• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.2
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• pp.183-195
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• 2003

In this study, the method of the finite element modeling for free vibration control of beam-type smart structures with bonded plate-type piezoelectric sensors and actuators is proposed. Constitutive equations for the direct piezoelectric effect and converse piezoelectric effect of piezoelectric materials are considered. By using the variational principle, the equations of motion for the smart beam finite element are derived. The proposed 2-node beam finite element is an isoparametric element based on Timoshenko beam theory. Therefore, by analyzing beam-type smart structures with smart beam finite elements, it is possible to simulate the control of the structural behavior by applying voltages to piezoelectric actuators and monitoring of the structural behavior by sensing voltages of piezoelectric sensors. By using the smart beam finite element and constant-gain feed back control scheme, the formulation of the free nitration control for the beam structures with bonded plate-tyPe Piezoelectric sensors and actuators is proposed.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.3
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• pp.33-39
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• 2007

This paper presents a detailed experimental study on the engineering and durability properties of nano mixed inorganic repair material with rehabilitation and enhancement of performance of concrete structure occur to crack. The performance of specimens was evaluated using bond strength, chloride ion ingress, carbonation and brine resistance. It was shown in the results of the experiments that it had a superior function in the bond strength under the standard and wet-dry condition of all the repair material. Moreover, it had a good function in the experiments for chloride ion ingress, carbonation and brine resistance. Judging from the above-mentioned results, it is expected to be used for the rehabilitation and enhancement of the performance of concrete structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.594-600
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• 2021

Curved beam structures are generally used as components in structures such as railroad bridges and vehicles. The stability analysis of curved beams has been studied by a large number of researchers. Due to the complexities of structural components, it is difficult to obtain an analytical solution for any boundary conditions. In order to overcome these difficulties, the differential quadrature method (DQM) has been applied for a large number of cases. In this study, DQM was used to solve the complicated partial differential equations for buckling analysis of curved beams. The governing differential equation was deduced and solved for beams subjected to uniformly distributed radial loads. Critical loads were calculated with various opening angles, boundary conditions, and parameters. The results of the DQM were compared with exact solutions for available cases, and the DQM gave outstanding accuracy even when only a small number of grid points was used. Critical loads were also calculated for the in-plane inextensional buckling of the asymmetric curved beams, and two theories were compared. The study of a beam with extensibility of the arch axis shows that the effects on the critical loads are significant.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.165-169
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• 1997

기존 구조물의 보강을 하는 데는 휨모멘트 및 전단력에 대하여 충분한 보강 효과를 가지는 것과 함께 시공성을 만족해야만 한다. 현재 연속 섬유시트 중 아라미드섬유시트(AFS) 및 탄소섬유시트(CFS)는 기존구조물의 보강재로 사용한 사례가 증가하고 있으나 합리적인 보강설계방법이 확립되어 있지 않은 현 시점에서는 적절한 보강이 이루어지지 않는 경우가 많다 AFS 및 CFS에 의해 RC보의 적절한 보강을 위해서는 AFS 및 CFS를 이용한 기존 콘크리트 구조물의 보강설계방법의 구축이 급선무이다. (중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.05a
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• pp.51-56
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• 1998

기계설비 및 구조물의 파괴는 대부분 예고 없이 일어나서, 인명이나 물적 재산에 많은 손해를 준다. 이러한 구조물의 파괴에 관여하는 재료파괴는 겉으로 보기에는 아주 간단하게 보이나 파괴가 일어나기까지 많은 원인과 과정이 있다. 한편, 각종 재해원인을 해석하고 그 구체적인 방지 대책을 수립하는 안전공학의 대상인 대부분의 기계 구조물 사고에는 그 원인, 과정 및 결과에서 파괴현상이 깊이 관여된다. 따라서 파괴 현상을 정량적으로 분석하는 것은 구조물의 안정성을 평가하는 데 매우 중요하다. (중략)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.2
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• pp.81-86
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• 2000

For on-shore structures, dynamic analysis becomes increasingly important as the water depth increases and the structural configuration becoines slenderer. In this study, an estimation method for equivalent three dimensional (30) hydrodynamic coefficients is introduced as a part of beam permutation technique development. The beam pemlUtation technique is being developed for obtaining an equivalent beam to a frame structure in order to reduce the degrees of freedom and thus the analysis time significantly. Two 3D structures are used in order to verify the obtained equivalent 3D hydrodynamic coefficients. Two commercial softwares, ANSYS and SACS, are used for the verification. The results of the present analysis are found to be satisfactory in comparison with those by the two softwares.

