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研究船舶随机斜浪中大幅参数激励非线性横摇运动的计算方法。将船舶稳性高度GM作为时域变化的随机参数激励,波浪力为随机强迫激励项,建立船舶在随机斜浪航行情况的参—强激励横摇运动微分方程。参数激励项的求解考虑了船体型线、纵摇、升沉及波浪运动对稳性高度变化的影响。分别取不同波高、航速、航向,计算出随机斜浪中船舶的时域横摇运动响应。计算结果表明,此方法可以用于计算随机斜浪中船舶的参—强激励横摇运动,据此分析随机斜浪对船舶横摇和倾覆的重要影响。 相似文献
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随机斜浪中船舶参数-强迫激励横摇运动计算 总被引:1,自引:0,他引:1
研究船舶随机斜浪中大幅参数激励非线性横摇运动的计算方法.将船舶稳性高度GM作为时域变化的随机参数激励,波浪力为随机强迫激励项,建立船舶在随机斜浪航行情况的参-强激励横摇运动微分方程.参数激励项的求解考虑了船体型线、纵摇、升沉及波浪运动对稳性高度变化的影响.分别取不同波高、航速、航向,计算出随机斜浪中船舶的时域横摇运动响应.计算结果表明,此方法可以用于计算随机斜浪中船舶的参-强激励横摇运动,据此分析随机斜浪对船舶横摇和倾覆的重要影响. 相似文献
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针对国际海事组织(IMO)正在制定的船舶第二代完整稳性衡准中的纯稳性丧失直接评估衡准,本文提出了纵荡-横荡-横摇-首摇4自由度运动耦合的标准数学模型,进行了纯稳性丧失直接评估.该方法首先基于MMG操纵性标准方法,构建纵荡-横荡-横摇-首摇4自由度运动方程,同时考虑了舵控制方程,其次在纵荡、横荡、横摇、首摇方程右边考虑时域波浪力/力矩,且横摇方程右边进一步考虑了粘性横摇阻尼力矩和波浪中复原力臂变化.最后采用ONR内倾船进行了尾斜浪中纯稳性丧失直接数值计算,为纯稳性丧失直接稳性评估衡准的应用奠定了基础. 相似文献
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《舰船科学技术》2017,(22)
在波浪的影响下,常规的船舶横摇运动时,没有建立横摇运动的模型,降低了预测的精度,不能有效地减小船舶的横摇,存在船舶耐波性较差的问题。当前方法进行船舶横摇运动的建模时,不能减小船舶的横摇,降低了船舶的耐波性。提出一种基于时间序列预测的船舶横摇运动数学建模研究方法。该方法建立波浪扰动船舶横摇运动模型,依据随机的过程理论,求出空间上某固定点波浪倾角的数学模型,依据横摇运动模型得出横摇运动的数据。对船舶横摇运动进行时间序列预测克服了传统方法存在的弊端,运用时间序列的分析方法建立AR模型,应用于船舶横摇运动的时间序列的预测,减小船舶的横摇性,提高了船舶的耐波性,完成对波浪影响下船舶横摇运动的时间序列预测数学建模的研究。实验的结果表明,利用该方法能有效地减小船舶的横摇,提高船舶的耐波性。 相似文献
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迎浪条件下的参数横摇现象,作为一种重要的稳性失效模式受到了国际海事组织(IMO)的高度关注。由于横摇惯性矩对横摇固有周期的作用,使之成为参数横摇的决定性影响因素之一。本文比较了4种实船横摇惯性矩的计算方法,并采用一种三自由度弱非线性模型研究了其对参数横摇预报的影响。辐射力和绕射力的计算基于三维频域理论,时延效应采用脉冲响应函数法考虑。通过对3艘集装箱船的参数横摇敏感性分析,讨论了横摇惯性矩的不同计算方法对运动响应预报的影响,并给出了可用于第二代完整稳性参数横摇衡准的横摇惯性矩简化估算方法。 相似文献
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波浪中船舶横摇稳性的研究 总被引:14,自引:1,他引:13
本文采用瞬时湿表面变化的时域分析法。研究波浪中的船舶横摇稳性。通过对实例的分析与计算,得到小浪中船舶横摇稳性的特性,同时亦看到的船舶在波浪中的横摇恢复力居大角度横摇时表现出明显的非线性。本文给出了船舶在波浪中横摇稳性的计算方法以及波浪中稳性衡准的初步建议。 相似文献
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摘要:为进一步研究船舶在大幅度转向时艏摇和横摇的耦合机制,在非线性船舶运动数学模型的基础上,进行了不同情形下的操纵仿真试验。试验结果显示在大舵角转向时,船舶的艏摇和横摇运动存在较强的耦合作用,横摇幅度和艏摇幅度存在正相关性。指出大幅度的横摇使艏摇出现相位滞后和偏离基准航向的现象;在横摇过大的情况下,大幅度动舵和加速操纵将导致稳性迅速消失和航向打横。 相似文献
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《船舶与海洋工程学报》2016,(4)
In this paper, Neural Networks(NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method. 相似文献
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In this paper, Neural Networks (NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method. 相似文献
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文章以稳定性理论为基础提出了一种张力腿平台横摇固有周期计算模型,分析了横摇临界角对平台横摇稳定性的影响,并将其应用于分析平台设计参数对横摇固有周期的影响。提出在一个横摇周期里,最后稳定横摇临界角对应的时间历程为1/4横摇固有周期这一假设,基于此假设,编制计算机计算程序,计算横摇运动中每一个横摇角,判断其稳定性,找出一个横摇周期内最后稳定横摇临界角对应的时间历程,求解横摇运动固有周期。考虑两种横摇阻尼情况,计算不同初始横摇角、横摇下沉位移、张力腱长度、平台重量和横摇阻尼的横摇固有周期,论证了平台设计参数对横摇固有周期的影响。该计算模型克服了从结构角度计算固有周期工作量大、计算周期长、计算结果不可靠的弱点,使横摇固有周期计算简单、有效。通过与不考虑横摇阻尼的情况对比,分析了横摇阻尼对横摇固有周期的影响。可以快速计算处于设计阶段或者已服役张力腿平台横摇固有周期。结合一型设计中的张力腿平台,应用文中提出的横摇固有周期计算模型对该平台进行了横摇固有周期的计算,并且分析了平台参数对横摇固有周期的影响。结果表明该方法可以对张力腿平台横摇固有周期进行快速计算。并可推广应用于其它海上结构物的横摇固有周期计算。 相似文献
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IMO第二代完整稳性衡准对现有万箱船设计的影响 总被引:1,自引:1,他引:0
国际海事组织(IMO)正在制定基于水动力学的第二代完整稳性衡准,新衡准的实施必然对现有船舶的设计带来巨大影响。集装箱船大型化是航运界的发展趋势,万箱船船型订单近年也大幅上升。已有的事故发现大型集装箱船对参数横摇、过度加速度等衡准相对敏感,但现有船舶的设计对此类事故模式考虑较少,因此有必要开展相关研究。本文选取了某万箱集装箱船,对其大量装载工况进行四种稳性失效模式的计算分析,研究了第二代完整稳性的实施对大型集装箱船的稳性影响,并对其装载、设计等提出一定的建议。 相似文献
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Michio Ueno Yasuo Yoshimura Yoshiaki Tsukada Hideki Miyazaki 《Journal of Marine Science and Technology》2009,14(4):469-484
Circular motion test data and uncertainty analysis results of investigations of the hydrodynamic characteristics of ship maneuvering
are presented. The model ships used were a container ship and two tankers, and the measured items were the surge and sway
forces, yaw moment, propeller thrust, rudder normal and tangential forces, pitch and roll angles, and heave. The test parameters
