Artículos de revistas: "Electromechanical admittance"

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Ai, Demi, Chengxing Lin, Hui Luo y Hongping Zhu. "Temperature effect on electromechanical admittance–based concrete structural health monitoring". Structural Health Monitoring 19, n.º 3 (9 de julio de 2019): 661–92. http://dx.doi.org/10.1177/1475921719860397.

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Concrete structures in service are often subjected to environmental/operational temperature effects, which change their inherent properties and also inflict a challenge to their extrinsic monitoring systems. Recently, piezoelectric lead zirconate titanate (PZT)-based electromechanical admittance technique has been increasingly growing into an effective tool for concrete structural health monitoring; however, uncertainty in the changes of monitoring signals induced by temperature impact on concrete/PZT sensor would inevitably cause interference to structural damage detection, which adversely hinder its application from laboratory to engineering practice. This article, aiming at exploring the temperature effect on the electromechanical admittance–based concrete damage evaluation, primarily covered a series of theoretical/numerical analysis with rigorously experimental verifications. Three aspects of comparative studies were performed in theoretical/numerical analysis: (1) thermal-dependent parameters were inclusively evaluated in contribution to the electromechanical admittance characteristics via PZT-structure interaction models; (2) three-dimensional finite element analysis in multi-physics coupled field was employed to qualitatively assess the singular temperature effect on the electromechanical admittance behaviors of free-vibrated PZT, surface-bonded PZT/inside-embedded PZT coupled healthy concrete cubes; and (3) depending on the modeling of surface-bonded PZT-/inside-embedded PZT-cracked concrete cube, thermal effect on damage evaluation was addressed via quantification on the electromechanical admittance variations. In the experimental study, rigorous validation tests were carried out on a group of lab-scale concrete cubes, where surface-bonded PZT/inside-embedded PZT transducers were simultaneously employed for electromechanical admittance monitoring in view of thermal difference between concrete surface and its inner part. Correlation coefficient deviation value-based effective frequency shifts algorithm was also employed to compensate the temperature effect. Moreover, temperature effect was further testified on the monitoring of a full-scale shield-tunnel segment structure. Experimental results indicated that temperature triggered different behaviors of electromechanical admittance signatures for surface-bonded PZT/inside-embedded PZT transducers and contaminated the electromechanical admittance responses for damage detection. Structural damage severity level can be disadvantageously amplified by temperature increment even if under the same damage scenarios.

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APARNA, M., M. RAGHAVENDER, G. PRASAD y G. S. KUMAR. "ELECTROMECHANICAL CHARACTERIZATION OF LANTHANUM-DOPED SODIUM BISMUTH TITANATE CERAMICS". Modern Physics Letters B 20, n.º 09 (10 de abril de 2006): 475–80. http://dx.doi.org/10.1142/s0217984906010664.

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The effect of lanthanum doping on the electromechanical properties of lanthanum-doped sodium bismuth titanate was studied. The ferroelectric system under investigation was Na 1/2( La x Bi 1-x)1/2 TiO 3 ceramics, with x=0, 0.1, 0.15 and 0.2. Admittance measurements were carried out in the frequency range of 100 Hz to 13 MHz and in the temperature range from room temperature to 550°C. Combined impedance and admittance spectroscopy was used to analyze admittance data. The electromechanical parameters were calculated from the resonant and anti-resonant frequencies obtained from vector admittance plots. The electromechanical coefficients for pure sodium bismuth titanate ceramic samples were found to be much larger than the reported values. Also, it was observed that lanthanum-doping decreased the values of electromechanical coupling coefficients.

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3

Xu, Guidong, Baiqiang Xu, Chenguang Xu y Ying Luo. "Temperature effects in the analysis of electromechanical impedance by using spectral element method". Multidiscipline Modeling in Materials and Structures 12, n.º 1 (13 de junio de 2016): 119–32. http://dx.doi.org/10.1108/mmms-03-2015-0015.

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Purpose – The purpose of this paper is to develop a spectral element modeling to predict electromechanical admittance in the surface-bonded piezoelectric wafer and beam structure considering temperature effects. Design/methodology/approach – For modeling the beam, the axial and transverse vibrations of the beam have been considered, and temperature-dependent mechanical and electromechanical properties of piezoelectric wafer active sensor and aluminum have been analyzed. The influences of temperature effects on electromechanical admittance are investigated. Findings – The results show that a frequency left shift and a decrease in amplitude of admittance in any natural frequencies with increasing temperature have been observed. The mechanism of these changes is discussed. Originality/value – The numerical results may be considered helpful for structural health monitoring using electromechanical impedance technique.

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4

Zuo, Chunyuan, Xin Feng y Jing Zhou. "A Three-Dimensional Model of the Effective Electromechanical Impedance for an Embedded PZT Transducer". Mathematical Problems in Engineering 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/218026.

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A three-dimensional model of the effective electromechanical impedance for an embedded PZT transducer is proposed by considering the interaction between a PZT patch and a host structure. By introducing an effective mechanical impedance, the coupled electromechanical admittance formulations are derived using the piezoelectric constitutive equations. Then, a modified methodology for monitoring structure changes using an electromechanical impedance (EMI) technique is proposed. In the proposed method, the changes in the host structure are monitored by using the “active” part associated with the structural mechanical impedance, which is extracted from the measured raw admittance signatures. The strength gain of a concrete beam with embedded PZT transducers during the curing age was monitored with the proposed methodology. The experimental results demonstrate that the use of the “active” part is more sensitive as opposed to the raw admittance signatures for structural health monitoring (SHM).

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Providakis, Costas P. "Repair of Cracked Structures under Dynamic Load Using Electromechanical Admittance Approach". Key Engineering Materials 348-349 (septiembre de 2007): 49–52. http://dx.doi.org/10.4028/www.scientific.net/kem.348-349.49.

