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

• 한국항해항만학회지
• /
• 제37권6호
• /
• pp.567-574
• /
• 2013

Although Korea coastal area has the increasing potential marine accident due to frequent ship's encounter, increased vessel traffic and large vessel, there is no specific model to evaluate the navigating vessel's risk considering the domestic traffic situation. The maritime transport environmental assessment is necessary due to the amended maritime traffic law. However, marine safety diagnosis is now carried out by foreign model. In this paper, therefore, we suggest a domestic traffic model reflecting the characteristics of korea coastal area and navigator's risk as we named PARK(Potential Assessment of Risk) model. We can evaluate the subjective risk by establishing the model and model output into maritime risk exposure system. To evaluate this model's effectiveness, we used ship handling simulation and applied, analyzed collision accident which occurred in korea coastal area. And also, we applied integrated to an ECDIS program for monitoring traffic risk of vessels with real time based AIS data and apply to evaluate traffic risk in busan harbor waterway. As a result, we could evaluate busan harbor waterway risk effectively.

• 한국항해항만학회지
• /
• 제28권8호
• /
• pp.709-714
• /
• 2004

본 연구는 최근 물동량이 빠른 속도로 증가하고 있는 대련항, 천진항, 청도항, 상해항 등을 화물의 목적항으로 설정하고, 선박의 운항패턴 시나리오를 바탕으로 부산항에서 환적하는 경우와 중국항 직기항 등의 총운송비용 차이를 분석하였다. 이를 바탕으로 하여 부산항에서 환적할 때 직기항하는 경우보다 초과 발생하는 비용을 항만 당국이 선사에게 보전해 주는 인센티브 규모로 하고, 이를 충당할 수 있는 전대사용료 산정 방법을 제시하였다.

• 대한조선학회논문집
• /
• 제60권2호
• /
• pp.86-94
• /
• 2023

Tonnage taxation has contributed to developing the Korean maritime industry through tax relief for shipping companies. The current tonnage taxation relies on the net tonnage as an earning-capacity indicator in a merchant ship. Although the tonnage tax accords with horizontal equity, it does not match vertical equity because of the different taxable capacities of an individual company. Nowadays, maritime transport uses a dedicated vessel, and each shipping freight embeds a different value of time. It means the tonnage taxation regime should consider the added value of each shipping freight. Meanwhile, as the environmental regulations led by the International Maritime Organization are being strengthened, the Korean merchant fleet must be eco-friendly soon after. This study explores the alternative to renewing tonnage taxation by utilizing the Greenship certification and considering the ability-to-pay principle. Because the Greenship certification scheme encourages shipping decarbonization, maritime transport by a certified ocean-going vessel comes to be treated as an activity for the green economy. Special taxation for the green economy may contribute to shipping sustainability and market competitiveness.

• 방사성폐기물학회지
• /
• 제21권4호
• /
• pp.439-450
• /
• 2023

In this study, the impact load resulting from collision with the fuel rods of surrogate spent nuclear fuel (SNF) assemblies was measured during a rolling test based on an analysis of the data from surrogate SNF-loaded sea transportation tests. Unfortunately, during the sea transportation tests, excessive rolling motion occurred on the ship during the test, causing the assemblies to slip and collide with the canister. Hence, we designed and conducted a separate test to simulate rolling in sea transportation to determine whether such impact loads can occur under normal conditions of SNF transport, with the test conditions for the fuel assembly to slide within the basket experimentally determined. Rolling tests were conducted while varying the rolling angle and frequency to determine the angles and frequencies at which the assemblies experienced slippage. The test results show that slippage of SNF assemblies can occur at angles of approximately 14° or greater because of rolling motion, which can generate impact loads. However, this result exceeds the conditions under which a vessel can depart for coastal navigation, thus deviating from the normal conditions required for SNF transport. Consequently, it is not necessary to consider such loads when evaluating the integrity of SNFs under normal transportation conditions.

• Journal of Radiation Protection and Research
• /
• 제32권4호
• /
• pp.158-167
• /
• 2007

본 논문의 목적은 노외 중성자 선량 감시자를 이용하여 원자로 압력용기 중성자 조사취화의 핵심 요인이 되는 고속중성자 ($1{\ge}MeV$) 조사량 평가 방법을 제시하고 적용성을 검증하는 것이다. 다양한 중성자 반응에너지를 갖는 다수의 선량감시자를 원자로 외벽 보온 단열재와 1차 생물학적 차폐체 사이의 공간에 설치하고 한 주기 동안 조사시킨 후 인출하여 생성핵종에 대한 방사선을 측정하여 반응률을 도출하였다. 또한 상업용 코드를 이용한 중성자 수송계산을 통해 감시자 위치에서의 중성자 스펙트럼을 계산하였다. 두 결과로부터 감시자에 대한 반응률을 직접 비교할 수 있었으며 또한 최소자승 조정 절차를 통해 최적의 중성자 스펙트럼도 도출할 수 있었다. 감시자 측정 결과와 해석적으로 계산한 중성자 조사량 사이에는 관련 규정에서 제시한 ${\pm}30%$ 이내의 오차를 보였다.

