• Journal of Power System Engineering
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• v.3 no.4
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• pp.36-44
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• 1999

회로내에 capacitor를 부가 연결시켜 이론과 실험적으로 고찰한 새로운 기법의 연구이다. 종래에 사용되어 온 전자회로는 낮은 주파수의 진동진폭을 억제할 때에 큰 inductance 값을 필요로 하는 결점이 있었다. 이런 문제점을 해결하기 위하여 본 연구에서는 강화된 압전 분권회로에 병렬로 capacitor를 연결하도록 설계하였다. 새로운 기법은 기계적인 analogy 이론에 의해 증명을 하였으며, 알루미늄 보에 대하여 필요한 동조 모드에서 실험적으로 입증하였다. 따라서 이러한 결과들은 electronic passive damping 에 있어서 예전부터 요구되어 온 절반정도의 inductance값만으로도 구조물의 진동응답을 아주 심도 있게 감소시킬 수 있다는 것을 보여주고 있다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.216-221
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• 2002

In this paper, the transmitted noise reduction of smart panels of which passive piezoelectric shunt damping is used, is experimentally studied. Shunt damping experiments are based on the measured electrical impedance model. A passive shunt circuit composed of inductors, and a load resistor is devised to dissipate the maximum energy into the joule heat energy. For multi-mode shunt damping, the shunt circuit is redesigned by adding a blocking circuit. Also the optimal location of the piezoelectric patch is studied by FEM in order to cause the maximum admittance from the patch for each mode of aluminum plate. In results, the transmitted sound pressure level of panels is efficiently reduced for multi-modes

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.4
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• pp.37-42
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• 2001

Active vibration control of laminated composite plates has been carried out to design structure with maximum possible damping capacity, using piezoceramic sensor/actuators and passive constrained-layer damping treatment. The equations of motion are derived for symmetrical, multi-layer laminated plates. The damping ratio(ζ) and modal damping(2ζ$\omega$) of the first bending and torsional modes are calculated by means of iterative complex eigensolution method for both passive and active vibration control. This paper addresses a design strategy of laminated composite plate under structural vibrations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.624-629
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• 2003

In this paper, broadband shunt technique for increasing transmission loss is experimentally investigated. Piezoelectric shunt damping is studied using resonant shunt circuit and negative capacitor shunt circuit. A resonant shunt circuit is implemented by using a resistor and inductor. Negative Capacitor shunt damping is similar in nature to resonant shunt damping techniques, as a single piezoelectric material is used to dampen multi-mode. Performance of both methods is experimentally studied for noise reduction. This is based upon SAE J1400 test method and a transmission loss measurement system is provided for it. This paper will present the test setup fer transmission loss measurement and the tuning procedure of shunt circuits. Finally the results of sound transmission tests will be shown.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.148-153
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• 2001

Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained layer damping hale been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1089-1094
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• 2003

A main vibration source in HDD is arisen from high rotating disk/spindle, and vibration suppression of the disk-spindle system becomes a critical issue and a major concern for high performance of the drive. In this paper, we study the feasibility of suppressing unwanted vibration of disk-spindle system of the HDD by external shock and excitation utilizing piezoelectric shunt damping methodology. By considering dynamic characteristics of the disk-spindle system through modal analysis, a target vibration mode is determined and then the piezoelectric material is carefully integrated to the modified drive. In order to maximize improvement of vibration characteristics of the proposed system, shunt circuit is optimally designed via tuning processes. Finally, the vibration characteristics of the high rotating disk-spindle system of the proposed drive is experimentally evaluated in frequency domain.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.12
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• pp.950-955
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• 2002

The coupled finite/boundary element method is used in numerical analysis for acoustic radiation from the vibration of rectangular composite plate which is simply supported. This analysis is validated using the Wallace equation for an isotropic plate. Active control of sound fields has been tarried out using 3 pairs of piezoelectric sensor/actuator and a pair of viscoelastic material by Passive constrained layer damping treatment. The results show that the optimal placement of piezoelectric sensor/actuator and VE patch is required to control the sound fields from a vibrating composite plate.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.6
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• pp.169-174
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• 2001

Optimization of the collocated piezoceramic sensor/actuator placement is investigated numerically and verified experimentally for vibration control of laminated composite plates. The finite element method is used for the analysis of dynamic characteristics of the laminated composite plates with the piezoceramic sensor/actuator. The structural damping index(SDI) is defined from the modal damping(2$\omega$ζ) . It is chosen as the objective function for optimization. Weights for each vibrational mode are taken into account in the SDI calculation. The gradient method is used for the optimization. Optimum location of the piezoceramic sensor/actuator is determined by maximizing the SDI. Numerical simulation and experimental results show that the optimum location of the piezoceramic sensor/actuator is dependent upon the outer layer fiber orientations of the plate, and location and size of the piezoceramic sensor/actuator.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.6
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• pp.193-199
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• 2001

Active control of forced vibration of the cantilevered laminated composite plates using collocated piezoceramic sensor/actuator is analyzed numerically and verified experimentally for various fiber orientations. Impact on the stiffness and the damping properties is studied by varying stacking sequence of [$\theta$$_{4}$O$_{2}$90$_{2}$]s for the laminated composite plate. For the forced vibration control, the plate is excited by one pair of collocated PZT exciters in resonance and its vibrational response is suppressed by the other collocated PZT sensor/actuator using direct negative velocity feedback. It is shown that the active control of forced vibration is more effective for the smart laminated plate with higher modal damped stiffness(2ζ$\omega$/aup 2/) .

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.7
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• pp.261-266
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• 2001

The flexural vibration of laminated composite beams with active and passive constrained layer damping has been investigated to design a structure with maximum possible damping capacity. The equations of motion are derived fro flexural vibrations of symmetrical,. multi-layer laminated beams. The damping ratio and model damping of the first bending mode are calculated by means of iterative complex eigensolution method. The direct negative velocity feedback control is used for the active constrained layer damping. It is shown that the flexible laminated beam is more effective in the vibration control for both active and passive constrained layer damping. and this paper addresses a design strategy of laminated composite under flexural vibrations with constrained layer damping.