• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.467-474
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• 2001

This paper is for the buckling and vibration analysis of thick plate with concentrated mass on a inhomogeneous pasternak foundation. A thick rectangular plate resting on a inhomogeneous pasternak foundation is isotropic, homogeneous and composite with linearly elastic material. In order to analyize plate which is supported on inhomogeneous pasternak foundation, the value of winkler foundation parameter(WFP) of centural and border zone of plate are chosen as Kwl and Kw2 respectively. The value of Kwl and Kw2 can be changed as 0, 10, 10 /sup 2/, 10 / sup 3/ and the value of SFP(shear foundation parameter) also be changed 0, 5, 10, 15 respectively. Finally, In this paper, buckling stress of rectangular plate on the inhomogeneous pasternak foundation, natural frequency of this plate with or without uniform in-plane axial stresses are calculated

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.465-472
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• 1998

In this study, analytic solution and finite element formulation for the free vibration analysis of thin-walled circular arch, based on linearized virtual work and Vlasov's assumption, including restrained warping effect and second order terms of finite semitangential rotations, is presented. The total potential energy is derived by applying the Hellinger-Reissner principle. In this formulation, all displacement parameters of deformation are defined at the centroid axis. For the finite element formulation, the two node cubic Hermitian polynomials are utilized as shape functions. In special case, potential energy functional of thin-walled curved beam with monosymmetric cross section is derived. From this methodology, analytic solution for the free vibration of monosymmetric circular arch with simply supported is derived. In order to illustrate the accuracy of this study, various parameter studies for free vibration of circular arches are presented and compared with numerical solution analyzed by the FEM using straight beam element.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.431-438
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• 1998

An efficient solution method is presented to solve the eigenvalue problem arising in tile dynamic analysis of non-proportionally damped structural systems with multiple or close eigenvalues. The proposed method is obtained by applying the modified Newton-Raphson technique and the orthonormal condition of the eigenvectors to the quadratic eigenvalue problem. Even if the shift value is an eigenvalue of the system, the proposed method guarantees nonsingularity, which is analytically proved. The initial values of the proposed method can be taken as the intermediate results of iteration methods or results of approximate methods. Two numerical examples are also presented to demonstrate the effectiveness of the proposed method and the results are compared with those of the well-known subspace iteration method and the Lanczos method.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.349-356
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• 1998

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the three span continuous reinforced concrete bridge with elastic intermediate supports in presented. Such bridge represents either concrete or sandwich type three span bridge on polymeric supports for passive control or on actuators for active control. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purpose, In this paper. The influence of the modulus of the foundation and $D_{22}$, $D_{l2}$, $D_{66}$ stiffnesses on the natural frequency is thoroughly studied.d.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.373-380
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• 1998

Generally the excessive caused by isolated sources in localized to members closely located to the vibration sources. In this case it may not be economical to model the whole structure to obtain the responses of a specific member. In this study, a substructuring technique has been used for local vibration of a framed structure. The boundary conditions of members selected are determined by condensing the degrees of freedom of the remaining members. Fixed and hinged boundary condition are also assumed for comparison. According to the results, the substructuring technique is quite efficient in predicting the responses of a structure on which the vibration source in located, but is not very reliable for the members located for away from the source.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
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• pp.266-273
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• 1995

An efficient dynamic analysis method is developed f3r building structures subjected to ground home loadings. The soil medium is modeled using the finite elements and infinite elements. Then, the dynamic stiffness of the soil medium is calculated at the interfacial nodes between the soil and the building foundation. The equivalent subway loading at the interfacial nodes are obtained from the wave propagation analysis of the subway loading through the soil medium. The dynamic response of the building Is computed using the mode superposition method equipped with gauss-seidel iteration technique. The analysis is carried out by the frequency domain and the time domain methods.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.11-16
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• 2002

The differential equations governing free vibrations of the elastic, horizontally curved beams with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates, in which the effect of torsional inertia is included. Frequencies are computed numerically for the sinusoidal curved beams with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without torsional inertia, as functions of three non-dimensional system parameters: the horizontal rise to chord length ratio, the span length to chord length ratio, and the slenderness ratio.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
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• pp.341-348
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• 1998

A method of calculating the natural frequency corresponding to the first mode of vibration of beams and tower structures, with irregular cross sections and with arbitrary boundary conditions was developed and reported by Kim, D. H. in 1974. In this paper, the result of application of this method to the subject problem is presented. The structure considered for this report is two span continuous special orthotropic plates with elastic intermediate support. The use of elastic support as one of the passive control means is common. Any method may be used to obtain the deflection influence surfaces needed for this vibration analysis. Finite difference method is used for this purposa in this paper. The influence of the modulus of the foundation, and $D_{ij}$ stiffnesses on the natural frequency is thoroughly studied.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.414-421
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• 2001

Recently, the damping effect of building structures are greatly reduced because the use of non-structures members as like curtain wall are decreased and large open space are in need for the service of buildings. Assembly and office buildings with a lower natural frequency have a higher possibility of experiencing excessive vibration induced by human activities as like jumping, running and walking. These excessive vibration make the occupants uncomfortable and the serviceability deterioration. The common method of application of walking loads for the vibration analysis of structures subjected to walking loads is to inflict a series unit walking load and a periodic function at a node. But this method could not consider the moving effect of walking. In this study, natural frequency and damping ratio of plate structure are evaluated by heel drop tests. And new application of equivalent walking loads are introduced for vibration analysis of real slab system subjected to walking loads. The response obtained from the numerical analysis are compared well to the results measured by experimental tests. It is possible to efficiently analyze the vibration of floor which is subjected to walking loads by applying equivalent walking loads.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.35-42
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• 1999

This study is to analyze the buckling and the vibration of the rectangular stiffened plates with elastic springs by Finite Element Method. Boundary conditions are two types, one is all simply supported edges, another all clamped edges. To validate Finite Element Method, the buckling stresses of the stiffened plates without elastic springs are compared with the existing ones. The natural frequency parameters of the stiffened plates with or without elastic springs by Finite Element Method are also compared with the ones of SAP2000. The natural frequency parameters and the buckling stresses of the stiffened plates with elastic springs by Finite Element Method are calculated for the variation of the stiffness of the elastic springs and aspect ratio.