• Journal of Energy Engineering
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• v.29 no.3
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• pp.91-96
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• 2020

For the anchor bolts and brackets that fix the stone wall, which is an external finishing material, it is necessary to maintain the performance required for the mechanical structure from the initial design stage and secure high durability. For this, the design and safety evaluation in consideration of the load conditions are necessary, so the structural analysis applying the finite element analysis technique was performed as a method to verify durability. As a result of structural analysis for various shapes for optimal design, a reinforcing structure was added to alleviate the maximum stress generated at the rear part of the bracket in contact with the bolt. In addition, a reinforcing plate was additionally attached to the bracket to relieve the stress concentration of the L-shaped bracket to make the stress distribution uniform, so that the safety factor satisfies the standard conditions. In addition, the fatigue life analysis by cyclic load was performed, and the fatigue safety factor was analyzed. As a result, the durability was obtained.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.723-730
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• 2008

Due to the higher ratio of live load to total loads of railway bridges, the accumulated damage by cyclic fatigue is significant. Moreover, it is highly possible that the initiated crack grows faster than that of highway bridges. Therefore, it is strongly needed to assess the safety for the accumulated damage analytically. The initiation and growth of fatigue-crack are related with the stress range, number of cycles, and the stiffness of the structural system. The stiffness of the structural system includes uncertainties of the planning, design, construction and maintenance, which varies as time goes. In this study, the authors developed the design and risk assessment techniques based on the reliability theories considering the uncertainties in load and resistance. For the probabilistic risk assessment of crack growth and the remaining life of the structures by the cyclic load of railway and subway bridges, response surface method (RSM) combined with first order second moment method were used. For composing limit state function, the stress range, stress intensity factor and the remaining life were selected as input important random variables to the RSM program. The probabilities of failure and the reliability indices of fatigue life for the considered specimen under cyclic loads were evaluated and discussed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.283-289
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• 2011

As leisure boats become large-scaled and high value-added, their design requirements gradually get more complicated and accordingly their manufacturing processes get more complicated than those of existing ones. Leisure boat builders overseas make efforts to overcome this circumstance by establishing a 3-D model-based design system which is based on the concept of PLM. On the other hand, Korean shipbuilders still remain in the development process of traditional leisure boats which are mainly based on 2-D drawings. There have been some efforts made to have the 3-D model-based design system; however, they belong to a very early stage. This study carried out initial research to apply DMU technology to the development process of leisure boats. It established the design process based on a DMU model and proved its usefulness through a case study on the design of 40-ft class aluminum leisure boats.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1323-1327
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• 2006

일반적으로 화력발전소는 원활한 원료 및 냉각수의 공급과 환경적인 요인으로 인해 내륙보다는 해안에 위치하고 있다. 발전소의 안정성을 확보하기 위해서는 고열의 발전기를 냉각하는 냉각설비들이 반드시 필요하며 이를 위해 취수로를 통한 냉각수의 원활한 공급이 이루어져야 한다. 이러한 냉각수 공급은 대용량 펌프에 의해 이루어지며, 취수로 구조물의 형상 및 냉각수의 흐름조건에 따라 성능과 수명이 좌우된다. 특히 해안에 위치하는 지리적 여건상 직접취수가 많으며 이러한 경우 유사가 취수로에 유입되어 펌프 흡입 시 균열과 임펠러 마모 등을 유발시켜 펌프의 안전에 악영향을 미치게 된다. 따라서 취수로에 유사의 퇴적을 유도하는 침사지를 설계하게 되며 Hydraulic Institute Standards(1998)에서는 허용설계유속을 0.2 m/s 이하로 정하고 있다. B 발전소는 직경 3 m의 대형 취수관로 3개를 통해 매우 빠른 유속으로 취수로에 유입되는 냉각수 계통 구조물을 가지고 있어 침사지 내 유속이 허용기준을 초과하였다. 본 연구에서는 침사지내 유속을 만족시키기 위해 다양한 에너지 소산 구조물 설계방안을 제시하였다. 각 설계방안에 따른 흐름 특성 및 유속 분포를 파악하고 common bay 내에서의 난류특성을 분석하여 비교.검토하였다. 수리모형실험 결과를 통해 각각의 설계방안에 따른 침사지의 효율을 평가하였으며 최적의 에너지 소산 구조물에 대한 설계방안을 제안하였다.

• Journal of Ocean Engineering and Technology
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• v.13 no.3 s.33
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• pp.29-35
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• 1999

At the design of Mark III membrane type LNG tank, an analytical and experimental approach on the fatigue strengths of membrane and its welds are very important in order to assist designers and surveyors. In this study, fatigue tests of lap weld of Mark III membrane type LNG tank were carried out and cumulative damage factor was calculated in order to estimate the fatigue life by probability density function and rule methods. It contained the following tests and reviews : 1) The fatigue tests of lap weld of stainless steel according to statistical testing method recommended by JSME, 2)Preparation of S-N curve for lap welds considering the statistical properties of the results of fatigue tests. 3) Procedure for estimating the initiation life of fatigue crack of lap welds under variable loads by the rule lf classification society and probability density function, 4) Guideline for inspection of lap welds fo membrane type LNG tank.

