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海洋平台环境参数的单因素设计标准无法反映真实海况,文章针对该缺点提出了基于最大熵边缘的三维嵌套逻辑模型。该模型采用的最大熵边缘可以涵盖大多数设计线型,如Gumbel分布、Weibull分布、对数正态分布等;三维嵌套逻辑模型可以反映海洋环境参数的相关关系及变量的不对称性。总结并提出了三种海洋环境条件设计标准,即单因素统计方法、条件概率分布设计法和联合环境条件设计法。利用南海涠洲岛后报的年极值风速及对应有效波高、平均周期数据,对三维模型和海洋平台环境条件联合设计标准进行了实例验证。结果表明,三维模型对数据拟合良好,联合设计标准更符合实际。 相似文献
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介绍了环境舒适性指标分类,重点对热环境以及空气品质开展研究,调研分析了暖通行业和船舶行业舒适性设计标准和规范,开展了各类主要邮轮系类空调设计参数调研。结合适应中国游客的环境舒适性指标分析,给出我国邮轮舱室舒适性设计指标参数。 相似文献
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本文以风暴状态下自升式平台为研究对象,借助随机NewWave理论给出了给定波面极值时平台结构随机动力响应极值概率特征分析步骤.研究了平台结构随机动力响应极值统计分布随最大波面极值的演化规律,确定出两种具有统一形式的概率分布,并对其进行有效统计描述.通过对平台结构随机动力响应极值统计分布参数与波面极值之间映射关系的模拟,建立起平台结构随机动力响应极值的概率特性数值仿真器.计算结果表明,本文所提供的方法以有限次结构分析为代价,可完成对任意给定最大波面极值时平台结构随机动力响应极值概率特性的有效模拟,从而为进一步建立高效、实用的结构动力可靠性分析模型奠定了必要的基础. 相似文献
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风暴模型是Tomita等提出的用来评估船舶结构疲劳强度的一种随机波浪载荷简化模型,它能表达波浪载荷是与时间相关的随机过程。文中介绍了风暴模型及波浪诱导应力短期分布的基本特征。将风暴模型和裂纹扩展率单一曲线模型及焊趾表面裂纹应力强度因子的计算方法结合起来,探讨了复杂载荷作用下船舶结构疲劳裂纹扩展预报方法。并用权函数法计算了给定残余应力分布的表面裂纹应力强度因子。预报了对接焊接接头焊趾处表面裂纹在风暴波浪载荷作用下的疲劳裂纹扩展行为,结果表明风暴的大小、顺序,初始裂纹尺寸及残余应力对裂纹扩展行为影响明显。合理的风暴模型参数及初始裂纹尺寸的确定对船舶结构的疲劳寿命预报是非常重要的。 相似文献
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王言英 《船舶与海洋工程学报》2008,7(3):162-167
In order to respond the discredit on the design wave standard and to recommend new consideration on design wave parameters, based on the long-term distribution of statistic characteristics of waves and the short-term probability properties of sea state defined by giving the return period, the calculation of the return period, the height, the period, and the oceanic wave parameters of the design wave and the forecasting methods are discussed in this paper. To provide references for the operation reliability of floating structures in the extreme sea state, the method of determining the design wave parameters is resurveyed. A proposal is recommended that the design wave, which can be either significant wave with 500-year of the return period, or the maximum wave with 1/N of exceeding probability, 100-year of the return period, can be applied in the engineering design practice. 相似文献
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Atiela Incecik John Bowers Gill Mould Oguz Yilmaz 《Journal of Marine Science and Technology》1998,3(3):145-150
Floating moored offshore structures have a significant future in offshore operations as an attractive economic alternative
to fixed structures in deep waters and/or in areas where there is no existing infrastructure. This paper describes an analysis
procedure based on the structure variable approach to estimate load and response values of a moored offshore platform at a
given return period by taking into account the joint occurrence of wave, wind, and current. The results show that the most
severe mooring loads may not occur when wind, wave, and current are collinear and are at their maximum design values, i.e.,
the 50- or 100-year case. It is recommended that the extreme mooring design loads for moored offshore systems should be determined
through a range of physical or numerical simulations where wave, wind, and current are noncollinear and act with less severe
