• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2859-2874
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• 2024

This paper presents the finite element deformation and failure simulation of a typical Korean high-power reactor vessel under a severe accident characterized by large break loss of coolant (LBLOCA) with in-vessel retention of molten corium through external reactor vessel cooling (IVR-ERVC) conditions. Temperature distributions calculated using Modular Accident Analysis Program Version 5 (MAAP5) as thermal boundary conditions were used, and ABAQUS thermal and structural analyses were performed. After full ablation, the temperature of the inner surface in the thinnest section remained high (920 ℃), but the stress remained relatively low (less than 6 MPa). At the outer surface, the stress was as high as 250 MPa; however, the resulting plastic strain was small owing to the low temperature of 200 ℃. Variations in stress, inelastic strain, and temperature with time in the thinnest section suggest that the plastic and creep strains are saturated owing to stress relaxation, resulting in low cumulative damage. Thus, the lower head of the vessel can maintain its structural integrity under LBLOCA with IVR-ERVC conditions. The sensitivity analysis of internal pressure indicates the occurrence of failure in the thinnest section at an internal pressure >9.6 MPa via local necking followed by failure due to high stresses.

• 한국생산제조학회지
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• 제22권1호
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• pp.50-55
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• 2013

In order to understand the biomaterial like the blood vessel of artery, there is a need to quantify the biomechanical behavior of the vessel. However, theoretical framework to describe and quantify the behaviour of blood vessel was not well established so far. For studying the biomechanical behavior of artery, Rubber-liked material which is similar to passive artery is selected since conventional theoretical interpretation is very limited to understand and predict the behavior of biomaterial. Rubber-like material is assumed to be very similar to artery and has properties of isotropy, homogeneity and is undergoing large deformation. Based on this assumption, stress developed on Rubber-like material is described by strain energy function and strain invariants which are required to understand the nonlinear elastic behavior of biomaterial. The descriptor which would be used for understanding the biomechanical behavior of artery is studied in this work.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1995년도 춘계학술발표회 논문집
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• pp.59-64
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• 1995

The impediment in enhancing the ship safety and combating vessel-source marine pollution depends on the combination of the immediate and mediate factors. The former is mainly caused by human errors and failure in compliance with the international convention standards in operation of compliance with the international convention standards in operation of vessel. The latter by the attitudes and activities of some of the flay states taking little responsibilities with appropriate seriousness in policing their fleets due to the lack of implementing capability of adminstrations. So long as there exists a large size of variation in implementing capability of administration between flag states a globally remarked progress cannot expect to be made in assuring the ship safety and preventing the vessel-source pollution Therefore a new regulatory regime is suggested to be adopted by IMO to maintain high standard flag state adminstrations by recommending standard paradigm to member states so that the development of a implementing culture is encouraged and supported.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2003년도 추계학술발표회
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• pp.127-133
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• 2003

In this study, the impact analysis for the steel fender system that designed for protection of collision between vessel and bridge was performed The size of objective collision vessel assumed as 3000 dead weight tonnage(DWT). The impact forces and the impact energies were estimated by formulas of several design codes, and the steel fender system was designed based on the estimated forces and energy. The bow of objective vessel was modeled as rigid body, and bridge substructure was modeled as fixed support. Since, the impact analysis have the dynamic nonlinear features, such as, material nonlinear, large deformation and contact, explicit structural analysis program was used The analysis results presented that the impact forces formulas in codes have the sufficient conservativeness.

• 한국진공학회지
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• 제8권4A호
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• pp.391-396
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• 1999

KSTAR vacuum vessel mockup was fabricated by Korea Heavy Industries. The fabrication technology chosen for the mockup is introduced and assessed in this paper. KSTAR vacuum vessel is a huge vacuum chamber of 52 cubic meters never built in this country. Through the experiency of the KSTAR mockup fabrication, welding methods for obtaining both ultra high vacuum and structural integrity of the large vacuum chamber are extracted. The fabrication and assembly techniques for the complicated structure composed of reinforced ribs, double walls and various ports are also developed. A nondestructive test on the welding spot was performed and the results show that no major leaks violating the criterion were found. The one of the main objectives of the mockup fabrication is to measure the dimensions of the structure before and after fabrication, which plays an important role in the fabrication and the assembly. By assaying the problems occurred during mockup fabrication, the KSTAR mockup will provide the techniques for the fabrication of the main vacuum vessel.

