• 한국전산구조공학회논문집
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• 제20권1호
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• pp.39-50
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• 2007

본 논문은 다중 적층지반상의 지반-구조물 상호작용 해석을 위한 3차원 무한요소를 소개한다. 본 무한요소는 Cartesian 좌표계에서 정식화되었으며, 수평, 수평모서리, 수직, 수직 모서리 그리고 수평 수직 모서리 무한요소로서 총 5개의 무한요소로서 구성된다 적용한 형상함수 내부의 파동함수들은 적층지반의 파동문제를 효과적으로 모사하며 다중파동성분을 포함하고 있다. 본 요소의 성능을 검증하기 위하여 주파수영역에서 여러 가지 예제해석을 수행하였다. 균질 및 적층지반상 강체기초와 묻힌 케이슨 기초의 무차원 동적 거동(compliance & impedance)을 구하였으며, 기연구자들의 값과 비교 검토하였다.

• 대한조선학회지
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• 제5권1호
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• pp.1-7
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• 1968

In this problem the ragid punch in the form of a flat-ended circular cylinder of unit radius is cemented to the stress free surface of an elastic half-space. An axial load P is then applied to the punch to force it into half-space to depth $\varepsilon$. It is assumed that the adhesive between the punch and can be reduced to the system of Abel type integral equations which are equation (13) and (14). It is also shown that the stress and displacement components on the portions of boundary where they are not prescribed can be expressed in terms of $\phi(t)$ and/or $\phi(t)$ which are introduced in equation (9) and (10). Those functions can be obtained from the solution of the system of integral equations (13) and (14).

• 대한기계학회논문집A
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• 제21권4호
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• pp.673-678
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• 1997

Stress wave propagations in an elastic half space to a normal point force of ramp type in time are analyzed. The governing equations are transformed by applying the Laplace and Hankel transforms with respect to time and radial distance. The inversion of Laplace transforms are performed by employing the Cagniard-de Hoop method, where the Rayleigh waves at surface are obtained by including the residue terms. The stress waves computed at the location very cose to the surface are shown to be almost identical to the surface waves obtained by the residue method except the Rayleigh wavefront. It is found that at the surface, the stresses are dominated by the Rayleigh waves, whose amplitudes increase linearly with time when time is very large. It is also found that in the interior part, the radial stress has a logarithmic singularity at the shear wavefront, while tangential stress shows no singularity.

• 대한지구과학교육학회지
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• 제7권2호
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• pp.151-158
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• 2014

본 연구는 57명의 고등학생들이 환경의 변화에 대해 갖고 있는 인식을 그리기 활동을 통해서 분석하였다. 절반이 넘는 학생들이 현재의 환경을 순수한 자연 공간으로, 미래의 환경을 인공적 요소들이 포함된 공간으로 표현하여 과학기술의 발달을 그림속에 나타내었다. 대부분의 고등학생들은 현재의 환경 상태를 인간에 의해 오염된 공간으로 표현하여 부정적 인식을 드러내었다. 미래의 환경 상태에 대해서는 절반의 학생들이 긍정적으로, 나머지 절반의 학생들은 부정적으로 표현하고 있어 학교 현장에서 환경을 개선하려는 의지를 드높이고 긍정적 인식으로 전환시킬 수 있도록 노력해야 할 것이다.

• 한국전자파학회논문지
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• 제14권8호
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• pp.803-808
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• 2003

손실 반공간에 두 개의 원통형 파이프가 묻혀 있는 경우 파이프와 주변 매질의 특성을 반복 기법 최적화 역산란을 적용하여 구했다. 산란 전계는 경계요소법을 이용하여 계산하였으며 파이프의 크기, 위치, 내부매질의 비유전을, 도전을, 주변 매질의 비유전을, 도전을 등의 파라미터는 측정 산란 전계로부터 유전 알고리즘과 Levenberg-Marquardt 알고리즘의 혼합 알고리즘을 이용하여 역으로 계산하였다. 두 파이프가 거의 근접해 있는 경우도 역산란이 가능함을 보였다. 산란 전계의 측정오차에 의한 illposednes 는 파수 영역에서 지수 함수적으로 감쇄하는 감쇄모드를 제거하여 안정화시켰다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.257-266
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on/in horizontally layered half.space considering the effects of the interior fluid and exterior soil medium in the frequency domain. To capture the essence of fluid-structure-soil interaction effects effectively, a mixed finite element with two-field (u, p) approximation is employed to model the compressive inviscid fluid, while the structure and soil medium are presented by the 3-D axisymmetric finite elements and dynamic infinite elements. The present FE-based method can be applied to the system with complex geometry of fluid region as well as with inhomogeneous near-field soil medium, since it can directly model both the fluid and the soil. For the purpose of verification, dominant peak frequencies in transfer functions for horizontal motions of cylindrical fluid storage tanks with rigid massless foundation on a homogeneous viscoelastic half.space are compared with those by two different added mass approaches for the fluid motion. The comparison indicates that the Present FE-based methodology gives accurate solution for the fluid-structure-soil interaction problem. Finally, as a demonstration of versatility of the present study, a seismic analysis for a real-scale LNG storage tank embedded in layered half.space is carried out, and its member forces along the height of the structure are compared with those by an added mass approach developed by the present writers.

• Earthquakes and Structures
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• 제13권6호
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• pp.573-588
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• 2017

The earthquake input is required when the soil-structure interaction (SSI) analysis is performed by the direct finite element method. In this paper, the earthquake is considered as the obliquely incident plane body wave arising from the truncated linearly elastic layered half space. An earthquake input method is developed for the time-domain three-dimensional SSI analysis. It consists of a new site response analysis method for free field and the viscous-spring artificial boundary condition for scattered field. The proposed earthquake input method can be implemented in the process of building finite element model of commercial software. It can result in the highly accurate solution by using a relatively small SSI model. The initial condition is considered for the nonlinear SSI analysis. The Daikai subway station is analyzed as an example. The effectiveness of the proposed earthquake input method is verified. The effect of the obliquely incident earthquake is studied.

• 대한수학회논문집
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• 제29권3호
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• pp.451-461
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• 2014

We study the geometry of indefinite trans-Sasakian manifold $\bar{M}$, of type (${\alpha},{\beta}$), admitting a half lightlike submanifold M such that the structure vector field of $\bar{M}$ does not belong to the screen and coscreen distributions of M. The purpose of this paper is to prove several classification theorems of such an indefinite trans-Sasakian manifold.

• 대한수학회보
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• 제54권4호
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• pp.1337-1346
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• 2017

We define Bloch-type spaces of ${\mathcal{C}}^1({\mathbb{H}})$ on the upper half plane H and characterize them in terms of weighted Lipschitz functions. We also discuss the boundedness of a composition operator ${\mathcal{C}}_{\phi}$ acting between two Bloch spaces. These obtained results generalize the corresponding known ones to the setting of upper half plane.

• Structural Engineering and Mechanics
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• 제9권2호
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• pp.209-214
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• 2000

The main purpose of this paper is to develop the results introduced in Artan (1996) and to find a general nonlocal linear elastic solution for Boussinesq problem. The general nonlocal solution given Artan (1996) is valid only when the distance to the boundary is greater than one atomic measure. The nonlocal stress field presented in this paper is valid for the whole half plane.