• Ocean Systems Engineering
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• 제3권1호
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• pp.35-53
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• 2013

In this study, a hybrid floating structure with cylinder was introduced to reduce the hydrodynamic motions of the pontoon type. The hybrid floating structure is composed of cylinders and semi-opened side sections to penetrate the wave impact energy. In order to exactly investigate the hydrodynamic motions and structural behavior of the hybrid floating structure under the wave loadings, integrated analysis of hydrodynamic and structural behavior were carried out on the hybrid floating structure. Firstly, the hydrodynamic analyses were performed on the hybrid and pontoon models. Then, the wave-induced hydrodynamic pressures resulting from hydrodynamic analysis were directly mapped to the structural analysis model. And, finally, the structural analyses were carried out on the hybrid and pontoon models. As a result of this study, it was learned that the hybrid model of this study was showed to have more favorable hydrodynamic motions than the pontoon model. The surge motion was indicated even smaller motion at all over wave periods from 4.0 to 10.0 sec, and the heave and pitch motions indicated smaller motions beyond its wave period of 6.5 sec. However, the hybrid model was shown more unfavorable structural behavior than the pontoon model. High concentrated stress occurred at the bottom slab of the bow and stern part where the cylinder wall was connected to the bottom slab. Also, the hybrid model behaved with the elastic body motion due to weak stiffness of floating body and caused a large stress variation at the pure slab section between the cylinder walls. Hence, in order to overcome these problems, some alternatives which could be easily obtained from the simple modification of structural details were proposed.

• 한국해안·해양공학회논문집
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• 제25권6호
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• pp.357-364
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• 2013

이전 연구에서는 부유구조체의 동요저감을 위해 폰툰과 반잠수식 부유구조체 형식을 결합하여 하이브리드 부유구조체를 제안한 바 있다. 하이브리드 부유구조체는 입사파랑에 대한 동요감소에는 효과적이었으나 부유구조체에 충분한 부력을 제공할 수 없는 단점이 있었다. 이와 같은 단점을 보완하기 위해 본 연구에서는 새로운 형식의 콤비네이션 부유구조체를 제안하였다. 입사 파랑하중에 대한 부유구조체의 동요감소 효과를 비교하기위해 폰툰, 콤비네이션 그리고 하이브리드 부유구조체에 대한 수치해석을 동수역학 해석프로그램 ANSYS AQWA를 이용하여 수행하였다. 본 연구에서 제안된 콤비네이션 부유구조체가 다른 부유구조체에 비해 동요감소에 효과적인 것을 확인할 수 있었다. 따라서 콤비네이션 부유구조체는 앞으로 개발될 초대형 부유구조체 건설을 위한 신형식 부유구조체로서 매우 유용하게 사용될 것으로 판단된다.

• 한국해안·해양공학회논문집
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• 제34권6호
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• pp.275-289
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• 2022

최근 연안에서 해상관광레저, 플로팅 건축 등의 사업발굴이 활발히 진행 중에 있어 해상조건에 적합한 부유식 구조물의 필요성이 대두되고 있다. 본 연구에서는 육상 이동이 가능한 단위 모듈의 수직 및 수평 적층으로 확장된 하이브리드 부유식 구조물의 안정성을 향상시키기 위해 수평감쇠판을 적용하였다. 적용된 수평감쇠판의 길이 변화에 따른 하이브리드 부유식 구조물의 거동 특성을 상용 프로그램인 ANSYS AQWA를 이용하여 분석하였다. 하지만 제안된 하이브리드 부유식 구조물의 경우 구조물에 의해 둘러싸인 유체영역이 존재하고 이로 인해 특정 주기에서 공진이 발생할 가능성이 있다. 따라서 구조물에 의해 둘러싸인 유체영역에 ANSYS AQWA에서 제공되는 감쇠존 효과를 고려하여 부유식 구조물의 거동 특성을 주파수 영역 수치해석을 통해 면밀하게 분석하였다.

