• Title/Summary/Keyword: acoustic actuator

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Suppression of Sound Radiation from Composite Plate Structures Using Piezoelectric Materials (압전재료를 이용한 복합재료 평판 구조물의 음향파워 억제)

  • 윤기원;김승조
    • Journal of KSNVE
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    • v.6 no.6
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    • pp.781-790
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    • 1996
  • The goal of current research is to suppress the acoustic noise radiated from vibration of composite plate structure. The induced noise can be reduced through the control of the corresponding structural vibration modes by using the piezoelectric materials as actuator. The acoustic fields are to be analyzed through the boundary element method (BEM) based on the Rayleigh intergral equation and structural system through the finite element method (FEM). The suppression of rediated sound is studied by adaping the piezoelectric material as the distributed actuator. Numerical results are presented on the sound radiation from composite plate of arbitrary boundary conditions, the noise reduction adapting the piezoelectric materials as distributed actuator. The results show the effectiveness and possibility of piezoelectric actuator in the control of sound radiation from composite structure.

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Optimal Design of a Piezoelectric Smart Structure for Cabin Noise Control (실내 소음제어를 위한 압전지능구조물의 최적 설계)

  • 고범진;이중근;김재환;최승복;정재천
    • Journal of KSNVE
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    • v.8 no.3
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    • pp.428-434
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    • 1998
  • Optimal design of a piezoelectric smart structure is studied for cabin noise control. A cubic shaped acoustic cavity with a flat plate which covers one side is taken as the problem. The sensor signal is returned to the actuator through a negative gain. The acoustic cavity is modeled using the modal approach which represents the pressure fields in the cavity as a sum of mode shapes of the cavity with unknown coefficients. By using orthogonality of the mode shapes of the cavity, finite element equation for the structure with the influence of the acoustic cavity is derived. The objective function is the average pressure at a certain region, so-called silent zone, in the cavity and the design variables are the locations and sizes of the piezoelectirc actuator and sensor. The optimal design is performed at several frequencies and the results show a remarkable noise reduction. To see the robustness of the optimally designed result, the configuration is used to examine the noise reduction at different frequencies. By adjusting the gain at each frequencies, it is possible to reduce the noise in comparison with the result when the actuator is not activated.

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Health Monitoring of a Composite Actuator with a PZT Ceramic during Electromechanical Fatigue Loading

  • Woo, Sung-Choong;Goo, Nam-Seo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.6
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    • pp.541-549
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    • 2007
  • This work describes an investigation into the feasibility of using an acoustic emission (AE) technique to evaluate the integrity of a composite actuator with a PZT ceramic under electromechanical cyclic loading. AE characteristics have been analyzed in terms of the behavior of the AE count rate and signal waveform in association with the performance degradation of the composite actuator during the cyclic tests. The results showed that the fatigue cracking of the composite actuator with a PZT ceramic occurred only in the PZT ceramic layer, and that the performance degradation caused by the fatigue damage varied immensely depending on the existence of a protecting composite bottom layer. We confirmed the correlations between the fatigue damage mechanisms and AE signal types for the actuators that exhibited multiple modes of fatigue damage; transgranular micro damage, intergranular fatigue cracking, and breakdown by a short circuiting were related to a burst type signal showing a shortly rising and slowly decaying waveform with a comparably low voltage, a continuous type signal showing a gradual rising and slowly decaying waveform with a very high voltage and a burst and continuous type signal with a high voltage, respectively. Results from the present work showed that the evolution of fatigue damage in the composite actuator with a PZT ceramic can be nondestructively identified via in situ AE monitoring and microscopic observations.

Development of Ultra-Micro Indentation Device using the PZT Actuator (압전구동기를 이용한 초미세 압입장치의 개발)

  • 박기태;박규열;홍동표
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.05a
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    • pp.51-55
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    • 1999
  • Recently, manufacturing work has been transformed to advanced technology intensive form from mass production with a little items required in the past. It was demanded that superior workpiece surface integrity. However, the study of ductile mode machining was proceeded actively.In this paper, it is developed Ultra-Micro Indentation Device using the PZT actuator. Experimentally, by using theUltra-Micro Indentation device, the micro fracture behavior of the silicon wafer was invesgated. It was possible that ductile-brittle transition point in ultimate surface of brittle material can be detected by adding an acoustic emission sensor system to the Ultra-Micro Indentation apparatus.

