• 대한토목학회논문집
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• 제3권4호
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• pp.143-148
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• 1983

크리이프, 건조수축(乾燥收縮), 노화현상(老化現象), 온도변형등(溫度變形等) 콘크리트구조물(構造物)의 시간의존성변형(時間依存性變形)에 대한 일반적(一般的) 수치해석법(數値解析法)을 제시(提示)하였다. 크리이프는 콘크리트의 연령(年齡)과 온도변화(溫度變化)의 함수인 중량적분(重量積分)으로 표시하였는데 특수(特殊)한 형태(形態)의 크리이프함수(凾數)를 사용함으로써 효과적(効果的)인 수치해석(數値解析)이 가능(可能)하게 되었다. 수치해석예(數値解析例)를 통하여 이 방법(方法)의 정확성(正確性)을 입증하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.35-42
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• 1997

The two-state or mutual M-integral which is derived from tile M-integral and is applicable for two elastic states, is applied for computing all intensity of a singular near-tip field around the vertex of a class of wedge, encountered in adhesive lap joints under mechanical loading. Numerically we verify that a simple auxiliary field associated with every eigenfunction for the composite wedge under consideration exists in the form of the conjugate solution in the sense of tile M-integral. The auxiliary field is then employed for superposition with the elastic field under consideration, and the associated two-state M-integral is computed via the domain integral technique. This enables us to extract the intensity for a singular field information for a singular elastic boundary layer is extracted form the domain integral representation without resort to singular finite element for the wedge vertex.

• 한국공간구조학회논문집
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• 제1권2호
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• pp.101-110
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• 2001

A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an elastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of reduced model test. Satisfactory agreement is found between theory and experiment.

• 한국산업융합학회 논문집
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• 제4권4호
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• pp.433-439
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• 2001

A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an clastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of previous model test. Satisfactory agreement is found between theory and experiment.

• Coupled systems mechanics
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• 제9권1호
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• pp.77-89
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• 2020

This study is dedicated to the dynamic elasticity problem for a semi-strip. The semi-strip is loaded by the dynamic load at the center of its short edge. The conditions of fixing are given on the lateral sides of the semi-strip. The initial problem is reduced to one-dimensional problem with the help of Laplace's and Fourier's integral transforms. The one-dimensional boundary problem is formulated as the vector boundary problem in the transform's domain. Its solution is constructed as the superposition of the general solution for the homogeneous vector equation and the partial solution for the inhomogeneous vector equation. The matrix differential calculation is used for the deriving of the general solution. The partial solution is constructed with the help of Green's matrix-function, which is searched as the bilinear expansion. The case of steady-state oscillations is considered. The problem is reduced to the solving of the singular integral equation. The orthogonalization method is applied for the calculations. The stress state of the semi-strip is investigated for the different values of the frequency.

• 한국정보통신학회논문지
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• 제12권12호
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• pp.2271-2276
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• 2008

본 논문에서는 3D 영상의 해상도 개선을 위한 크기가변 확대 기법 기반의 컴퓨터적 집적 영상 재생 방법을 제안한다. 먼저 컴퓨터적 집적 영상 재생 방법에서 요소 영상 사이의 간섭 문제를 설명한다. 큰 확대개수는 요소 영상의 확대 중첩 과정에서 큰 간섭을 야기하여 재생 3D 영상의 해상도를 저하시킨다. 이 간섭 문제를 극복하기 위해서 최소 확대 계수를 계산하는 방법을 제안한다. 새로운 최소 확대 계수는 해상도가 향상된 3D 영상을 제공하며, 제안하는 방법은 기존의 방법보다 계산량이 작다. 제안하는 방법의 유용함을 보이기 위해서 컴퓨터 복원 실험을 수행하고 그 결과를 보고한다.

