• Title/Summary/Keyword: Floating Type Offshore Structure

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Analysis of Effects of Mooring Connection Position on the Dynamic Response of Spar type Floating Offshore Wind Turbine (계류장치 연결 위치가 Spar Type 부유식 해상풍력 발전기의 동적 응답에 미치는 영향 해석)

  • Cho, Yanguk;Cho, Jinrae;Jeong, Weuibong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.5
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    • pp.407-413
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    • 2013
  • This paper deals with the analysis of dynamic characteristics of mooring system of floating-type offshore wind turbine. A spar-type floating structure which consists of a nacelle, a tower and the platform excepting blades, is used to model the floating wind turbine and connect three catenary cables to substructure. The motion of floating structure is simulated when the mooring system is attached using irregular wave Pierson-Moskowitz model. The mooring system is analyzed by changing cable position of floating structure. The dynamic behavior characteristics of mooring system are investigated comparing with cable tension and 6-dof motion of floating structure. These characteristics are much useful to initial design of floating-type structure. From the simulation results, the optimized design parameter that is cable position of connect point of mooring cable can be obtained.

A study on the Motion Analysis of the Fishing Spot of Floating Offshore Structure Type (부유체식 바다 낚시터의 동요해석에 관한 연구)

  • 박성현;박석주;이돈출
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.1006-1012
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    • 2003
  • Recently, floating offshore structure is studied as one of the effective utilization of the ocean space. And floating structure are now being considered for various applications such as floating airports, offshore cities and so on. The motion analysis of the fishing spot of floating offshore structure as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this structure. And the analysis is carried out using the boundary element method in the fluid division. In order to know the characteristics of the motion of the floating fishing spot structures, effects of wavelength, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

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Estimation of Dynamic Motions and Mooring Forces for Floating Type Offshore Platform Based on Hydrodynamic Analysis (동수력학 해석 기반 부유식 해양 플랫폼의 동적 운동 및 계류력 산정)

  • Cha, Ju-Hwan;Moon, Chang-Il;Song, Chang-Yong
    • Journal of Ocean Engineering and Technology
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    • v.26 no.2
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    • pp.48-57
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    • 2012
  • This paper deals with numerical analyses in the context of estimations of hydrodynamic motions and dynamic loads for a floating type offshore platform using some exclusive simulation code such as code for the simulation of a floating type of offshore crane based on multi-body dynamics, along with the commercial code AQWA. Verifications of numerical models are carried out by comparing the RAO results from the simulation code. In the verification analyses, hydrodynamic motions are examined in the frequency domain for the floating type offshore platform according to the mooring lines. Both the hydrodynamic motions and dynamic loads are estimated for floating type offshore platforms equipped with the catenary type and taut mooring lines. A review and comparison are carried out for the numerically estimated results. The structural safety of the connection parts in an offshore structure such as a floating type offshore platform is one of the most important design criteria in view of fatigue life. The dynamic loads in the connecting area between a floating type offshore platform and its mooring lines are estimated in detail according to variations in the mechanical properties of the mooring lines. The dynamic tension load on the mooring lines is also estimated.

A Experimental Study on the Hydroelastic Behavior of Large Floating Offshore Structures (대형부체구조물(大型浮體構造物)의 유(流).탄성(彈性) 연성거동에 관한 실험적 고찰)

  • Lee, Sang-Yeob
    • Journal of Korean Association for Spatial Structures
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    • v.1 no.2 s.2
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    • pp.101-110
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    • 2001
  • A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an elastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of reduced model test. Satisfactory agreement is found between theory and experiment.

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Hydroelastic Response Characteristics of a Very Large Offshore Structures of Somisubmersible Type in waves (반잠수식 초대형 해양구조물의 파랑중 탄성응답특성)

  • Goo, Ja-Sam;Kim, Kyung-Tae;Hong, Bong-Ki
    • Journal of Ocean Engineering and Technology
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    • v.13 no.4 s.35
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    • pp.19-27
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    • 1999
  • To design a very large floating structure, such as a floating airport, we have to estimate the hydroelastic responses of a very large floating structure (VLFS) exactly. We developed the numerical method for estimating the hydroelastic responses of the VLFS. The developed numerical approach is based on a combination of the three-dimensional source distribution method, the wave interaction theory and the finite element method for structurally treating the space frame elements. The Numerical results of the hydroelastic responses and steady drift forces of a somisubmersible type offshore structure, which is supported by the 33(3 by 11) floating bodies, with various bending rigidities are illustrated.

