• 대한기계학회논문집A
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• 제28권9호
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• pp.1384-1390
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• 2004

The full containment Liquefied Natural Gas(LNG) storage tank is based on a double liquid container concept : two separate containers, one within the other, are capable of containing the LNG. The outer concrete tank provides comer protection(secondary containment) to withstand and safely contain any spill from the inner tank. The comer protection is installed on inside corner surface of outer concrete tank. Because of high and complex stresses, corner protection is designed by ASME section ⅧI Div. 2, Appendix 4 on behalf of API 620 which is main design code for LNG tank. Design guidelines to determine design factors such as liner thickness and knuckle radius are not well understood because Appendix 4 is the design method not based on equation but FEM. Recently, the volume of LNG tank shows a tendency to increase. So it is necessary to set up the design guidelines to cope with change of LNG tank capacity and height/diameter ratio. In this paper, optimum design of corner protection was performed and the design guidelines were suggested by the results of FEM for LNG tanks which have different capacities and height/diameter ratio.

• 한국수소및신에너지학회논문집
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• 제10권3호
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• pp.151-157
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• 1999

The development of hydrogen vehicles has been actively progressed in the developed countries such as U. S., Japan and Germany. The most important technology of using hydrogen fuel is to develope a compatible storage tank with respect to the fossil fuel tank. Among many storage methods, the liquid hydrogen is the most desirable state because of the lowest volume and weight. The metal hydride tank is too heavy and the compressed hydrogen tank is too bulky. Because of these reasons, it is the principal purpose to analyze the theoretical heat transfer for designing and manufacturing an actual $LH_2$ tank. The insulation methods of the room between inner and outer vessel are non-vacuum, vacuum, vacuum with MLI(Multi-Layer Insulation). According to the results of the numerically calculated heat leak through the walls of the $LH_2$ tank, the vacuum insulated tank has 20 times and the MLI tank has 5616 times less heat leak than the non-vacuum tank.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권1호
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• pp.114-125
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• 2017

This paper addresses a study of inner-tank sloshing effect on motion responses of a Floating Liquefied Natural Gas (FLNG) system, through experimental analysis and numerical modeling. To investigate hydrodynamic characteristics of FLNG under the conditions of with and without LNG-tank sloshing, a series of numerical simulations were carried out using potential flow solver SESAM. To validate the numerical simulations, model tests on the FLNG system was conducted in both liquid and solid ballast conditions with 75% tank filling level in height. Good correlations were observed between the measured and predicted results, proving the feasibility of the numerical modeling technique. On the verified numerical model, Response Amplitude Operators (RAOs) of the FLNG with 25% and 50% tank filling levels were calculated in six degrees of freedom. The influence of tank sloshing with varying tank filling levels on the RAOs has been presented and analyzed. The results showed that LNG-tank sloshing has a noticeable impact on the roll motion response of the FLNG and a moderate tank filling level is less helpful in reducing the roll motion response.

• 한국소음진동공학회논문집
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• 제13권10호
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• pp.791-797
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• 2003

A liquid storage rectangular tank structures are used In many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks In contact with Inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine or propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. In the previous report, we have developed numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present report, using the numerical analysis, vibrations characteristics In deep water tank are investigated and discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.1079-1084
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• 2003

A liquid storage rectangular tank structures are used in many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks ill contact with fluid near engine or propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. In the previous report, we have developed numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present report, using the numerical analysis, vibrations characteristics in deep water tank are investigated and discussed.

• 한국가스학회지
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• 제8권3호
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• pp.57-62
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• 2004

본 연구는 천연가스 생산기지를 구성하는 설비 가운데 핵심설비라 할 수 있는 LNG 저장탱크의 설계 기술을, 세계에서 다섯 번째로 국내 기술로 설계를 완료하여 건설 중에 있는, OO 생산기지 LNG 저장탱크(용량 ; 14만kl, 형식 : 지상식, $9\%$ Ni강 내조 $\cdot$ Prestressed Concrete 외조) 1기에 대한 공정설비의 설계 적합성과 탱크 외벽에 대한 소화설비의 설계 적합성에 관하여 연구하였다.

