检索结果-内蒙古大学图书馆

hydroelastic response of cylindrical shell structures during earthquakes in ice-covered seas

INTERNATIONAL JOURNAL OF OFFSHORE AND POLAR ENGINEERING 2003年第1期13卷 4-11页

作者： Hamamoto, T Nojima, T Musashi Inst Technol Dept Architecture Tokyo 158 Japan

An analytical approach is presented for the seismic hydroelasticity of fixed cylindrical shell structures in ice-covered seas. The sea surface is regarded as the combination of free surface and solid boundary. Both the confined effect due to the surrounding ice sheet and the dissipated effect due to the structure-ice gap are considered for the evaluation of earthquake forces in ice-covered seas. Hydrodynamic pressures are derived in closed forms by the domain division method. Wet mode properties are obtained by the Rayleigh-Ritz method. Seismic responses are evaluated by wet mode superposition and random vibration approaches. Based on the numerical results, the changes in wet mode properties, hydrodynamic pressures and response quantities due to confined and dissipated effects are investigated.

关键词： earthquake force ice-covered seas hydroelastic response cylindrical shell confined effect dissipated effect

来源：评论

学校读者我要写书评

暂无评论

hydroelastic response of a floating plate on the falling film: A stability analysis

引用

WAVE MOTION 2021年 104卷

作者： Selvan, S. A. Ghosh, S. Behera, H. Meylan, M. H. Univ Melbourne Sch Math & Stat Melbourne Vic 3010 Australia SRM Inst Sci & Technol Dept Math Kattankulathur 603203 Tamil Nadu India Indian Inst Technol Jodhpur Dept Math Jheepasani 342037 Rajasthan India Univ Newcastle Sch Math & Phys Sci Callaghan NSW 2308 Australia

The role of a floating elastic plate on the hydrodynamic instability of a gravity-driven flow down an inclined plane is examined in the linear and nonlinear regimes. Linear instability of the system with respect to infinitesimal disturbances is captured using normal-mode analysis. The critical conditions for instability are obtained analytically utilizing the small film aspect ratio. The bifurcation of the nonlinear evolution equation is analyzed using weakly nonlinear stability analysis. The time evolution of the surface elevation is analyzed using the nonlinear analysis. The Orr-Sommerfeld boundary value problem corresponding to the perturbed flow is derived, and it is solved numerically using the spectral collocation method. The behavior of the marginal stability curves and temporal growth of the unstable waves are portrayed for a range of dimensionless flow parameters. Moreover, the pressure acting on the surface are calculated and analyzed for various structural parameters, applicable to different flow configurations. The study reveals that the structural parameters such as rigidity and mass per unit length play a crucial role in suppressing and facilitating the unstable surface waves of the flow. However, the compressive force acting on the plate results in the flexural destabilization. Thus, the plate parameters are more efficient in damping the shorter wave disturbances. Numerical observations imply that the floating elastic plate assists in stabilizing the free-falling flow and dampens the high amplitude waves. (C) 2021 Elsevier B.V. All rights reserved.

关键词： hydroelastic response Floating elastic plate Linear stability Orr-Sommerfeld system Spectral collocation method Asymptotic analysis

来源：评论

学校读者我要写书评

暂无评论

A B-spline Galerkin scheme for calculating the hydroelastic response of a very large floating structure in waves

引用

Journal of Marine Science and Technology 1998年第1期3卷 37-49页

作者： Kashiwagi, Masashi Res. Institute for Applied Mechanics Kyushu University Kasuga Fukuoka 816-8580 6-1 Kasuga-koen Japan

This paper presents an effective scheme for computing the wave-induced hydroelastic response of a very large floating structure, and a validation of its usefulness. The calculation scheme developed is based on the pressure-distribution method of expressing the disturbance caused by a structure, and on the mode-expansion method for hydroelastic deflection with the superposition of orthogonal mode functions. The scheme uses bi-cubic B-spline functions to represent unknown pressures, and the Galerkin method to satisfy the body boundary conditions. Various numerical checks confirm that the computed results are extremely accurate, require relatively little computational time, and contain few unknowns, even in the region of very short wavelengths. Measurements of the vertical deflections in both head and oblique waves of relatively long wavelength are in good agreement with the computed results. Numerical examples using shorter wavelengths reveal that the hydroelastic deflection does not necessarily become negligible as the wavelength of incident waves decreases. The effects of finite water depth and incident wave angle are also discussed.

关键词： B-spline function Galerkin scheme hydroelastic response Very large floating structure

来源：评论

学校读者我要写书评

暂无评论

A study on an optimal arrangement of upper facilities on a very large floating structure considering with the hydroelastic response in waves

A study on an optimal arrangement of upper facilities on a v...