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A theoretical study on the hydroelastic behavior of Large floating offshore structures (대형부체구조물(大型浮體構造物)의 유체(流體)·탄성체(彈性體) 연성거동의 이론적 해석에 관한 연구(硏究))

  • Lee, Sang-Yeob;Rha, Young-Ho
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.4
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    • pp.433-439
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    • 2001
  • A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an clastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of previous model test. Satisfactory agreement is found between theory and experiment.

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A Study on the Reduction Analysis of the Response of the Mega-Float Offshore Structure in Regular Wave (1st Report) (대형 부류해양구조물의 파낭중 응답의 저감해석에 관한 연구(제1보))

  • 박성현;박석주
    • Journal of the Korean Institute of Navigation
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    • v.24 no.1
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    • pp.85-95
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    • 2000
  • In the country where the population concentrates in the metropolis with the narrow land, development of the ocean space is necessary. Recently, mega-float offshore structure has been studied as one of the effective utilization of the ocean space. And very large floating structures are now being considered for various applications such as floating airports, offshore cities and so on. This very large structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. And it is necessary to examine the effect of ocean wave external force received from the natural environment. In this study, the mat-type large floating structure is made to be analytical model. And the analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this model. And the analysis is carried out using the boundary element method in the fluid division. The validity of analysis method is verified in comparison with the experimental result in the Japan Ministry of Transport Ship Research Institution. In order to know the characteristics of the dynamic response of the large floating structures, effects of wavelength, bending rigidity of the structure, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

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Structural integrity of a 2.5-MW spar-type floating offshore wind turbine under extreme environmental conditions

  • Hanjong Kim;Jaehoon Lee;Changwan Han;Seonghun Park
    • Wind and Structures
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    • v.37 no.6
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    • pp.461-471
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    • 2023
  • The main objective of this study was to establish design guidelines for three key design variables (spar thickness, spar diameter, and total draft) by examining their impact on the stress distribution and resonant frequency of a 2.5-MW spar-type floating offshore wind turbine substructure under extreme marine conditions, such as during Typhoon Bolaven. The current findings revealed that the substructure experienced maximum stress at wave frequencies of either 0.199 Hz or 0.294 Hz, consistent with previously reported experimental findings. These results indicated that the novel simulation method proposed in this study, which simultaneously combines hydrodynamic diffraction analysis, computational dynamics analysis, and structural analysis, was successfully validated. It also demonstrated that our proposed simulation method precisely quantified the stress distribution of the substructure. The novel findings, which reveal that the maximum stress of the substructure increases with an increase in total draft and a decrease in spar thickness and spar diameter, offer valuable insights for optimizing the design of spar-type floating offshore wind turbine substructures operating in various harsh marine environments.

Wave Response Analysis and Future Direction of Mega-Float

  • Park, Sung-Hyeon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2001.10a
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    • pp.153-168
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    • 2001
  • In the country where the population concentrates in the metropolis with the narrow land, development of th ocean space is necessary. Recently, mega-float offshore structure is studied as one of the effective utilization of the ocean space. And very large floating structure are now being considered for various applications such as floating airports, offshore cities and so on. This very large structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. And it is necessary to examine the effect of ocean wave eternal force received from the natural environment. In this study, the mat-type large floating structure is made to be analytical model. And the analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structure part of this model. And the analysis is carried out using the boundary element method in the fluid part. In order to know the characteristics of the dynamic response of the large floating structures, effects of wavelength, bending rigidity of the structure, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

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Analysis of wave induced vibration of a typical very large floating-type offshore airport platform (초대형 부유식 해상공항의 파도에 의한 진동응답특성 해석)

  • 이현엽;전영기;신현경
    • Journal of Ocean Engineering and Technology
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    • v.10 no.4
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    • pp.10-16
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    • 1996
  • The vibration due to progressive ocean waves is analyzed for a typical footing-type offshore airport platform. The platform is modelled as a spring-supported Euler beam and buoyancy change due to wave is considered as excitation force, under the assumption that the wave propagates without distortion by the structure. The results show that the natural frequencies of this structure are distributed very closely and are little affected by boundary conditions and that the response charateristics due to ocean waves are quite different according to the wave frequency. In this study, the wave frequencies are divided into three regions; the resonance region at which the response is governed by the resonance between the natural mode at the wave frequency and the corresponding modal component of the wave excitation force, the bending governed region at which the response is governed by the bending stiffness, and the spring (buoyancy) governed region at which the response is governed by the spring constant ahd therefore is same as the incident wave form.

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