• Structural Engineering and Mechanics
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• 제67권1호
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• pp.9-20
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• 2018

In this paper, a framework is proposed for dynamic analysis of train-bridge systems with a damaged pier after barge collision. In simulating the barge-pier collision, the concrete pier is considered to be nonlinear-inelastic, and the barge-bow is modeled as elastic-plastic. The changes of dynamic properties and deformation of the damaged pier, and the additional unevenness of the track induced by the change of deck profile, are analyzed. The dynamic analysis model for train-bridge coupling system with a damaged pier is established. Based on the framework, an illustrative case study is carried out with a $5{\times}32m$ simply-supported PC box-girder bridge and the ICE3 high-speed train, to investigate the dynamic response of the bridge with a damaged pier after barge collision and its influence on the running safety of high-speed train. The results show that after collision by the barge, the vibration properties of the pier and the deck profile of bridge are changed, forming an additional unevenness of the track, by which the dynamic responses of the bridge and the car-body accelerations of the train are increased, and the running safety of high-speed train is affected.

• 수산해양기술연구
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• 제56권3호
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• pp.223-229
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• 2020

We analyzed the cutting mechanism of laver harvesting machine in the sea area near Gooam Port in Goheung, Jeollanam-do, and investigated the change and efficiency of laver collecting operation in the working ship. The laver working ship slides uniformly from the bow to the upper part of the laver collecting machine on the deck and cuts the wet laver attached to the bottom of the net at the blade of the havesting machine. The laver farming net, which was loaded with laver turrets on the deck by gravity and collected primitives, consisted of a ship structure that led to the stern side and into the sea. The working ship operation is in harvesting process while driving in a S-shape that is separated by one space to efficiently collect the laver net. During laver working ship operation, the speed was 0.51 m/s in the access stage, 0.56 m/s in the havesting stage, and 0.52 m/s in the exit stage. Considering the cutting edge life and production efficiency of the laver harvesting machine, it is appropriate to harvest 1.15 to 1.26 kg/rpm by operating at a rotational speed of about 700 to 800 rpm rather than forcibly harvesting the product at high speed. On the deck of the working ship, 959.7 kg of starboard and 1048.7 kg of center were 964.7 kg of port side. Based on the starboard, 9.3% of the central part and 0.5% of the port side appeared. The reason for this was due to the difference in harvest time according to the turning direction of the working ship.

• 대한조선학회지
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• 제27권2호
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• pp.31-39
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• 1990

불규칙 해상을 항해하는 선박이 겪게 되는 갑판침수 현상은 의장품 및 갑판화물의 손상과 승무원의 활동제한 등을 초래하여 선박의 성능을 감소시키는 작용을 하며 거친 해상에서의 잦은 갑판침수는 전복을 야기시킬 수도 있다. 따라서 거친해상에서의 작업이 요구되는 군함이나 갑판에 화물을 적재하게 되는 콘테이너선 등은 설계시 갑판침수 현상을 최소화하기 위한 선수부 현상이 고안되어야 한다, 갑판침수 현상은 현상자체의 비선형성 및 희귀성으로 인해 이론적 추정이 난점이 있으므로 설계목적의 갑판침수 현상해석은 주로 모형시험에 의존하고 있다. 본 논문에서는 용량식 파고계의 원리를 이용한 갑판침수계측 시험방법을 소개하였으며, ITTC 내항성분과 표준모형선인 S-175 고속콘테이너선의 1/43.75 모형으로, 유의파고 7.88m, 평균주기 10.5초의 선수파 해상상태에서 Froude수 0.15와 0.275의 두 조건에 대해 갑판침수계측 시험을 수행하였다. 계측시험 결과를 통계적 관점에서 고찰하였고 Rayleigh 분포의 가정에 따른 Ochi의 갑판침수계산 공식에 의한 계산결과로 비교하였다.

