• Title/Summary/Keyword: Mechanical Vibration

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자기유변유체를 이용한 공학 장치의 설계 (Design of Magneto-rheological Fluid Based Device)

  • 김정훈;이종원;정병보;박영진
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집A
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    • pp.544-549
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    • 2001
  • The effect of power supply voltage on the performance limits in a laboratory Magneto-rheological fluid based device was identified by experiments. It suggests that the frequency range of motion for control be limited by the voltage attenuation due to the coil inductance and the maximum power supply voltage set for practical use of MRF devices. In this work, the magnetic and electrical characteristics of MRF device are investigated and a design procedure is formulated to achieve the desired performance for a given power supply.

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WIGNER-VILLE INTERPRETATION OF MUSICAL SOUND AND TRANSIENT VIBRATION SIGNALS

  • Kim, Yang-Hann;Park, Yon-Kyu
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
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    • pp.752-757
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    • 1994
  • Very often, one would like to have visual image of mechanical or acoustical events such as musical sound and transient vibrations. Conventional methods to visualize the signal, such as power spectrum, do not normally allow to cultivate the signal of interests due to their inherent limitation on transient signals. Other than the conventional method, one could use an instantaneous frequency which can reveal the variation of frequency in terms of time. Nevertheless it is quite sensitive to noise and can not resolve the frequency components of signals; normally produces additional components other than those of the signals. In this paper, we introduce the Wigner-Ville spectrum to see the transient characteristics of signal, especially musical sound and transient mechanical vibration signatures. For musical sound, several popular western classic music have been selected for the analysis. For the transient mechanical signature, the signals obtained from the car door experiment and the beam experiment are interpreted in terms of Wigner-Ville spectrum. Results demonstrate the visual expressions of transient signals; musical sound and vibrations.

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엘리베이터 직접 구동용 박형 영구자석 동기전동기의 진동에 관한 연구 (A Study on vibration of slim type Permanent Magnet Synchronous Motor for driving elevator)

  • 김성주;김경호;조윤현
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.6-8
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    • 2003
  • Electromagnetic system of motor is being minimized by superior magnetic material and advanced design technology. But this type of motor causes a serious vibration. This is a big problem of motor operation. To decrease a vibration, motor is need to be designed considering mechanical vibration. This paper study about torque, natural frequency and mechanical vibration according to displacement.

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ISO TC 108/SC2(기계.차량.구조물의 기계적 진동.충격의 측정 및 평가) 규격 제정 동향 (Standard Activity of ISO TC 108/SC 2 (measurement and evaluation of mechanical vibration and shock as applied machines, vehicles and structures))

  • 박종포
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문집
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    • pp.285-288
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    • 2002
  • In this paper, standardization activities and trends of ISO TC 108/SC 2 (measurement and evaluation of mechanical vibration and shock as applied machines, vehicles and structures) are reviewed.

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ISO TC 108/SC 2 (기계. 차량. 구조물의 기계적 진동-충격의 측정 및 평가) 규격 제정 동향 (Standardization Activity of ISO TC 108/ SC2 (Measurement and evaluation of mechanical vibration and shock as applied machines, vehicles and structures))

  • Park, Jong-Po
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.333.2-333
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    • 2002
  • In this paper, standardization activities and trends of ISO TC 108/SC 2(Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures) are reviewed.

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VIBRATION PROPERTIES OF PEARS

  • Kim, M. S.;H. M. Jung;Park, I. K.;Park, J. M.
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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    • pp.533-542
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    • 2000
  • Instrumentation and technologies are described for determining the vibration response characteristics of the pear with frequency range 5 to 320Hz. The computer program for controlling the vibration exciter and the function generator and for measuring the vibration response characteristics of the pear was developed. Mechanical properties such bioyield deformation, rupture deformation and apparent elastic modulus etc. were compared with the vibration response characteristics of the pear. The resonant frequency of the pear ranged from 53 to 102Hz and the amplitude at resonance was between 1.08 and 2.48g-rms. The resonant frequency and amplitude at resonance decreased with the increase of the sample mass, and they were slightly affected by mechanical properties such as bioyield deformation and rupture deformation. Regression analysis was performed among the relatively high correlated parameters from the results of correlation coefficient analysis.

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전기적-기계적 수동감쇠기를 이용한 빔의 진동제어 (Vibration Control of Beams Using Mechanical-Electrical Hybrid Passive Damping System)

  • 박철휴;안상준;박현철
    • 한국소음진동공학회논문집
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    • 제13권8호
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    • pp.651-657
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    • 2003
  • A new mechanical-electrical hybrid passive damping treatment is proposed to improve the performance of structural vibration control. The proposed hybrid passive damping system consists of a constrained layer damping treatment and a shunt circuit. In a passive mechanical constrained layer damping, a viscoelastic material damping layer is used to control the structural vibration modes in high frequency range. The passive electrical damping is designed for targeting the nitration amplitude in the low frequency range. The governing equations of motion are derived through the Hamilton's principle. The obtained mathematical model Is validated experimentally. The presented theoretical and experimental techniques provide invaluable tools for controlling the multiple modes of a vibrating structure over a wide frequency band.

A Magnetostrictive Force and Vibration Mode Analysis of 3 kW BLDC Motor by a Magneto-Mechanical Coupling Formulation

  • Shin, Pan-Seok;Cheung, Hee-Jun
    • Journal of Electrical Engineering and Technology
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    • 제6권1호
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    • pp.76-80
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    • 2011
  • This paper proposes a method to calculate magnetostrictive forces, displacement, and vibration modes of a large-scale Brushless DC(BLDC) motor by using a magneto-mechanically strong coupling formulation. The force is calculated using the energy method with magnetostrictive stress tensor. The mechanical vibration modes are also analyzed by using the principle of Hamilton and the calculated magneto-elastic forces acting on the surfaces of the stator. To verify the algorithm, 3 MW BLDC motor is simulated, and the forces, displacements, and vibration modes are calculated. The result shows that the mechanically stressed core has more deformation or displacements than those of the normal condition.

왕복동 수소 압축기의 진동 분석 및 평가 (Vibration Analysis of Reciprocating Hydrogen Compressor)

  • 조성원;이정환;김효중;최병근
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.1020-1025
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    • 2007
  • The reciprocating type hydrogen compressor is for high pressure and volume. However this type compressor makes pulsation caused by mechanical characteristic. This type compressor also makes noise and vibration that cause negative effect to machine and working condition. Therefore, diagnosis and countermeasure are needed to decrease vibration for safety on hydrogen compressor. therefore in this paper, the numerical analysis and vibration measurement is conducted in order to investigate vibration characteristic and to evaluation vibration condition, Respectively

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공진분기회로를 이용한 평판의 진동제어 (Vibration Control of Plates Using Resonant Shunted Piezoelectric Material)

  • 김영호;박철휴;박현철
    • 대한기계학회논문집A
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    • 제27권10호
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    • pp.1778-1784
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    • 2003
  • Vibration control of plates with a passive electrical damper is presented in this paper. This electrical absorber, piezoelectric patches connected with a resistor and an inductor in series, is analogous to the damped mechanical vibration absorber. For estimating the effectiveness of piezoelectric absorber, the governing equations of motion are derived using a classical laminate plate theory and Hamilton principle. The developed theoretical analysis is validated experimentally for a simply-supported aluminum plate in order to demonstrate the performance of passive electrical damper. The result shows that the vibration amplitude is reduced about 14dB for the targeted first vibration mode.