• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제17권7호
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• pp.565-571
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• 2007

In the process of accurate manufacture and measurement, it is necessarily required to isolate external or internal vibration due to external disturbance and internal actuators. The higher vibration isolation system gets damping around resonance, the better it is generally. This paper analyzes the performance of an existing passive air-spring for vibration isolation table by using experiment and simulation. Optimal design for a passive air spring can be obtained by tuning the size of the orifice. Also design for an active isolation system is carried out by applying PID controller and considering non-linearity of pneumatic characteristics with help of look-up table. We have developed the active vibration isolation table with the better isolation performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제20권11호
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• pp.1046-1051
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• 2010

This paper presents design and performance evaluation of magnetorheological(MR) damper for integrated isolation mount. The MR damper needs two functions for the integrated isolation mount. The one is vibration absorption and the other is isolation of vibration transmission. For vibration absorption, the MR damper requires wide damping force range. And for isolation of vibration transmission, the friction of MR damper needs to be eliminated. In order to achieve this goal, a novel type of MR damper is originally designed in this work. Subsequently, the MR damper is mathematically modeled and its damping force characteristics are evaluated. In addition, the vibration control performance of the MR damper associated with the stage mass is evaluated. From the result, this paper evaluates the performance of MR damper for integrated isolation mount.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.831-836
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• 2006

In the process of accurate manufacture and measurement, it is necessarily required to isolate external or internal vibration due to external disturbance and internal actuators. The higher vibration isolation system gets damping around resonance, the better it is generally. This paper analyzes the performance of an existing passive air-spring for vibration isolation table by using experiment and simulation. Optimal design for a passive air spring can be obtained by tuning the size of the orifice. Also design for an active isolation system is carried out by applying PID controller and considering non-linearity of pneumatic characteristics with help of look-up table. We have developed the active vibration isolation table with the better isolation performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.415-420
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• 2000

This paper describes a part of the results obtained in the process of the development of thin sound isolation sheets filled mineral compound powder with PVC. The raw materials used are pyrophillite, pottery stone and graphite. The physical properties such as the crystal structures, compositions, and specific gravities, etc. of raw materials are analyzed and discussed from a point of view of sound isolation material. From the analysis of experimental results, the particle size and the additive amount of mineral compound powder for manufacturing sample isolation sheets are decided. The resistant capability against fire of sound isolation sheets including mechanical, thermal and physical properties is tested. The transmission loss measuremenst of sound isolation sheets are performed using two-microphone method in an impedance tube. It is shown that the sound isolation capability of thin sheets has an excellent performance in excess of the object of development.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.324-329
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• 2012

Isolation tables are widely used for precision equipments and their isolation performances have been usually expressed and evaluated by transsmissibility. However, transmissibility is a concept for 1-degree of freedom(DOF) system. In practice, isolation tables are supproted by more than 4 springs. Each spring is subjected to vertical and horizontal ground vibrations, and also the table has more than 1-DOF. Therefore, isolation tables should be treated as multi-input/multi-output(MIMO) system of which isolation performance is expressed by transmissibility matrix. However, the matrix is too complicated to be an index for a system. In this paper, maximum singular value of transmissibility matrx is suggested as a simple performance index of a MIMO isolation system. Physical meaning of singular value is explained using a simple a 2-DOF isolation table. Furthermore, maximum singular values of passive, 3-DOF active and 6-DOF active isolation tables are obtained through experiments, and their meaning are explained and compared with each other.

• Journal of the Korea Institute of Military Science and Technology
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.472-472
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• 2009

The safety of cultural properties, medical treatment and electrical communication equipments in a building was hardly considered against the earthquake induced vibration, while the integrity of the building structure has been taken into account through the resistant earthquake design. This paper presents design of a seismic isolation table for both indoor and outdoor electrical communication equipment. First of all, artificial earthquake waves compatible with floor and ground response spectra for electrical communication equipments are generated using previously recorded seismic waves. Two kinds of one-degree-of-freedom seismic isolation table systems: spring-linear damper and spring-friction damper systems are considered and their responses to artificial earthquake waves are simulated. Design parameter study for two seismic isolation tables are performed through simulations and a seismic isolation table for both indoor and outdoor electrical communication equipment is designed considering the simulation results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.59-64
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• 2001

Recently, among those general contractors and construction material production companies in korea, this concept is lively obtained to reduce the floor impact sound. This attempt is continuously tried for developing the floor impact isolation material. However the assesment of the isolation performance is often ignored and even there seems no differences in comparison with the general the isolation performance of the floor impact. This is often occurred for their only respect with the material of the floor impact isolation performance. Therefore, this study analysed the expected problems for site application of currently applied the isolation material and its capacity which as the floor impact reducing material, and presented several major assesment items and checklist which should be inspected in advance of their development or site application.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제16권3호
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• pp.307-312
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• 2006

In this study a vibration isolation system with the cradle-type support was designed so as to reduce the transient vibration due to positioning motion of the moving mass on worktable as well as to achieve the desired isolation efficiency on the floor vibration. The design procedure was performed in the two steps. The first step to select appropriate isolators to meet the isolation efficiency, and the second step is to reduce the transient vibration of the worktable by adopting the cradle-type support. After the application of the selected isolators with the cradle-type support to the system it was shown that the required vibration criterion(VC-D) was easily satisfied and that the undesirable transient vibration was reduced remarkably.