were the oblique angle and yaw rate for the conditions of a hull with a rudder and propeller in which the rudder angle was
set to zero and the propeller speed was set to the model self-propulsion conditions. Carriage data showing the accuracy of
the towing conditions in the circular motion test are also presented. It was confirmed that the uncertainties in the hydrodynamic
forces such as the surge and sway forces, yaw moment, rudder tangential and normal forces, and propeller thrust were fairly
small. The reported uncertainty analysis results of the circular motion test data may be beneficial in validating data quality
and in discussing reliability for simulation of ship maneuvering performance. 相似文献
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This paper introduces a new method for the prediction of ship maneuvering capabilities. The new method is added to a nonlinear
six-degrees-of-freedom ship motion model named the digital, self-consistent ship experimental laboratory (DiSSEL). Based on
the first principles of physics, when the ship is steered, the additional surge and sway forces and the yaw moment from the
deflected rudder are computed. The rudder forces and moments are computed using rudder parameters such as the rudder area
and the local flow velocity at the rudder, which includes contributions from the ship velocity and the propeller slipstream.
The rudder forces and moments are added to the forces and moments on the hull, which are used to predict the motion of the
ship in DiSSEL. The resulting motions of the ship influence the inflow into the rudder and thereby influence the force and
moment on the rudder at each time step. The roll moment and resulting heel angle on the ship as it maneuvers are also predicted.
Calm water turning circle predictions are presented and correlated with model test data for NSWCCD model 5514, a pre-contract
DDG-51 hull form. Good correlations are shown for both the turning circle track and the heel angle of the model during the
turn. The prediction for a ship maneuvering in incident waves will be presented in Part 2. DiSSEL can be applied for any arbitrary
hull geometry. No empirical parameterization is used, except for the influence of the propeller slipstream on the rudder,
which is included using a flow acceleration factor. 相似文献
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Anil Kumar Dash Praveen Perumpulissery Chandran Mohammed Kareem Khan Vishwanath Nagarajan Om Prakash Sha 《Journal of Marine Science and Technology》2016,21(4):689-708
In this paper, a mathematical model is developed for the maneuvering motion of a naval ship and bifurcations of its equilibrium are identified in roll-coupled motion. The subject ship is a high-speed surface combatant with twin-propeller twin-rudder system. Captive model tests are conducted for the ship using planar motion mechanism. Maneuvering coefficients are calculated by polynomial curve fitting of the test data. Uncertainty distribution in the coefficients is assumed same as that of the curve fitting errors. Uncertainty in the model coefficients is propagated to full-scale simulation results by the stochastic response surface method (SRSM). This method is computationally efficient as compared to standard Monte Carlo simulation technique. The SRSM uses polynomial chaos expansion of orthogonal to fit any probability distribution. Bifurcation analysis of the mathematical model is performed by varying the vertical center of gravity as the bifurcation parameter. Hopf bifurcation is identified. It is found that the bifurcations occur due to the coupling of roll motion with sway, yaw motion and rudder angle. In the presence of wind, roll angle response in bifurcation diagram is discussed. 相似文献