• Tunnel and Underground Space
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• v.18 no.5
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• pp.317-327
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• 2008

About 70% of domestic land is mountainous and the construction of many geotechnical structures is inevitable for building transportation networks across region. Many geotechnical surveys, including rock physical and mechanical tests, are performed during construction. Thus study is a basic research for establishing database of physical and mechanical properties in domestic rocks, and analyzing the rock mechanical relationships between 2,000 rock properties obtained from laboratory tests in KOLAS. For the construction of useful database, systematic management, based on the standard information as well as reliable data accumulation, is required.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.700-702
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• 2002

원자력발전소 1차계통 주요기기와 2차계통 주요기기들에 대한 가동 중 검사시 발견된 결함은 ASME Sec. XI, IWB와 IWC에 근거하여 허용여부를 결정한다. 이때, 결함 크기가 허용기준을 초과하는 경우에는, 기기의 안전성 확보를 위해 ASME Sec. XI에 규정된 절차에 따라 파괴역학분석(Fracture Mechanics Analysis: FMA)을 수행하고, 그 결과에 따라 운전중지 후 보수 또는 계속운전의 판단을 한다. 따라서, 원자력발전소 주요기기에 대한 FMA기술은 안전성평가의 핵심이 되는 부분이다. 원자력발전소의 안전성평가에는 결함의 형상 정보, 환경 정보, 재료 물성치, 응력 데이터 등 방대한 양의 데이터가 필요할 뿐 아니라 파괴역학적 분석절차도 매우 복잡하여 전문가도 많은 시간과 노력이 요구된다. 이러한 문제점을 해결하고자 일부 평가절차를 컴퓨터 프로그램화하여 효율적인 안전성평가가 이루어지도록 노력하고 있다. 본 논문에서는 파괴역학적 분석에 필요한 응력 데이터를 관리하는 응력 데이터베이스를 구축하고, 응력확대계수계산 프로그램(KEVA)과 결함허용여부를 결정하는 프로그램(Acceptance Standard)과 결함성장률 계산 프로그램(FLEVA)을 Web 기반으로 개발하고 구현결과를 소개한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.213-214
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• 2015

용융 합금의 표면 장력은 도금, 용접등 금속 제조 공정중 큰 영향을 미치는 재료의 물성 중 하나이다. 표면 장력의 측정을 위해 다양한 방법이 개발 되었으며 많은 합금계에 대해 표면 장력값이 온도와 조성의 변화에 대해 알려져 있다. 그럼에도 불구하고 실험 측정의 어려움, 실용적인 다원계 합금에서의 표면 장력 측정치의 부족으로 인해 전술한 금속 제조 공정에서 나타나는 현상에 대한 해석에 사용하기에 아직 해결해야 할 부분들이 많이 있다. 본 연구에서는 표면 장력이 합금의 Gibbs free energy의 한 부분으로 기술되는 열역학 원리 및 표면 장력이 Gibbs energy 수식 내 표면적에 대응하는 포텐셜 함수로 얻을수 있다는 Pajarre등의 제안에 근거하여 용융합금의 표면 장력을 계산하는 방법을 제시한다. 다양한 열역학 성질과 상태도를 계산하기 위해 개발된 열역학 소프트웨어 및 데이터베이스를 활용하여 2원계-다원계 용융 합금의 표면장력을 계산하고 이를 알려진 실험 자료와 비교하였다. 철강 제품의 표면 도금에 사용되는 용융 아연 합금의 표면 장력을 전술한 방법을 통해 예측하고 그 결과를 토의한다.

• Tunnel and Underground Space
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• v.22 no.5
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• pp.354-364
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• 2012

In order to evaluate the physical properties of rock which might serve as a database for both mining and civil works, a lot of laboratory tests for Jecheon limestones were conducted to find unit weight, absorption ratio, porosity, elastic wave velocity, uniaxial compressive strength, Young's modulus, poisson's ratio, tensile strength, shore hardness, friction angle and cohesion. On investigation of the mechanical properties of both the gray limestone and the clayey limestone distributed in the studied region, the clayey limestone turned out to have more weak mechanical properties which might come from low unit weight, high absorption ratio and high porosity of rocks. The failure criteria of Jecheon limestones were discussed by means of both Mohr-Coulomb criterion and Hoek-Brown criterion. Regression analyses of the physical properties obtained from a lot of laboratory tests were also conducted by means of both linear and multiple regression analyses.

• International Journal of Highway Engineering
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• v.5 no.4 s.18
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• pp.23-35
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• 2003

In this study, compaction evaluating program based on ASTM critria is developed bu analyzing the results of laboratory tests. And the laboratory tests such as compaction test, triaxial test and resonance column test of subgrade soils are performed to develop compaction management methodology at seven test sites. Especially, to figure out chararteristic with changing compactive efforts, the test was carried out at five levels of compactive efforts at each soil sample. Database was set up from the test results. With the methodology using mechanical property - the elastic modulus, the gap between road design and management and road construction management is narrowed. The regression equation of G/$G_{max}$ is proposed at each strain level of subgrade soils according to AASHTO criteria, and the relationship between fundamental properties of soil mass and degree of compaction is derived as well. The development of compaction management and field compaction management method is proposed by the elastic modulus based on mechanical tests.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.84-89
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• 2007

In order to guarantee the safety of the facility systems, one of the essential components is information on mechanical properties of materials used for the construction. However, acquisition or accumulation of the mechanical property data in industrial fields is limited because this operation does not yield profit, excepting few materials production companies. Corresponding to the urgent needs and poor economical features, the MOCIE has founded the National Center for Standard Reference Data in the KRISS and also designated the Data Center of Mechanical Properties for Metallic Materials (DCMP) as a principal operating section. The DCMP plays roles of collection, edition and evaluation of the mechanical data and development of reference standards. In this study, several functions of the DCMP and standardization procedures of mechanical properties data will be introduced the prospective of standard reference researches will be discussed based on active feedbacks from industrial fields.

• Resources Recycling
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• v.10 no.1
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• pp.16-24
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• 2001

In this study, various mechanical properties of concretes employing waste concrete as aggregate were examined. These concretes were obtained by mixing seven types of aggregate for different ratios. So, the experimental variables are the kinds of aggregates (some different aggregate compositions) and W/C ratio (0.40, 0.45, 0.50). From experimental results, the reliable regression analysis equations between compressive strength and various experimental data for recycled aggregate concrete are presented. Consequently, this study was accomplished to investigate basic engineering properties of recycled aggregate concrete using waste concrete.