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预报超大型浮体水弹性响应的模态函数展开方法和特征函数展开方法比较 总被引:2,自引:0,他引:2
超大型海洋浮式结构物对于开发海洋资源和利用海洋空间有着很大的实用价值,目前国际海洋工程界已掀起了研究超大型浮式结构物的热潮。如何计算浮体结构在波浪中的水弹性响应是设计过程中的一个非常重要的技术问题。Wu,C.,Watanabe,E.and Utsunomiya,T.(1995)提出了利用平板模态函数展开方法预报超大型浮体的水弹性响应;Kim,J.w.and Ertekin,R.C.(1998)提出利用特征函数展开方法预报超大型浮体的水弹性响应。本文对这两种方法进行了系统的比较,分别根据这两种方法计算了浮体结构的挠曲变形及弯矩、剪力的分布,并辐讨了不同参数对于水弹性响应的影响。 相似文献
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超大型海洋浮式结构物水弹性响应预报的研究现状和发展方向 总被引:10,自引:3,他引:7
超大型海洋浮式结构物在未来的海洋资源开发和海洋空间利用方面有重要应用前景,但它在波浪中的水弹性响应是该结构物设计过程中所遇到的一个重要技术问题。国际上在这方面已做了大量的研究工作。本文比较全面地介绍了国内外关于VLFS在波浪中的水弹性响应的研究现状,并对今后需要开展的研究工作的方向提出了作者的看法。 相似文献
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航行船舶的三维非线性水弹性分析 总被引:3,自引:0,他引:3
基于Wu提出的浮体二阶水弹性理论[1],研究大浪中航行船舶的非线性水弹性响应,给出了数值方法和计算结果.在二阶水弹性分析中,主要考虑了大角度刚体转动和瞬时湿表面变化引起的非线性水动力.根据三维线性水弹性理论[2],采用移动脉动源格林函数和Kelvin定常兴波假定,求解了对二阶水动力做主要贡献的一阶速度势及响应.最后以航行于不规则波中的小水线面双体船为例,讨论了航速和定常兴波流场对水弹性响应的影响,并对线性和非线性响应的预报结果进行了比较. 相似文献
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为了实现半潜式海洋平台气隙预报, 应用边界元数值方法计算平台垂荡运动的频率响应函数,根据线性变换原理计算给定海况下波浪与平台相对位移的谱函数, 建立平台在波浪中运动的气隙响应计算程序.通过对Veslefrikk半潜式平台气隙设计参数的校验计算表明, 所提供的气隙响应预报数值算法可以为工程设计提供参考依据. 相似文献
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波浪作用下带式舟桥的水弹性响应研究 总被引:5,自引:0,他引:5
对于设计和使用在波浪和流作用下作业的浮桥,充分了解其水弹性性能尤为重要.就在国防和桥梁工程中极为重要的带式舟桥而言,预报其在波浪中的水弹性响应在实际工程中就显得十分必要.该文主要研究带式舟桥在波浪作用下的水弹性性能.首先,简要地介绍了预报浮桥动力响应的不同方法及它们与试验比较的结果;其次,在三维水弹性理论的基础上采用模态叠加法对带式舟桥的有限元模型进行了水弹性分析,同时与十分之一模型试验结果做了比较(该试验由上海交通大学海洋工程国家重点实验室承担).研究表明,文中的方法计算分析波浪中浮桥的水弹性响应是可行的. 相似文献
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大型船舶的水弹性分析,对于船舶结构设计尤为重要。论文以某万箱级集装箱船为目标船型,采用三维结构分析与二维耐波性相结合的混合水弹性预报方法,进行快速波激振动响应分析。数值模拟采用MSC. Patran&Nastran有限元方法进行模态分析和基于MFS算法的STF切片法进行耐波性计算,并分别利用Bernoulli梁的解析解和HydroSTAR软件进行模型验证,最后基于模态叠加原理进行频域的波激响应预报。数值结果表明:该混合数值方法简化了网格划分耗时、提高了计算效率、满足了工程计算精度,具有较好的工程实用价值。 相似文献
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为准确计算滑行艇在波浪中的水动力性能,基于粘性理论,采用随体网格技术、耦合求解运动方程,完成了滑行艇在迎浪规则波中运动响应的数值预报.对滑行艇运动响应结果采用时域和频域方法分析,给出了入射波的周期与滑行艇固有频率对滑行艇运动响应的影响分析结果,对数值计算值与模型试验值进行比较.结果表明,数值计算方法可以准确且高效预报滑行艇在波浪中高速航行时的运动姿态及水动力特性,为滑行艇设计提供指导和参考依据. 相似文献
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In the past several decades, extensive investigations have been carried out on the hydroelastic responses of Very Large Floating Structures (VLFS) in the deep open sea by researchers around the world. However, when tackling the hydroelastic problems of VLFS used as the protection and exploitation of marine resources near offshore and islands, the effects of complex environments, such as the seabed profile and inhomogeneous wave conditions should be taken into account. Based on the development history of VLFS and the process of classical hydroelasticity of VLFS, the research results of hydroelastic responses of VLFS in complex environments have been systematically summarized in this paper, so as to provide a basis for the further research. 相似文献
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Takashi Tsubogo Koji Masaoka Hiroo Okada Yoshisada Murotsu 《Journal of Marine Science and Technology》1999,4(2):84-92
This paper deals with the dynamic response and strength of very large floating structures (VLFS) in regular and irregular
waves, considering the propagation of the hydroelastic deflection wave of the structure. First, a simplified estimation method
is presented for the dynamic response and strength of the structure in regular waves. Then, the validity of the method is
demonstrated by comparing its results with analytical results and experimental results for a mat-type floating structure model.
Next, a simplified estimation method for dynamic responses under long crested irregular wave conditions is presented by using
the above results and by combining them with irregular sea wave spectra. Finally, the applicability of the method is investigated
through numerical examples carried out for a 4,800-m class VLFS under trial design. Characteristics of the hydroelastic waves,
short-term responses, and reliability levels are numerically identified.