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In the present paper, the repair of a cracked structure under dynamic load using the electromechanical admittance (EMA) approach is investigated. Conceptually, appropriate electrical field are applied on the outer surfaces of piezoelectric (PZT) patches to effect closure of the crack. This has the effect of altering the electromechnaical (E/M) admittance signature, extracted at the electrical terminals of a specific PZT patch, considered as an admittance calculating sensor (ACS) patch, towards that of the healthy structure, which is the criterion concept used for the repair in this paper. To demonstrate the present repair methodology, a cantilever 3D beam numerical example is considered in combination with a FEM-based minimization of the difference between the healthy and cracked structure’s (E/M) admittance signature, for specific frequency ranges.

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VIJAYA BHASKAR RAO, P. y T. BHIMA SANKARAM. "ELECTRO MECHANICAL AND IMPEDANCE STUDIES OF (Na1-xKx)1/2Bi1/2TiO3". International Journal of Modern Physics B 23, n.º 14 (10 de junio de 2009): 3131–45. http://dx.doi.org/10.1142/s0217979209052443.

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Ceramic samples of [( Na 1-x K x)1/2 Bi 1/2 TiO 3] (NKBT) (x = 0.1, 0.15, 0.2, 0.3, 0.45) were prepared by double sintering method. The admittance measurements were carried out in the frequency range of 1 KHz to 10 MHz in the temperature range of 30°C–600°C. The dielectric nature as deduced from admittance data shows a strong temperature and frequency dependence, apart from the relaxor behavior. The admittance data was analyzed by complex plane diagrams i.e., Y′ versus Y′′ at different temperature. The frequency explicit plots of imaginary component of electric modulus (M′′) at various temperatures show peaks shifting to higher frequencies with temperature (> 400° C ). The relaxation peaks were effected by the doping. The activation energies are obtained from the data. The electromechanical coefficients KP, K31 were calculated from the resonant and anti-resonant frequencies obtained from vector admittance plots. The temperature dependence of electromechanical coefficients is studied. The solid solution samples show higher KP, K31 values as compared to pure sodium bismuth titanate.

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7

Karlash, V. "Modeling of the energy-loss piezoceramic resonators by electric equivalent networks with passive elements". Mathematical Modeling and Computing 1, n.º 2 (2014): 163–77. http://dx.doi.org/10.23939/mmc2014.02.163.

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This paper is devoted to analysis of the modern achievements in energy loss problem for piezoceramic resonators. New experimental technique together with computing permits us to plot many resonators' parameters: admittance, impedance, phase angles, and power components etc. The author's opinion why mechanical quality under resonance is different from that under anti-resonance is given. The reason lies in clamped capacity and electromechanical coupling factor's value. The better electromechanical coupling, the stronger capacity clamping, and the higher its influence on anti-resonant frequency and quality. It is also established that considerable nonlinearity of admittance in constant voltage regime is caused by instantaneous power level.

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8

Sofuoğlu, Mehmet A., Gökhan Haydarlar, Melih C. Kuşhan, Sezan Orak y Mesut Tekkalmaz. "Investigation of electromechanical impedance and residual stress relation for samples machined by hot ultrasonic-assisted turning". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 236, n.º 8 (30 de octubre de 2021): 4180–93. http://dx.doi.org/10.1177/09544062211050473.

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Electromechanical impedance (EMI) method has been widely used in recent years to evaluate the condition of structures. In this method, piezoelectric sensors are added to the structure to examine material properties. The impedance/admittance signals are recorded with the aid of the impedance analyzer without any conversion. When there is any change in structures, differences occur in these signals. Thus, changes in structures can be easily determined. It is known that residual stress plays a vital role in materials in terms of crack initiation, breakage, fatigue life, etc. In contrast, the detection of residual stress is time-consuming and it requires experience. This study reveals the effect of cutting parameters on residual stress and electromechanical impedance/admittance values. Firstly, hot ultrasonic-assisted turning was performed for Ti6Al4V material. A parametric study was carried out with different cutting depth, feed rate, and cutting speed. In the second stage, residual stress values measured by X-Ray diffraction (XRD) method and impedance/admittance values measured by an impedance analyzer were compared. In this context, empirical equations with their values between stress/impedance–admittance values have been derived. In general, it has been observed that stress values are significantly associated with impedance/admittance values and the highest correlation was obtained with the reactance values.

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9

Choi, S.-B., H. S. Kim y J.-S. Park. "New design methodology for piezoelectric shunt structures using admittance analysis". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, n.º 2 (1 de febrero de 2008): 131–45. http://dx.doi.org/10.1243/09544062jmes591.

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In this paper, a new design method for a piezoelectric shunt circuit to reduce unwanted vibration of flexible structures is proposed. Admittance is introduced to represent electromechanical characteristics of piezoelectric structures and to predict the performance of piezoelectric shunt system. It is shown that admittance of the piezoelectric structure is proportional to the dissipated energy in the shunt circuit. Admittance is used as a design index to construct the piezoelectric shunt system and obtained by finite-element method. The location, area, shape, and material property of piezoelectric patches are determined by admittance analysis. Vibration reduction of the piezoelectric structure with shunt circuit is realized by experiments. It is proved from damped system response of the piezoelectric structure in frequency and time domains that the admittance is proportional to the performance of the piezoelectric shunt system. A flow chart for design procedures using admittance analysis is presented to save design cost of the piezoelectric shunt system.

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10

Zhang, Chenxu. "Pavement damage monitoring using electromechanical impedance of embedded piezoelectric plate". Applied and Computational Engineering 25, n.º 5 (30 de noviembre de 2023): 30–42. http://dx.doi.org/10.54254/2755-2721/25/ojs/20230729.

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Piezoelectric transducers have seen widespread usage in the monitoring of structural health. It has tremendous potential for monitoring the health of infrastructure, especially pavement monitoring. In the present study, the impedance characteristics of a piezoelectric plate embedded in the pavement is utilized to monitor the health status of the pavement. Based on the piezoelectricity principle, a model of an electromechanical piezoelectric plate embedded in pavement is established. The damage of the pavement is considered as the thickness decreasing of the pavement layer. The present proposed model is verified by comparing its degeneration with the exact solution of a single layer model. Numerical results demonstrated that with the deceasing of the thickness of the pavement, which is considered as the deterioration of the pavement, the achievable maximum electromechanical impedance characterization including impedance, admittance and conductance decreased. This demonstrated that the achievable maximum impedance, admittance and conductance of an embedded piezoelectric plate could be used as the indicator of pavement health monitoring. This study primarily presents theoretical underpinnings for pavement monitoring using electromechanical impedance of piezoelectric plates.

