http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
장윤석,석창성,김영진,Chang, Yoon-Suk,Seok, Chang-Sung,Kim, Young-Jin 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.11
In order to perform leak-before-break design of nuclear piping systems and integrity evaluation of reactor vessels, full stress-strain curves and fracture resistance (J-R) curves are required. However it is time-consuming and expensive to obtain J-R curves experimentally. The objective of this paper is to modify two J-R curve prediction methods previously proposed by the authors and to propose an additional J-R curve prediction method for nuclear piping materials. In the first method which is based on the elastic-plastic finite element analysis, a blunting region handling procedure is added to the existing method. In the second method which is based on the empirical equation, a revised general equation is proposed to apply to both carbon steel and stainless steel. Finally, in the third method, both full stress-strain curve and finite element analysis results are used for J-R curve prediction. A good agreement between the predicted results based on the proposed methods and the experimental ones is obtained.
관통균열 세관의 파열압력 예측을 위한 탄소성 파괴역학 해석
장윤석,문성인,김영진,황성식,김정수,김윤재,Chang Yoon-Suk,Moon Seong-In,Kim Young-Jin,Hwang Seong-Sik,Kim Joung-Soo,Kim Yun-Jae 대한기계학회 2005 大韓機械學會論文集A Vol.29 No.10
The structural and leakage integrity of steam generator tubes should be sustained all postulated loads with appropriate margin even if a crack is present. During the past three decades, for effective integrity evaluation, several limit load solutions have been used world-widely. However, to predict accurately load carrying capacities of specific components under different conditions, the solutions have to be modified by using lots of experimental data. The purpose of this paper is to propose a new burst pressure estimation scheme based on fracture mechanics analyses for steam generator tube with an axial or circumferential through-wall crack. A series of three dimensional elastic-plastic finite element analyses were carried out and, then, closed-form estimation equations with respect to both J-integral and crack opening displacement were derived through reference stress method. The developed engineering equations were utilized for structural integrity evaluation and the resulting data were compared to the corresponding ones fiom experiments as well as limit load solutions. Thereafter, since the effectiveness was proven by promising results, it is believed that the proposed estimation scheme can be used as an efficient tool for integrity evaluation of cracked steam generator tubes.
조우민(Woo-Min Cho),장윤석(Yoon-Suk Chang) 대한기계학회 2022 大韓機械學會論文集A Vol.46 No.3
사용후핵연료 임시 저장시설인 사일로는 콘크리트, 철근 및 라이너로 구성되어 구조적 강도 및 방사선 차폐기능을 수행한다. 예기치 못한 사고 상황에서 독성 물질 누출 방지를 위해 각 부품의 건전성은 유지되어야 한다. 본 연구는 수치해석 기법을 활용하여 폭발하중이 가해지는 연료저장 사일로의 동적 파괴거동을 분석하고 적절한 파손기준을 제시하는 것이다. 재료의 비선형성과 변형률 속도 효과를 고려하여 연료저장 사일로의 손상, 변형률과 회전각도를 조사하였다. 폭발조건 및 콘크리트 압축강도를 변화시켜 해석을 수행하였고 파손기준과 해석 결과를 비교하였다. 모든 경우에서 철근과 라이너는 파손되지 않았으나 콘크리트는 일부의 경우 파손되었다. 콘크리트의 외부 하중에 대한 일차 방호 기능 및 해석 결과의 보수성을 고려하여 해당 파손기준을 사일로 평가를 위한 기준으로 제시하였다. Fuel storage silo, which is an interim dry storage facility of spent nuclear fuel, provides structural strength and radiation shielding. In this study, a numerical analysis was used to analyze the dynamic failure behavior of a fuel storage silo under blast loads and to present appropriate failure criteria. Damage, strain, and support rotation of the fuel storage silo were investigated considering the non-linearity and strain effect of the materials. The explosive condition and concrete strength were changed. The analyses results were compared with the failure criteria of each component. In all cases, reinforcement and liner were not damaged, but the concrete wall exceeded the failure criteria at several analyses. Considering the conservative characteristics of nuclear facilities and the importance of concrete to protect spent nuclear fuel while serving as a primary barrier from external loadings, concrete failure criteria was presented as criteria for silo evaluation.
Churg - Strauss 증후군과 특발성 호산구 증다 증후군은 동일한 질환군에 속하는가?: 두 가지 임상양상을 동시에 보인 증례를 통한 고찰
장윤석(Yoon Suk Chang),손지웅(Jee Wong Son),이상록(Sang Rock Lee),박재경(Jae Kyung Park),조상헌(Sang Heon Cho),민경업(Kyung Up Min),김유영(You Young Kim) 대한천식알레르기학회 1999 천식 및 알레르기 Vol.19 No.2
Sometimes, it is difficult to distinguish Churg-Strauss syndrome from idiopathic hypereosino- philic syndrome and there may be overlap syndrome in the differential diagnosis of systemic vasculitis with hypereosinophilia. Recently, we experienced a 42-year-old female patient who presented signs and symptoms of cardiac failure and neuropathy with peripheral hypereosinophilia. She had no history of asthma. She had erythematous skin lesions and distal digit necrosis. The cause of hypereosinophilia could not be identified. Skin and nerve biopsy revealed vasculitis with eosinophilic infiltration. Cardiac failure improved dramatically with steroid, inotropics and diuretics. Other symptoms including digital necrosis also improved. During steroid, tapering peripheral eosinophilia recurred. For maintenance therapy, we added daily cyclophosphamide to every-other-day prednisolone therapy. We report the case with a review of the literature.
장윤석(Yoon-Suk Chang),이상민(Sang-Min Lee),최재붕(Jae-Boong Choi),김영진(Young-Jin Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
The integrity of nuclear piping systems has to be maintained sufficiently all the times during operation. In order to maintain the integrity, reliable assessment procedures including fracture mechanics analysis, etc, are required. Up to now, the integrity assessment has been performed using conventional deterministic approach even though there are lots of uncertainties to hinder a rational evaluation. In this respect, probabilistic approach is considered as an appropriate method for piping system evaluation. The objectives of this paper are to develop a probabilistic assessment program using reliability index and simulation technique and to estimate the failure probability of wall-thinned pipes in secondary systems. The probabilistic assessment program consists of three evaluation modules which are first order reliability method, second order reliability method and Monte Carlo simulation method. The developed program has been applied to evaluate failure probabilities of wall-thinned pipes subjected to internal pressure, global bending moment and combined loading. The sensitivity analysis results as well as prototypal evaluation results showed a promising applicability of the probabilistic integrity assessment program.
장윤석(Yoon-Suk Chang),윤강옥(Kang-Ok Yun),박영재(Young-Jae Park),김영진(Young-Jin Kim) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.8
The deterministic evaluation methods could not predict exactly the real material behaviors due to the uncertainties. Recently, worldwide researches for economic operation and safe maintenance of nuclear power plant are being carried out based on risk and failure probability. However, unfortunately, few efficient tools to predict the failure probability of wall-thinned piping have been developed from the researches at this time. So, to settle the wall-thinned piping problem, it is necessary to develop the enhanced deterministic evaluation method and to put the probabilistic evaluation method on a firm footing based on the deterministic one. This paper describes enhanced deterministic evaluation method based on a series of finite element analyses, and development of the probabilistic evaluation program based on FORM and Monte Carlo simulation, and calculate failure probability of wall-thinned piping.