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船舶倾覆机理的新见解 总被引:2,自引:0,他引:2
利用“对振式可控力矩横摇装置”进行船模允许甲板入水的系列激振横摇实验,得到非线性横摇的实际而准确的数学模型,据此通过风浪联合作用下的动态横摇过程的数值模拟,探讨船模在横风横浪下的倾覆机理,从而形成新见解:翻船是动力横摇的极限运动,临界倾覆于高位平衡点稳定性的丧失。 相似文献
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The time dependency of the survivability of passenger ships in flooding accidents leading to ship’s loss is shown to be confined within short times after the flooding initiation. RoRo ferry and cruise type ships demonstrate similar behaviour, though vessel types differ with respect to the subdivision and the flooding process. The presented research is based on numerical simulations of the flooding of two sample passenger ships in collision damages and the estimation of the probability to capsize. The systematic fast character of capsize events is shown to be primarily a consequence of the extent of hull breaches. The IMO regulatory concept for orderly abandonment of damaged passenger ships, in addition to the safe return to port regulatory provisions, are discussed in view of the present results. The timely onboard damage identification by ship’s master and the enhancement of the SOLAS survivability requirements for passenger ships appear to be the most effective operational and design measures leading to improved survivability of the ship and to enhanced safety of people onboard. 相似文献
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用Melnikov方法研究船舶在随机横浪中的倾覆 总被引:4,自引:0,他引:4
本文应用Melnikov函数和相空间转移率研究船舶在随机波浪中的强非线性横摇运动及其倾覆问题,分析了波浪特征频率、特征波高、船舶非线性恢复力臂以及阻尼特性对相空间转移率的影响.以长30.7m、宽6.9m的渔船为例,采用ISSC波浪谱,在时域内计算了Melnikov函数,得到了相空间转移率与Melnikov函数之间的关系以及有义波高对相空间转移率的影响.研究表明:随有义波高增大,相空间转移率不断增大,船舶航行的安全域迅速减小.从而揭示了相空间转移率与船舶倾覆内在的密切联系,为船舶的设计和稳性衡准提供了有价值的参考. 相似文献
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分析了共同结构规范(CSR)对好望角型散货船设计的影响,并着重就好望角型散货船为适应CSR所进行的优化改进设计,以及对工艺方法的最新成果的应用作了介绍。 相似文献
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装载含水量较高矿砂的船舶在长时间摇摆和振动时,装载的矿砂会出现液化现象,其中的水分会析出,并在矿砂表面形成自由液面.受液化矿砂的粘性流动及表层液面的影响,运输该类货物的船舶易发生倾覆事故.建立了载有液化矿砂的三维货舱数值模型,探讨了货舱晃荡时矿砂液面、壁面载荷以及货舱横摇力矩的变化规律等;结合横摇实验现象对液化矿砂晃动机理和危害性进行了初步验证.结果表明:货舱内粘性矿砂的流动滞后于货舱的横摇运动,因而货舱横摇力矩的变化与货舱运动存在着相位滞后的关系,其最大值发生在货舱处于最大晃动角度后返回到平衡位置的过程中;货舱回摇过程中,倾侧的液化矿砂不能及时回流,会在一侧产生堆积,进而增加船舶倾侧力矩,最终可能会导致船舶倾覆. 相似文献
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船舶内共振动力学行为的研究 总被引:5,自引:0,他引:5
本文考虑船舶横摇与纵摇的非线性耦合运动,采用摄动分析及数值计算方法,研究了船舶存在内共振时的非线性动力学行为。研究表明,船舶非线性运动的重要特征是响应不对称、调幅调相及饱和等现象,为揭示船舶在高海情下的倾覆机理奠定了基础。 相似文献
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Dimitris A. Spanos Apostolos D. Papanikolaou 《Journal of Marine Science and Technology》2012,17(1):40-46
The time dependence of survivability of ROPAX vessels, when sustaining side collision damage in waves, is investigated herein by use of numerical simulations of ship motion and flooding. Conducted research confirms that ROPAX ships characteristically capsize fast, when sustaining damage leading to capsizing. A probabilistic analysis of the survive time after collision damage reveals that even for the most generic damage conditions assumed, the survival time in the case of capsizing remains short, which is characteristic of this type of ship design, disposing the typically large undivided deck to be subject to flooding in higher waves. In a case study, the unconditional survivability in waves, corresponding to survival s-factor of SOLAS regulations, is alternatively assessed with numerical simulations. The estimated survivability proves to be time independent in terms of practical implications. Observed deviations between current SOLAS formulation and simulations, suggest the employment of comprehensive simulation methods when more reliable estimations and assessments of survivability are required. 相似文献
