• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.25-30
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• 2001

The stress intensity factors for edge cracks located at the bonding interface between the semiconductor chip and the adhesive layer subjected to a uniform transverse tensile strain are investigated. Such cracks might be generated due to a stress singularity in the vicinity of the free surface. The boundary element method (BEM) is employed to investigate the behavior of interface stresses. The amplitude of complex stress intensity factor depends on the crack length, but it has a constant value at large crack lengths. The rapid propagation of interface crack is expected if the transverse tensile strain reaches a critical value.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.10a
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• pp.197-199
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• 2010

해상교통관제는 선박 통항의 안전과 효율성을 증진시키고 환경을 보호하는데 큰 기여를 하였다. 이러한 성과를 바탕으로 현재는 선박이 항만으로 진입하기 이전 단계에서부터 미리 관제를 실시하여 해양사고의 위험을 사전에 방지하고자 관제범위가 확대되고 있는 추세이다. 이를 위해서는 통항 선박에 관련된 정보가 지속적으로 관리 유지되어야 한다. 본 연구에서는 항만 관제와 인근 관제 및 접근 관제와의 효율적인 연계 및 운영 방안을 집중적으로 검토하였다. IALA에서 논의되고 있는 IVEF(Inter-VTS Exchange Format) 및 광역 AIS망을 이용하여 인근 관제실 간에 관제정보를 연계하는 방안을 살펴보고, 관제실 및 유관기관 간에 정보의 원활한 공유를 통해서 관제수역의 확대에 따른 VTS의 효율적인 운영 방안을 모색하여 보았다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1592-1602
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• 1990

Mixed mode surface crack in finite-width plate subjected to uniform tension and bending has been analyzed in 3-D problem by using boundary element method. The calculations were carried out for the surface crack angles(.a/pha.) of 0.deg., 15.deg., 30.deg., 45.deg., 60.deg., and 75.deg., and for the aspect ratio(a/c) of 0.2, 0.4, 0.6 and 1.0 to get stress intensity factors at the boundary points of the surface crack. For the aspect ratio of 1.0 and the surface crack angles, finite element method was used to check the results in this study. Comparison of the results from both methods showed good agreement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1120-1131
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• 2003

A recently developed numerical method based on a mixed volume and boundary integral equation method is applied to calculate the accurate stress intensity factors at the crack tips in unbounded isotropic solids in the presence of multiple anisotropic inclusions and cracks subject to external loads. Firstly, it should be noted that this newly developed numerical method does not require the Green's function for anisotropic inclusions to solve this class of problems since only Green's function for the unbounded isotropic matrix is involved in their formulation for the analysis. Secondly, this method takes full advantage of the capabilities developed in FEM and BIEM. In this paper, a detailed analysis of the stress intensity factors are carried out for an unbounded isotropic matrix containing an orthotropic cylindrical inclusion and a crack. The accuracy and effectiveness of the new method are examined through comparison with results obtained from analytical method and volume integral equation method. It is demonstrated that this new method is very accurate and effective for solving plane elastostatic problems in unbounded solids containing anisotropic inclusions and cracks.

• KOREAN POULTRY JOURNAL
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• v.40 no.5 s.463
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• pp.96-101
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• 2008

2003/04년에 국내 첫 발생한 고병원성 조류인플루엔자(이하 HPAI)가 2006/07년에 재 발생되었고, 금년 4월 들어 3번째로 발생하면서 농가는 물론, 국민들의 불안감은 더욱 고조되고 있다. 올해 발생 상황에 따르면 4월 1일 전북 김제시 산란계 농장을 기점으로 20일 사이에 50여 농가에서 신고가 접수되었고, HPAI가 19차례(08.04.23현재) 발생했다. 첫 발생일로부터 2주 뒤엔 최초 발생농장에서 200km 떨어진 경기도 평택에서도 발생되면서 지난 15일 전남북도에 한해 실시하던‘경계’단계의 위기 경보를 전국으로 확대한 바 있다. 특히나 예년과는 다르게 겨울철이 지난 4월에 첫 발생된 점과 전북 김제의 한 농장에서 방역초소를 뚫고 구입한 오리를 전남북 및 충청도 일대 음식점으로 납품하는 등 예기치 못한 상황이 발생하면서 AI가 급속히 확산될 가능성이 커지는 가운데 가금업계가 큰 위기에 직면하게 되었다. 본고는 금년에 발생된 HPAI 발생 현황에 대해 정리해보았다.

• Computational Structural Engineering
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• v.9 no.1
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• pp.85-91
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• 1996

The focus of the present work is on the computation of the stress intensity factor for the crack at the elastic-viscoelastic bimaterial interface. First, the stress intensity factor for an interface crack in dissimilar elastic and viscoelastic materials is dervied by applying the correspondence principle to associated elastic expression. Then the time-domain boundary element analysis is performed to calculate the stress intensity factor. Numerical results show that the proposed method is very useful for the analysis of the interface crack in elastic and viscoelastic materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.560-566
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• 2000

Many researchers have dealt with the problems of fracture mechanics. Generally, these researches are concerned with crack in isotropic material without other micro defects. Actual structure, however, may contain micro defects as well as crack in manufacture processing or operation. If it contains mi defects near a crack, some different characteristics will be appear in fracture behaviors of the crack. This study examines the effect of the micro defect on stress intensity factor of center slant crack rectangular plate subjected to uniform uniaxial tensile stress. In this study, boundary element method(BEM) is used for analysis in stress intensity factor(SIF).

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.72-84
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• 1998

In order ot study the influence of a circular inclusion on a stress field near a crack tip, mutual interference of a slant crack and the circular inclusion is analyzed of a bimaterial inclusion. As the crack emanates at the equivalent slant crack angle the correction factors FⅠ and FⅡ for the inclusion wit small Young's modulus were found to decrease as the inclusion radius increased. The correction factors for inclusion with large Young's modulus increase as the inclusion radius increases at the equivalent radius of the inclusion, the correction factors decrease as the slant crack angle increases for the aspect ratio $\frac{c}{W}$ = 0.1 irrespective of the Young's modulus. For $\frac{c}{W}$ greater than 0.2, they increase as the slant crack angle increases. There is no influence of stress mutual interfce after crack emanates beyond the inclusion radius.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.311-317
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• 2009

우리나라에서 발생하는 화재의 대부분은 건축물 화재이며, 이중 노후화된 시가지 등 화재에 취약한 지역에서 화재발생시 도시화재로 확대될 우려가 높다. 이러한 도시화재 확대를 방지하기 위한 도시화재의 물리적 연소성상예측모델과 도시화재 리스크평가기법의 개발이 필요하다. 본 연구에서는 우리나라의 도시화재위험성평가 구축을 위한 한 일 공동연구체계와 주요 대상인 화제경계지구에 대하여 소개하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.179-189
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• 1991

Composite materials are generally treated as anisotropic or an orthotropic materials. Unlike isotropic materials, the orthotropic materials can divided three groups depending upon the relationship of the four material constants or depending upon the characteristic roots of orthotropic materials. In particular, the fundamental solutions of two dimensional BEM for composite materials (orthotropic or anisotropic material) generally have a singularity in the conventional method when the characteristic roots are equal. In consideration of this singularity in the conventional method when the characteristic roots are equal. In consideration of this singular problems, in this paper, the fundamental solutions of BEM are systematically analysed for orthotropic materials. And the stress and displacement fields for a crack in an orthotropic materials are singular when the characteristic roots of orthotropic materials are equal. Therefore, these fields for a crack in an orthotropic materials are analysed by the analogous method to isotropic materials when the characteristic roots are equal.