• 한국정보통신학회논문지
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• 제11권5호
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• pp.991-996
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• 2007

최근 3차원 디스플레이 기술로서 유망한 집적 영상 기술을 이용하여 3차원 물체에 대한 컴퓨터 재생 방식이 활발히 연구되고 있다. 이 방식은 집적 영상 기술로 픽업되는 요소 영상을 가상의 핀홀 배열 모델을 이용하여 컴퓨터적으로 특정한 거리의 재생 평면에 확대 중첩함으로서 3차원 영상을 효과적으로 재생하는 방식이다. 그러나 많은 수의 요소 영상은 일반적으로 사각형의 구조를 가지기 때문에 확대 중첩될 경우에 재생 영상에서 격자 구조의 밝기 불균일 문제로 인한 해상도를 떨어뜨리는 문제가 존재하였다. 본 논문에서는 이러한 문제점을 극복하기 위해서 원형 매핑 모델에 기초한 컴퓨터 집적 영상 재생 방식을 제안한다. 제안하는 방식은 기존의 방식에서 발생하는 3차원 재생 영상에서의 불균일 문제를 극복할 수 있으며 3차원 영상의 해상도를 개선할 수 있다. 제안된 방식의 유용함을 보이기 위해서 컴퓨터적 모의 실험과 광학적 실험을 수행하고 그 결과를 보고한다.

• 한국전산구조공학회논문집
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• 제15권3호
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• pp.433-440
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• 2002

본 연구에서는 균일한 인장과 굽힘을 받는 반무한 평판내의 분기균열에 대하여 해석하였다. 중첩의 원리를 이용하여 인장과 굽힘을 받는 분기균열에 대하여 응력 및 모멘트 확대계수를 해석하였다. 응력확대계수는 유한요소법과 J 기저 상호매개적분을 이용하여 해석하였고, 모멘트확대계수는 균열선단의 모멘트로부터 모멘트외삽을 이용하여 계산하였다 무차원화된 응력확대계수와 모멘트확대계수에 대한 수치해석 결과는 분기균열 길이와 주균열의 비, 그리고 분기균열각의 함수로 나타내었다.

• Structural Engineering and Mechanics
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• 제70권6호
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• pp.765-779
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• 2019

Most of the existing evaluation criteria of vibration serviceability rely on the peak acceleration of the structure rather than that of the people keeping their own body unmoved on the structure who is the real receiver of structural vibrations. In order to accurately assess the vibration serviceability, therefore, a full path assessment approach of vibration serviceability based on vibration source, path and receiver is not only tentatively proposed in this paper, taking the peak acceleration of receiver into account, but also introduce a probability procedure to provide more instructive information instead of a single value. In fact, semi-rigid supported on both sides of the structure is more consistent with the actual situation than simply supported or clamped due to the application of the prefabricated footbridge structures. So, the footbridge is regarded as a beam with semi-rigid supported on both sides in this paper. The differential quadrature-integral quadrature coupled method is not only to handle different type of boundary conditions, but also after being further modified via the introduction of an approximation procedure in this work, the time-varying system problem caused by human-structure interaction can be solved well. The analytical results of numerical simulations demonstrate that the modified differential quadrature-integral quadrature coupled method has higher reliability and accuracy compared with the mode superposition method. What's more, both of the two different passive control measures, the tuned mass damper and semi-rigid supported, have good performance for reducing vibrations. Most importantly, semi-rigid supported is easier to achieve the objective of reducing vibration compared with tuned mass damper in design stage of structure.

• 대한조선학회지
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• 제14권3호
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• pp.5-12
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• 1977

In shipyard production processes, lots of steel plates are assembled by welding. Some rectangular steel plates are buttwelded to build a large block in panel production lines. There are some advantages to take the tandem arc welding in butt joints of rectangular plates with respect to welding speed. Hence, the thermal stresses and the temperature distribution of the tandem arc welding are studied in this paper. The solutions in the case of the infinite plate with two instantaneous point heat sources have been obtained. And then the solutions have been extended to the case of two moving heat sources corresponding to the tandem arc welding with the aid of Duhamel's superposition integral. It was found that the temperature distribution was good agreement with the results of the experiments by Rosenthal and Park and the thermal stresses calculated were acceptable with respect to a physical phenomenon. These solutions are able to be applied to the problem such as a line heating.