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Zhang, Chenxu. "Pavement damage monitoring using electromechanical impedance of embedded piezoelectric plate". Applied and Computational Engineering 25, n.º 1 (7 de noviembre de 2023): 30–42. http://dx.doi.org/10.54254/2755-2721/25/20230729.

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Piezoelectric transducers have seen widespread usage in the monitoring of structural health. It has tremendous potential for monitoring the health of infrastructure, especially pavement monitoring. In the present study, the impedance characteristics of a piezoelectric plate embedded in the pavement is utilized to monitor the health status of the pavement. Based on the piezoelectricity principle, a model of an electromechanical piezoelectric plate embedded in pavement is established. The damage of the pavement is considered as the thickness decreasing of the pavement layer. The present proposed model is verified by comparing its degeneration with the exact solution of a single layer model. Numerical results demonstrated that with the deceasing of the thickness of the pavement, which is considered as the deterioration of the pavement, the achievable maximum electromechanical impedance characterization including impedance, admittance and conductance decreased. This demonstrated that the achievable maximum impedance, admittance and conductance of an embedded piezoelectric plate could be used as the indicator of pavement health monitoring. This study primarily presents theoretical underpinnings for pavement monitoring using electromechanical impedance of piezoelectric plates.

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12

Park, Hyun Woo. "Evolution of electromechanical admittance of piezoelectric transducers on a Timoshenko beam from wave propagation perspective". Journal of Intelligent Material Systems and Structures 28, n.º 9 (8 de septiembre de 2016): 1221–45. http://dx.doi.org/10.1177/1045389x16667555.

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This article analytically formulates and investigates the evolution of electromechanical admittance of piezoelectric transducers collocated on a finite beam from wave propagation perspective. First, the analytic wave solutions are obtained based on the linear piezoelectricity and the Timoshenko beam theory. Then, the evolution of wave propagation to vibration on a finite beam has been formulated in terms of a wave unit which appears periodically due to the multiple reflections at beam supports. The formulation has been extended to describe the underlying mechanism how electromechanical signatures evolve from wave units. The support conditions and material damping of a beam have been considered explicitly for both wave units and electromechanical signatures. The validity of the proposed formulation has been demonstrated through proof-of-concept numerical examples providing valuable physical insights into the relevance between wave units and electromechanical signatures.

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13

Providakis, Costas P. "Electro-Mechanical Admittance-Based Damage Detection Using Extreme Value Statistics". Key Engineering Materials 385-387 (julio de 2008): 561–64. http://dx.doi.org/10.4028/www.scientific.net/kem.385-387.561.

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This paper presents the use of statistically rigorous algorithms combined with electromechanical (E/M) impedance approach for health monitoring of engineering structures. In particular, a statistical pattern recognition procedure is developed, based on frequency domain data of electromechanical impedance, to establish a decision boundary for damage identification. In order to diagnose damage with statistical confidence, health monitoring is cast in the context of outlier detection framework. Inappropriate modeling of tail distribution of outliers imposes potentially misleading behavior associated with damage. The present paper attempts to address the problem of establishing decision boundaries based on extreme value statistics so that the extreme values of outliers associated with tail distribution can be properly modeled. The validity of the proposed method is demonstrated using finite element method (FEM) simulated data while a comparison is performed for the extreme value analysis results contrasted with the standard approach where it is assumed that the damage-sensitive features are normally distributed.

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Naidu, Akshay S. K. "Electromechanical Admittance Signature Analysis of Piezo-ceramic Transducers for NDE". Materials Today: Proceedings 5, n.º 9 (2018): 19933–43. http://dx.doi.org/10.1016/j.matpr.2018.06.359.

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Annamdas, Venu Gopal Madhav, Yaowen Yang y Chee Kiong Soh. "Influence of loading on the electromechanical admittance of piezoceramic transducers". Smart Materials and Structures 16, n.º 5 (7 de septiembre de 2007): 1888–97. http://dx.doi.org/10.1088/0964-1726/16/5/045.

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16

Ai, Demi, Hui Luo y Hongping Zhu. "Diagnosis and validation of damaged piezoelectric sensor in electromechanical impedance technique". Journal of Intelligent Material Systems and Structures 28, n.º 7 (28 de julio de 2016): 837–50. http://dx.doi.org/10.1177/1045389x16657427.

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Piezoelectric sensor diagnosis and validity assessment as a prior component of structural health monitoring system are necessary in the practical application of electromechanical impedance technique. This article proposed an innovative sensor self-diagnosis process based on extracting the characterization of the real admittance (inverse of impedance) signature within a high-frequency range, which covered both diagnosis on damaged sensor after its installation and discrimination of sensor and structural damages during structural health monitoring process. Theoretical analysis was derived from the impedance model of piezoelectric-bonding layer-structure dynamic interaction system. Experimental investigations on piezoelectric sensor-bonded steel beam involved with structural damages of mass addition and notch damage were conducted to verify the process. It was found that the real admittance was reliable and critical in sensor diagnosis, and sensor faults of debonding, scratch, and breakage can be identified and differentiated from structural damage. Validity assessment of the diagnosed damaged sensor was addressed through resonant frequency shift method. The results showed that the validity of damaged sensor for structural health monitoring was inordinately depreciated by sensor damage. This article is expected to be useful for structural health monitoring application especially when damaged piezoelectric sensors existed.

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17

Ayano, Kenjiro, Katuyori Suzuki, Gen Hashiguchi y Hiroyuki Fujita. "Electromechanical Analysis of a Micromachined Comb-Drive Actuator by Admittance Measurement". IEEJ Transactions on Sensors and Micromachines 126, n.º 7 (2006): 281–85. http://dx.doi.org/10.1541/ieejsmas.126.281.

