• Tunnel and Underground Space
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• v.22 no.2
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• pp.120-129
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• 2012

Recently, mining facilities have being installed in an underground space according to a social demand for environment-friendly mine development. The underground structures for mining facilities usually requires a large volume of space with width greater than height, and thus the stability assessment of the large-scale underground mine structure is an important issue. In this study, we analysed a factor of safety based on strength reduction method, and proposed a numerical design approach to determining the dimension of underground mine structures in combination with a strength reduction method and a multivariate regression analysis. Input design parameters considered in the present study were the stress ratio and shear strength of rock mass, and the width and cover depth of underground mine structures. The stabilities of underground mine structures were assessed in terms of factor of safety under different conditions of the above input parameters. It was calculated by the strength reduction method, and several kinds of fit functions were obtained through various multivariate regression analyses. Using a best-fit regression model, we proposed the charts which provide preliminary design information on the dimension of underground mine structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4C
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• pp.153-162
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• 2009

This paper investigates the effects of excavation-induced ground movements on nearby structures, considering soil-structure interactions of different soil and structural characteristics. The response of four and two-story block structures, which are subjected to excavation-induced advancing ground movements, are investigated in different soil conditions using numerical analysis. The structures for numerical analysis are modelled to have cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four and two-story block structures are investigated with advancing ground movement phases and compared with the response of structures which are subjected to excavation-induced total ground movement. The response of structures is compared among others in terms of the magnitude and shape of deformations and cracks in structures for different structure and ground conditions. The results of the comparison provide a background for better understandings for controlling and minimizing building damage on nearby structures due to excavation-induced ground movements.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.292-292
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• 2022

가뭄은 사회기반시설, 인적 자본 등과 같은 자산에 직접적인 영향을 미치지 않으나 물을 중요한 투입재로 사용하는 농업부문에 피해가 집중된다. 가뭄 재해는 준비와 대응에 따라 피해에 큰 차이가 크기 때문에 다른 재해와는 달리 강도뿐만 아니라 지속기간을 고려해야 한다. 효과적인 가뭄 위험 관리를 위해서는 가뭄의 특징과 가뭄 준비 및 대응 수단에 따른 환경 및 경제적 영향을 평가할 수 있는 모형 구축과 다양한 농업자원을 동시적으로 연계 평가하여 지속가능성을 판단할 수 있는 기술 개발이 필요하다. 이에 본 연구에서는 기후변화 등의 외부요인을 반영한 물-에너지-식량 (Water-Energy-Food, WEF) 넥서스 기반 농업 가뭄 평가 플랫폼 설계를 제안하고자 한다. 이를 위해 물-에너지-식량 넥서스 연계 해석 고도화 기술을 개발하고, 생물-물리학적 모델 및 경제학적 모델 연계형 기후-토양-물-에너지-식량 넥서스 (CS-WEF NEXUS) 플랫폼을 구축하여, 최종적으로 기후변화 및 농업부문 가뭄 준비 및 대응 수단의 영향 평가를 바탕으로 한 의사결정 지원 도구를 제시하는 것이 최종 목표이다. 본 연구에서 구축된 플랫폼은 넥서스 연계 해석을 통해 농업 가뭄 대응을 위한 식량 및 에너지 안보 정책에도 미칠 수 있는 영향을 분석할 수 있으며, 다양한 식량-물-에너지 정책들이 타 요소들에 미치는 영향을 쉽게 평가할 수 있다는 점에서 정책적 의사결정 지원 시스템으로서 활용도가 높을 것으로 예상한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.28-35
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• 2005

It is now well recognized that the ultimate limit state approach is a much better basis for design and strength assessment of ships and offshore structures since it is difficult to determine the realistic margin of safety using the traditional allowable working stress approach on the basis of linear elastic method solutions together with buckling strengthchecks adjusted by a simple plasticity correction. This paper outlines ALPS theory for ultimate limit state assessment of ship structures. ALPS is a computer software which stands for nonlinear Analysis of Large Plated Structures. Application examples of ALPS program to ultimate limit state assessment of plates, stiffened panels and ship hull girders are presented. A benchmark study is made by a comparison with the ALPS solutions with other methods including class rule formulae, nonlinear finite element methods and experimental results. Future trends on ultimate limit state assessment of ship structures are addresse[1]

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.301-304
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• 2007

