• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.12-19
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• 2001

In this study, the physical properties of the piezoelectric sounder with metal-piezoelectric ceramics were analyzed. The dielectric and piezoeletric properties of 0.5wt% 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 acoustic characteristics of a thin circular disc-type with metal-piezoceramics have been investigated. Also, the acoustic characteristics for the geometrical form of case were investigated. The piezoelectric sounder with 200kHz resonant frequency and 20kHz bandwidth was designed by considering the sharp directivity and the sound pressure.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.804-806
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• 1998

In this study, piezoelectric composites with 1-3-0 connectivity have been studied. A Piezoelectric ceramic PZT Prepared by Wet-Dry Combination method is used as a filler in mixture of Eccogel polymer matrix and third Phase. The density and stiffness of 1-3-0 type composites were decreased with increasing the third phase.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.877-880
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• 2001

This paper presents the new linear motion device so called "inch-worm" which gets large displacement by incrementally summing small displacements of PZT actuators. Dynamics stiffness of inch-worm is generally low compared to its driving condition due to the requirement of inch-worm like small size and light weight. This low stiffness may degenerate the positional precision of inch-worm. An inch-worm is realized using three PZT actuators, a monolithic moving device and a guide way frame. Driving input signal is shaped to reduce the residual vibration of inch-worm by LQG controller and cycloid step input. The practical feasibility of inch-worm is also examined by running test.ning test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.175-178
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• 2000

In this study, the ultrasonic transducer was fabricated with piezoceramic-polymer 1-3 type composites. Pulse-echo response of that transducer in water was investigated with variable water-level. Output of LED was under the control of the signal, which was analyzerd by the self-made Electric Unit. This paper represents automatically water-detecting system with variable water level. There was in good agreement water level between the virtual level and output signal by using the self-made water-detecting system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.283-286
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• 2000

In this study, the acoustic transducer of a thin circular disc-type with PZT/Metal was manufactured. The piezoelectric transducer with 200kHz resonance frequency was designed by considering the sharp directivity and the sound pressure. The dielectric and piezoelectric properties of 0.5 weight percent $MnO_2$ and NiO doped $0.1Pb(Mg_{1/3}Nb_{2/3})O_3-0.45PbTiO_3-0.42PbZrO_3$ ceramics were investigated aiming at acoustic transducer applications. Also, the acoustic characteristics of a thin circular disc-type with metal-piezoceramics have been Investigated.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.147-150
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• 2002

For lightweight and flexible structures, it is important to suppress the vibrations induced by interactions between fluid and structures. This paper presents the PPF/Adaptive control of the vortex-induced vibration of composite beam with rigid cylinder in which the fluid force is considered as an external excitation on the structure. For the problems considered here, the excitation frequency (vortex-shedding frequency) is assumed to be equal to the natural frequency of the structure. A pair of piezoceramic devices attached bottom of the composite structure was used as actuators. Simulation and experiment were carried out with the designed controller and effectiveness of the PPF/Adaptive PPF control was verified by both experimental and simulation results.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.22-26
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• 2001

In this paper, we examine the steady state dynamic electromechanical behavior of an eccentric Yoffe crack in a piezoelectric ceramic layer bonded between two orthotropic elastic layers under the combined anti-plane mechanical shear and in-plane electrical loadings. We adopted permeable crack face condition. Numerical values on the dynamic energy release rate are obtained. The initial crack propagation orientation for PZT-5H piezoceramic is also predicted by maximum energy release rate criterion.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.673-678
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• 2001

This paper proposes a new type of piezoactuator-driven valve system. The piezoceramic actuator bonded to both sides of a flexible beam surface makes a movement required to control the pressure at the flapper-nozzle of a pneumatic valve system. After establishing a dynamic model, an appropriate size of the valve system is designed and manufactured. Subsequently, a robust $H_{\infty}$ control algorithm is formulated in order to achieve accurate tracking control of the desired pressure. The controller is experimentally realized and control performance for the sinusoidal pressure trajectory is presented in time domain. The control bandwidth of the valve system, which directly represents the fastness, is also evaluated in the frequency domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.121-126
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• 2001

This paper presents the experimental study for the reduction of transmitted shock waves in smart structures incorporating MR insert. MR fluid is filled within the two aluminum layers and two piezoceramic disks are embedded on the host plate as a transmitter and a receiver of the shock wave. Pulse wave generated by the transmitter is transmitted to the receiver through the MR insert and the plate. By applying magnetic field to the MR insert, the amplitude of the transmitted shock wave is reduced remarkably. The attenuation performance is tested by changing the applied magnetic field on MR inserts in two ways: by changing angle of permanent rubber magnet from 90 to 5 with 5 decrements, by using electromagnet in which magnetic field is controllable. The propagating wave speed of MR insert is also investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.328.2-328
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• 2002

General modeling of a resonant shunting damper has been made Iron piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned eledtrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.