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18

Taha, Hussameldin, Richard J. Ball y Kevin Paine. "Sensing of Damage and Repair of Cement Mortar Using Electromechanical Impedance". Materials 12, n.º 23 (27 de noviembre de 2019): 3925. http://dx.doi.org/10.3390/ma12233925.

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Lead zirconium titanate (PZT) has recently emerged as a low-cost material for non-destructive monitoring for civil structures. Despite the numerous studies employing PZT transducers for structural health monitoring, no studies have assessed the effects of both damage and repair on the electromechanical impedance response in cementitious materials. To this end, this study was conducted to assess the effects of the damage and repair of mortar samples on the electromechanical response of a surface-mounted PZT transducer. When damage was introduced to the specimen in stages, the resonance frequencies of the admittance signature were shifted to lower frequencies as the damage increased, and an increase in the peak amplitude was detected, indicating an increase in the damping and a reduction in the material stiffness properties. Also, increasing the damage in the material has been shown to decrease the sensitivity of the PZT to further damage. During the repair process, a noticeable difference between the after-damage and the after-repair admittance signatures was noted. The root-mean-square deviation (RMSD) showed a decreasing trend during the repair process, when compared to the before repair RMSD response which indicated a partial recovery for the material properties by decreasing the damping property in the material.

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19

Wang, Dansheng, Junbing Zhang y Hongping Zhu. "Embedded Electromechanical Impedance and Strain Sensors for Health Monitoring of a Concrete Bridge". Shock and Vibration 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/821395.

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Piezoelectric lead zirconate titanate (PZT) is one of the piezoelectric smart materials, which has direct and converse piezoelectric effects and can serve as an active electromechanical impedance (EMI) sensor. The design and fabrication processes of EMI sensors embedded into concrete structures are presented briefly. Subsequently, finite element modeling and modal analysis of a continuous rigid frame bridge are implemented by using ANSYS and MIDAS and validated by the field test results. Uppermost, a health monitoring technique by employing the embedded EMI and strain sensors is proposed in this paper. The technique is not based on any physical model and is sensitive to incipient structural changes for its high frequency characteristics. A practical study on health monitoring of the continuous rigid frame bridge is implemented based on the EMI and strain signatures. In this study, some EMI and strain sensors are embedded into the box-sectional girders. The electrical admittances of distributed EMI active sensors and the strains of concrete are measured when the bridge is under construction or in operation. Based on the electrical admittance and strain measurements, the health statuses of the continuous rigid frame bridge are monitored and evaluated successfully in the construction and operation stages using a root-mean-square deviation (RMSD) index.

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20

Soh, Chee Kiong y Yee Yan Lim. "Detection and Characterization of Fatigue Induced Damage Using Electromechanical Impedance Technique". Advanced Materials Research 79-82 (agosto de 2009): 2031–34. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.2031.

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In this paper, the feasibility of damage detection and characterization using the EMI technique on high cycles fatigue induced damage is investigated. Cyclic tensile load is applied on a lab sized aluminium beam up to failure. Piezo-impedance transducer in the form of PZT patch (lead zirconate titanate) is surface bonded on the specimen for crack detection. Progressive shift in admittance signatures measured by the PZT patch corresponding to increase of loading cycles reflects effectiveness of the EMI technique in tracing the process of fatigue damage progression.

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Yang, Yao Wen y Ai Wei Miao. "Structural Parameters Identification Using PZT Sensors and Genetic Algorithms". Advanced Materials Research 79-82 (agosto de 2009): 63–66. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.63.

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Piezoelectric ceramic lead zirconate titanate (PZT) based electro-mechanical impedance (EMI) technique for structural health monitoring (SHM) has been successfully applied to various engineering systems [1-5]. In the traditional EMI method, statistical analysis methods such as root mean square deviation indices of the PZT electromechanical (EM) admittance are used as damage indicator, which is difficult to specify the effect of damage on structural properties. This paper proposes to use the genetic algorithms (GAs) to identify the structural parameters according to the changes in the PZT admittance signature. The basic principle is that structural damage, especially local damage, is typically related to changes in the structural physical parameters. Therefore, to recognize the changes of structural parameters is an effective way to assess the structural damage. Towards this goal, a model of driven point PZT EM admittance is established. In this model, the dynamic behavior of the structure is represented by a multiple degree of freedom (DOF) system. The EM admittance is formulated as a function of excitation frequency and the unknown structural parameters, i.e., the mass, stiffness and the damping coefficient of many single DOF elements. Using the GAs, the optimal values of structural parameters in the model can be back-calculated such that the EM admittance matches the target value. In practice, the target admittance is measured from experiments. In this paper, we use the calculated one as the target. For damage assessment, these optimal values obtained before and after the appearance of structural damage can be compared to study the effects of damage on the structural properties, which are specified to be stiffness and damping in this study. Furthermore, the identified structural parameters could be used to predict the remaining loading capacity of the structure, which serves the purpose for damage prognosis.

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Jiang, Xie, Xin Zhang y Yuxiang Zhang. "Piezoelectric Active Sensor Self-Diagnosis for Electromechanical Impedance Monitoring Using K-Means Clustering Analysis and Artificial Neural Network". Shock and Vibration 2021 (1 de julio de 2021): 1–13. http://dx.doi.org/10.1155/2021/5574898.

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Piezoelectric sensor is a crucial part of electromechanical impedance technology whose state will directly affect the effectiveness and accuracy of structural health monitoring (SHM). So carrying out sensor self-diagnosis is important and necessary. However, it is still difficult to distinguish sensor faults from structural damage as well as identify the cases and degrees of sensor faults. In the study, three characteristic indexes of admittance which have different indication intervals for damages of structure and sensors were selected from six indexes after comparison. To improve the discrimination effect, three principal components (PC) were extracted by principal component analysis (PCA). And the damage information represented by PCs was clustered by the K-means algorithm to identify the cases of damage. Then, the degrees of sensor damages were classified with the artificial neural network (ANN). The results show that the K-means clustering analysis based on admittance characteristics can accurately distinguish and identify the structural damage and four kinds of sensor damages, namely, pseudosoldering, debonding, wear, and breakage. The trained ANN model has a good recognition effect on the damage degrees and the accuracy of recognition reaches 100%. This study has a certain reference value for piezoelectric sensor self-fault identification.