• Journal of Welding and Joining
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• v.10 no.4
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• pp.44-57
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• 1992

본 보에서는 용접 구조물의 파괴 방지를 위한 제반 용접 구조 설계에 대하여 전반적으로 기술 하였다. 현대 용접 구조물의 각 선급이나 spec.에서 규정한 식들에 의해 산정된 정적하중으로 구조 설계되는 종래의 방법과는 달리, 유한 요소 구조 해석에 의한 강도 평가, 외부하중의 직접 계산에 의한 보다 정확한 설계 하중의 설정 및 통계적 처리를 통한 합리적인 구조해석(피로강도 포함)등으로 설계되고 있다. 더우기 구조설계시 구조물의 취성파괴를 고려한 파괴강도 및 인성 개념을 도입하였을 뿐 아니라 균열의 존재와 성장을 파괴 역학적으로 해석하여 구조물의 조업 중에서의 파괴관리 및 제어도 실시할 수 있는 총합적인 설계에 의하여 용접 구조물은 제작되고 있다. 비록 구조물의 총합적인 구조 설계로 제작되었을지라도, 구조물의 사용 성능은 용접부의 특성에 의하여 크게 변하게 되므로 용접 설계의 역할을 매우 중요하다. 용접 설계란 용접시공법, 구조부재 및 용접재료의 선정, 용접 이음부의 구조적 형상과 세부 형상 및 그외 용접에 관련된 제 인자들을 상호 유기적으로 조합함으로써 보다 경제적이고 신뢰성 있는 용접부를 얻고자 함에 그 목적이 있다.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.6
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• pp.1-9
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• 2010

Most of shear wall structures require openings in shear walls and thus shear walls are linked by floor slabs or coupling beams resulting in the coupled shear wall structures. When these structures are subjected to seismic excitations, excessive shear forces are induced in coupling beams. Accordingly, brittle failure of coupling beams may occur or shear walls may yield first. To avoid this problem, damping devices can be installed in coupling beams. It can increase the vibration control effect and improve the seismic resistance performance of the coupled shear wall structure by avoiding stress concentration and the brittle failure of coupling beams. Based on this background research, an LRB (lead rubber bearing) was introduced in the middle of the coupling beam in this study and the authors investigated the seismic response control effect and stress distribution of the proposed system. To this end, a modeling technique that can effectively predict the structural behavior of coupled shear wall structures has been proposed. With this proposed technique, time history analyses of the example coupled shear wall structure subjected to seismic excitation were performed and the vibration control effects of the seismic responses were investigated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.290-291
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• 2011

본 논문에서는 열-전기-기계 하중 하의 지능형 복합재료 보 모델을 전산점근해석기법에 기초하여 개발하였다. 열-전기-기계 하중 하의 구조물은 지난 십년간 많은 연구가 있어왔으나, 주로 고전적 보 모델에 기반을 두어 진행되어져 왔다. 멀티피직스 환경하의 구조물은 여러 가지 하중의 조합과 이에 따른 연성효과의 고려가 필수적이다. 따라서 공학적인 가정이 없는 점근해석기법은 보다 정확한 등가 보 모델을 개발하는데 있어 기반요소가 될 수 있다. 본 연구에서는 3차원 멀티피직스 구성방정식으로부터 출발하여 점근기법을 적용 체계적으로 등가 보 모델을 유도하고 그 해석 결과를 고찰하고자 한다.

• Journal of Korean Association for Spatial Structures
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• v.7 no.1 s.23
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• pp.55-62
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• 2007

The Paper presents three methods for calculating the natural frequencies of cantilevered curved Beams. A summary is given of the development of two techniques: theoretic value and the result of the experiment. Theoretic value of curved beam vibration analysis are derived from complementary variational principles assuming as unknown stress-displacement result fields. In order to perform free vibration analysis of curved beam, Aluminum-made cantilevered curved beam is used in experiment. Experimental input and output signals are derived from the impact hammer and the one accelemeter are amplificated by an amplifier. The validity of the modal analysis method