• 농촌계획
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• 제20권3호
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• pp.21-31
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• 2014

The purpose of this study is to develop promotion strategies for revitalizing mountain eco-villages through social economic support. In order to fulfill this purpose, this study analyzed operation conditions, income creation structures of 240 mountain eco-villages formed by Korea Forest Service, and reviewed systems for social economic support. As summarized in research outputs, this study confirmed that the activities of organizations for joint projects had not been properly implemented due to the absence of supporting systems following the construction of mountain eco-villages. In addition, 159 villages formed as experience villages could not be qualified for enterprise systems due to aging population and absence of network systems. As for income creation, as indicated by comparing net incomes for joint projects calculated based on the classification of village management evaluation, the average net income of 51 highly-rated villages was 22 million Won and that of 128 moderately-rated villages was 3.5 million Won. Experience-based projects and the sales of processed forestry products made by young adult associations or women's societies were major sources of income, and the absence of inner economic bases or villages' jobs caused young adults and returned farmers to focus on working for outside economic activities. Finally, this study developed strategies for mountain eco-village's social economic promotion and suggested four stages of social economic revitalization provisions.

• 대한조선학회논문집
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• 제54권1호
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• pp.1-9
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• 2017

LNG has significant advantages in regard to environmental aspects comparing with conventional fuel oil. In fact, it is estimated that NOx and SOx emission can be reduced by about 90% and 100%, respectively in case of using LNG as a fuel. LNG-fuelled ship has been considered to be the best option both from an environmental and an economic point of view. Along with these trends, some major shipyards and Classification Societies have started to carry out the risk-based system design for LNG-fuelled ship such as passenger ship, platform supply vessel and large container vessel etc. However, new conceptual gas fuelled ship has high risk level compared with vessel using traditional crude oil especially in view of gas explosion accident. Therefore safety area where installed fuel gas supply system is required risk based system design with special considerations. On this paper, the entire process necessary for the quantitative risk analysis was explained to meet the satisfactory safety level of gas fuelled ship.

• Structural Engineering and Mechanics
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• 제50권6호
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• pp.835-852
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• 2014

Despite the availability of other transport methods such as land and air transportations, marine transportation is the most preferred and widely used transportation method in the world because of its economical advantages. In service, ships experience cyclic loading. Hence, it can be said that fatigue fracture, which occurs due to cyclic loading, is one of the most critical failure modes for vessels. Accordingly, this makes fatigue failure prevention an important design requirement in naval architecture. In general, a ship structure contains many structural components. Because of this, structural modeling typically relies on Finite Element Analysis (FEA) techniques. It is possible to increase fatigue performance of the ship structures by using FEA in computer aided engineering environment. Even if literature papers as well as rules of classification societies are available to assess effect of fatigue cracks onto the whole ship structure, analytical studies are relatively scarce because of the difficulties of modeling the whole structure and obtaining reliable fatigue life predictions. As a consequence, the objective of this study is to improve fatigue strength of a mercantile vessel against fatigue loads via analytical method. For this purpose, the fatigue life of the mercantile vessel has been investigated. Two different type of fatigue assessment models, namely Coffin-Manson and Morrow Mean stress approaches, were used and the results were compared. In order to accurately determine the fatigue life of the ship, a nonlinear finite element analysis was conducted considering plastic deformations and residual stresses. The results of this study will provide the designer with some guidelines in designing mercantile vessels.

• 대한조선학회논문집
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• 제30권4호
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• pp.112-126
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• 1993

본 논문에서는 선급규칙중 파랑하중 부분의 개정과 관련하여 선체종강도의 국제선급연합 통일규칙(IACS UR)을 검증하기 위하여 단기파랑하에서 비선형 파랑하중 해석을 수행하였고, 선체구조의 직접강도해석시에 사용하여야 할 지침으로 IACS WAVE DATA에 대한 검증을 수행하였다. 컨테이너선등과 같은 대형개구를 가진 선박의 응력을 구하기 위하여 수평전단력, 수평굽힘모멘트 및 비틂모멘트 산식을 일관성 있게 구하여 새로이 제시하였다. 또한 선체 외관에 작용하는 유체동압력을 선박의 길이 및 깊이방향에 대한 분포 산식으로 제시하였고 이를 타 선급 규칙과 비교, 검토하였다. 이상의 제시된 산식들은 각 선종, 크기 별로 17척 선박의 실선계산을 통하여 결정되었다. 이 산식들은 앞으로 선체구조부재 Scantling 산식이 결정되면 실선에 대한 적용계산을 통하여 검증될 것이다.

• 대한조선학회논문집
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• 제47권4호
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• pp.598-605
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• 2010

The structural design of oil tankers and bulk carriers should be performed based on the Common Structural Rules(CSR) which were recently established by the International Association Classification Societies(IACS). At first, in the structural design viewpoint, the scantling and hullweight based on the CSR should be compared with those of existing rules, and then a minimum weight/cost design should be performed by considering the variation of the number of web and the material property. In this study, the optimum web space and material property will be proposed by performing a minimum weight/cost design of a large oil tanker, and the results will be compared with those of existing ship. The longitudinal members are determined by SeaTrust-Holdan developed by the Korean Register of Shipping(KR), and the transverse members are determined by NASTRAN and PULS.

