• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.76-83
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• 2005

Membrane type LNG Carriers are characterized by their special structures such as trunk deck above upper deck. It is necessary to introduce an appropriate structure arrangement taking into account transition of the trunk deck to the upper deck or deckhouse in fore and aft parts. The transition area at aft part -from trunk deck to the deckhouse - is to be specially considered because of high longitudinal stresses applied at the area. This study has been carried out to tackle the transitional structure problem in design stage This paper deals with not only mesh size of FE models for scantling evaluation and fatigue assessment but also technical issues regarding fatigue assessment.

• 한국도로학회논문집
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• 제4권1호
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• pp.171-181
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• 2002

강상판의 포장에 사용되는 구스아스팔트는 시공시 $220^{\circ}C$에서 $260^{\circ}C$의 고온 상태에서 시공되기 때문에 강상판에 과도한 응력 및 변형을 발생시킬 수 있다. 따라서 구스아스팔트의 포설시 강상판에 미치는 열영향을 평가하고 그 영향의 최소화를 위한 포설폭과 패턴을 선정하여야 할 필요가 있다. 본 연구에서는 영종대교 상로도로의 구스아스팔트에 의한 열영향을 평가하기 위하여 일련의 수치해석을 수행하였으며 그 결과를 계측결과와 비교하여 수치해석방법의 타당성을 검증하고, 구스아스팔트가 강상판에 미치는 열영향을 검토하였다.

• 대한조선학회논문집
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• 제43권3호
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• pp.331-339
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• 2006

The objective of this paper is to calculate the fatigue strength for upper deck hatch corner insert plate of large container carriers without wave load analysis and global finite element analysis at the initial design stage. Wave load analysis and global F.E. analysis for three container carriers have been performed by GL(Germanischer Lloyd) procedure to propose the equation for hatch corner stress range which is the important factor in fatigue strength calculation. Considering the restraining effect of bulkhead, three types of equation, that is, single tight bulkhead, double tight bulkhead and support bulkhead have been proposed. Using the proposed equations, a simplified fatigue analysis based on GL rules has been performed for two container carriers of which fatigue strength analysis was carried out by GL. From the comparison between fatigue strength result of using the proposed equations and that of GL, it has been found that proposed stress range equations are useful for scantling of upper deck hatch corner insert plates for over 8,000 TEU class container carriers.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.25-28
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• 2005

This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

• 대한조선학회논문집
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• 제31권3호
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• pp.119-128
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• 1994

기관실 상갑판 특히 거주구 외부의 상갑판 판부재는 외적인 수직하중이 거의 작용하지 않음에도 불구하고 건조중인 대형선박에서 갑판에 널리 대처짐 현상이 발생할 때가 있는 반면에 수직하중이 작용하는 거주구 내부의 기관실 상갑판은 처짐발생 크기 및 분포정도가 미미한, 규명하기 어려운 현상들이 나타나고 있다. 따라서, 본 연구에서는 3차원 구조해석으로부터 얻은 거주구 및 자중에 의한 정적하중의 영향, 손상보고에 따라 계측된 처짐량 자료 및 분포상황, 초기처짐의 크기 및 형상, 용접잔류응력, 면내하중 성분들을 대상으로 비선형 시리즈 해석을 수행하고, 이로부터 판부재에 발생하는 최대처짐 추정식을 제시하였다. 또한, 본 연구를 통하여 개발된 추정식을 이용하여 기존 손상선박의 처짐원인 분석, 거주구 탑재 및 진수 전후의 기관실 상갑판의 처짐거동 그리고 기존의 선각품질관리기준이 기관실 상갑판의 처짐에 미치는 영향을 살펴보았고, 마지막으로 건조예정에 있는 기관실의 처짐현상을 예측하여 보았다.

• 한국추진공학회지
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• 제25권2호
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• pp.42-54
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• 2021

Aft-deck은 가스터빈 배기 플룸을 차폐하거나, 제트를 확산하여 외부 공기와 혼합율을 증가시켜 배기가스의 온도를 저감하기 위한 용도로 최신 무인항공기에 적용되고 있다. 본 연구에서는 Aft-deck의 설계 변수에 따라 노즐의 성능이 어떻게 영향을 받는지 알아보고자 하였다. Aft-deck의 설계 변수로는 길이, 확산각, 상부 덱 형상으로 선정하였으며, 길이 변수에 따른 추력과 차폐율 간의 상관관계를 제시하였다. 그리고 확산 각도의 범위에 따라 노즐 추력과 제트 확산에 대한 상관관계를 제시하였다. 또한, 상부 덱 제거를 통해 추력 향상 효과를 확인하였으며, 횡 방향 속도 벡터의 특성이 외부 유동과의 혼합 성능을 결정하는 것을 알게 되었다.