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Naidu, Akshay S. K. "Characterization of the Electromechanical Admittance Signatures of Piezo-Impedance Transducers based on its Location". Materials Today: Proceedings 18 (2019): 4398–407. http://dx.doi.org/10.1016/j.matpr.2019.07.408.

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Braun, Stefan, Helmut Nowotny, Ewald Benes y Martin Gröschl. "Layered piezoelectric structures with arbitrary acoustic termination impedances". Journal of the Acoustical Society of America 153, n.º 3 (marzo de 2023): 1733–53. http://dx.doi.org/10.1121/10.0017600.

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Multilayer piezoelectric transducers and resonators are widely used for generating propagating and standing acoustic waves as well as for sensor devices. More recently, layered piezoelectric structures based on thin film technology became increasingly important for electromechanical filters used in mobile phones. As a consequence, analytical mathematical modeling of such structures is of high interest. In this paper, a general rigorous transfer matrix description for one-dimensional (1D) layered structures consisting of piezoelectric, visco-elastic, and dielectric layers of arbitrary number is introduced to characterize the electrical and mechanical behavior of a general piezoelectric transducer or resonator with two electrodes and arbitrary acoustic termination impedances (Rig-1D-model). This model is the most general 1D analytical description of layered piezoelectric structures available and can be used for the characterization of various composite transducer and resonant sensor applications. Considered in detail are layered structures with the technically important cases of only one electromechanically coupled mode, and the structure at one or both outer surfaces is in contact with semi-infinite media. For such devices, it is shown how the frequency dependence of the total electrical admittance and spatial dependence of the displacements can be calculated.

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Naoum, Maria C., George M. Sapidis, Nikos A. Papadopoulos y Maristella E. Voutetaki. "An Electromechanical Impedance-Based Application of Realtime Monitoring for the Load-Induced Flexural Stress and Damage in Fiber-Reinforced Concrete". Fibers 11, n.º 4 (11 de abril de 2023): 34. http://dx.doi.org/10.3390/fib11040034.

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Effective real-time structural health monitoring in concrete structures is paramount to evaluating safety conditions and the timely maintenance of concrete structures. Especially, the presence of discrete fibers in fiber-reinforced concrete restrains crack propagation into small and thin cracks, which increases the difficulty in detecting damage. In this study, an array of piezoelectric lead zirconate titanate (PZT) transducers was applied to study the effects of external load-induced flexural stress and damage in fiber-reinforced concrete beams using the electromechanical impedance (EMI) or electromechanical admittance (EMA) methods. Beams were subjected to a four-point bending test under repeatable loading, while PZTs evaluated corresponding flexural stress and induced damage simultaneously. Due to the influence of the medium’s stress fields in the different types of wave propagation in structural elements, PZT transducers measurements are accordingly affected under variable stress fields, in addition to the effect of the higher level of damage that occurred in the medium. According to the results of the tests, variation in EMA signatures, following flexural stress and gradual damage changes, provided convincing evidence for predicting stress and damage development.

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Choi, M. H. M., Z. S. Tang, R. Vasquez Padilla, Y. Y. Lim y A. Mostafa. "A study on monitoring the hydration process of glasscrete using electromechanical impedance technique". IOP Conference Series: Materials Science and Engineering 1229, n.º 1 (1 de febrero de 2022): 012005. http://dx.doi.org/10.1088/1757-899x/1229/1/012005.

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Abstract Glass has been suggested as a viable material to replace aggregates in concrete to maintain sustainable development for the future. However, a concern is raised about the cementitious reaction with glass that could cause concrete spalling and loss of strength. Therefore, monitoring the concrete hydration process and the structural health throughout its service life is essential. In this study, the hydration process of lab-scale glasscrete prisms is monitored using the electromechanical impedance (EMI) technique. This technique employs one piezoelectric-based transducer that encases a material called Lead Zirconate Titanate (PZT) to operate as an actuator and senor. The experimental result shows that the embedded transducer is an effective means to monitor the glasscrete hydration process. The acquired admittance signature was able to capture the strength development during the glasscrete hydration period via interpreting the PZT and structural resonance peaks

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He, Cun Fu, Xiao Ming Cai, Shen Yang, Zeng Hua Liu y Bin Wu. "Truss Structure Health Monitoring Based on Electromechanical Impedance Method". Applied Mechanics and Materials 330 (junio de 2013): 357–63. http://dx.doi.org/10.4028/www.scientific.net/amm.330.357.

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Truss structure is widely used in civil engineering applications for its advantages of easy transportation, convenient assembly and uniform loading. However, it is difficult to achieve real-time health monitoring because of connection diversity and complexity of truss structures. As a novel structural health monitoring technique, electro-mechanical impedance method could monitor the health state of one structure by measuring the spectra of impedance or admittance of the piezoelectric elements, which are bonded on the surface of this structure. This approach has the advantages of nonparametric model analysis, easy sensor installation and high local sensitivity, especially in sensitive frequency range. The damage information, which is tested and recorded by using electromechanical impedance method, could convert into intuitive results through neural network because of its good ability for nonlinear mapping. In this paper, a three-layer assembly truss structure was chosen as experimental object, piezoelectric elements were bonded on structure joints to measure structural impedance spectra, the change of these structural impedance spectra was tested and recorded under high frequency excitations when different truss bars were loosed, and then, one back-propagation (BP) neural network was built and trained by this damage information, which were treated as input samples. These results show that the sensitivity of impedance method is not the same to different frequency range and trained neural network could quickly identify loosen truss bars.

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28

Ai, Demi, Zeliang Yang, Hedong Li y Hongping Zhu. "Heating-time effect on electromechanical admittance of surface-bonded PZT sensor for concrete structural monitoring". Measurement 184 (noviembre de 2021): 109992. http://dx.doi.org/10.1016/j.measurement.2021.109992.