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Reduction Method of Acoustic Vibrating Plate Using Piezo Electric Material (압전 소자를 이용한 음향 진동 박판에 대한 제어 기법)

  • Jung, Do-Hee;Park, Seen-Ok;Kim, Woo-Young;Lee, Sang-Kee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.10
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    • pp.777-784
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    • 2003
  • Acoustic response control of a corner-pinned plate using piezoelectric wafers was studied, both theoretically and experimentally Three different sizes of aluminum alloy plates were used and available ball joints were employed to hold the plate at the four corners. The plate with the largest aspect ratio showed the largest and most clear responses to the acoustic excitation in the range of frequencies (0∼200 Hz), and sound pressure levels (80∼100 dB) as predicted. The reduction of the acoustic response of the plate by piezoelectric actuator was very significant, more than expected, but abatement of the sound transmission through the plate was only slightly altered by the piezoelectric actuator. This work is an original work extending earlier work with doors excited by acoustic fields. The important difference is the used of ball joints to simulate the joints.

Optimal design of a piezoelectric smart structure for cabin noise control (실내소음제어를 위한 압전지능구조물의 최적 설계)

  • 고범진;김재환;최승복
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.445-450
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    • 1997
  • Optimal design of a piezoelectric smart structure is studied for cabin noise control. A cubic shaped acoustic cavity with a flat plate which covers one side is taken as the problem. The sensor signal is returned to the actuator through a negative gain. The acoustic cavity is modeled using the modal approach which represents the pressure fields in the cavity as a sum of mode shapes of the cavity with unknown coefficients. By using orthogonality of the mode shapes of the cavity, finite element equation for the structure with the influence of the acoustic cavity is derived. The objective function is the average pressure at a certain region, so-called silent zone, in the cavity and the design variables are the locations and sizes of the piezoelectric actuator and sensor. The optimal design is performed at several frequencies and the results show a remarkable noise reduction.

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Design of Acoustic Element and Case for the Piezoelectric Acoustic Transducer (압전형 음향변환기용 음향소자 및 케이스의 설계)

  • 김현철;고영준;박재성;남효덕;장호경
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.711-714
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    • 2000
  • In this study, the physical properties of the acoustic element and case with metal-piezoelectric ceramics were analyzed. The dielectric and piezoelectric properties of 0.5 wt% MnO$_2$and NiO doped 0.1Pb(Mg$\_$1/3Nb$\_$2/3)O$_3$-0.45PbTiO$_3$-0.45PbZrO$_3$ceramics were investigated aiming at acoustic transducer applications. The vibration characteristics for the laminated circular plate was analyzed for the various thickness and diameter of the piezoceramic layer and metal layer. Also, the acoustic characteristics for the geometrical form of case have been investigated. The design and fabrication method worked in this paper can be utilized in development of actuator and acoustic device.

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Fabrication and Acoustic Characteristics of the Piezoeletric Acoustic Transducer (압전형 음향변환기의 제작과 음향특성)

  • 김현철;고영준;남효덕;장호경
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.413-416
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    • 2000
  • In this study, the physical properties of the acoustic element and case with metal-piezoelectric ceramics were analyzed. The dielectric and piezoelectric properties of 0.5 wt% MnO$_2$ and NiO doped 0.1Pb(Mg$_{1}$3/Nb$_{2}$3/)O$_3$-0.45PbTiO$_3$-0.45PbZrO$_3$ceramics were investigated aiming at acoustic transducer applications. The vibration characteristics for the laminated circular plate was analyzed for the various thickness and diameter of the piezoceramic layer and metal layer. Also, the acoustic characteristics for the geometrical form of case have been investigated. The design and fabrication method worked in this paper can be utilized in development of actuator and acoustic device.

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Formation of the Quiet Zone in an Automobile using Headset (헤드셋을 이용한 승용차 실내 저소음 영역의 생성)

  • Lee, Chul;Kim, In-Soo;Hong, Suk-Yoon
    • Journal of KSNVE
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    • v.7 no.2
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    • pp.301-310
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    • 1997
  • This paper presents active noise control method to form the near-field quiet zone for passengers in an automobile. The actuator model including interior acoustic plant, speaker and amplifier is experimentally identified in forms of auto-regressive and moving average by means of least mean square algorithm, The digital controller is composed of the regulator and Kalman filter to be designed based on LQG (linear quadratic gaussian). If the actuator model is prefiltered with digital filter to be properly designed for concentrating control performance index on the frequency band of primary noise source, LQG design approach can be effectively applied for the design of headset controller. Experimental results demonstrate that near-field quiet zone showing about 10dB noise reduction at microphone position can be formed using the headset located at passenger seat.

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