引用

16th International Offshore and Polar Engineering Conference (ISOPE 2006)

作者： Murai, Motohiko Inoue, Yoshiyuki Mori, Kazuyoshi Yokohama Natl Univ Yokohama Kanagawa 240 Japan

ISBN: (纸本)1880653664

In the recent years, there are some researches about hydroelastic responses of VLFSs considering with effects of upper facilities which must be constructed on the VLFS. An arrangement of the upper facilities on the VLFS, however, was treated as a fixed factor, by the most of the researches. And there is no discussion about the reason why the arrangement had been rationally chosen by considering the hydroelastic response. In this paper, we focus on how the arrangement of the facilities affects the hydroelastic response of the VLFS. And we also examined these optimal arrangements by using a response surface method. In the optimization, we have chosen vertical deformation amplitude and vertical acceleration of the VLFS as the evaluation factor.

关键词： VLFS hydroelastic response optimization arrangement upper facility a response surface method

来源：评论

学校读者我要写书评

暂无评论

Artificial neural network framework for prediction of hydroelastic response of very large floating structure

引用

APPLIED OCEAN RESEARCH 2023年 139卷

作者： Tay, Zhi Yung Singapore Inst Technol Engn Cluster 10 Dover Dr Singapore 138683 Singapore

The response of a very large floating structure (VLFS) must take into consideration the elastic deformation of the structure (commonly termed hydroelastic response) under wave action. Conventionally, the hydroelastic response could be computed by using the coupled finite element-boundary element (FE-BE) method, where the mat-like structure is modelled using plate theory and the water modelled using the potential theory. The FE-BE method requires the structure to be discretised into finer elements and the wetted surface boundary to be represented by smaller panels to accurately capture the hydroelastic response of the structure. Thus, the coupled FEBE method could be computationally expensive when the structure gets larger or when subjected to waves of smaller wavelengths. To accelerate the computational time in predicting the hydroelastic response of the VLFS, a surrogate model trained using the feed-forward neural network is proposed. The hydroelastic responses under different wavelengths, structural stiffnesses and wave directions are first generated where these data are split into three groups for training, validation, and testing (prediction) purposes. The accuracy of the prediction in terms of correlation coefficient R is compared for the different train datasets, the number of neurons and hidden layers as well as the optimisation techniques. The finding shows that an accuracy of close to 99% to the ground truth could be achieved with only 80% of the train dataset. The hydroelastic response under irregular wave conditions predicted using the feed-forward neural network framework is also presented.

关键词： Feed -forward neural network Very large floating structure hydroelastic response Irregular wave Machine learning Surrogate model

来源：评论

学校读者我要写书评

暂无评论

Vertical and horizontal bending moments on the hydroelastic response of a large-scale segmented model in a seaway

引用

MARINE STRUCTURES 2021年 79卷

作者： Jiao, Jialong Ren, Huilong Soares, C. Guedes South China Univ Technol Sch Civil Engn & Transportat Guangzhou 510641 Peoples R China Harbin Engn Univ Coll Shipbldg Engn Harbin 150001 Peoples R China Univ Lisbon Ctr Marine Technol & Ocean Engn CENTEC Inst Super Tecn P-1049001 Lisbon Portugal Int Joint Lab Naval Architecture & Offshore Techn Harbin 150001 Peoples R China

Wave-induced vertical bending moment (VBM) and horizontal bending moment (HBM) on a large-scale segmented model with a box-type backbone beam in short-crested irregular seas are systematically analyzed using sea trial measurement data. New insights into the relationship between nonlinear VBM and HBM of the ship sailing in short-crested sea waves are explored and presented. The results indicate that the HBM significantly contributes to the total sectional loads when the ship is sailing in a seaway and the HBM has a strong correlation with VBM in both magnitude and tendency. Therefore, design loads of HBM and the corresponding lateral structural strength issues should also be concerned in addition to VBM at the ship design phase.

关键词： Ship wave loads hydroelastic response Vertical bending moment (VBM) Horizontal bending moment (HBM) Large-scale model sea trial

来源：评论

学校读者我要写书评

暂无评论

Numerical investigation of cavitation flow on hydroelastic response of a flexible 3D hydrofoil

引用

SHIPS AND OFFSHORE STRUCTURES 2023年第1期18卷 53-67页

作者： Sajedi, Hasan Mahdi, Miralam Shahid Rajaee Teacher Training Univ Fac Mech Engn Tehran Iran

The dynamical response of a 3D hydrofoil in the cavitation flow is investigated. Fluid and Structure Interaction (FSI) simulation was performed using ANSYS Fluent Software. First, the validation of cavitation flow around NACA 0015 hydrofoil was carried out. To predict the essential features of cavitation flow, like the shedding of vortex and cloud cavities, the turbulent viscosity of SST (Shear-Stress Transport) k-omega model was modified by writing a UDF (User-Defined Function) code. To ensure the simulation of two-way Fluid-Structure Interaction (FSI), the results of NACA 66 hydrofoil in the uniform flow at non-cavitation conditions (wetted flow) are compared with experimental results, which indicates a good agreement. The results show that metallic alloys (aluminium and magnesium) have a slight effect on hydrofoil performance in comparison to each other. At the flexible foils, the hydrodynamic loads would cause bending and twisting deformations of the foil and the foil vibration.