• 대한조선학회논문집
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• 제41권1호
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• pp.64-69
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• 2004

In recent years, Medium size high speed Ro-Pax vessel has appeared at European sea and especially Agean sea is a center of operating in this type of Ro-Pax. This vessel operates its high Froude number range and requires higher engine power due to considerably increased resistance in comparing to large Ro-Pax in high speed range. SHI has investigated this kind of high speed Ro-Pax in accordance with market requirements and developed more advanced vessel to meet the future market needs. Process of hull form development, model test results and design of general arrangement results are introduced in this paper.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.71-78
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• 2003

In this study, the impact analysis for the steel fender system that designed for protection of collision between vessel and bridge was peformed. The size of objective collision vessel assumed as 3000 dead weight tonnage(DWT). The impact forces and the impact energies were estimated by formulas of several design codes, and the steel fender system was designed based on the estimated forces and energy. The bow of objective vessel was modeled as rigid body, and bridge substructure was modeled as fixed support. Since, the impact analysis have the dynamic nonlinear features, such as, material nonlinear, large deformation and contact, explicit structural analysis program was used. The analysis results presented that the impact forces formulas in codes have the sufficient conservativeness.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2013년도 춘계학술대회
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• pp.354-356
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• 2013

우리나라 항만의 최근 5년간 항만별 입출항척수, 대형선박 통항 비율, 위험화물 운반선 통항 비율 및 해양사고 발생 현황을 통하여 항만별 해상교통 위험도를 식별하였다. 이와 함께 해상교통관제 구역에 대하여 기초 조사를 실시하여 현재 VTS센터에 설정된 관제구역 수가 이러한 해상교통 위험도 인자들과 비교하여 적정하게 설정되어 있는지를 검토하였다.

• 해양환경안전학회지
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• 제23권7호
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• pp.810-819
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• 2017

현행 방제선 배치 항만의 합리적인 방안을 모색하고자 국내 주요 항만을 대상으로 이용실태와 위험요인의 분포현황을 조사하여 각 항만별 위험도를 평가하고 위험도 산정 값을 기준으로 전체 항만을 4단계의 위험군으로 분류하여 방제선 배치 항만의 현실화를 추구하였다. 그 결과 항만의 위험도는 대규모 석유화학 산업시설이 위치하고 있는 여수 광양항(1.85), 울산항(1.33), 대산항(1.25)이 특히 높게 나타나고, 선박 통항량이 많은 부산항(0.95), 인천항(0.83)과 최근 항만시설의 확충으로 대형선 통항량이 증가한 목포항(0.71)과 제주항(0.49), 주변에 어업권 허가건수가 많은 마산항(0.44) 순서로 나타났다. 또한, 위험도 값이 가장 높게 나타난 여수 광양항을 기준으로 각 항만의 상대적 비율을 등급화하여 위험군을 4단계로 구분했을 때 최고위험군은 여수 광양항, 울산항, 대산항, 부산항이고, 고위험군은 인천항, 목포항, 제주항, 마산항이며, 중위험군은 평택 당진항, 포항항, 군산항, 동해 묵호항, 저위험군은 삼천포항, 옥계항, 장승포항으로 분류되었다. 이 중 현행 법률상 방제선 배치항만은 모두 중위험군 이상의 항만이며 중위험군으로 새롭게 평가되는 목포항, 제주항, 동해 묵호항은 제외되어 있다. 따라서 이들 3개 항만을 방제선 배치항만으로 새롭게 지정하여 기름오염사고에 대비할 필요가 있다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권2호
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• pp.442-458
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• 2014

Wave induced vibrations increase the fatigue and extreme loading, but this is normally neglected in design. The industry view on this is changing. Wave induced vibrations are often divided into springing and whipping, and their relative contribution to fatigue and extreme loading varies depending on ship design. When it comes to displacement vessels, the contribution from whipping on fatigue and extreme loading is particularly high for certain container vessels. A large modern design container vessel with high bow flare angle and high service speed has been considered. The container vessel was equipped with a hull monitoring system from a recognized supplier of HMON systems. The vessel has been operating between Asia and Europe for a few years and valuable data has been collected. Also model tests have been carried out of this vessel to investigate fatigue and extreme loading, but model tests are often limited to head seas. For the full scale measurements, the correlation between stress data and wind data has been investigated. The wave and vibration damage are shown versus heading and Beaufort strength to indicate general trends. The wind data has also been compared to North Atlantic design environment. Even though it has been shown that the encountered wind data has been much less severe than in North Atlantic, the extreme loading defined by IACS URS11 is significantly exceeded when whipping is included. If whipping may contribute to collapse, then proper seamanship may be useful in order to limit the extreme loading. The vibration damage is also observed to be high from head to beam seas, and even present in stern seas, but fatigue damage in general is low on this East Asia to Europe trade.