• Title/Summary/Keyword: Impedance model

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Quantitative damage identification in tendon anchorage via PZT interface-based impedance monitoring technique

  • Huynh, Thanh-Canh;Kim, Jeong-Tae
    • Smart Structures and Systems
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    • v.20 no.2
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    • pp.181-195
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    • 2017
  • In this study, the severity of damage in tendon anchorage caused by the loss of tendon forces is quantitatively identified by using the PZT interface-based impedance monitoring technique. Firstly, a 2-DOF impedance model is newly designed to represent coupled dynamic responses of PZT interface-host structure. Secondly, the 2-DOF impedance model is adopted for the tendon anchorage system. A prototype of PZT interface is designed for the impedance monitoring. Then impedance signatures are experimentally measured from a laboratory-scale tendon anchorage structure with various tendon forces. Finally, damage severities of the tendon anchorage induced by the variation of tendon forces are quantitatively identified from the phase-by-phase model updating process, from which the change in impedance signatures is correlated to the change in structural properties.

A Study on the Electrical Circuit Model of the Electrode/Electrolyte Interface for Improving Electrochemical Impedance Fitting (전기화학적 임피던스 Fitting 개선을 위한 전극/전해질 계면의 전기회로 모델 연구)

  • Chang, Jong-Hyeon;Pak, Jung-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.6
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    • pp.1087-1091
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    • 2007
  • Exact impedance modeling of the electrode/electrolyte interface is important in bio-signal sensing electrode development. Therefore, the investigation of the equivalent circuit models for the interface has been pursued for a long time by several researchers. Previous circuit models fit the experimental results in limited conditions such as frequency range, type of electrode, or electrolyte. This paper describes a new electrical circuit model and its capability of fitting the experimental results. The proposed model consists of three resistors and two constant phase elements. Electrochemical impedance spectroscopy was used to characterize the interface for Au, Pt, and stainless steel electrode in 0.9% NaCl solution. Both the proposed model and the previous model were applied to fit the measured impedance results for comparison. The proposed model fits the experimental data more accurately than other models especially at the low frequency range, and it enables us to predict the impedance at very low frequency range, including DC, using the proposed model.

Modifications of Numerical Impedance Boundary Conditions Considering Incident Acoustic Pressure (음향 입사파를 고려한 수치적 임피던스 경계조건의 보정)

  • Kim, Min-Woo;Park, Yong-Hwan;Kim, Sung-Tae;Lee, Soo-Gab
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.344-348
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    • 2007
  • The acoustic liner has been used for the suppression of noise. The impedance characteristics of the acoustic liner are increased by the incident pressure. For the estimation of the acoustic liner on the incident acoustic pressure effect, the modified impedance model is suggested on the basis of the GE impedance prediction model. The modified impedance model is originated from the 3 parameter impedance model, and extended to the incident pressure parameter. The modified model is applied on the simple duct analysis with variant source pressure. Through the computation, it is observed that the fore directivity patterns of the duct are varied by the incident SPL level.

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Acoustic impedance model of perforated elements with both grazing and bias flow (스치는 유동과 관통 유동의 영향을 고려한 천공 요소의 음향 임피던스 모델)

  • Lee, Seong-Hyun;Ih, Jeong-Guon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1372-1375
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    • 2006
  • The simplified impedance model which can consider a combined flow condition was suggested. Although the strength and position of the shear layer cannot be obtained by a linear sum of two separate contributions when both flows occur together, it was simply assumed that the impedance under the combined flow follows from summing the separate flow impedance. To validate the simplified impedance model, acoustic properties of a concentric resonator was predicted and measured. The predicted transmission loss using the simplified model shows reasonable agreements with measurements. One can find that the simplified impedance model obtained by the superposition of the separate flow impedances can be adjusted to predict the acoustic properties of a concentric resonator.

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An Investigation on the Acoustic Impedances and Estimation Models of Multiple Layer Perforated Plate Systems (다중 다공판 시스템의 음향임피던스와 계산모델에 관한 고찰)

  • 이동훈;허성춘;허성욱;김민배
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1238-1243
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    • 2002
  • In this study, the validity of the acoustic impedance model and the estimation model by electro-acoustic analogy suggested by Maa for predicting the absorptive performance of multiple layer perforated plate systems is investigated. From the comparison between the experiment and calculation for the absorption performance of double layer perforated plate system, the calculated results of using Rao and Munjal's impedance model and transfer matrix method are closer to the experimental values than those of using Maa's impedance model and electro-acoustic analogy. Therefore, in order to apply the acoustic impedance model and the estimation model by electro-acoustic analogy suggested by Maa to the multiple layer perforated plate systems, it is necessary that the suggested acoustic impedance and estimation models should be re-examined.