본 연구에서는 폐탄광 지역에서 발생하는 지반침하에 영향을 주는 주요 요인들을 추출하기 위하여 다변량 통계분석 방법의 하나인 주성분분석(Principle Component Analysis : PCA)기법과 지리정보시스템 (Geographic Information System : GIS)을 이용하였다. 이를 위해 연구지역에서 수행한 지표지질조사， 정밀조사, 실내암석시험 등으로부터 취득된 자료를 데이터베이스로 구축하고, 지반침하 위험지역 분포를 공간적으로 해석할 수 있는 지질, 토지이용, 경사도， 지표로부터 지하 갱도까지의 심도, 갱도의 지표상 위치로부터의 수평거리, 지하수심도, 투수계수, RMR(Rock Mass Rating) 값을 분석대상으로 선정하였다. 각 요인들이 연구지역 전체에 걸쳐 분포하도록 GIS의 공간분석 기법의 하나인 표면분석(Surface Analysis), 버퍼링기법(Buffering) 및 내삽법(Interpolation)을 이용하여 래스터 데이터베이스로 구축하고 이로부터 추출된 자료들을 입력값으로 하는 주성분분석을 수행하였다. 주성분분석 결과 폐탄광 지역의 지반침하에 영향을 주는 주요인을 추출하는 것이 가능하였으며, 연구지역은 지질 및 지반강도 관련 요인이 침하발생의 가장 큰 요인인 것으로 분석되었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.262-269
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• 2004

Ship structures are basically an assembly of plate elements and the load-carrying capacity or the ultimate strength is one of the most important criteria for safety assessment and economic design. Also, Structural elements making up ship plated structures do not work separately, resulting in high degree of redundancy and complexity, in contrast to those of steel framed structures. To enable the behavior of such structures to be analyzed, simplifications or idealizations must essentially be made considering the accuracy needed and the degree of complexity of the analysis to be used. On this study, to investigate effect of analysis range, the finite element method are used and their results are compared varying the analysis ranges. The model has been selected from bottom panels of large merchant ship structures. For FEA, three types of structural modeling are adopted in terms of the extent of the analysis. The purpose of the present study is to numerically calculate the characteristics of ultimate strength behavior according to the analysis ranges of stiffened panels subject to uniaxial compressive loads.

• Bulletin of the Society of Naval Architects of Korea
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• v.22 no.1
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• pp.31-37
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• 1985

In ship's structure, deck and bottom plate are main strength member subjected to the inplane load due to longitudinal bending, i.e. tensile and/or compressive load. The deck and bottom plate are subdivided into many plate members by stiffeners and girders longitudinally and transversely. Since the plate members are thin, it is likely to be collapsed under compressive load, and when we consider the local strength of deck and bottom, the plate members play an important role in the longitudinal strength. Therefore the precise analysis of their compressive ultimate strength is required for the optimal design of ship's structures. In this paper, the modified analytical method using the incremental form of principle of virtual displacement is introduced to determine the compressive ultimate load of plate members. The results by the present method is satisfactory, and the present method is more effective and economical than the finite element method.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1032-1034
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• 2005

초고압 차단기 내부에는 여러 종류의 절연물들이 존재하며, 절연물들중 노즐은 차단현상에 큰 영향을 미치는 요소 중에 하나로 작용을 하고 있다. 노즐의 형상과 노즐 목의 길이, 노즐의 재질에 따라 전계강도의 차이와 유동의 흐름에 영향을 미치고 있으며 결국 차단기의 차단성능의 변화를 발생시킬수 있다. 따라서 본 논문에서는 서로 다른 형상의 노즐을 가지고 차단기 내부 접점의 이동에 따른 스트로크별 해석 데이타와 시험 데이타를 비교함으로써 절연성능의 변화를 연구하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.501-504
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• 2011

In this study, structural design of the propeller blade for turboprop aircraft was performed. The propeller shall have high strength to get the thrust to fly at high speed. The high stiffness and strength carbon/epoxy composite material was used for the major structure and skin-spar-foam sandwich structural type was adopted for improvement of lightness. As a design procedure for the present study, firstly the structural design load was estimated through investigation on aerodynamic load and then flanges of spars from major bending loads and the skin from shear loads were preliminarily sized using the netting rule. In order to investigate the structural safety and stability, stress analysis was performed by finite element analysis code MSC. NASTRAN. Finally, it is investigated that designed blade have high efficiency and structural safety to analyze of aerodynamic and structural design results.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.1
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• pp.31-42
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• 2009

Common structural rule (CSR) doesn' t provide any other specific regulations for permanent means of access (PMA) platform structure in a cargo oil tank. The PMA platform is recommended to comply with scantling requirement of local support member. However, it leads to too conservative scantlings compared with actual loads imposed on the platform. This paper proposes a strength assessment procedure for the PMA structure based on a nonlinear ultimate strength. The ultimate strength is evaluated in a sufficiently conservative way. The first linear buckling mode is used as an initial imperfection shape and its magnitude is determined using the definitions of DNV PULS. Since the same imperfection mode as the failure mode of the ultimate limit state is assumed, it can accelerate the failure. Au ultimate strength capacity curve obtained from a series of nonlinear FE analysis is compared with actual stresses calculated by CSR cargo hold analysis.