• International Journal of Aeronautical and Space Sciences
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• 제16권1호
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• pp.1-7
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• 2015

In order to provide some references for suitability of carrier-based aircrafts, this paper studies the flow field of exhaust jets and its impact on the flight deck. The geometrical models of aircraft carrier and carrier-based aircrafts are firstly built, on which unstructured tetrahedral meshes are generated for numerical analysis. Then, this paper simulates the flow field of exhaust jets to evaluate its impact on the Jet Blast Deflector (JBD) and the flight deck, when four carrier-based aircrafts are ready to start off in the bow. The standard k-${\varepsilon}$ equations, three-dimension N-S equations and the Computational Fluid Dynamics (CFD) theory are used in the analysis process. To solve the equations, the thermal coupling of the wind and the jet flow are also considered. The velocity and temperature distributions are provided with the simulation of the CFD software, FLUENT. The results indicate that: (1) this analytical method can be used to simulate aerodynamic problems with complex geometrical models, and the results are of high reliability; (2) the safety working area, the installation scheme of the JBD and the arrangement of the take-off position can be optimized through analysis.

• 대한조선학회논문집
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• 제60권2호
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• pp.135-145
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• 2023

Developing high-fidelity Computational Fluid Dynamics (CFD) simulation methods used to evaluate the airwake characteristics along a flight deck of a large ship, the various kind of data such as actual ship measurement and wind tunnel results are required to verify the accuracy of CFD simulation. Inflow velocity profile at the bow, local unsteady flow field data around the flight deck, and highly reliable wind tunnel data which were measured after reviewing Atmospheric Boundary Layer (ABL) simulation and Reynolds Number effects were also used to determine the key parameters such as turbulence model, time resolution and accuracy, grid resolution and type, inflow condition, domain size, simulation length, and so on in STAR CCM⁺. Velocity ratio and turbulent intensity difference between Full-scale CFD and actual ship measurement at the measurement points show less than 2% and 1.7% respectively. And differences in velocity ratio and turbulence intensity between wind tunnel test and small-scale CFD are both less than 2.2%. Based upon this fact, the selected parameters in CFD simulation are highly reliable for a specific wind condition.

• 한국실내디자인학회논문집
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• 제16호
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• pp.59-67
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• 1998

This study classifies distinctive peculiarities of cruise interior design which is different from that of structures on the land through the theoretical study on the cruise equipped with functions of hotel and ship. The distinguishing marks are : The first one of the main peculiarities is associated with the International agreement and the safety of passangers and the ship required by the specific regulation. The cruise interior design should be also selectively chosen. The third in comply with the peculiarity of the space plan the base of planning the cruise spaces are as follows : The course of bow and stern the pillar the center line of ship main vertical bulkhead watertight subdivision bulkhead and the deck. The last by special peculiarity of construction materials, materials and products applied for the cruise should meet the regulation of SOLAS and IMCO.

• 대한조선학회 특별논문집
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• 대한조선학회 2006년도 특별논문집
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• pp.34-39
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• 2006

In rough seas, water breaker of the sea-going ships is subject to high impact loads due to the green water and some ships' water breaker suffers structure damage. So, a substantial research on the structural response caused by green water impact is required. In this paper, the green water flow on bow deck is simulated by FDM(finite differential method). Using the results of green water simulation, impact loads on water breaker are calculated. Calculation results of the 6200TEU container ship's structural response to this green water impact pressure are shown and discussed for two condiered calculation conditions.

• 헤리티지:역사와 과학
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• 제55권4호
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• pp.242-275
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• 2022