关键词： Cavitation flow cavity shedding flexible hydrofoil hydroelastic response Fluid-Structure Interaction

来源：评论

学校读者我要写书评

暂无评论

Comparative analysis of fatigue assessment considering hydroelastic response using numerical and experimental approach

引用

STRUCTURAL ENGINEERING AND MECHANICS 2020年第3期76卷 355-365页

作者： Kim, Beom-il Jung, Byung-hoon Korean Register R&D Inst Ship & Offshore Technol Ctr 36 Myeongji Ocean City 9-Ro Busan 46762 South Korea Hyundai Heavy Ind Hyundai Maritime Res Inst Ship Struct Res Ctr 1-33 Ilsan Dong Ulsan 44032 South Korea

In this study, considering the hydroelastic response represented by the springing and whipping phenomena, we propose a method of estimating the fatigue damage in the longitudinal connections of ships. First, we screened the design sea states using a load transfer function based on the frequency domain. We then conducted a time domain fluid-structure interaction (FSI) analysis using WISH-FLEX, an in-house code based on the weakly nonlinear approach. To obtain an effective and robust analytical result of the hydroelastic response, we also conducted an experimental model test with a 1/50-scale backbone-based model of a ship, and compared the experimental results with those obtained from the FSI analysis. Then, by combining the results obtained from the hydroelastic response with those obtained from the numerical fatigue analysis, we developed a fatigue damage estimation method. Finally, to demonstrate the effectiveness of the developed method, we evaluated the fatigue strength for the longitudinal connections of the real ship and compared it with the results obtained from the model tests.

关键词： hydroelastic response springing and whipping fatigue damage design stage VLOC weakly nonlinear approach WISH-FLEX

来源：评论

学校读者我要写书评

暂无评论

Experimental investigation of the hydroelastic and the structural response of a moored pontoon-type modular floating breakwater with flexible connectors

引用

COASTAL ENGINEERING 2017年 121卷 240-254页

作者： Loukogeorgaki, Eva Lentsiou, Elpida Niki Aksel, Murat Yagci, Oral Aristotle Univ Thessaloniki Dept Civil Engn Thessaloniki 54124 Greece Istanbul Kultur Univ Dept Civil Engn TR-34156 Istanbul Turkey Istanbul Tech Univ Fac Civil Engn Div Hydraul TR-34469 Istanbul Turkey

In this paper, 3D experiments are conducted aiming at the combined investigation of the hydroelastic and the structural (connectors' internal forces) response of a pontoon-type modular Floating Breakwater (FB), consisting of flexibly connected, moored with chains modules, under the action of perpendicular and oblique regular waves. Regarding the FB's hydroelastic response (i.e. 3D displacements of the modules under the wave action), video recording of the horizontal and the vertical displacements of specific points on the FB relatively to some fixed points is implemented, and this response is determined through an appropriate image processing procedure. For asseasing the FB's structural response, strain rosettes are utilized, enabling the evaluation of the connectors' forces through the corresponding strains' measurements. The effect of the incident wave characteristics (period, height, obliquity) on the FB's hydroelastic and structural response is analyzed. The correlation between the connectors' forces and the FB's hydroelastic response is extensively discussed. The FB's hydroelastic and structural response depends strongly upon the wave period, while the wave height and obliquity affect this response in the low frequency range. Strong dependency of the connectors' forces upon the existence or not of a FB's intense deformed shape is demonstrated.

关键词： Floating breakwater Flexible connectors hydroelastic response Connectors' internal forces 3D experiments

来源：评论

学校读者我要写书评

暂无评论

Solving for hydroelastic ship response using a high-order finite difference method on overlapping grids at zero speed

引用

MARINE STRUCTURES 2024年 95卷

作者： Zhou, Baoshun Amini-Afshar, Mostafa Bingham, Harry B. Shao, Yanlin Malenica, Sime Andersen, Matilde H. Tech Univ Denmark Dept Civil & Mech Engn DK-2800 Lyngby Denmark Bur Veritas Res Dept F-92937 Paris France b telligent Sternengasse 17 CH-4051 Basel Switzerland

This work extends an existing seakeeping tool (OceanWave3D-seakeeping) to allow for the efficient and accurate evaluation of the hydroelastic response of large flexible ships sailing waves. OceanWave3D-seakeeping solves the linearized potential flow problem using high -order finite differences on overlapping curvilinear body -fitted grids. Generalized modes are introduced to capture the flexural responses at both zero and non -zero forward speed, but we focus on the zero speed case here. The implementation of the hydroelastic solution is validated against experimental measurements and reference numerical solutions for three test cases. The ship girder is approximated by an Euler-Bernoulli beam, so only elastic bending deformation considered and sheer effects are neglected. Some controversy has long existed in the literature about the correct form of the linearized hydrostatic stiffness terms for flexible modes, with Newman (1994) and Malenica and Bigot (2020) arriving at different forms. We provide here a complete derivation of both forms (including the gravitational terms) and demonstrate the equivalence of the buoyancy terms for pure elastic motions.

关键词： hydroelastic response Ships Potential flow Hydrostatic model Finite difference scheme Euler-Bernoulli beam

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：