• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.5
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• pp.131-139
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• 2001

In this paper, aerials gas pipeline vibrations due to the passing of vehicles have been measured, and peak values and characteristics of vibration were analyzed. In order to develop isolation system for gas pipeline, six cases with various support condition and hanging method were tested. The hanger used instead of wore rope isolated almost all vibrations transmitted from main beam. In the results of test, we could decrease response of vibration velocity from 49 % to 56 % and response of vertical vibration acceleration from 49 % to 60 %, because hanger instead of wire rope was used and rubber pads instead of wooden shield plates at support positions for Proofing horizontal vibration were used.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.443-446
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• 2003

The vibration mode shape changed by the phase angle that can be controlled by phase-shifting ESPI system is discussed. For the phase-shifting ESPI experiment the stroboscopic illumination by using AOM(Acousto-Optic Modulator) is needed, and the initial phase angle can be adjusted by the program. The vibration mode shape is changed when the initial phase angle is changed. We examined the vibration mode shape change due to the initial phase angle change at each resonance frequency. Through this study, we found that in the vibration testing using phase-shilling ESPI the vibration mode shape is improved in the quality by adjusting exact phase angle and the error of the quantitative vibration analysis can be reduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.369.2-369
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• 2002

For the evaluation of the plasma display panel (PDP)'s noise, vibration and sound characteristics of fanless PDP are measured and investigated. PDP is a type of two-electrode vacuum tube which operatres on the same principle as a household fluorescent light. An inert gas such as argon or neon is injected between two glass plates on which transparent electrodes have been formed, and the glass is illuminated by generating discharge. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.147-152
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• 1992

본 연구에서는 같은 직경의 2개 원형구멍이 동축상에 있는 4변고정, 등반성 정사각형판의 자유진동특성을 충격진동실험과 유한요소 해서방법으로 원형 구멍직경의 변화에 다른 고유진동수와 무차원 진동수 매개변수를 구하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1992.10a
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• pp.153-157
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• 1992

본 연구에서는 복합재료와 혼합적층 외팔형 삼각판의 동적거동을 실험을 통하여 파악하였다. 또한 실험 결과들의 비교를 위해서 FEM 해석을 수행하였다. 실험과 FEM의 결과들은 고유진동수(Hz)로 제시하였고, 또한 참고문헌과의 비교를 위해서 무차원 진동수매개 변수로 나타내었다. 그리고 외팔형 삼각판의 노달라인을 나타내었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.47-55
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• 2003

Curved beams are one of the most important basic structural units as well as the beams, columns and plates. Most complicated structures consist of only these basic units and therefore it is very attractive research subject to analysis both the static and dynamic behavior of such units including the arches. The problems of free vibrations of curved beams have been the subject of much work due to their many practical applications.(an ellipsis)

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.85-90
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• 1996

In the word, there is varied types of vibration, and these affect the mechanical industry. In this paper is plates with two parallel sides fixed. Electronic speckle pattern interferometry (ESPI) is one of the optical nondestructive testing technique. By using the ESPI, vibration modes for excitation point, a/b(ratio of longuitudinal and lateral length), and kind of specimen are measured and compared qualitatively with theoritical analysis that Warburton proposed.

• Journal of the Korean Society of Safety
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• v.4 no.1
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• pp.47-58
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• 1989

This paper treats the vibration analysis of a simply supported rectangular plate stiffened with viscoelastic beams. The effect of viscoelastic beams on the vibration of the plate is analyzed by using Dirac delta function and the equation of motion can be expressed only one equation. The frequency equation is obtained by applying Laplace transformation. The effect of volumes, numben and aspect ratios of beam on the frequency of the plate is analyzed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.1
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• pp.56-63
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• 2004

Exact solutions are presented for the free vibration and buckling of rectangular plates haying two opposite edges ( x=0 and a) simply supported and the other two ( y=0 and b) clamped, with the simply supported edges subjected to a linearly varying normal stress $\sigma$$_{x}$=- $N_{0}$[1-a(y/b)]/h, where h is the plate thickness. By assuming the transverse displacement ( w) to vary as sin(m$\pi$x/a), the governing partial differential equation of motion is reduced to an ordinary differential equation in y with variable coefficients. for which an exact solution is obtained as a power series (the method of Frobenius). Applying the clamped boundary conditions at y=0 and byields the frequency determinant. Buckling loads arise as the frequencies approach zero. A careful study of the convergence of the power series is made. Buckling loads are determined for loading parameters a= 0, 0.5, 1, 1.5. 2, for which a=2 is a pure in-plane bending moment. Comparisons are made with published buckling loads for a= 0, 1, 2 obtained by the method of integration of the differential equation (a=0) or the method of energy (a=1, 2). Novel results are presented for the free vibration frequencies of rectangular plates with aspect ratios a/b =0.5, 1, 2 when a=2, with load intensities $N_{0}$ / $N_{cr}$ =0, 0.5, 0.8, 0.95, 1. where $N_{cr}$ is the critical buckling load of the plate. Contour plots of buckling and free vibration mode shapes ate also shown.shown.

• Computers and Concrete
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• v.25 no.6
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• pp.575-585
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• 2020

Based on a refined shear deformation finite strip, transient vibrations of graphene oxide powder (GOP) reinforced plates due to external pulse loads have been investigated. The plate has uniformly and linearly distributed GOPs inside material structure. Applied pulse loads have been selected as sinusoidal, linear and blast types. Such pulse loads result in transient vibrations of the GOP-reinforced plates which are not explored before. Finite strip method (FSM) has been performed for solving the equations of motion and then inverse Laplace transform technique has been employed to derive transient responses due to pulse loading. It is reported in this study that the transient responses of GOP-reinforced plates are dependent on GOP dispersions, GOP volume fraction, type of pulse loading, loading time and load locations.