• 대한조선학회논문집
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• 제54권5호
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• pp.393-405
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• 2017

This paper deals with the buckling strength of the skirt structure in the spherical LNG carriers. The spherical cargo tank systems consist of spherical tank, skirt, tank cover, pump tower, etc. The skirt supports the spherical cargo tank and is connected with ship hull structure. It is designed to act as a thermal brake between the tank and the hull structure by reducing the thermal conduction from the tank to the supporting structure. It is built up of three parts, upper aluminum part, middle stainless steel part and lower carbon steel part. The 150K spherical LNG carrier was designed and carried out the strength verification under Classification Societies Rule. The design loads due to acceleration, thermal distribution, self-weight and cargo weight were estimated considering requirements of the Class Rule and numerical simulation analyses. Based on the obtained design loads and experienced project data, the initial structure scantling was carried out. To verify the structural integrity, theoretical and numerical analyses were carried out and strength was evaluated aspect of buckling capacity. The results by LR and DNV design code are shown and discussed.

• 수산해양교육연구
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• 제28권3호
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• pp.645-652
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• 2016

At the initial stage of propulsion shaft design, in line with shaft alignment, an intensified consideration of lateral vibration is needed to verify its operational safety. Recently the alignment problem affecting the lateral vibration has been becoming issues. However, the theoretical method of forced lateral vibration analysis is not cleary established so far and it is about to simply limited among the classification societies and international standards to avoid the blade natural frequency resonance cpm outside of ${\pm}20%$ of engine rpm at MCR. On the other hand, longer center distance between each support bearing shows an affirmative result normally in shaft alignment analysis whereas the blade order resonance speed may cause lowering near the limitation in the aspect of lateral vibration. Therefore, it is required careful attention to engineers as described above. As a method to solve the problem, it is mainly considered that remove forward stern tube bearing. In this paper, based on a medium size container ship case, theoretical study was carried out in the context of the forward stern tube bearing. The various effects and functions of forward stern tube bearing are reviewed and evaluated. Then an guidance note to lead the conclusion is proposed.

• 한국실내디자인학회논문집
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• 제20권4호
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• pp.201-210
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• 2011

This study is on the space planning of accommodation area in accommodation barge, which is a kind of offshore plant supply vessel providing workers with exclusive accommodation facilities. Firstly, the space layout of accommodation area is analyzed using the general arrangement drawings of 10 actually-built accommodation barges currently in use. Secondary, the design guides and standards for living quarters of offshore plants issued from overseas classification societies such as ABS, NORSOK etc. are analyzed and based on the analysis design guidelines for accommodation area of accommodation barge are newly suggested. Thirdly, a model of accommodation area in accommodation barge is set up and space arrangements and movement lines for each deck of the accommodation area of the model are planned. Fourthly, cabins, dinning room and galley, recreation spaces, and sanitary spaces of the accommodation area of the model are planned. The results of this study may be summarized as follows. An accommodation barge has 'barge deck' for small scale work and material storage, and 'accommodation area' for the living and resting of workers. The accommodation area is made of workers accommodation sector, service sector, crew sector and business sector. The interior design guidelines for accommodation area of accommodation barge should be made soon by Korea Register of Shipping.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.331-337
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• 1999

Cracks on the cylinder block of diesel engines will often happen due to cyclic load and thermal stress. According to the Classification Societies' rules welding reparis of cylinder block made of cast irons are generally not permitted. However such welding repairs became inevitable taking enormous cost and time for their renewal into consideration. In this study repair welding methods for the clinder blocks made of gray cast irons were reviewed and the tests of their welds were carried out in order to purpose the repair welding meth-ods of packing seat and o-ring seat of cylinder block and apply them to the practice. The following conclusions are botained :1 The tensile strength of weld of cast iron more than that of base metal can be obtained by means of preheating keeping temperature above $100^{\circ}C$ between welding pass-es preventing slag inclusion peening and cramping weld metal by studs. 2. The suspected crack by a magnetic particle test due to different magnetic permeability can be identified which are not associated with a mechanical discotinuity.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.1096-1110
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• 2014

Whipping/springing research started in the 50'ies. In the 60'ies inland water vessels design rules became stricter due to whipping/springing. The research during the 70-90'ies may be regarded as academic. In 2000 a large ore carrier was strengthened due to severe cracking from North Atlantic operation, and whipping/springing contributed to half of the fatigue damage. Measurement campaigns on blunt and slender vessels were initiated. A few blunt ships were designed to account for whipping/springing. Based on the measurements, the focus shifted from fatigue to extreme loading. In 2005 model tests of a 4,400 TEU container vessel included extreme whipping scenarios. In 2007 the 4400 TEU vessel MSC Napoli broke in two under similar conditions. In 2009 model tests of an 8,600 TEU container vessel container vessel included extreme whipping scenarios. In 2013 the 8,100 TEU vessel MOL COMFORT broke in two under similar conditions. Several classification societies have published voluntary guidelines, which have been used to include whipping/springing in the design of several container vessels. This paper covers results from model tests and full scale measurements used as background for the DNV Legacy guideline. Uncertainties are discussed and recommendations are given in order to obtain useful data. Whipping/springing is no longer academic.