主要失效模式之一。在以往工程应用中，疲劳评估一般采用简化计算方法或者结构有限元法与简化计算方法相结合，并且一般在零航速下计算关键节点的疲劳累积损伤。本文主要研究线性波浪载荷作用下的船体结构疲劳问...
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摘 要
随着船舶尺度的大型化，高强度材料的应用以及新的结构形式的研发应用等因素，导致船舶疲劳问题日益突出，并成为船舶与海洋结构物主要失效模式之一。在以往工程应用中，疲劳评估一般采用简化计算方法或者结构有限元法与简化计算方法相结合，并且一般在零航速下计算关键节点的疲劳累积损伤。本文主要研究线性波浪载荷作用下的船体结构疲劳问题，并且重点考虑航速对于疲劳累积损伤度的影响，着重对以下几个方面进行研究与探讨。
（一）阐述船舶结构疲劳分析的基础理论和基本方法，包括 曲线与Miner线性累积损伤理论，疲劳评估的简化计算方法，疲劳评估直接计算方法中的谱分析法。
（二）根据船舶在波浪上运动的三维势流理论，研究了时域内有航速船舶波浪诱导运动与载荷的计算方法，波浪载荷短期与长期预报方法，三维时域Rankine源方法的基本理论。
（三）以一艘5000车汽车滚装船为例，采用三维时域全航速理论预报了典型装载情况下滚装船在波浪上的运动性能与剖面载荷，通过分析运动与载荷随航速变化的规律，得到船体纵荡、横荡、横摇以及波浪弯矩航速效应显著。
（四）基于设计波法对整船结构强度进行评估。阐述了设计波方法的基本理论以及设计波参数选取的方法。根据载荷响应函数以及波浪诱导载荷长期预报值选取六组设计波参数，对滚装船的典型装载情况下进行了结构有限元强度分析，为疲劳校核点的选取提供依据。
（五）采用疲劳谱分析法，研究了考虑航速情况下受线性波浪载荷结构的疲劳累积损失度以及疲劳寿命。比较不同航速下疲劳累积损伤度的值，以及不同波浪入射角对于疲劳累积值的贡献度，得出高航速船舶在疲劳评估中考虑航速是必要的。
关键词：滚装船 疲劳评估 航速 设计波法 谱分析法
Abstract
With the factor of large-scale vessel, using of high-strength material and research and development of new form of structure, the question of ship hull structure’s fatigue strength is becoming more outstanding, fatigue damage become one of the main failure modes for ship and ocean structures. In the past of application of engineering, fatigue assessment is always caught out by simplified method or the combination of finite element method and simplified method, cumulative fatigue damage is calculated in zero forward speed in crucial spot. The major purpose of this thesis is to make research on fatigue assessment of ship structure under linear wave-induced loads. The key point is the effect of forward speed in calculation of cumulative fatigue damage. The main contents are as follows:
1) The basic theory and principal method of fatigue of ship structure is expatiated. It contains S-N curve and Miner’s rule of cumulative damage, simplified method of fatigue assessment, spectral fatigue analysis in direct method of fatigue assessment.
2) The research on the calculation of wave-induced motions and loads in a harmonic wave with a forward speed which based on three-dimensional potential theory, method of long-term and short-term predictions for wave-induced motions and loads, basic theory of Rankine panel method.
3) The predictions of a 5000car PCTC’s motion performance and sectional loads in typical loading conditions based on three-dimensional time domain full speed theory. By analyzing the law of change between forward speed and motions and loads, we find the speed effect of surge, sway, roll and wave-induced moment is very remarkable.
4) Strength analysis of overall ship’s structure based on design wave approach. The basic theory of design wave approach and method of design wave parameters selection are expatiated. The six groups of design wave parameters are selected based on RAO and long-term predictions for wave-induced motions and loads. Finite element analysis in typical loading conditions is performed. The selection of fatigue point is according to the calculation result.
5) The research on the cumulative fatigue damage and fatigue life of structure based on spectral fatigue analysis. The compare of cumulative fatigue damage in different forward speed is carried out. The conclusion is necessity of consideration of forward speed in fatigue assessment of high-speed vessel.
Key words: PCTC ship，fatigue assessment，forward speed，design wave approach，spectral method
目 录
摘 要 I
Abstract III
第1章 绪论 1
1.1 引言 1
1.2 船舶结构疲劳强度研究现状与发展趋势 2
1.2.1 疲劳简化计算法和直接计算法 2
1.2.2 船体结构疲劳评估仍需完善的内容 3
1.3 船舶运动和波浪载荷的发展动态和研究现状 4
1.4 论文的研究内容及方法 5
1.4.1 研究内容 5
1.4.2 研究方法 5
1.5 研究中的关键技术 6
第2章 疲劳评估的基本理论 7
2.1 引言 7
2.2 S-N曲线和疲劳疲劳累积损伤理论 7
2.2.1 S-N曲线 7
2.2.2疲劳累积损伤模型 8
2.3 疲劳评估的简化计算方法 11
2.4 疲劳评估的直接计算方法 12
2.5 疲劳谱分析法 13
2.5.1 概述 13
2.5.2 应力响应的传递函数 13
2.5.3 应力的响应谱 14
2.5.4 应力范围的短期分布 15
2.5.5 应力范围的长期分布 15
2.5.6 疲劳累积损伤度计算 16
2.6 本章小结 17
第3章 时域内波浪载荷的计算理论 18
3.1 引言 18
3.2 三维线性势流理论基础 18
3.2.1 基本假定 18
3.2.2 船舶在规则波中的运动坐标系 1..
