• Journal of KSNVE
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• v.11 no.3
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• pp.416-421
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• 2001

The flexural vibration of laminated composite beams with an electro-rheological(ER) fluid has been investigated to design a structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, mu1ti-layer laminated beams. The damping radio and modal damping of the first bending mode are calculated by means of iterative complex eigensolution method. Finite element method is used for the analysis of dynamic characteristics of the laminated composite beams with an ER fluid. For the validation of modeling methodology using viscoelastic theory the predicted dynamic properties are compared to the measured ones by author's previous work. They are in good agreement. This paper addresses a design strategy of laminated composite under flexural vibrations with an ER fluid.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.576-579
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• 2005

MR (Magneto Rheological) fluids are well known as a smart fluid and their application researches to control vibration have been conducted by many researchers. However, their dynamic properties have not been identified clearly yet. Therefore, the MR effect is investigated by using a rotational viscometer and a single degree of freedom system with an MR damper. The results obtained from the experimental study show that stiffness and viscous damping coefficients of the system with an MR damper are changed according to the variation of the applied current.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.638-643
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• 2005

This study is about a semi-active quarter car simulation method including a MR(magneto-rheological) damper. The MR damper was modeled as Spencer model that can capture nonlinear and hysteretic behavior. The parameters of the Spencer model were extracted from a random excitation test and optimum treatment of the test data. Then, a suspension control algorithm based on Sky-hook theory was applied for the quarter car simulation. Also, an experiment was dong using a quarter car simulator to confirm the simulation results with the Spencer MR damper model

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1991.04a
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• pp.175-181
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• 1991

정밀장비의 진동환경을 평가, 제어하기 위해서는 우선적으로 미진동 환경을 측정할 수 있는 장비와 기술이 필요하며, 방진 system 구성시 국내에서는 방진소재의 개발이 요구되고 있다. 그리고 진동에 민감한 정밀장비들을 사용 하는 반도체 및 정밀공장에서는 진동허용 기준을 나타내는 data sheet가 필 요하고 사용자측에서도 장비의 진동 test성적서를 장비구매시 제작사에 요구 할 필요성이 있다. TEM(투과형 전자현미경)의 경우 음압에 의한 가진문제도 대두되고 있으며 정밀장비가 최대의 성능을 발휘하기 위해서는 이러한 문제 를 검토해야 한다. 만일 국내에서 진동에 민감한 정밀장비를 제작시 장비의 진동 특성을 평가할 수 있는 실험장치와 기술이 필요하다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.228-229
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• 2008

In this study, we propose an effective method to improve the clarity and period of the beat in a ring structure. Ring is an simplified model of a Korean bell, in which beating vibration and sound are very important features. An equivalent ring theory is applied and finite element analysis on the equivalent ring is performed to determine the condition of the asymmetric element for the clear and proper period beat. The clarity and the period of the beat are improved by attacking asymmetric mass and decreasing local thickness. Using the equivalent ring, the amount and position of the local variation for the required beat condition are determined and the results are verified by experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.439-443
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• 2006

In this paper, a design of milli-gripper using piezoelectric actuator and flexible hinge structure has been suggested, and the dynamic characteristics of the milli-gripper has been analysed and improved. The milli-gripper consists of the operating and amplifier parts, and the perfomance of the gripper be heavily influenced by base excitation disturbances. The dynamic characteristics of milli-gripper has been measured by the FRF based on experimental modal analysis. It has been found by a series of experiments that the performance of the milli gripper using PID control is made a remarkable improvement in terms of gripping forces.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.498-501
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• 2006

When an object or objects, rigid or flexible, presents in incident sound field, the sound wave is scattered. This, we call, is scattered sound field. It, of course, depends on the amplitude and the direction of the incident sound field as well as the geometry and the surface impedance of the scatterer(object). This paper addresses the way to measure scattered sound field by using arbitrary incident sound wave. This means that the method can decompose the scattered field from measured sound field with respect to any magnitudes and directions of incident plane-waves.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.313-316
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• 2004

진공펌프의 상태를 미리 알고 대처하는 것은 수많은 진공펌프를 사용하는 반도체 회사에게는 경제적인 이익을 준다. 진공펌프의 상태를 파악하기 위해서는 실제 공정에서 많은 실험을 해야만 한다. 하지만 실제 공정에서 실험을 하기에는 많은 제약과 문제점들이 따른다. 이를 해결하기 위해 본 연구는 MFC(Mass Flow Controller)를 이용하여 실제 공정과 유사한 압력조건을 생성할 수 있는 시뮬레이션 시스템을 구축하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.1015-1021
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• 2002

Optical disk is the media which is used generally in data storage device, but it has a disadvantage in the vibration by spinning and the shock. For overcoming these disadvantage, we must control the optical disk to minimize the focusing error and tacking error. The present study investigates the disk profile for minimizing the focusing error subjected to environmental shock and weight of the disk. In this study, the disk is assumed to be a cantilever beam to determine the disk profile for the minimum displacement as to the shock considering only the first mode. Also, for the optimally determined profile by ADS program this paper recalculate the robust caltilever profile by using orthogonal array and ANOM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.187-189
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• 2002

This paper presents property of the squeeze mode type mount using Magneto-Rheological fluid(MR fluid). The mount can isolate multi-directional vibrations, and also effectively reduce the vibrations in a wide range of disturbance frequencies by controlling the applied magnetic field. The shape of the mount is the same that of squeeze film damper. In the present work, the performance of this mount was experimentally investigated according to changing the magnetic field strength.