Received for publication on April 14, 1999; accepted on Sept. 10, 1999 相似文献
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《船舶与海洋工程学报》2019,(3)
The hydroelastic response of very large floating structures(VLFS) under the action of ocean waves is analysed considering the small amplitude wave theory. The very large floating structure is modelled as a floating thick elastic plate based on TimoshenkoMindlin plate theory, and the analysis for the hydroelastic response is performed considering different edge boundary conditions.The numerical study is performed to analyse the wave reflection and transmission characteristics of the floating plate under the influence of different support conditions using eigenfunction expansion method along with the orthogonal mode-coupling relation in the case of finite water depth. Further, the analysis is extended for shallow water depth, and the continuity of energy and mass flux is applied along the edges of the plate to obtain the solution for the problem. The hydroelastic behaviour in terms of reflection and transmission coefficients, plate deflection, strain, bending moment and shear force of the floating thick elastic plate with support conditions is analysed and compared for finite and shallow water depth. The study reveals an interesting aspect in the analysis of thick floating elastic plate with support condition due to the presence of the rotary inertia and transverse shear deformation. The present study will be helpful for the design and analysis of the VLFS in the case of finite and shallow water depth. 相似文献
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The fluid-structure interaction of oblique irregular waves with a pontoon-type very large floating structure (VLFS) edged with dual horizontal/inclined perforated plates has been investigated in the context of the direct time domain modal expansion theory. For the hydroelastic analysis, the boundary element method (BEM) based on time domain Kelvin sources is implemented to establish water wave model including the viscous effect of the perforated plates through the Darcy’s law, and the finite element method (FEM) is adopted for solving the deflections of the VLFS modeled as an equivalent Mindlin thick plate. In order to enhance the computing efficiency, the interpolation-tabulation scheme is applied to assess rapidly and accurately the free-surface Green function and its partial derivatives in finite water depth, and the boundary integral equation of a half or quarter VLFS model is further established taking advantage of symmetry of flow field and structure. Also, the numerical solutions are validated against a series of experimental tests. In the comparison, the empirical relationship between the actual porosity and porous parameter is successfully applied. Numerical solutions and model tests are executed to determine the hydroelastic response characteristics of VLFS with an attached anti-motion device. This study examines the effects of porosity, submerged depth, inclined angle and gap distance of such dual perforated anti-motion plates on the hydroelastic response to provide information regarding the optimal design. The effects of oblique wave angle on the performance of anti-motion and hydroelastic behavior of VLFS are also emphatically examined. 相似文献
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Motohiko Murai Hiroshi Kagemoto Masataka Fujino 《Journal of Marine Science and Technology》1999,4(3):123-153
New numerical methods are presented for hydroelastic analyses of a very large floating structure (VLFS) of several kilometers
length and width. Several methods are presented that accelerate computation without an appreciable loss of accuracy. The accuracy
and efficiency of the proposed methods are validated through comparisons with other numerical results as well as with existing
experimental results. After confirming the effectiveness of the methods presented, various characteristics of the hydroelastic
behavior of VLFSs are examined, using the proposed methods as numerical tools.