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纵浪上船舶的动稳性研究 总被引:4,自引:2,他引:4
在纵浪上航行的船舶,当升沉(或纵摇)固有频率约为横摇固有频率的2倍时将发生参数激励主共振。本文考虑升沉对横摇的耦合作用,建立了非线性参数激励横摇运动方程。用多尺度方法对方程进行求解,用Floquet理论和分岔理论对定常解进行稳性分析,获得了参数激励主共振下的不稳定域和可以导致船舶倾覆的多数区域,为船舶的动稳性研究提供了一种新的方法。与数值结果的比较验证了本文的结论。 相似文献
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随机波浪作用下船舶倾覆前持续时间的研究 总被引:2,自引:0,他引:2
本文建议采用在随机波作用下船舶保持不倾覆状态所能持续的时间作为表征船舶稳性的指标。由于波浪外载荷随机性的特性 ,这一持续时间是一个随机变量 ,和某一概率相联系。本文运用马尔科夫过程理论和首次通过的概念研究确定这一持续时间和相应的概率。并将理论计算的结果与模型试验的结果进行了比较 ,两者之间有较好的吻合。 相似文献
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巴西拥有丰富的矿产资源和天然深水良港TUBARAO、PDM等。PDM地处热带地区,12月到6月份正是巴西的雨季,一天之中会轮番出现晴、云、阴、雨、雾等复杂的天气现象,几乎天天都下雨。另外,由于特殊的地形地貌造成港内海况 相似文献
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本文介绍船模倾覆试验的结果及其数值模拟。试验表明,在横浪情况下船舶因装载造成的横倾角,会大大增加倾覆的危险性。对这一结论进行的数值模拟与实测结果符合良好。 相似文献
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在船舶临界倾覆的状态的仿真过程中,用动能定理进行了各种因素的功能分析。证明;阻尼耗散能达到位能之半,导致临界风倾力矩显著增大,不可忽略。要准确地估算临界风倾力矩还需计及波浪扰动力矩作功和变惯性矩所引起的动能增量。 相似文献
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本文从横摇运动微分方程出发,结合随机微分方程理论,讨论了船舶在横对随机波时的倾覆概率问题。可以看出关于船舶在随机波上倾覆概率问题目前提出的几种方法间的联系。最后用Fokker-Planck方程解出了随时间演变的概率分布函数,分析了倾覆问题。 相似文献
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《船舶与海洋工程学报》2015,(3)
Centrifugal forces are commonly created when ships turn, which may cause a ship to capsize in a critical situation. A mathematical model has been developed to optimize the stability coefficients for ship, with the aim to prevent capsizing and to increase ship maneuverability in high-speed water craft. This model can be used to develop algorithms for control system improvement. The mathematical model presented in this paper optimized the use of multipurpose hydrofoils to reduce heeling and the trimming moment, maintaining an upright ship's position and lessening the resistance via transverse force. Conventionally, the trimming and heeling of a ship are controlled using ballast water; however, under variable sea conditions it is sometimes difficult to control a ship's motion using ballast water. In this case, a hydrofoil would be more stable and maneuverable than a ballast tank controlled vessel. A movable hydrofoil could theoretically be adapted from moveable aerofoil technology. This study proves the merit of further investigation into this possibility. 相似文献
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This study investigates determinants of the number of non-fatal crew injuries, fatal crew injuries and missing crew in freight ship, tanker and tugboat vessel accidents based upon individual accidents investigated by the US Coast Guard for the 1991-2001 period. Poisson and negative binomial regression estimates suggest that: (1) freight ship and tanker non-fatal injuries are higher when the vessel is moored or docked and during high winds and cold temperatures; (2) tugboat non-fatal injuries are higher during poor visibility; (3) freight ship fatal injuries increase with vessel age and tanker and tugboat fatal injuries are higher for fire and capsize accidents, respectively; and (4) freight ship missing crew increase with vessel age and tugboat missing crew are higher for fire and lake accidents. 相似文献