• Nuclear industry
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• v.38 no.7
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• pp.9-19
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• 2018

존 켈리 회장은 7월 12일 경주시 힐튼호텔에서 열린 '원자력 안전 및 해체산업 육성 국제 포럼'에 참석하여 'Perspectives on the Future of Nuclear Power in the United States'를 주제로 특별강연을 했다. 켈리 회장은 강연을 통해 미 행정부의 원자력정책, 미국 원자력산업의 단기 도전 과제, 전력 생산에서의 이산화탄소 감축과 원전 역할, 원전의 지속적인 운영, 미국에서 진행되는 신형 원자로 설계 등을 피력했다. 켈리 회장은 이날 언론과의 인터뷰에서 "한국은 원자력산업 강국인데, 원전 안전성에 대한 과학적인 근거보다 정치적 이슈로 신규 원전을 짓지 않고 수명 연장 대신 조기 폐쇄를 결정한 것은 우려할 사안"이라고 말하고 "원전산업 축소는 장기적으로 기업의 전력 확보가 어려워져 경제적 타격을 입는다. 특히 한국은 원전을 수출하면서 탈원전정책을 펴면 수출에 지장을 받지 않을까 걱정된다."고 밝혔다. 켈리 회장은 MIT 원자력공학박사로 미국 에너지부(DOE) 원자력에너지 기술책임자를 지냈다. 본고는 발표 내용을 정리한 것이다.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.542-548
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• 1997

In this study an evaluation method of fatigue strength of membrane type LNG tank is presented with FEM analysis and experimental approach of seam and raised edge welds. The study contains the following : l)FEM analysis of test specimens 2)Fatigue tests of seam and raised edge welds 3)Estimation of cumulative damage factor of the welds on the basis of safe life design concept complying with the rules of classification society 4)Review of the effect of mean stress on the fatigue strength 5)Modelling of fatigue life of the welds which is changeable by weld heights With the results obtained in this study, a model ${\Delta}{\delta}/h^2=0.13553\;{N_{f}}^{-0.3151}$ for seam and raised edge welds having a given weld height is proposed to be useful for designers and inspectors.

• Journal of the Korea Safety Management & Science
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• v.14 no.3
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• pp.167-174
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• 2012

In the manufacturing process the most widely used $\bar{X}$ chart has been applied to control the process mean. Also, Accelerated Life Test(ALT) is commonly used for efficient assurance of product life in development phases, which can be applied in production reliability acceptance test. When life data has lognormal distribution, through censored ALT design so that censored ALT data has asymptotic normal distribution, $ALT\bar{X}$ control chart integrating $\bar{X}$ chart and ALT procedure could be applied to control the mean of process in the manufacturing process. In the situation that process variation is controlled, $Z_p$ control chart is an effective method for the very small fraction nonconforming of quality characteristic. A simultaneous control scheme with $ALT\bar{X}$ control chart and $Z_p$ control chart is designed for the very small fraction nonconforming of product lifetime.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.219-224
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• 2001

본 연구는 울진 원자력발전소 5＆6호기 Class 1680, Parallel Gate 16-inch, Motor Operated Valve (Valve ID No. SI-653 and 654)에 부착되는 Equalizing Bypass Pipe Line (EBPL)이 밸브 시스템에 발생시키는 진동하중에 의한 영향을 동적 피로안정성 관점에서 규명하기 위하여 수행된 것이다. Equalizing Bypass Line Part의 최종 설계된 형상을 Fig. 1에 나타내었다. 본 해석을 위하여 운용 중 발생되는 부착부의 잔류진동 레벨이 3축 방향 가속도로 측정되었다. 본 연구에서는 해당 시변 가속도 데이터를 바탕으로 정확한 시간-응력 이력을 얻기 위하여 시간영역에서 천이 진동해석 (Transient Vibration Analysis)을 수행하였으며, 이를 실제적인 피로해석에 활용하였다. 시간영역에서의 천이 진동해석 및 피로해석을 위해 상용유한요소 해석프로그램인 ANSYS (Version 5.6)를 활용하였다.(중략)

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.508-514
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• 2002

IEC60300의 국제 규격은 시간종속성 경영 시스템의 규격으로써 제1부는 시간종속성 경영 프로그램. 제 2부는 시간종속성 프로그램 구성요소와 업무, 제 3부는 응용지짐 표준의13개의 규격으로 구성되어 있다. 이 규격은 제품의 초기 단계서부터 폐기 단계까지 수명주기 전 단계에 걸쳐 운영의 효율성, 시간, 비용의 제약 하에 위험을 최소화하고 안전성을 최적화하기 위만 지짐을 제공한다. 본 연구에서는 현재 기업들이 기본적으로 적용하고 있는 경영 모델인 ISO 9000시스템과 안전 설계를 위한 신뢰성 분야의 IEC 60300시스템의 통합모형을 모색하고자 한다.