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29

Kim, Eun Jin y Hyun Woo Park. "The Evolution of Electromechanical Admittance from Mode-converted Lamb Waves Reverberating on a Notched Beam". Transactions of the Korean Society for Noise and Vibration Engineering 26, n.º 3 (20 de junio de 2016): 270–80. http://dx.doi.org/10.5050/ksnve.2016.26.3.270.

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30

Ai, Demi, Hui Luo y Hongping Zhu. "Numerical and experimental investigation of flexural performance on pre-stressed concrete structures using electromechanical admittance". Mechanical Systems and Signal Processing 128 (agosto de 2019): 244–65. http://dx.doi.org/10.1016/j.ymssp.2019.03.046.

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31

Providakis, C. P., D.-P. N. Kontoni y M. E. Voutetaki. "Development of an electromechanical admittance approach for application in the vibration control of intelligent structures". Smart Materials and Structures 16, n.º 2 (23 de enero de 2007): 275–81. http://dx.doi.org/10.1088/0964-1726/16/2/005.

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32

Rautela, Mahindra y C. R. Bijudas. "Electromechanical admittance based integrated health monitoring of adhesive bonded beams using surface bonded piezoelectric transducers". International Journal of Adhesion and Adhesives 94 (octubre de 2019): 84–98. http://dx.doi.org/10.1016/j.ijadhadh.2019.05.002.

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33

Li, Hedong, Yaozhi Luo y Demi Ai. "Restoration of electromechanical admittance signature via solving constrained optimization problems for concrete structural damage identification". Measurement 214 (junio de 2023): 112803. http://dx.doi.org/10.1016/j.measurement.2023.112803.

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34

Tang, Bo, Jiangen Yang, Wei Chen y Xu Ming. "Analysis of Coupled Vibration Characteristics of Linear-Angular and Parameter Identification". Measurement Science Review 24, n.º 1 (1 de febrero de 2024): 17–26. http://dx.doi.org/10.2478/msr-2024-0003.

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Abstract A steady-state sinusoidal and distortion-free excitation source is very important for the accuracy and consistency of the calibration parameters of micro-electro-mechanical systems (MEMS) inertial sensors. To solve the problem that the current MEMS inertial measurement unit (IMU) calibration device is unable to reproduce the spatial motion of linear and angular vibration coupling, research topics on the coupling vibration characteristics and parameter identification for an electromagnetic linear-angular vibration exciter are proposed. This research paper used Ampere’s law and Lorentz force to establish the analytical expressions for the electromagnetic force and electromagnetic torque of the electromagnetic linear-angular vibration exciter. Then, the main purpose of this paper is to establish uniaxial and coupled vibration electromechanical analogy models containing mechanical parameters based on the admittance-type electromechanical analogy principle, and the parameter identification model is also obtained by combining the impedance formula with the additional mass method. Finally, the validity of the coupling vibration characteristics and the parameter identification model are verified by the frequency response simulation and the additional mass method, and the relative error of each parameter identification is within 5% in this paper.

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35

Gayakwad, Himanshi y Jothi Saravanan Thiyagarajan. "Structural Damage Detection through EMI and Wave Propagation Techniques Using Embedded PZT Smart Sensing Units". Sensors 22, n.º 6 (16 de marzo de 2022): 2296. http://dx.doi.org/10.3390/s22062296.

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Lead Zirconate Titanate (PZT) sensors have become popular in structural health monitoring (SHM) using the electromechanical impedance (EMI) technique for damage identification. The vibrations generated during the casting process in concrete structures substantially impact the conductance signature’s (real part of admittance) magnitude and sensitivity. The concept of smart sensing units (SSU) is presented, composed of a PZT patch, an adhesive layer, and a steel plate. It is embedded in the concrete structure to study the impact of damage since it has high sensitivity to detect any structural changes, resulting in a high electrical conductance signature. The conductance signatures are obtained from the EMI technique at the damage state in the 10–500 kHz high-frequency range. The wave propagation technique proposes implementing the novel embedded SSUs to detect damage in the host structure. The numerical simulation is carried out with COMSOL multiphysics, and the received voltage signal is compared between the damaged and undamaged concrete beam with the applied actuation signal. A five-cycle sine burst modulated by a Hanning window is employed as the transient excitation signal. For numerical investigation, six cases are explored to better understand how the wave travels when a structural discontinuity is accounted for. The changes in the received signal during actuator–receiver mode in the damage state of the host structure are quantified using time of flight (TOF). Furthermore, the numerical studies are carried out by combining the EMI-WP technique, which implies synchronous activation of EMI-based measurements and wave stimulation. The fundamental idea is to implement EMI-WP to improve the effectiveness of SSU patches in detecting both near-field and far-field damage in structures. One SSU is used as an EMI admittance sensor for local damage identification. Meanwhile, the same EMI admittance sensor is used to acquire elastic waves generated by another SSU to monitor damages outside the EMI admittance sensor’s sensing area. Finally, the experimental validation is carried out to verify the proposed methodology. The results show that combining both techniques is an effective SHM method for detecting damage in concrete structures.

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36

Lim, Yee Yan y Chee Kiong Soh. "Effect of varying axial load under fixed boundary condition on admittance signatures of electromechanical impedance technique". Journal of Intelligent Material Systems and Structures 23, n.º 7 (15 de marzo de 2012): 815–26. http://dx.doi.org/10.1177/1045389x12437888.

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37

Wang, Dansheng, Hongyuan Song y Hongping Zhu. "Electromechanical Impedance Analysis on Piezoelectric Smart Beam with a Crack Based on Spectral Element Method". Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/713501.

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An electromechanical impedance (EMI) analysis of a piezoelectric smart beam with a crack is implemented in this paper. Spectral element method (SEM) is used to analyze the EMI response of the piezoelectric smart beam. In this analysis, the spectral element stiffness matrices of different beam segments are derived in this paper. The crack is simulated using spring models, and the EMI signatures of piezoelectric smart beam with and without crack are calculated using SEM, respectively. From the analysis results, it is found that the peak position and amplitude of the EMI signatures have significant changes with the change in crack depth, especially in higher frequency ranges. Different vibration modes of the piezoelectric smart beam are analyzed, and the effect of thickness of the adhesive layer on the admittance is also researched. An experimental study is also implemented to verify the validity of the analysis results using SEM.