magnitudes than the 50- or 100-year case. This recommendation has also been adopted in the ITTC/Ocean Engineering Committee
recommendations to the ITTC Conference held in September 1996. 相似文献
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通过确定不同重现期的风速极值,阐述建立风生海流推算关系及风生海流的特点,给出渤海湾海区风因子的合理取值范围.并描述海流极值的计算方法和计算过程,以解决近岸海区海流极值的计算问题。结合唐山LNG终端站码头区工程海流现场调查及当地历年连续风速数据,确定不同重现期风速极值及风生海流极值,并给出海流极值的结果。该工程采用重现期法进行风生海流计算及海流分析,对于海洋功能开发、灾害预防、港口建设及各种建筑设计具有重要作用。 相似文献
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通过台风期间北仑港实测潮位、波浪资料统计分析,研究台风期间风暴潮增水特性和统计规律,采用概率统计理论研究风暴潮增水和波浪的相关性,建立风暴潮增水与波高的联合分布,提出考虑风暴潮影响的设计潮位、波浪组合的推算方法。 相似文献
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基于马尔可夫链的极值波高预测 总被引:1,自引:0,他引:1
本文研究了由日最大波高系列估算设计极值波高时,相邻日最大波高间的相关性对极值预测的影响,从日最大波高系列遵从马尔可夫链的假定出发,考虑到国内外经常采用对数一正态分布的韦布尔分布拟合波高长期分布的现实,本文用解析法求解了对数一正态分布情况下的极值预测。同时,对解析法难以求解的非正态随机变量情况(如韦布尔分布),用计算机随机模拟方法求解其极值预测,用上述两种方法对北大西洋和北海有关日最大波高系列的预测 相似文献
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《船舶与海洋工程学报》2019,(3)
API RP2 A WSD is a design code in practice for design of jacket platforms in the Persian Gulf but is based on the Gulf of Mexico environmental condition. So for the sake of using this code for the Persian Gulf, it is better to perform a calibration based on this specific region. Analysis and design of jacket platforms based on API code are performed in a static manner and dynamic analysis is not recommended for such structures. Regarding the fact that the real behavior of the offshore jacket platforms is a dynamic behavior, so in this research, dynamic analysis for an offshore jacket platform in the Persian Gulf under extreme environmental condition is performed using random time domain method. Therefore, a new constructed offshore jacket platform in the Persian Gulf is selected and analyzed. Fifteen, 1-h storm, simulations for the water surface elevation is produced to capture the statistical properties of extreme sea condition. Time series of base shear and overturning moment are derived from both dynamic and static responses. By calculating the maximum dynamic amplification factor(DAF) from each simulation and fitting the collected data to Weibull distribution, the most probable maximum extreme(MPME) value for the DAF is achieved. Results show that a realistic value for DAF for this specific platform is 1.06, which is a notable value and is recommended to take into practice in design of fixed jacket platform in the Persian Gulf. 相似文献
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大连长兴岛北港区波浪条件数值模拟研究 总被引:4,自引:3,他引:1
利用国际通用的MM5风场模式和SWAN浪场模式,通过推算影响工程海域的台风和寒潮大风天气过程,得到工程海域-30 m等深线处不同重现期设计波要素,然后采用MIKE 21 NSW和BW波浪数学模型,对工程规划方案设计波要素和港内波况进行了计算。结果表明:工程受N向和NNE向风浪影响相对较大,外海波浪传播至防波堤处无明显衰减;设计高水位重现期50 a时防波堤处最大H1%约7.3 m;防波堤对港内围堰掩护较好,建成后港内波浪条件明显改善。 相似文献
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采用SWAN波浪模型对江苏南黄海地区1979~2018年共40 a的波况进行模拟及验证,将模拟结果与实测资料进行比对,吻合良好。百年重现波高分布通过基于年极值和月极值的广义极值分布函数(GEV)和超阈值取值方法(POT)的广义帕累托分布模型(GP)计算得出。计算结果表明,不同方法的计算结果在辐射沙洲北部地区差别最大,采用月极值所得重现波高偏小,采用年极值计算的重现波高在辐射沙洲南北外围地区最大,其余地区则以POT方法为大值。在分别采用不同数据长度计算重现波高的试验中得出,取月极值的GEV分布计算结果对时间跨度的改变不敏感,而取年极值受之影响最大,POT方法介于两者之间。 相似文献