• 한국건축시공학회지
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• 제12권6호
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• pp.607-614
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• 2012

In this study, the evolution of the electro-mechanical impedance (EMI) of a piezoelectric (PZT) patch embedded in fresh cement paste was investigated to discuss the possibility of monitoring the setting process of cement-based materials using an EMI sensing technique. A tailored thin square PZT patch was embedded in cement paste before casting, and EMI signatures of the embedded patch were continuously measured from casting up to 12 hours. A standard penetration resistance test was performed to compare and correlate the evolution of EMI during the setting process. The results showed that EMI responses differ according to the age of the cement paste, and that the behavior of the EMI resonance peak has a clear correlation with the penetration resistance of the cement paste. Based on the results, it is concluded that an EMI sensing technique using embedded PZT patch can be effectively applied to monitor the setting process of cement-based materials.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.573-574
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• 2009

The feasibility of electro-mechanical impedance (EMI) sensing technique, utilizing piezo-ceramic (PZT) patches, for online strength gain monitoring of early age concrete is investigated. An experimental study is conducted on PZT patch instrumented concrete specimens. The applicability of the EMI sensing technique for strength gain monitoring is discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.772-775
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• 2001

This paper investigated that resonant frequencies of microstrip patch antenna were frequency aigle when PZT were used as the antenna substrates. The resonant frequencies of the antenna using the piezoelectric substrate were able to be controlled by applied voltage. The frequency variation of the air gap antenna was 16MHz when the voltage variation was 12[KV/cm].

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 전자세라믹스 센서 및 박막재료 반도체재료 일렉트렛트 및 응용기술
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• pp.164-167
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• 2000

This paper investigated that resonant frequencies of microstrip patch antenna were tunable when piezoelectric materals were used as the antenna substrates. The resonant frequencies of the air-gap antenna using the piezoelectric substrate were able to be controlled by applied AC voltage. The frequency variation of the antenn was great when PZT were applied voltage of the resonant frequency.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.568-574
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• 2004

On-line phase tracking of an extrinsic Fabry-Perot interferometer (EFPI) and experimental vibration control of a composite beam with a sensing-patch are investigated. We propose a sensing-patch for the compensation of the interferometric non-linearity. In this paper, a sensing-patch that comprises an EFPI and a piezo ceramic(PZT) is fabricated and the characteristics of the sensing-patch are experimentally investigated. A simple and practical logic is applied for the real-time tracking of optical phase of an interferometer. Experimental results show that the proposed sensing-patch does not have the non-linear behavior of conventional EFPI and hysteresis of piezoelectric material. Moreover, it has good strain resolution and wide dynamic sensing range. Finally, the vibration control with the developed sensing-patch has been performed using Fuzzy logic controller, and the possibility of sensing-patch as a sensoriactuator is considered.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.315-318
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• 2007

Non-Destructive Health Monitoring using PZT sensors is a major concern and has great significance for research about NDT (Non-Destructive Test). In this paper, we study about the guided wave measurement method using PZT sensors to find cracks and estimate locations. Two aluminum beams bonded with PZT sensors were tested for estimating about the guided wave propagation characteristics and shape of each beam are decided in terms of analytical purpose. NI Signal Acquisition Device and specially designed LabVIEW VI program were used for data acquisition and analysis. The measured data were progressed by using a high-pass filtering.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.188-191
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• 2005

Taguchi method is used to determine the optimal configuration of PZT (Lead Zirconate-Titanate) patch on the host structure for improving the performance of piezoelectric shunt system. The charges generated on the surface of PZT patch are selected to be the objective function in the Taguchi method. Full three dimensional finite element models are used to simulate vibration of smart panel and to obtain the admittance of the piezoelectric shunt system. Using Taguchi method in Minitab, the optimal model is obtained. The experiment with piezoelectric shunt circuit is performed to verify the validity of the optimal model comparing with initial model.

• Smart Structures and Systems
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• 제1권4호
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• pp.339-353
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• 2005

This paper presents the results of a feasibility study on an impedance-based damage detection technique using thickness modes of piezoelectric (PZT) patches for steel structures. It is newly proposed to analyze the changes of the impedances of the thickness modes (frequency range > 1 MHz) at the PZT based on its resonant frequency shifts rather than those of the lateral modes (frequency range > 20 kHz) at the PZT based on its root mean square (RMS) deviations, since the former gives more significant variations in the resonant frequency shifts of the signals for identifying localities of small damages under the same measurement condition. In this paper, firstly, a numerical analysis was performed to understand the basics of the NDE technique using the impedance using an idealized 1-D electro-mechanical model consisting of a steel plate and a PZT patch. Then, experimental studies were carried out on two kinds of structural members of steel. Comparisons have been made between the results of crack detections using the thickness and lateral modes of the PZT patches.

• 한국소음진동공학회논문집
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• 제14권8호
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• pp.726-733
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• 2004

On-line phase tracking of an extrinsic Fabry-Perot interferometer (EFPI) and experimental vibration control of a composite beam with a sensing-patch are investigated. We propose a sensing-patch for the compensation of the interferometric non-linearity. In this paper. a sensing-patch that comprises an EFPI and a piezo ceramic(PZT) is fabricated and the characteristics of the sensing-patch are experimentally investigated. A simple and practical logic is applied for the real-time tracking of optical phase of an interferometer Experimental results show that the proposed sensing-patch does not have the non-linear behavior of conventional EFPI and hysteresis of piezoelectric material. Moreover, it has good strain resolution and wide dynamic sensing range. Finally, the vibration control with the developed sensing-patch has been performed using Fuzzy logic controller, and the possibility of sensing-patch as a sensoriactuator is considered.

• 비파괴검사학회지
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• 제24권3호
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• pp.268-274
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• 2004

스마트 구조물에 적합한 탄성파 검출 센서로서 고분자 압전센서를 이용한 부착형 센서에 대한 연구를 수행하였다. PVDF와 P(VDF-TrFE)에 대하여 센서로서의 특성을 평가하였으며 상용화된 PZT 센서와 비교하였다. 음향임피던스가 서로 다른 여러 가지 재료에 고분자 압전센서를 부착하여 연필심 파괴 시 발생하는 탄성파를 검출하여 분석하였다. 센서의 직경이 증가함에 따라 검출 신호의 최대 진폭 값은 증가하였으나 센서의 주파수 검출한계는 감소하는 것으로 나타났다. 시편의 음향임피던스가 감소할수록 검출신호의 최대 진폭 값은 증가하였으며 주로 저주파수의 주파수 성분의 신호에 민감한 것으로 분석되었다. 전반적으로 P(VDF-TrFE) 센서가 PVDF 센서보다 감도 면에서 다소 양호한 것으로 나타났다.