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Simulated Analysis for the Transient Impedance Behaviors of Counterpoises Subjected to the Impulsive Currents (임펄스전류에 의한 매설지선의 과도임피던스특성에 대한 모의해석)

  • Joe, Jeong-Hyeon;Lee, Bok-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.10
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    • pp.1861-1868
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    • 2009
  • A ground electrode subjected to lightning surge current shows the transient impedance behaviors. The ground electrode for protection against lightning should be evaluated in view of the transient grounding impedance and conventional grounding impedance, not ground resistance. The transient impedance characteristics of ground electrodes are influenced by the shape of ground electrode and the soil characteristics, as well as the waveform of lightning surge current. In order to propose a simulation method of analyzing the transient impedance characteristics of the grounding system in practical use, this paper suggests a theoretical analysis method of distributed parameter circuit model to simulate the transient impedance characteristics of counterpoise subjected to lightning surge current. EMTP and Matlab programs were employed to compute the transient grounding impedances of three counterpoises with different lengths. As a consequence, the simulated results using the proposed distributed parameter circuit model are in good agreement with the measured results.

Analysis for the impulsive impedance of counterpoise (매설지선의 임펄스임피던스의 해석)

  • Joe, Jeong-Hyeon;Kim, Jong-Ho;Beak, Young-Hwan;Kim, Dong-Seong;Lee, Gang-Su;Kim, Ki-Bok;Lee, Bok-Hee
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2009.05a
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    • pp.88-91
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    • 2009
  • For lightning currents, a grounding system shows the transient grounding impedance characteristics. A grounding system for protection against lightning should be evaluated by the transient grounding impedance, not it's ground resistance. The transient grounding impedance varies with the shape of ground electrode and earth characteristics as well as the waveform of lightning surge current. For the analysis and practical use of transient grounding impedance, the characteristics of transient grounding impedance should be analyzed theoretically and this paper suggests the theoretical analysis for the transient grounding impedance of counterpoise by using the distributed parameter circuit model. EMTP and Matlab are used to simulate the distributed parameter circuit model of counterpoise and the adequacy of the distributed parameter model of counterpoise is examined by comparing the simulated results with the measured results.

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Electrical Impedance Response Model of Concrete in Setting Process (응결 과정 콘크리트의 전기 임피던스 응답 해석 모델)

  • Shin, Sung Woo;Hwang, Garam;Lee, Chang Joon
    • Journal of the Korean Society of Safety
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    • v.29 no.5
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    • pp.116-122
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    • 2014
  • Assessment of setting process of concrete is important as it provides useful information to schedule concreting work in construction site. Electrical impedance measurement method, which utilizes the change of electrical resistance of concrete, has been applied to assess setting process of cement-based materials. However, the applicability of the method has been demonstrated only for cement paste and mortar. The main purpose of this research is to develop the electrical impedance based setting process assessment for concrete. To this end, electrical impedance response model for concrete should be developed in advance since it is essential to estimate the electrical resistance of concrete from measured impedance response. The electrical resistance of concrete is a key parameter for the setting process assessment. In this study electrical impedance responses of the concrete in setting process are measured and analyzed. Thereby, an electrical impedance response model of the liquid state concrete is developed and schematically validated.

Impedance Calculation of the Rectangular Power Plane by the Waveguide Model (구형 도파관 모델에 의한 직사각형 전원평면의 임피던스 계산)

  • Park Myun-Joo;Lee Byungje
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.12 s.91
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    • pp.1147-1151
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    • 2004
  • A novel impedance model is proposed fur the rectangular power plane along with the analytic impedance expression derived from it. The power plane is modeled as a section of a rectangular waveguide with appropriate boundary conditions around its periphery. As a result, the derived impedance expression based on the proposed model has the one-dimensional series form, which is simpler and computationally more efficient than the existing formula based on cavity model of the power plane.

High-Frequency Equivalent Circuit Model for Differential Mode Noise Analysis of DC-DC Buck Converter (DC-DC 벅 컨버터의 차동모드 노이즈 분석을 위한 고주파 등가회로 모델)

  • Shin, Juhyun;Kim, Woojung;Cha, Hanju
    • KEPCO Journal on Electric Power and Energy
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    • v.6 no.4
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    • pp.473-480
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    • 2020
  • In this paper, we proposed a high frequency equivalent circuit considering parasitic impedance components for differential noise analysis on the input stage during DC-DC buck converter switching operation. Based on the proposed equivalent circuit model, we presented a method to measure parasitic impedance parameters included in DC bus plate, IGBT, and PCB track using the gain phase method of a network analyzer. In order to verify the validity of this model, a DC-DC prototype consisting of a buck converter, a signal analyzer, and a LISN device, and then resonance frequency was measured in the frequency range between 150 kHz and 30 MHz. The validity of the parasitic impedance measurement method and the proposed equivalent model is verified by deriving that the measured resonance frequency and the resonance frequency of the proposed high frequency equivalent model are the same.