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38

Miao, Ai Wei y Yao Wen Yang. "Monitoring Vibrating Structures Using PZT Impedance Transducers". Advanced Materials Research 47-50 (junio de 2008): 85–88. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.85.

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Electromechanical impedance (EMI) technique using lead zirconate titanate (PZT) transducers has been increasingly applied to structural health monitoring (SHM) of aerospace, civil and mechanical structures. The PZT transducers are usually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at the desired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI) signatures which can be used to estimate the structural health or integrity according to the changes of the signatures. In the existing EMI method, the monitored structure is only excited by the PZT transducers for the interrogating of EMI signature, while the vibration of the structure caused by the external excitations other than the PZT actuation is not considered. However, in real situation many structures work under vibrations. To monitor such structures, issues related to the effects of vibration on the EMI signature need to be addressed because these effects may lead to misinterpretation of the structural health. This paper develops an EMI model for beam structures, which takes into account the effect of beam vibration caused by the external excitations. An experimental study is carried out to verify the theoretical model. A Lab sized specimen with external excitation is tested and the effect of excitation on EMI signature is discussed.

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39

Shanker, Rama, Suresh Bhalla, Ashok Gupta y Matta Praveen Kumar. "Dual use of PZT patches as sensors in global dynamic and local electromechanical impedance techniques for structural health monitoring". Journal of Intelligent Material Systems and Structures 22, n.º 16 (11 de septiembre de 2011): 1841–56. http://dx.doi.org/10.1177/1045389x11414219.

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In this article, a new approach is proposed to effectively detect the initiation and progression of structural damage by combining the global dynamic and the local electromechanical impedance (EMI) techniques, using the same set of surface-bonded piezoelectric ceramic (PZT) patches as sensors. The PZT patches are used to determine the natural frequencies and the strain mode shapes of the structure (for use in the global dynamic technique) as well as to acquire the electromechanical admittance signature (for use in the EMI technique) to facilitate an improved damage assessment. Occurrence and location of the incipient damage are determined using the EMI technique, whereas for moderate to severe damages, the location and the severity are arrived at through the global dynamic technique. Finally, damage severity is determined in terms of the original stiffness of structure using the strain mode shapes directly determined using the PZT patches. The proposed technique is illustrated using two specimens—a 4-m long steel beam and a mild steel plate 1260 mm × 630 mm × 6.5 mm in size. The integrated approach provides greater information about damage, is simple to apply, does not involve any numerical/analytical modeling a priori, and is at the same time very cost effective.

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40

Fujita, Shuji, Nobuhiko Azuma, Hideaki Motoyama, Takao Kameda, Hideki Narita, Yoshiyuki Fujii y Okitsugu Watanabe. "Electrical measurements on the 2503 m Dome F Antarctic ice core". Annals of Glaciology 35 (2002): 313–20. http://dx.doi.org/10.3189/172756402781816951.

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AbstractThe 320 kyr climatic record from the 2503 m Dome Fuji (Antarctica) ice core was analyzed using two electrical methods: AC-ECM and ECM (electrical conductivity measurements). AC-ECM is a method to detect the complex admittance between electrodes dragged on the ice surface with mm-scale resolution and uses 1V and 1 MHz. the ratio of the real to imaginary part of the admittance is the AC loss factor, which responds linearly to the amount of sulfuric acid and hydrogen ions. Both the AC loss factor and the ECM current respond to acid, but the ECM signal tends to saturate at high acidities. Dome Fuji ice was measured to be highly acidic, with background values of 2–7 μM, and had 4500 major peaks with acidities of up to 90 μM. This ice-core evidence and earlier snow-chemistry survey around the dome region indicates that Dome F may have a better connection to the stratosphere than have sites at lower altitude, which allows more stratospheric aerosol and gases to reach the snow surface. Acidity tends to be high in interglacial periods, but correlation between acidity and δ18O is not straightforward. Electrical signals decreased and smoothed out with increasing depth; the diffusion coefficients deduced from this smoothing were 10–102 times greater than in solid ice. the ice core exhibited electromechanical effects and expelling effects from sulfate peaks.

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41

Ai, Demi, Fang Mo, Yihang Han y Junjie Wen. "Automated identification of compressive stress and damage in concrete specimen using convolutional neural network learned electromechanical admittance". Engineering Structures 259 (mayo de 2022): 114176. http://dx.doi.org/10.1016/j.engstruct.2022.114176.

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42

Li, Hedong, Demi Ai, Hongping Zhu y Hui Luo. "An Orthogonal Matching Pursuit based signal compression and reconstruction approach for electromechanical admittance based structural health monitoring". Mechanical Systems and Signal Processing 133 (noviembre de 2019): 106276. http://dx.doi.org/10.1016/j.ymssp.2019.106276.

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43

Naciri, I., A. Rguiti, L. Elmaimouni, J. E. Lefebvre, F. E. Ratolojanahary, J. G. Yu, Y. Belkassmi y A. El Moussati. "Numerical Modelling of Vibration Characteristics of a Partially Metallized Micro Electromechanical System Resonator Disc". Acta Acustica united with Acustica 105, n.º 6 (1 de noviembre de 2019): 1164–72. http://dx.doi.org/10.3813/aaa.919393.

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In this paper, we report an extension of a polynomial and numerical vibrational characterization of an annular piezoelectric disc resonator partially covered with electrodes. The three governing partial differential equations of motion are solved to provide the frequency response of the piezoelectric disc using a polynomial approach. This method makes use of Legendre polynomials series to express the mechanical displacement components and the electrical potential which are introduced into the equations of motion of the piezoelectric structure. The principal advantage of this method consists of incorporating the electrical source, the boundary and continuity conditions directly into the governing equations by the use of position-dependent physical constants and by a wise choice of the polynomial expansions for the independent variables, the mechanical displacement components and the electrical potential. Both harmonic and modal analyses were studied and are presented. Numerical calculations based on the foregoing method were performed to present resonance and anti-resonance frequencies, electromechanical coupling coefficient, field profiles and electrical input admittance for PIC151 and PZT5A disc resonators with various metallization rates. The high accuracy and reliability of our approach is confirmed via a comparison of our results with their counterparts reported in literature.

