• 소음진동
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• 제7권5호
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• pp.803-810
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• 1997

This paper is concerned with the vibration control of multi-layer structure for ultra-tall buildings and main tower of large bridge etc. We have modeled the multi-layer structure with the distributed mass system as the lumped mass system of two-degree-of-freedom structure and made experimental equipment. The $H_\infty$control theory was applied to the design of the control system. The designed control system was simulated by computer. As a result, the designed $H_\infty$controller showed the good vibration control performance to impulse response and frequency response.

• 산업기술연구
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• 제29권A호
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• pp.19-25
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• 2009

The proper orthogonal decomposition (POD) analysis of vibration of a steel frame structure is performed to extract modal parameters. The theoretical background of the POD method is introduced briefly, and this technique is further applied to free vibration displacements of one bay-two story steel frame structure to extract the modal parameters. From the POD analysis of the steel frame structure, it is found that important modal parameters such as true mode shapes, modal kinematic energy, natural frequencies, and damping ratios can be obtained for the building efficiently and in detail. Therefore, it is concluded that the POD method could be one of the useful techniques in analysis of vibration of structures.

• Structural Engineering and Mechanics
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• 제55권2호
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• pp.413-434
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• 2015

The vibrations caused by metro operation propagate through surrounding soil, further induce secondary vibrations of the nearby underground structures and adjacent buildings. In order to investigate the effects of vibrations caused by metro on use performance of buildings, vibration experiment of Chengdu museum was carried out firstly. Then, the coupling tunnel-soil-structure finite element model was established with software ANSYS detailedly, providing a useful tool for investigating the vibration performances of structures. Furthermore, the dynamic responses and vibration predictions of museum building were obtained respectively by the whole process time-domain analysis and frequency-domain analysis, which were compared with the vibration reference values of museum. Quantitative analyses of the museum building performance were carried out, and the possible tendency and changing laws of vibration level with floors were proposed. Finally, the related vibration isolation measures were compared and discussed. The tests and analysis results show that: The vertical vibration responses almost increased with the increasing of building floors, while weak floors existed for the curve of horizontal vibration; The vertical vibrations were larger than the horizontal vibrations, indicating the vibration performances of building caused by metro were characterized with vertical vibrations; The frequencies of the museum corresponding to the peak vibration levels were around 6~17Hz; The damping effect of structure with 33m-span cantilever on vertical vibration was obvious, however, the damping effect of structure with foundation vibration isolators was not obvious.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.586-590
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• 2006

This paper presents a new vibration control device by which the mass and damping of a structure is increased equivalently. The vibration control system, named toggle-rotational inertia-viscous damper, can be utilized effectively in applications of small structural drift. Numerical analysis shows that because the relative drift of a structure can be effectively amplified by the toggle system, the device has a great performance in the vibration control without the increase of the damper capacity and size. It is also observed that vibration control effects is caused by the increase of equivalent mass and damping due to the rotational inertia and damping of the device.

• 한국해안·해양공학회논문집
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• 제23권1호
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• pp.18-25
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• 2011

본 연구에서는 진동기반 자기회귀모델을 이용하여 항만케이슨의 지반-구조 경계부 손상모니터링을 수행하였다. 이를 위해, 첫째, 케이슨 구조물의 지반-구조 경계부 손상모니터링을 위한 기법으로써 진동기반 자기회귀모델을 선정하였다. 둘째, 케이슨의 유한요소해석을 통하여 지반-구조 경계부 모니터링을 위한 진동기반 자기회귀모델 기법을 수치적으로 검증하였다. 마지막으로, 모형케이슨의 진동실험을 통해 진동기반 자기회귀모델 기법의 케이슨 지반-구조 경계부 손상 모니터링의 적용성을 검증하였다.

• 한국소음진동공학회논문집
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• 제25권5호
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• pp.337-344
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• 2015

As many of armored vehicles are seriously exposed to threat of IEDs(Improvised Explosive Devices) in the Afghanistan war and the Iraq war. V-shaped military vehicles are deeply studied in order to protect crews and mounted soldiers against land mines. Generally the experiment on full-scaled V-shaped structure needs excessively high cost, which becomes a huge barrier to study. In this paper, we explore the possibility to make a half-scaled model of the V-shaped structure by using the geometric similarity scaling. We demonstrate the geometric similarity scaling between the original model and the half-scaled model is established on the momentum and deflections of structure via computer simulations and experiments. At this stage, we conduct only numerical analysis of predicting vibration of V-shaped structure because measuring vibration of structure is difficult in the mass-explosion experiment, which is remained as future work.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.390-393
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• 2005

In this study, examined heavy-weight floor impact sound to rahmen structure(steel reinforced concrete structure) and bearing-wall structure(box frame type structure) that have slab thickness of 4 form at a standard laboratory through noise and vibration measured. The results of ANSYS modeling of structures was predicted that the nature natural frequency increased according to change of thickness of each slab by finite element analysis, and acceleration value decreased. Rahmen structures compares with bearing-wall structure, nature frequency was predicted low. Measurement results of natural frequency and acceleration level for structures at a standard laboratory, tendency department such as ANSYS modeling appeared. Rahmen structures appeared that reduction effect is less in Acceleration level and heavy impact sound transmission level comparing with bearing-wall structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.513-517
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• 2004

This study aims to evaluate factors of floor structure influencing to the floor impact sound. For this reasons, we measured the vibration of floor and the floor impact sound in moment flame structure. The main results from this study are that slab area and thickness are critical factors of the floor impact sound and aspect ratio slab is not verified in flor impact sound.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.463-470
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• 2000

In tunnel excavation by blast beneath the surface structures in urban area, the characteristics of ground vibration induced by blast and its influence on surface structures are analyzed by the field test and the numerical analysis on dynamic behaviors of the structure. According to the field test on the propagating characteristics of blast vibration through the rock mass and the concrete foundation pile. the attenuation index of peak particle velocity with distance shows the range of 1.7∼2.0 for the rock mass and the range of 2.0∼2.3 for the concrete pile. This shows that the blast vibration reduces more rapidly in the concrete pile. It is known from the numerical analysis on dynamic behavior of the structure that the coefficient of response, velocity ratio of structure response to input wave, is different according to the story of the structure. It can be said from this research that the characteristics of the ground vibration and the dynamic behavior of the structure should be well evaluated and be considered as important factors for safe blasting design especially in underground excavation at shallow depth in urban area.

• 동력기계공학회지
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• 제9권4호
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• pp.71-76
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• 2005

Marine structures are often in contact with inner or outer fluid as stern, ballast and oil tanks. The effect of interaction between fluid and structure has to be taken into consideration when we estimate the dynamic response of the structure appropriately. Fatigue damages can also be sometimes observed in these tanks which seem to be caused by resonance. Thin walled tank structures in ships which are in contact with water and located near engine or propeller where vibration characteristics are strongly affected by the added mass of containing water. Therefore it is essentially important to estimate the added mass effect to predict vibration characteristics of tank structures. But it is difficult to estimate exactly the magnitude of the added mass because this is a fluid-structure interaction problem and is affected by the free surface, vibration modes of structural panels and the depth of water. I have developed a numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present study, the effect of added mass of containing water, the effect of structural constraint between panels on the vibration characteristics are investigated numerically and discussed. Especially a natural frequencies by the fluid interaction between 2 panels and a breath mode of the water tank are focused on.