• 한국수소및신에너지학회논문집
• /
• 제13권2호
• /
• pp.110-118
• /
• 2002

The hydrogen storage vessel having a good heat conductivity along with a simple structure and a low cost for these alloys was designed and manufactured, and then its characteristic properties were studied in this study. The various parts in hydrogen storage vessel consisted of copper pipes and stainless steel of 250 mesh reached the setting temperature after 4~5 minutes, which indicated that storage vessel had a good heat conductivity that was required in application. And also the storage vessel had a good property of hydrogen transport considering that the reaction time between hydrogen and rare-earth metal alloys in storage vessel was found to be within 10 min at $18^{\circ}C$ under 10 atmospheric pressure. It showed that the average capacity of discharged hydrogen volume was found to be $120{\ell}$ for $MmNi_{4.5}Mn_{0.5}$ under discharging conditions of $40^{\circ}C{\sim}80^{\circ}C$ at a constant flow rate of $5{\ell}$/min. It was found that the optimum discharging temperature for obtaining an appropriate pressure of 3atm was determined to be $60^{\circ}C$ for $MmNi_{4.5}Mn_{0.5}$ hydrogen storage alloy.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
• /
• pp.269-274
• /
• 2006

최근 파나마 운하 확장이 국민투표로 결정됨에 따라 2014년부터는 12,000TEU급의 선박의 통행이 가능해진다. 파나마운하의 규모적 한계 때문에 포스트 파나막스급이상의 선박들은 파나마 운하대신 아메리칸 랜드브릿지 및 다른 운송루트를 이용해야 했다. 그러나 파나마 운하확장이 확정됨에 따라 향후 극동-북미 간 운송루트의 변화가 불가피할 것으로 예상된다. 따라서 본 연구는 극동-북미 간을 운행하는 선박의 규모별 루트별 총운송비용을 분석하여 두 구간의 경쟁력을 검토한다.

• 한국항해항만학회지
• /
• 제31권1호
• /
• pp.81-87
• /
• 2007

최근 파나마 운하 확장이 국민투표로 결정됨에 따라 2014년부터는 12,000TEU급의 선박의 통행이 가능해진다. 파나마운하의 규모적 한계 때문에 포스트 파나막스급이상의 선박들은 파나마 운하대신 아메리칸 랜드브릿지 및 다른 운송루트를 이용해야 했다. 그러나 파나마 운하 확장이 확정됨에 따라 향후 극동-북미 간 운송루트의 변화가 불가피할 것으로 예상된다. 따라서 본 연구는 극동-북미 간을 운행하는 선박의 규모별 루트별 총운송비용을 분석하여 두 구간의 경쟁력을 검토한다.

• 수산해양기술연구
• /
• 제52권4호
• /
• pp.364-371
• /
• 2016

The analysis on the international safety management code (ISM Code) and case of foreign national safety management for fishing vessel was conducted to serve as a basic data on the introduction of safety management system (SMS) for a deep-sea fishing vessel in Korea. As a result, Maritime New Zealand (MNZ) has managed operations of SMS in the maritime rules according to the Maritime Transport Act since 1994. MNZ underwent a safe ship management (SSM), which includes elements applied to shipping companies, ship and verification of the ISM Code for ships, except ISM Code application since 1998. In 2014 the introduction of the advanced maritime operator safety system (MOSS) superior to the SSM by MNZ was promoted actively switch and enforcement. Meanwhile, the safe operation manual of Japanese fishing vessel includes large part of the contents of the ISM Code, and voluntary implementation to fit the realities of the fishing vessel. The law application of SMS for a deep-sea fishing vessel after the newly establishment of the Ocean Industry Development Act to SMS would be advantageous to the schematic management, supervision, maintenance and application and, in 2016 from the implementation of maritime safety supervisor for a deep-sea fishing vessel that the management and supervision through the fishing vessel will be the efficient operation. The configuration of the safety management system in a deep-sea fishing vessel should be included as an element of ISM Code. The introduction of such a system is gradually applicable, such as nationality overseas vessel case study of the ISM Code, and vessels that are excluded from the application will be implemented as autonomous as Japan. The results are expected to contribute to sustainable development in the ocean industry safety culture spread throughout the ocean industry through the enhancement of safety fishing competency and safety management responsibility of fisher.