Received for publication on Dec. 3, 1999; accepted on Dec. 15, 1999 相似文献
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Takashi Tsubogo 《Journal of Marine Science and Technology》1999,4(2):76-83
This paper deals with the dispersion relation of hydroelastic waves in pontoon-type very large floating structures (VLFS)
using a simple beam modeling, where the term hydroelastic waves means propagation of deflection vibrations in VLFS. The purpose of this paper is to show the properties of the hydroelastic
waves. The dispersion relation of hydroelastic waves propagating in an infinite plate floating on the water is derived based
on the linear water wave theory. The effects of the water depth and of the bending rigidity of the floating plate on the wavelength,
phase velocity, and group velocity of the hydroelastic waves are shown theoretically or numerically. Then, the dispersion
relation of hydroelastic waves in a finite plate floating on shallow water is investigated. It is shown that the wavelength
or the phase velocity of the hydroelastic waves varies with the location in the plate.
Received for publication on April 7, 1999; accepted on Aug. 20, 1999 相似文献
18.
Shigeo Ohmatsu 《Journal of Marine Science and Technology》2000,5(4):147-160
This paper presents an effective scheme for calculating the wave-induced hydroelastic response of a pontoon-type very large
floating structure (VLFS) when it is near a breakwater. The basic numerical calculation method is the one previously developed
by the same author for a VLFS in the open sea (no breakwater), which is expanded to include the effect of the hydrodynamic
mutual interaction between the breakwater and the floating structure. The efficiency and accuracy of the proposed method are
validated through comparisons with other numerical results and with existing experimental results. After that confirmation,
various numerical calculations were conducted, paying special attention to the resonance phenomena which will occur depending
on the relation between the wavelength and the clearance between the breakwater and the floating structure. The irregular
frequency phenomenon which appears in the calculation of the fluid dynamic problem is discussed in the appendices, including
a method for its elimination.
Received: October 31, 2000 / Accepted: December 19, 2000 相似文献
19.
箱式超大型浮体水弹性分析的弹性地基梁法 总被引:2,自引:0,他引:2
如何快速而精确地估计箱式超大型浮体在波浪中的水弹性响应是设计中需要解决的一个重要问题。在所提出的各种简化分析方法中,弹性地基梁模型是最简单的。本文选择了四种弹性地基梁模型进行比较研究。它们分别称为S_Y_BOEF,T_BOEF,S_BOEF和A_BOEF模型。通过研究发现,由Suzuki和Yoshida提出的S_Y_BOEF模型显得太保守而不适合于实际应用,而其它三种模型是能够合理地估计箱式超大型浮体的水弹性响应的。相比而言,由S_BOEF模型延伸出的A_BOEF模型从概念上的一致性和精度方面都是最好的。弹性地基梁模型的最大优点是简单,可以很方便地在工程设计中应用。 相似文献