• Design & Manufacturing
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• 제12권1호
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• pp.52-57
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• 2018

With the recent strengthening of environmental regulations and the need for cost reduction, excavators, a type of construction equipment, are being miniaturized while components are being developed in consideration of stability. In the case of excavator press parts, mainly high-strength steel sheets are being used to enhance stability and reduce weight. However, in the case of high-strength materials, there is a need to research product forming methods to reduce Springback in defects arising in parts assembly due to Springback that result from the internal residual stress that occurs in press forming being released after product forming. Accordingly, regarding the tank cover, an excavator press-forming part, this study selected a method to reduce distortion through analysis of the Springback occurrence rate and Springback causes through a forming analysis. A forming analysis was conducted for the Springback of the tank cover. Deformations of 13.714 mm in the upper part and 6.244 mm in the inner part of the product occurred, while wrinkles occurred on the sides of the product due to uneven thickness. A forming analysis was conducted for the major shapes of the product to investigate the causes of Springback. Distortion deformation due to the bead in the center of the product was confirmed to be a large factor. A Springback reduction method of correcting uneven thickness in the product sides, a Springback reduction method of removing the bead, and a correction method of restriking after the final forming were used in a forming analysis to determine the degree of Springback reduction. For the forming method to correct uneven thickness in the sides, deformation was reduced by 12% in the upper side compared to the existing model, but deformation in the inner side increased by 1%. For the restriking forming method, deformation decreased by 25% in the upper side and 13% in the inner side. For the bead removal method, deformation decreased by 28% in the upper side and 13% in the inner side, the largest Springback correction results. This indicates that the bead has a large affect on Springback.

• Journal of Advanced Marine Engineering and Technology
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• 제32권6호
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• pp.841-846
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• 2008

Recently the LNG(liquified natural gas) public buses have been introduced to prevent the air pollution in metropolitan areas. As the LNG temperature in fuel tank is as low as $-162^{\circ}C$. the thermal and structural effects of tank components need to be studied for safe introduction in the market. Especially the support system of LNG fuel tank in vehicle, which has connected with inside and outside of tanks, should put attention to reduce the structural stress due to cryogenic temperature and to restrict the heat flux from ambient. There are two supporting systems in the tank, that one is connected between inside and outside tanks by welding, and the other is the inserted support system which is a cylindrical SUS bar inserted in a hole of the supporting plate. In this study the temperature distribution and thermal stress of the inserted support system were evaluated by using the utility program as ANSYS. The results showed that the rate of heat transfer to inner tank through this support system was quite small due to limited contact of support bar with plate. but the thermal stress of support plate was obtained beyond the limited tensile value of SUS304. The cautious design for the support plate part, therefore, should be given to make the safe support system of LNG vehicle fuel tank.

• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.81-84
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• 2013

일반적인 Bulk carrier는 Single deck, Double bottom, Hopper side tank, Top side tank와 함께 Single side skin 또는 Double side skin으로 구성되어 Single hull bulk carrier 또는 Double hull bulk carrier라 불린다. 본 논문의 연구선박인 Double hull bulk carrier는 CSR에서 규정짓고 있는 Double hull bulk carrier의 특징 중 Hopper side tank가 없기에 일반적인 Double hull bulk carrier와는 다른 구조를 가진다. 구조적 특징으로는 Inner bottom과 Inner hull 연결부위에 응력 집중 발생, Side shell의 Shear에 대해 구조적 안전성, Double hull에 대한 CSR for bulk carrier의 Rule적용 여부에 대한 판단 등이 있다. 따라서 본 연구에서는 Double hull bulk carrier의 구조적 특징과 구조해석을 통한 응력 집중 부위의 평가 및 Fatigue analysis을 통한 피로수명을 계산하여 이를 통해 구조의 안전성을 살펴보고자 한다.

• 한국가스학회지
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• 제17권4호
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• pp.77-82
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• 2013

LNG의 수요 증가와 함께 LNG기지의 저장탱크의 건설도 증가하고 있다. 내부탱크는 9%Ni강재 그리고 외부탱크는 콘크리트가 적용되는 형식의 LNG탱크의 단열은 내외부 탱크 사이에 펄라이트 분말이 충전되며, 이 펄라이트의 압력을 흡수하기 위하여 탄성이 있는 블랭킷을 사용한다. 본 연구에서는 이 블랭킷을 적용함에 있어 그 특성과 내부 탱크에 미치는 압력 등을 해석, 고찰하여 블랭킷의 적정 설계두께, 설계압력 등 설계기준을 얻고자 하였다. 연구결과, 블랭킷의 적정 두께설계 기준은 내외부 탱크 간격의 30~40%가 되었으며, 설계압력 기준은 블랭킷 두께에 따라 2,200~2,700Pa 이하가 적절한 것으로 얻어졌다.