• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.10a
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• pp.44-45
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• 2010

파랑 중에서 선체의 운동은 선체의 형상과 선속변화에 따라 다양하게 나타나며, 관련연구는 실험적 방법과 수치 해석을 함께 병행하여 지속적으로 진행되고 있다. 파랑조건에 적합한 최적 선형 확보는 선체의 운동응답 결과로 고찰할 수 있다. 파랑 중 선체의 운동응답을 알아보기 위해 초기 선형인 Wigley 선형에 적용하였으며, 수치해의 정도를 선행연구결과와 비교분석하였다. 그리고 서로 다른 모델에 대하여 나타나는 운동응답을 상호 비교하였다. 형상에 따른 Wigley 선형의 선체 운동응답에 대하여 일반화된 선형형상에서 나타날 수 있는 파랑 중 운동응답을 얻을 수 있었다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.83-90
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• 2010

The hydrodynamic interaction of two floating bodies in waves freely floating or connected by a rigid link is studied by using a boundary element method in the frequency-domain. The exact two-body hydrodynamic coefficients of added mass, wave damping and exciting force are calculated from the radiation-diffraction potential solution of the improved Green integral equation associated with the free surface Green function. The irregular frequencies in the conventional Green integral equation make it difficult to predict the physical resonance of the fluid in the gap between two bodies floating side by side. However, the improved Green integral equation employed in this study is free of irregular frequencies and always yields the exact solution of the multi-body radiation-diffraction potential boundary value problem. The 6 degree-of-freedom motions of two bodies freely floating side by side or connected parallel by a rigid link have been calculated for the incident wave frequencies ranging from 0.1 to 5 radians per second in head, left and right bow quartering seas. The 6-component load of the rigid link have also been presented.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.94-98
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• 2003

Remotely Operated Vehicle. ROV is a new concept equipment being made to replace the manned systems for investigating the deep sea environment. This paper presents the dynamic cable response during ROV launching considering the coupling effects of ship motion. By the harmonic response analysis, the variations of cable tensions were obtained. Harmonic forces in head/beam sea states were calculated by the concept of relative acceleration which obtained by ship motion analysis.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.10a
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• pp.83-86
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• 2003

선박은 근본적으로 파랑이 향상 존재하는 해상에서 운항하게 되므로 파랑 중에서의 선체운동 여객, 승무원, 화물 및 선박 자체의 안전과 밀접한 관계를 가지게 된다. 뿐만 아니라 선박의 운동은 해상에서의 각종 활동과 임무수행의 정도를 결정하는 주요한 인자가 되고 있다. 횡동요(Rolling)는 6 자유도 운동 가운데에서 가장 중요한 운동이며, 선박들이 근본적으로 횡동요에 대하여 낮은 감쇠특성을 갖고 있기 때문에 안정성 측면에서 볼 때에 가장 많이 제어되어 왔다. (중략)

• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.145-150
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• 2020

The ship motion of large LNG ships affects ships' safety. The purpose of this study was to estimate the transfer function of roll motion among the hull motion of 153,000 m3 class LNG vessels. The ship motion transfer function was modeled using a Linear Time-Invarient system with single input, single output, and transfer function. The transfer function of the ship motion was estimated by the system identification method using single ocean wave as input of the model, and using the roll motion of the LNG ship obtained through ANSYS as the output of the model. The usefulness of the experimental results was evaluated using the precision and estimation rate of the model for cases wherein the different transfer function dimensions. Results of the experiment showed a precision at 99% and 98%, with estimation rate at 78% and 50%. From these results, we found the proposed method of estimating the transfer function of ship motion in this study reasonable. In the future, data of ship motion in actual sea conditions will be acquired and it will be applied to make the construction of models with multiple inputs and multiple outputs for practical use.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.165-167
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• 2019

본 연구에서는 한국형 e-Navigation 선내시스템 원격 모니터링 서비스(SV20) 중 복원성 및 화재 판정 모듈의 개발과 운용개념에 대해서 소개하였다. 구체적으로는 선박의 복원성(안정성)과 관련된 메타센터 높이(GM), 복원성지수, 운동성지수 그리고 선체-파랑 동조위험성의 산출 및 표출에 대한 방안과 선내 화재정보의 표출 방안을 설명하고, 개발 진행사항 그리고 향후 연구 등을 기술하였다.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.3
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• pp.53-58
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• 1992

The memory effect in maneuvering motion is very small and usually neglected. But, considering the maneuvering motion in waves, we need to calculate the memory effect strictly. Meanwhile. it is popular to treat the wave exciting forces as the steady sinusoidal forces and simply add to the right-hand side of the equation of the motion. This paper treats the memory effect in maneuvering motion when we take the wave exciting forces as the simple external forces and discuss the validity of such treatments.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.3
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• pp.99-109
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• 2000

Elastic dynamic responses analysis program for ship hulls considering slamming impact loads due to the voyage in large amplitude waves is developed. Ship hull structures are modeled by a thin-walled beam model in order to consider effects of shear deformation. The momentum slamming theory is used to derive nonlinear hydrodynamic forces considering intersection between wave particles and ship section. For the validation of the developed computer program, motions of a V-shaped simple section model and S-175 standard container model are calculated and analyzed. In each numerical example, time histories of relative displacement, velocity and vertical bending moment of a ship section are derived, considering the effect of slamming impacts in various wave conditions.ures near the free surface as well as the wake of the hydrofoil.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.41-46
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• 2001

The very large vessels like VLCC and container ship have been built recently and those vessels have smaller structural strength in comparison with the other convectional skips. As a result the fatigue destruction of upper deck occurs a frequently due to the springing phenomenon at the encountering frequencies. In this study, the hydrodynamic loads are calculated by three-dimensional source distribution method with the translating and pulsating Green function. A ship is longitudinally divided into 23 sections and the added mass, damping and hydrodynamic force of each section is calculated. focusing only on the vertical motion. Stiffness matrix is calculated by the Euler beam theory. The calculation is carried out for Esso Osaka.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.228-233
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• 2014

In this paper, the motion performance in waves for the training ship Kaya of Pukyong National University is obtained by using a computer program based on Strip method. To guarantee the pleasant seafaring in ocean, the vertical acceleration of ship motion is calculated according to the location of the ship. The results of calculation by changes of ship speed are compared with the guideline of MSI(Motion Sickness Incidence). The degree of motion sickness is shown and discussed through the comparison between calculated vertical acceleration spectrum and MSI guideline. The computational results of MSI were as follow; when ship speed increased in the order of 5 knots, 10 knots, 12 knots and encounter angle became the bow quartering sea of $120^{\circ}$ compared to $180^{\circ}$ and $150^{\circ}$, the vertical acceleration values grew higher.