• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11a
• /
• pp.459-464
• /
• 2001

Vibration control of a plate using an optical fiber sensor and a PZT actuator is considered in this study. An aluminum plate with attached Extrinsic Fabry-Perot Interferometer (EFPI) and PZT actuator is prepared for experimental investigation. Vibration level of EFPI that can represent the mechanical strain without severe distortion is validated by forced vibration experiment. A numerical model of the plate is constructed based on the experimentally obtained frequency responses, and an optimal controller is designed for the multi-modal vibration suppression. It is found that the vibration level of the first three modes can be greatly reduced. The effect of low-pass filtering used to eliminate high frequency noise on the stability and control performance is also considered.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.9
• /
• pp.881-887
• /
• 2007

This paper is concerned with the vibration analysis of a rectangular plate with multiple rectangular holes. Even though there have been many methods developed for the addressed problem, they suffer from computational time. In this paper, we applied the Independent Coordinate Coupling Method(ICCM) to the addressed problem, which was developed to compute natural vibration characteristics of the rectangular plate with a rectangular hole and proven to be computationally effective. The ICCM is based on Rayleigh-Ritz method but utilizes independent coordinates for each hole domain. By matching the deflection conditions for each hole imposed on the expressions, we can easily derive the reduced mass and stiffness matrices. The resulting equation is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the Independent Coordinate Coupling Method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.10a
• /
• pp.136-142
• /
• 2011

The equations of motion for composite plates incorporating magneto-thermo-elastic effects have been derived via Hamilton's principle. In order to get the insight into the implications of a number of geometrical and physical features of the system, the vibrational responses of finite composite rectangular plates immersed in a transversal magnetic field are investigated by applying the extended Galerkin method. The vibration response characteristics of a composite plate are exploited in connection with the magnetic field intensity, thermal load, and electric conductivity of fibrous composite materials. Some pertinent conclusions, which highlight the various effects induced by the magneto-thermo-elastic couplings, are outlined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.831-835
• /
• 2003

The objective of this paper is to suggest an experimental technique to measure the out-of-plane vibration intensity of a coupled plate. In order to measure the out-of-plane vibration intensity of the plate, the frequency response technique has been implemented. In this technique, the 2-D intensity vector at a measurement point has been estimate from the frequency response functions measured at 4 points in the neighborhood of the measurement point. The experimental result has been compared with a theoretical result. It showed that the experimental technique can be effectively used to measure the out-of-plane vibration intensity of plates.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.12 s.105
• /
• pp.1398-1407
• /
• 2005

This paper is concerned with the vibration analysis of a rectangular plate with a rectangular hole. Even though there have been many methods developed for the addressed problem, they suffer from computational time. In this paper, we developed a new methodology called Independent Coordinate Coupling Method which can couple two independent coordinate systems for the entire plate domain and the hole. By matching the deflection condition imposed on the expressions, the relationship between the global axes and the local axes is derived. This formula is then used for the calculation of the eigenvalue problem. The numerical results show the efficacy of the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.05a
• /
• pp.816-820
• /
• 2003

The objective of this paper is to develop an experimental technique to measure the in-plane vibration intensity of a plate. In order to measure the in-plane vibration intensity at a data point, the frequency response functions for the 2 components of an acceleration vector are measured at each point of 4 points in the neighborhood of the data point. This experimental technique has been implemented to measure the in-plane vibration intensity of a plate. The experimental result has been compared with a theoretical result. It showed that the experimental technique can be effectively used to measure the in-plane vibration intensity of plates.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1010-1014
• /
• 2001

A severe strip vibration in continuous galvanizing line facilities of the steel companies has sometimes occurred due to the exceeding wearing of the roll bush and bearing. This vibration brings on the lack of uniform coating thickness in steel plate. As a result, the total maintenance and product costs in this factory are increased by the shortage of operation time for the replacement of bush, bearings and these components. In this study, the vibration characteristics of this strip are investigated by the FEM using ANSYS. Also the vibration measurement of strip and its structure performed by the laser Doppler vibrometer(LDV) and accelerometers are compared to theoretical analysis results.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.110.1-110.1
• /
• 2016

국내외 최첨단 반도체 및 평판 디스플레이 공정에서 필요한 개별 건식 진공펌프들의 자기진단을 통한 예지보수의 실시간 구현 장치 개발과제의 2차년 전반기 수행된 연구결과의 일부를 본 논문에서 소개한다. 본 연구에서 최종 목표로 설정하고 있는 "smart" 진공펌프란 운전상태에 관련된 변수들의 측정치를 기반으로 한 자기진단 (self-diagnostics) 기능을 내장한 차세대 공정용 진공펌프를 의미한다. 1차년에 선정된 상태진단용 진공펌프의 상태변수(state variable)들의 효과적인 수집을 구현하기 위한 연구가 진행되었다. 기존의 반도체 공정용 진공펌프들에서 측정하고 있는 상태변수로는 온도, 유량, 배기관 압력, 모터 소비전류 등과 같은 정적인 변수들뿐 아니라, 회전기계류의 상태진단에 필수적인 진동신호를 추가한 상태 변수 수집 장치를 개발하였다. 본 연구팀은 진공펌프의 회전진동을 유발하는 대표적인 부품은 회전체, 베어링, 그리고 치차로 이들 3 종의 회전진동성분들을 효과적으로 측정할 수 있는 신호처리 기법을 개발하였다. 금번 연구에서 채택한 진동신호 처리기법은 초고속 FFT 변환 기반의 주파수 대역 별 진동 레벨 환산과 더불어 다단계로 구성된 디지털 필터 (multi-staged decimation filter) 기법을 개발 적용하였다. 이러한 신호처리 기법을 통하여 측정된 진동 신호로부터 회전체, 베어링, 그리고 치차의 회전 진동성분을 효과적으로 측정하는 방법을 금번 학술대회에서 소개한다. 그리고, 진공펌프 상태진단에 필요한 상태변수의 실시간 backup 방법, 그리고 공정관리 server와 통신기능, 그리고 펌프 현장 관리자용 PC와 통신 기법 등 상태변수 측정 모듈의 확장성에 대한 기술적 내용을 소개한다.

• Journal of the Society of Naval Architects of Korea
• /
• v.35 no.4
• /
• pp.76-86
• /
• 1998

Structural intensity of plates experiencing bending vibration is analytically evaluated using the modal analysis based on assumed mode method. To evaluate the convergence of structural intensity according to the number of superposition modes, the power obtained by structural intensity integration over the closed curve containing the excitation source is compared with the power injected into plates. The erect of power reduction due to the material internal loss is evaluated using the intensity around a localized damping point, In addition, the dominant component among internal forces in the power transfer by the bending vibration of plates and the change of power flow due to stiffener are also investigated.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.22 no.3
• /
• pp.635-643
• /
• 1998

A spectral element method(SEM) is introduced for the vibration analysis of a rectangular plate subject to dynamic concentrated loads. First, the spectral plate element is derived from the relations between the forces and displacements along the two opposite edges of plate element. The global spectral matrix equation is then formulated by assembling two spectral plate elements so that the dynamic concentrated load is located at the connection nodal line between two plate elements. the concentrated load is then spatially Fourier transformed in the direction of the connection nodal line to transform the two-dimensional plate problem into a simplified equivalent one-dimensional beam-like problem. We may benefit from these procedures in that the spectral results from the present SEM is compared with the exact analytical solutions to prove the remarkable accuracy of the present SEM, while this is not true for conventional finite element solutions, especially at high frequency.