• 한국강구조학회 논문집
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• 제14권6호
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• pp.793-802
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• 2002

수평곡선 I형교에 동적해석을 수행하기 위하여 박판곡선보 이론에 근거 뒴자유도를 포함한 절점당 7자유도를 갖는 곡선보요소와 7자유도 직선보요소를 사용하여 동적해석프로그램 EQCVB를 작성하였다. 이 프로그램에서는 자유진동해석을 위하여 Gupta의 방법을 사용하였고, 지진하중이 작용할 때 동적해석을 수행하기 위하여 Wilson-${\theta}$방법을 사용하였으며, 범용구조해석 프로그램인 ABAQUS를 사용한 해석 결과와 비교하여 프로그램의 효율성과 타당성을 입증하였다. 지진하중 작용시 수평곡선 I형교의 동적 거동 특성을 파악하기 위하여 다양한 예제에 대한 해석을 수행하였다.

• 한국전산구조공학회논문집
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• 제20권6호
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• pp.719-730
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• 2007

Timoshenko의 전통적인 보 이론에 근거한 유한 요소의 전단 잠김 현상을 해결하기 위하여 가정 변형도법을 적용한 7자유도 공간 박벽 뼈대요소를 개발하였다. 2개의 노드를 갖는 직선 보요소에서 한 요소내의 변형도가 일정하다고 가정하여 형상함수를 유도하고 이를 바탕으로 가상일의 원리에 따라 강성행렬을 구성하였다. Corotational 기하 비선형 해석법을 이용하여 불평형 하중을 산정하였으며 부재 길이의 비선형 효과를 반영하기 위하여 bowing effect를 정밀하게 고려하였다. 일축 비대칭 단면을 갖는 곡선 외팔보와 이축 비대칭 단면을 갖는 직선 외팔보에 대하여 횡-비틀림 좌굴에 의한 안정 해석과 후좌굴 해석을 수행한 결과 ABAQUS 쉘요소와 좋은 일치를 보여 주었다.

• Structural Engineering and Mechanics
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• 제43권4호
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• pp.411-437
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• 2012

In this paper, we propose a continuum mechanics based 3-D beam finite element with cross-sectional discretization allowing for warping displacements. The beam element is directly derived from the assemblage of 3-D solid elements, and this approach results in inherently advanced modeling capabilities of the beam element. In the beam formulation, warping is fully coupled with bending, shearing, and stretching. Consequently, the proposed beam elements can consider free and constrained warping conditions, eccentricities, curved geometries, varying sections, as well as arbitrary cross-sections (including thin/thick-walled, open/closed, and single/multi-cell cross-sections). We then study the modeling and predictive capabilities of the beam elements in twisting beam problems according to geometries, boundary conditions, and cross-sectional meshes. The results are compared with reference solutions obtained by analytical methods and solid and shell finite element models. Excellent modeling capabilities and solution accuracy of the proposed beam element are observed.

• 대한기계학회논문집A
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• 제30권1호
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• pp.76-83
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• 2006

This paper addresses the method for the shape design sensitivity analysis of the buckling load in the continuous elastic body. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Though the buckling problem is more efficiently solved by the structural elements such as beam and shell, the elastic solids are considered in this paper because the solid elements can be used in general for any kind of structures whether they are thick or thin. The initial stress and buckling analysis is carried out by the commercial analysis code ANSYS. The sensitivity is computed by using the mathematical package MATLAB using the results of ANSYS. Several problems including straight and curved beams under compressive load, ring under pressure load, thin-walled section and bottle shaped column are chosen to illustrate the efficiency of the presented method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.841-846
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• 2006

This paper addresses the method for the shape design sensitivity analysis of the buckling load in the continuous elastic body. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Though the buckling problem is more efficiently solved by the structural elements such as beam and shell, the elastic solids are considered in this paper because the solid elements can be used in general for any kind of structures whether they are thick or thin. The initial stress and buckling analysis is carried out by the commercial analysis code ANSYS. The sensitivity is computed by using the mathematical package MATLAB using the results of ANSYS. Several problems including straight and curved beams under compressive load, ring under pressure load, thin-walled section are chosen to illustrate the efficiency of the presented method.

• Computers and Concrete
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• 제31권5호
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• pp.371-384
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• 2023

Precast roofing systems employing prestressed elements often serve as smart structural solutions for the construction of industrial buildings. The precast concrete elements usually employed are highly engineered, and often consist in thin-walled members, characterised by a complex behaviour in fire. The present study was carried out after a fire event damaged a precast industrial building made with prestressed beam and roof elements, and non-prestressed curved barrel vault elements interposed in between the spaced roof elements. As a consequence of the exposure to the fire, the main elements were found standing, although some locally damaged and distorted, and the local collapse of few curved barrel vault elements was observed in one edge row only. In order to understand and interpret the observed structural performance of the roof system under fire, a full fire safety engineering process was carried out according to the following steps: (a) realistic temperature-time curves acting on the structural elements were simulated through computational fluid dynamics, (b) temperature distribution within the concrete elements was obtained with non-linear thermal analysis in variable regime, (c) strength and deformation of the concrete elements were checked with non-linear thermal-mechanical analysis. The analysis of the results allowed to identify the causes of the local collapses occurred, attributable to the distortion caused by temperature to the elements causing loss of support in early fire stage rather than to the material strength reduction due to the progressive exposure of the elements to fire. Finally, practical hints are provided to avoid such a phenomenon to occur when designing similar structures.

• 한국터널지하공간학회 논문집
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• 제6권4호
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• pp.279-290
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• 2004

이 논문은 I-단면 곡선강지보 (curved steel rib)의 등분포 하중 하에서, 비틀림 (warping)을 포함한, 외평면 (out-of-plane)의 안정성을 해석하였다. 미분구적법 (differential quadrature method, DQM)을 이용하여 다양한 경계조건, 굽힘각 (opening angles)과 강성매개변수 (stiffness parameter)에 따른 임계하중 (critical loads) 및 임계하중 매개변수 (dimensionless buckling parameter)를 계산하였고, Differential quadrature method (DQM)의 해석결과를 타 이론과 비교 분석 하였다. 또한 두 경계조건 (고정-고정, 고정-단순지지)하에서의 새로운 결과를 제시하였고, DQM을 이용한 곡선강지보의 좌굴해석은, 비교적 적은 요소 (grid points)를 사용하고도, 타 이론에 의한 해석적 결과에 비해 정확성과 안정성을 보여주었다.