• 소음진동
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• 제2권4호
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• pp.281-292
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• 1992

Two types of vibration problems are encountered in industrial field: active isolation and passive isolation. In a passive type of vibration isolation, a foundation of a delicated machinery such as TEM, SEM, inspection- probe test, photolithograph, etc. is designed to have a vibration amplitude lower than an acceptable limit. In an active type, the isolation is focused on the vibration reduction caused by the machine itself(pump, motor, press, compressor, etc.). The foundation for such a machine should be so designed as to reduce the transmitted vibration below the permissible level prescribed. At any case, a transmissibility and stability must to be considered. Since an active isolation type is aimed for a vibration source, it is useful to isolate the transmitted vibrations energy from a major vibration source at the specific location. In this paper, a designed methodology of double anti-vibration system has been examined in order to have low transmissibility and reliable stability. Also experiment of scale model behavior has been conducted. Finally, the experiment output of the transfer function is compared to the analytical data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.1026-1031
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• 2003

A vibration isolation system fur a large reverberation chamber (1,228㎥, 1,000ton) has been installed. The reverberation chamber generates loud noise and induces high level of vibration to perform spacecraft acoustic environmental tests. The isolation system prevents vibration transfer from the chamber to enclosure buildings. This paper describes logical design process and commissioning experiments of the system. Design criteria have been induced from rigid body model of the chamber. Finite element model has been employed to select the characteristics of rubber pads. A total of 21 rubber pads have been installed between the chamber and supporting pedestals. A sand bag of 800kg was dropped on the chamber floor to measure the natural frequency of the isolation system. Absolute transmissibility has been measured while generating 145㏈ in the chamber. The natural frequency of the chamber is 10.5㎐, which is 80% of estimated value. Overall transmissibility at working frequency range (25㎐-10,000㎐) is less than -6㏈.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.170-175
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• 2000

Vibration and vibration-induced noise, major sources of occupant complaint, are increasing in modern buildings, Lighter weight construction and equipment located in penthouses or intermediate level mechanical rooms increase structure-bone vibration and noise transmission. In this paper discusses about testing vibration isolation systems and about the effectness of floor flexibility for vibration transmission.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.448-453
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• 2001

This paper presents an analytical evaluation of the effect of motion on seismic responses of base isolated low-level building and experimental studies to evaluate isolation performances of a rubber bearing. Dynamic responses induced by earthquake were evaluated by response analyses, taking the rubber bearing of the base isolation devices into account. In the experiment, vibration tests were carried out using a model for rubber bearings as isolation devices against earthquake in order to investigate the isolation performances of the rubber bearings. Several kinds of rubber bearing for base isolated low-level building against earthquake are examined. As a result, it is shown that the effect of the motion on the response of the building and the base response is well controlled from a seismic design standpoint.

• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1066-1074
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• 2004

A vibration isolation system for a large reverberation chamber (1,228 $m^3$ and 1,000 ton) has been installed and verified. The reverberation chamber generates loud noise and induces high level of vibration while performing spacecraft acoustic reliability tests. The isolation system prevents vibration transfer from the chamber to the enclosure buildings. This paper describes design process and commissioning experiments of the system. Design criteria have been derived from rigid body model of the chamber. The stiffness of neoprene pads has been selected by employing finite element analysis of the reverberant chamber and isolation system. A total of 21 neoprene pads have been installed between the chamber and supporting Pedestals. A sand bag of 800kg was dropped on the chamber floor to measure the natural frequency of the isolation system. While 136.9 dB noise is generated in the chamber, absolute transmissibility of the isolation system has been measured. The measured natural frequency of the chamber is 10.2Hz, which is 80% of the predicted value. Overall transmissibility at working frequency range (25∼10.000 Hz) is less than -12.4 dB.

• 한국군사과학기술학회지
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• 제2권1호
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• pp.82-89
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• 1999

In this article, the performances of acoustic enclosure with double resilient mount system which was designed by ADD to reduce the radiated noise by main noise source of ships, was tested and evaluated. From test results, it was verified that the acoustic performances of acoustic enclosure satisfied the requirements; vibration isolation level at 1st stage mount system of 15 ㏈ and airborne noise reduction level of 20 ㏈ in broad band.

• 항공우주시스템공학회지
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• 제10권3호
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• pp.15-22
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• 2016

The on-board appendages of satellites with mechanical moving parts such as the fly-wheel, the control-moment gyro, the cryocooler, and the gimbal-type directional antenna can generate an undesirable micro-vibration disturbance, which is one of the main causes of the image-quality degradation that affects high-resolution observation satellites. Consequently, the isolation of the micro-vibration issue has always been considered as salient, and the micro-vibration is therefore the focus of this study wherein a complex system that can provide the dual functions of a guaranteed vibration-isolation performance and electrical energy harvesting is proposed. The vibration-isolation and energy-harvesting performances of the complex system are predicted through a numerical analysis based on the characteristics that are obtained from component-level tests. In addition, the effectiveness of the complex system that is proposed in this study is verified through an assembly-level functional-performance test.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.919-922
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• 2003

The correlation between noise and vibration by a heavy-weight floor impact was studied. The triggering technique was used for increasing the reliability and stability to measure the level of sound pressure, sound intensity and vibration acceleration. The simple finite element and rigid body analysis method were suggested to calculate the natural frequencies of the multi-layer floor system. The result show that the isolation material adapted to reduce the light-weight floor impact noise, causing the natural frequency lower, make resonance with dominant driving frequency, and increase the noise level very sharply. Therefore the noise level Peak in the region of low frequency, below 63Hz, would be related with the natural frequencies of the floor system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.269-274
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• 2004

The aims of this study were to Investigate the floor impact noise isolation performance of floating floor with isolation materials and propose the improvement direction of floor impact noise measurement method and evaluation classes using impact ball. Reduction of light-weight impact sound pressure level can be achieved by the finishing materials, such as vinyl finishing material and wooden flooring with isolation materials. Floor impact noise Isolation material which satisfy the properties of the floor impact noise isolation materials cause resonance in the low frequency band and worsen heavy-weight impact sound pressure level. Heavy-weight impact sound level can be reduced by using noise reduction flooring, ceiling and increase of slab thickness. Strong impact force in low frequency bang below 63Hz of bang machine is not similar to human impact source and causes some problem in evaluating heavy-weight impact noise but heavy-weight impact noise measurement and evolution using impact ball which is very similar to human impact is more reliable than bang machine. Correction value on the background noise and sensitivity of residents should be considered on the floor impact noise evaluation classes.

• 한국항공우주학회지
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• 제42권8호
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• pp.648-653
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• 2014

플라이 휠, 구동형 안테나, 기계식 자이로, 냉각기 등과 같이 기계적 구동부를 갖는 탑재장비는 궤도 운용 시 미소진동을 발생한다. 고해상도 관측위성의 영상품질 향상을 위해서는 주로 진동발생원으로부터의 미소진동이 주요 임무장비에 전달되지 않도록 진동절연기의 적용 등 추가적인 기술적 노력들이 요구된다. 본 연구에서는 항상 차폐의 대상으로 여겨진 미소진동에 주목하여 이로부터 전기에너지 재생이 가능하고 동시에 진동절연이 가능한 복합 시스템 구현을 위해 동 흡진기 형 전자기 하베스터와 결합된 수동형 진동절연 시스템을 제안하였으며, 수치해석을 통해 복합 시스템의 유효성을 입증하였다.