http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
고한옥,정명조,최재붕 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.1
About 40% of reactors in the world are being operated beyond design life or are approaching the end of their life cycle. During long-term operation, various degradation mechanisms occur. Fatigue caused by alternating operational stresses interms of temperature or pressure change is an important damage mechanism in continued operation of nuclear power plants. To monitor the fatigue damage of components, Fatigue Monitoring System (FMS) has been installed. Most FMSs have usedGreen's Function Approach (GFA) to calculate the thermal stresses rapidly. However, if temperature-dependent materialproperties are used in a detailed FEM, there is a maximum peak stress discrepancy between a conventional GFA and a detailedFEM because constant material properties are used in a conventional method. Therefore, if a conventional method is used inthe fatigue evaluation, thermal stresses for various operating cycles may be calculated incorrectly and it may lead to anunreliable estimation. So, in this paper, the modified GFA which can consider temperature-dependent material properties isproposed by using an artificial neural network and weight factor. To verify the proposed method, thermal stresses by the newmethod are compared with those by FEM. Finally, pros and cons of the new method as well as technical findings from theassessment are discussed
CANDU 원전 주요기기에 대한 웹기반 경년열화 평가 시스템 개발
고한옥(Han-Ok Ko),장윤석(Yoon-Suk Chang),최재붕(Jae-Boong Choi),김영진(Young-Jin Kim),최영환(Young-Hwan Choi) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
A couple of years ago, in Korea, Periodic Safety Review (PSR) was adopted in order to assure the continued safe operation of nuclear power plants. The PSR considering various aging effects is being performed every ten-years in general and, for this, complicated procedures are required such as inspection, structure analysis, failure assessment and combination of them. A Web-based Regulatory Aging Assessment Program (CANDU-RAAP) is proposed in this paper, which manages key operating data efficiently and assists effective evaluation of major components consisting CANDU type nuclear power plant. By using the proposed program, experts in different fields can co-operate to resolve industrial issues and all users can share informations and create valuable knowledge-base.
고한옥(Han-Ok Ko),장윤석(Yoon-Suk Chang),최재붕(Jae-Boong Choi),김영진(Young-Jin Kim),송무섭(Moo-Seop Song) 한국자동차공학회 2005 한국자동차공학회 Symposium Vol.- No.-
During the last couple of decades, several mesh-less methods have been proposed as alternatives of conventional finite element method that is a well-known useful tool for engineering evaluation but requires considerable time and efforts to generate complex mesh. The objectives of this paper are to introduce a particle method, initially developed for non-compressible fluid analyses, and to examine expandability for structural analyses. As prototypes of application, simple cantilever beams under different loading conditions were selected and dynamic as well as static analyses were carried out. Thereby, it was proven that the proposed mesh-less method could be applicable to simulate structural behaviors within 10% difference comparing to the corresponding reference solutions.
고한옥(Han-Ok Ko),장윤석(Yoon-Suk Chang),최재붕(Jae-Boong Choi),김영진(Young-Jin Kim),송무섭(Moo-Seop Song) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
During the last couple of decades, several mesh-less methods have been proposed as alternatives of conventional finite element method that is a well-known useful tool for engineering evaluation but requires considerable time and efforts to generate complex mesh. The objectives of this paper are to introduce a particle method, initially developed for non-compressible fluid analyses, and to examine expandability for structural analyses. As prototypes of application, simple cantilever beams under different loading conditions were selected and dynamic as well as static analyses were carried out. Thereby, it was proven that the proposed mesh-less method could be applicable to simulate structural behaviors within 10% difference comparing to the corresponding reference solutions.
최대가능성방법을 이용한 압력용기강 재료의 벽개파손확률 분석
고한옥(Han-Ok Ko),장윤석(Yoon-Suk Chang),최재붕(Jae-Boong Choi),김영진(Young-Jin Kim),김민철(Min-Chul Kim),이봉상(Bong-Sang Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.3
In ductile-brittle transition temperature(DBTT) region of low alloyed steels, two fracture mechanisms are in competition ductile fracture characteristic for high temperatures and transgranular cleavage characteristic for low temperature. Also, scatters of fracture toughness data and transferability problems among different configurations were pointed out as obstacles for application of PCVN(pre-cracked V-notch) specimens despite their efficiency. In this paper a procedure for the determination of the Weibull parameters m and σ<SUB>u</SUB> is developed. This procedure consists of two parts. The first part is the determination of the plastic zone ahead of the crack tip based on the finite element analysis. And the second part is the estimation of the parameters m and σ<SUB>u</SUB> using the maximum likelihood method. The paper concludes with calibrations of both m and σ<SUB>u</SUB> over the DBT region using maximum likelihood method and the fracture toughness data sets for an SA508 pressure vessel steel.