본 연구는 통신사(通信使)가 임진왜란 이후 1607년부터 1811년까지 약 200여 년간 12번에 걸쳐 일본을 왕래하며 남긴 사행록(使行錄) 중 선설(船說)을 중심으로 10~12차 사행에 정사 기선의 구조를 조선기술사적 측면에서 보다 깊이 있게 밝혀보고자 하였다. 본연구 결과 10~12차사행의 기선은 크기는 『계미수사록』과 『증정교린지』를 근거로 상장(갑판)의 길이가 19파(把)반(半), 너비 6파 2척(尺)이고, 삼판 높이는 2파 1척임을 알 수 있었다. 구조는 사행록에 따라 다르게 기록되어 있지만 이들을 종합해 보면 본판·선수(비아:이물)·선미(고물)·삼판·멍에·가룡·신방·궁지·갑판·두 개의 돛대와 돛·구레짝·판옥·선미판옥·타루·파도막이·호롱·계단·난간·치·노·닻 등을 갖추고 있는 것을 알 수 있다. 또한 각 부재를 서로 이음하거나 각단을 올릴 때는 연결하는 결구 못은 피삭(皮槊), 나무못[정: 釘], 쇠못[철정: 鐵釘] 등을 사용한 것을 알 수 있다. 돛의 종류는 초둔(草芚)으로 만든 돛[석범:席帆]과 베로 만든 돛[포범:布帆]을 사용한 것을 알 수 있다. 따라서, 본 연구를 통해 10~12차 사행에 정사가 타고 간 기선은 조선의 권위와 위엄을 보이기 위해 조선통신사 선단 중 길이를 가장 크게 하고, 선고(船高)를 높게 제작하였으며, 뱃전 바깥으로 이동 통로를 만들고, 뱃전과 판옥 사이에서 노를 젓고, 뱃전 안쪽으로 판옥을 올려 방을 만들고, 판옥 위 사방에 난간을 두어 안정적이며 선형의 미를 한층 더 향상시켰다. 판옥 벽면에는 궁궐 단청과 화려하게 벽화를 그려 장식하였다. 뿐만 아니라 선수에 귀면(鬼面)과 선안(船眼)을 그려 항해의 안전을 도모한 것을 알 수 있다. 이처럼 사행록에 기록된 선설을 통해 정사 기선은 국가에서 제작하고 국제를 항해할 수 있도록 기능과 구조를 갖추고 있는 것을 알 수 있다.

• 대한조선학회논문집
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• 제54권6호
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• pp.492-500
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• 2017

In the study, numerical simulation on the greenwater impact load of free surface offshore structure in the regular waves using fixed cartesian grid system and Modified Marker-Density (MMD) method were carried out and the results were reviewed. In order to compare numerical simulation and experimental results, the FPSO with the scale ratio of 1/100 model ship with fixed rectangular deck was selected and turbulence characteristic of the flow was considered by applying the Sub-Grid Scale (SGS) in laminar flow. As a result, it is reviewed how the greenwater impact load inflowed from bow in regular headsea wave influence the flow on the deck and the flow characteristic by numerical simulation and the experiment results were compared and reviewed. Based on this study, it would be useful to numerically study the effect of greenwater on offshore structure.

• 한국항해항만학회지
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• 제27권5호
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• pp.465-471
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• 2003

내항 탱커가 비교적 정온한 해역에서 타선을 피하기 위해 대각도 조타론 행한 결과, 선회 중에 전복하는 사고가 발생하였다. 저자들은 전 논문에서 비중량이 큰 액체화물의 자유표면영향에 의한 중심상승과 전진 항해 중에 발생하는 선체 침하와 이로 인하여 생기는 선체 트림의 변화 때문에 발생하는 복원력 감소를 고려하여 사고선박의 복원력 곡선을 계산하였다. 본 논문에서는 먼저 전복사고를 당한 선박의 모형선을 제작하여 자항 선회실험을 실시하고 전복선박의 정상 선회시의 선회반경, 편류각 및 선속을 계측한다. 그리고 자항 선회실험을 통하여 얻은 선회반경, 선속 및 횡 편류각을 기초로 하여 각 경사각에 따른 측 압력과 경사 모멘트에 관한 실험을 실시하고, 갑판상 해수 침입이 측 압력과 경사 모멘트에 미치는 영향에 대해서 파악한다. 마지막으로 선회시 해수 침입으로 인해 발생하는 외측 경사 모멘트와 측압 중심의 변화론 조사함으로써 전복사고가 발생한 저건현 내항 탱커의 복원성에 대하여 검토를 하였다.