• Wind and Structures
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• 제38권5호
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• pp.399-410
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• 2024

Long-span suspension bridges located in typhoon-prone regions face significant risks of flutter instability, particularly in girder erection. Despite the implementation of aerodynamic countermeasures designed for the service stage, the flutter stability of bridge in girder erection may not meet the required standards. Nowadays, the double-deck truss girder is increasingly common in practical engineering which exhibits different performance from the single-deck truss girder. To gain insights into the flutter performance of this girder type and determine temporary aerodynamic countermeasures for flutter suppression in girder erection, wind tunnel tests were conducted. The effects of affiliated members on the flutter performance were first examined. Subsequently, different aerodynamic countermeasures were designed and their effectiveness was tested. The results indicate that the stabilizers above and below the upper and lower decks are the most effective for the flutter stability of bridge at positive and negative angles of attack, respectively. The higher the stabilizers are, the better the effect on flutter suppression achieves. Considering the feasibility in practical engineering, a temporary stabilizer above the upper deck was considered. It is expected that the results could provide references for the aerodynamic design of double-deck truss girder during erection.

• Journal of Advanced Marine Engineering and Technology
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• 제33권2호
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• pp.336-343
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• 2009

Because ships are very isolated and independent objects when sailing on the ocean, if a fire and smoke occurs, nobody can be sure to escape safely from ship at the moment. On the focus of the relationship between the sight transmissivity by fire smoke density and the life safety, this study performs simulations and experiments, respectively. To evaluate the theoretical evacuation time, CFAST software which is known as a 2 zone model analysis tool is used, and the result is 54 seconds from ECR(Engine Control Room) exit to upper deck exit and 34 seconds from bosun store to upper deck exit. And totally 12 types of experiments are performed with other 10 persons per experiment. As the result, it is cleared that the low sight transmissivity leads to the low life safety and the obstruction which can be happen unexpectedly on the evacuation way on fire makes it worse. At the condition of the smoke density 0%, over 90% people arrive at upper deck exit safely. But with the transmissivity of 8%, 70%(from ECR) and 30%(from bosun store) among experiment persons of each can survive, and with same density and unexpected obstruction, the survival ratio goes down to only 20% and 10%.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.443-448
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• 2014

Recently, car-ferry passenger ships of navigating the coast area in the inside of our country are on an increasing trend of main engine power and the height of upper structure, which is increased to ship's speed and loading of large vehicles. The most ship with high-speed main engine is happened to excessive vibration by propeller induced excitation force on account of connecting the vibration of hull's girder and the upper structure by decreasing the shear stiffness and natural frequency for increasing the height of passenger deck. In this paper, By exchanging the propeller of alteration the number of blades, it could be keep to ship's speed and it's decreased the vibration of hull part that is located passenger deck on the upper deck, which is identified by countermeasure of protection against vibration to procure the safety ship's navigation through measuring the vibration of hull structure.

• 대한조선학회논문집
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• 제49권6호
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• pp.541-549
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• 2012

The study adopted a freezing prevention method of the upper deck which used heating coil, and carried out numerical analysis by using ANSYS 13.0 CFD for design guide of the vessel operating in cold region. It is based on the experimental results of the anti-icing performance tests which were carried at cold room chamber in MOERI. Numerical analysis for the design guide was performed by considering S.S.T. (Shear Stress Transport) turbulent model for flow separation effects and the turbulence which occurred in interfaces of the numerical model in order to express appropriate heat transmission phenomenon. The numerical result shows average temperature of the upper deck surface appeared similarly compared with the indoor chamber test. The design guide for optimum freezing prevention presented through heat transmission capability and interval of the heat coil in various outdoor temperature($10^{\circ}C{\sim}-30^{\circ}C$) and wind speed(1m/s~7m/s).