• 한국항만학회지
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• 제7권1호
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• pp.79-88
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• 1993

This study deals with the case of a fixed floating structure(FFS) at the mouth of a rectangular harbor under the action of waves represented by the linear wave theory. Modified forms of the mild-slope equation is applied to the propagation of regular wave over constant water depth. The model is extended to include bottom friction and boundary absorption. A hybrid element approximation is used for calculation of linear wave oscillation in and near coastal harbor. Modification of the model was necessary for the FFS. For the conditions tested, the results of laboratory experiments by Ippen and Goda(1963), and Lee (1969) are compared with the calculated one from this model. The cases of flat cylinderical structures, both fixed and floating, were taken to be in an intermediate water depth.

• 대한토목학회논문집
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• 제32권5B호
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• pp.313-320
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• 2012

본 논문에서는 폰툰형 콘크리트 부유구조체의 하부슬래브에 발생하는 인장력을 억제하여 구조적 안전성을 향상시킬 수 있는 방안으로 부유구조체 외측 모듈을 반잠수식 모듈로 구성하는 구조시스템을 제시하였다. 본 시스템의 적용성을 확인하기 위해 반잠수식 모듈 제원과 전체 시스템에 대한 반잠수식 모듈의 구성비를 변화시켜 외력에 대한 구조응답과 부유구조체 중량, 흘수를 종합적으로 검토하였다. 구조성능 검토 시 효율적인 매개변수 연구를 위해 이단계 등가 정적 해석법을 도입하였으며, 본 해석법을 바탕으로 시스템 제원 변화에 따른 각 구조부 작용 외력의 변화와 구조 거동을 분석하였다. 분석 결과, 본 시스템 도입 시 콘크리트 부유구조체의 하부슬래브 발생 인장력을 충분히 억제할 수 있는 것으로 나타났으며, 적정한 반잠수식 모듈의 구성비는 부유구조체 길이대비 약 15% 이하인 것으로 분석되었다.

• 대한조선학회논문집
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• 제56권5호
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• pp.396-409
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• 2019

In this paper, a comparative study on the radiation techniques for the motion analysis of the three dimensional floating structure with the forward speed was carried out. The Sommerfeld radiation condition, the damping technique, and the point shift technique were used for the comparative study. Radiated wave patterns and hydrodynamic coefficients of the heave motion of floating structure with the forward speed were compared and analyzed. The characteristics and limitations of each radiation technique were analyzed through the calculation results. To overcome the limitations of conventional radiation techniques, the hybrid radiation technique combining the Sommerfeld radiation condition with the damping technique was proposed. It is confirmed that the proposed method, the Hybrid radiation technique, improves the limitation of the speed range and the dissipation of the wave of the conventional radiation technique. The motion analysis code of the three dimensional floating structure with the forward speed based on the Rankine source method with hybrid radiation technique was developed. In order to validate the developed code, hydrodynamic analyses were carried and compared with published experiments.

• 한국공간구조학회논문집
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• 제1권2호
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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.

• 한국산업융합학회 논문집
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• 제4권4호
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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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.674-679
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• 2005

This paper is concerned with the application of perturbation method to the dynamic analysis of space structure floating in space. In dealing with the dynamics of space structure, the use of Lagrange's equations of motion in terms of quasi-coordinates were suggested to derive hybrid equations of motion for rigid-body translations and elastic vibrations. The perturbation method is then applied to the hybrid equations of motion along with discretization by means of admissible functions. This process is very tiresome. Recently, a new approach that applies the perturbation method to the Lagrange's equations directly was proposed and applied to the two-dimensional floating structure. In this paper, we propose the application of the perturbation method to the Lagrange's equations of motion in terms of quasi-coordinates. Theoretical derivations show the efficacy of the proposed method.

• 한국소음진동공학회논문집
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• 제15권9호
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• pp.1030-1036
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• 2005

This paper is concerned with the application of perturbation method to the dynamic analysis of space structure floating in space. In dealing with the dynamics of space structure, the use of Lagrange's equations of motion in terms of quasi-coordinates were suggested to derive hybrid equations of motion for rigid-body translations and elastic vibrations. The perturbation method is then applied to the hybrid equations of motion along with discretization by means of admissible functions. This process is very tiresome. Recently, a new approach that applies the perturbation method to the Lagrange's equations directly was proposed and applied to the two-dimensional floating structure. In this paper. we propose the application of the perturbation method to the Lagrange's equations of motion in terms of quasi-coordinates. Theoretical derivations show the efficacy of the proposed method.