随着船舶尺度的大型化，高强度材料的应用以及新的结构形式的研发应用等因素，导致船舶疲劳问题日益突出，并成为船舶与海洋结构物主要失效模式之一。在以往工程应用中，疲劳评估一般采用简化计算方法或者结构有限元法与简化计算方法相结合，并且一般在零航速下计算关键节点的疲劳累积损伤。本文主要研究线性波浪载荷作用下的船体结构疲劳问题，并且重点考虑航速对于疲劳累积损伤度的影响，着重对以下几个方面进行研究与探讨。
（一）阐述船舶结构疲劳分析的基础理论和基本方法，包括 曲线与Miner线性累积损伤理论，疲劳评估的简化计算方法，疲劳评估直接计算方法中的谱分析法。
（二）根据船舶在波浪上运动的三维势流理论，研究了时域内有航速船舶波浪诱导运动与载荷的计算方法，波浪载荷短期与长期预报方法，三维时域Rankine源方法的基本理论。
（三）以一艘5000车汽车滚装船为例，采用三维时域全航速理论预报了典型装载情况下滚装船在波浪上的运动性能与剖面载荷，通过分析运动与载荷随航速变化的规律，得到船体纵荡、横荡、横摇以及波浪弯矩航速效应显著。
（四）基于设计波法对整船结构强度进行评估。阐述了设计波方法的基本理论以及设计波参数选取的方法。根据载荷响应函数以及波浪诱导载荷长期预报值选取六组设计波参数，对滚装船的典型装载情况下进行了结构有限元强度分析，为疲劳校核点的选取提供依据。
（五）采用疲劳谱分析法，研究了考虑航速情况下受线性波浪载荷结构的疲劳累积损失度以及疲劳寿命。比较不同航速下疲劳累积损伤度的值，以及不同波浪入射角对于疲劳累积值的贡献度，得出高航速船舶在疲劳评估中考虑航速是必要的。
关键词：滚装船 疲劳评估 航速 设计波法 谱分析法
Abstract
With the factor of large-scale vessel, using of high-strength material and research and development of new form of structure, the question of ship hull structure’s fatigue strength is becoming more outstanding, fatigue damage become one of the main failure modes for ship and ocean structures. In the past of application of engineering, fatigue assessment is always caught out by simplified method or the combination of finite element method and simplified method, cumulative fatigue damage is calculated in zero forward speed in crucial spot. The major purpose of this thesis is to make research on fatigue assessment of ship structure under linear wave-induced loads. The key point is the effect of forward speed in calculation of cumulative fatigue damage. The main contents are as follows:
1) The basic theory and principal method of fatigue of ship structure is expatiated. It contains S-N curve and Miner’s rule of cumulative damage, simplified method of fatigue assessment, spectral fatigue analysis in direct method of fatigue assessment.
2) The research on the calculation of wave-induced motions and loads in a harmonic wave with a forward speed which based on three-dimensional potential theory, method of long-term and short-term predictions for wave-induced motions and loads, basic theory of Rankine panel method.
3) The predictions of a 5000car PCTC’s motion performance and sectional loads in typical loading conditions based on three-dimensional time domain full speed theory. By analyzing the law of change between forward speed and motions and loads, we find the speed effect of surge, sway, roll and wave-induced moment is very remarkable.
4) Strength analysis of overall ship’s structure based on design wave approach. The basic theory of design wave approach and method of design wave parameters selection are expatiated. The six groups of design wave parameters are selected based on RAO and long-term predictions for wave-induced motions and loads. Finite element analysis in typical loading conditions is performed. The selection of fatigue point is according to the calculation result.
5) The research on the cumulative fatigue damage and fatigue life of structure based on spectral fatigue analysis. The compare of cumulative fatigue damage in different forward speed is carried out. The conclusion is necessity of consideration of forward speed in fatigue assessment of high-speed vessel.
Key words: PCTC ship，fatigue assessment，forward speed，design wave approach，spectral method
目 录
摘 要 I
Abstract III
第1章 绪论 1
1.1 引言 1
1.2 船舶结构疲劳强度研究现状与发展趋势 2
1.2.1 疲劳简化计算法和直接计算法 2
1.2.2 船体结构疲劳评估仍需完善的内容 3
1.3 船舶运动和波浪载荷的发展动态和研究现状 4
1.4 论文的研究内容及方法 5
1.4.1 研究内容 5
1.4.2 研究方法 5
1.5 研究中的关键技术 6
第2章 疲劳评估的基本理论 7
2.1 引言 7
2.2 S-N曲线和疲劳疲劳累积损伤理论 7
2.2.1 S-N曲线 7
2.2.2疲劳累积损伤模型 8
2.3 疲劳评估的简化计算方法 11
2.4 疲劳评估的直接计算方法 12
2.5 疲劳谱分析法 13
2.5.1 概述 13
2.5.2 应力响应的传递函数 13
2.5.3 应力的响应谱 14
2.5.4 应力范围的短期分布 15
2.5.5 应力范围的长期分布 15
2.5.6 疲劳累积损伤度计算 16
2.6 本章小结 17
第3章 时域内波浪载荷的计算理论 18
3.1 引言 18
3.2 三维线性势流理论基础 18
3.2.1 基本假定 18
3.2.2 船舶在规则波中的运动坐标系 1..