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44

Park, Hyun Woo. "Understanding the electromechanical admittance of piezoelectric transducers collocated on a finite beam from the perspective of wave propagation". Journal of Intelligent Material Systems and Structures 25, n.º 17 (15 de septiembre de 2014): 2122–40. http://dx.doi.org/10.1177/1045389x14549874.

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45

NONAKA, Shota, Arata MASUDA y Takashi TANAKA. "Fluctuation of Electromechanical Coupling Admittance of a Piezoelectric Element Attached on the End Face of a Spur Gear". Proceedings of the Dynamics & Design Conference 2017 (2017): 522. http://dx.doi.org/10.1299/jsmedmc.2017.522.

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46

Nasrollahi, Amir, Wen Deng, Zhaoyun Ma y Piervincenzo Rizzo. "Multimodal structural health monitoring based on active and passive sensing". Structural Health Monitoring 17, n.º 2 (5 de abril de 2017): 395–409. http://dx.doi.org/10.1177/1475921717699375.

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We present a structural health monitoring system based on the simultaneous use of passive and active sensing. The passive approach is based on acoustic emission, whereas the active approach uses the electromechanical impedance and the guided ultrasonic wave methods. As all these methods can be deployed with the use of wafer-type piezoelectric transducers bonded or embedded to the structure of interest, this article describes a unified structural health monitoring system where acoustic emission, electromechanical impedance, and guided ultrasonic wave are integrated in the same hardware/software unit. We assess the feasibility of this multimodal monitoring in a large flat aluminum plate instrumented with six transducers. Acoustic emission events are simulated by exciting a tone burst or by using the conventional pencil lead break test, and the detected signals are processed with a source localization algorithm to identify the position of the source. For the active sensing, damage is simulated by adding a small mass to the plate: the raw waveforms are processed with a delay-and-sum algorithm to create an image of the plate, whereas the electrical admittance of each transducer is analyzed using the statistical index of the root-mean-square deviation. The results presented in this article show that the proposed system is robust, mitigates the weaknesses of each method considered individually, and can be developed further to address the challenges associated with the structural health monitoring of complex structures.

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47

Kuo, Ying Chyi y Shann Chyi Mou. "Equivalent Circuit Construction of a Novel Ultrasonic Actuator". Applied Mechanics and Materials 764-765 (mayo de 2015): 735–39. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.735.

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A thin-disc ultrasonic actuator using a piezoelectric buzzer is proposed as the actuating component for the shaft-driving type ultrasonic actuator. By placed the screw constraints on the metal sheet of a buzzer, a 3-phase reflected wave was constituted and propagated based on the purpose locations of constraints. This wave configuration could convert electrical energy to actuate the kinematical power for rotating the rotor. The input and output signals were acquisition according to the single-frequency exciting of system resonant frequency. The dynamic transfer function of a stator was obtained via the system identification technique, and, therefore, one model of a 3th-order equivalent circuit was built in which the dynamic features and electromechanical characteristics were considered based on material oscillating behaviors. Because of the admittance transfer function derived from measured method, it is more representative than that of past issues through the theoretical deduction in materials, physics, and mechanics.

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48

Ai, Demi y Rui Zhang. "Deep learning of electromechanical admittance data augmented by generative adversarial networks for flexural performance evaluation of RC beam structure". Engineering Structures 296 (diciembre de 2023): 116891. http://dx.doi.org/10.1016/j.engstruct.2023.116891.

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49

C. Papageorgiou, Panos y Antonio T. Alexandridis. "Controlled Impedance-Admittance-Torque Nonlinear Modeling and Analysis of Modern Power Systems". Energies 13, n.º 10 (13 de mayo de 2020): 2461. http://dx.doi.org/10.3390/en13102461.

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Modern power systems are continuously transformed into decentralized ones where distributed generation (DG) plays a key role. Almost all the different distributed energy resources (DERs) are connected in geographically dispersed places through controlled power electronic interfaces in a manner that essentially affects the dynamic performance and control of the whole power system. Simultaneously, rotating machines in power production or absorption, dominate the system response and stability. In this new frame, this paper proposes a novel generalized dynamic representation and full scale modeling of a modern power system based on the well-known impedance-admittance (IA) network model for the electricity grid, substantially extended to include in detail both the power converter devices by considering the controlled power electronic dynamics and the electrical machines by inserting their full electromechanical dynamics. This formulation results in a holistic nonlinear dynamic description, defined here as controlled impedance-admittance-torque (CIAT) model of the whole system which features common structural characteristics. The model is deployed in state space, involves all the controlled inputs in DG, namely the duty-ratio signals of each power converter interface, all the other external inputs affecting the system, namely all the known or unknown voltage, current, and torque inputs. As shown in the paper, the proposed CIAT model retains its fundamental properties for any DG and network topology, standard or varying. This enables the compression of the accurate analytic power system dynamic description into a matrix-based generic nonlinear model that can be easily used for analysis studies of such large-scale systems. Taking into account the nonlinear nature of the CIAT matrix-based model and the persistent action of the external inputs, Lyapunov methods deployed on recently established input to state stability (ISS) notions are systematically applied for the system analysis. Hence, the traditionally used small-signal model-based analysis that suffers from the intermittent and continuously changing operation of DERs is completely substituted by the proposed formulation. A modern power system example with different DERs involved is analyzed by this way and is extensively simulated to verify the validity of the proposed method.

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50

Ali, Liaqat, Sikandar Khan, Naveed Iqbal, Salem Bashmal, Hamad Hameed y Yong Bai. "An Experimental Study of Damage Detection on Typical Joints of Jackets Platform Based on Electro-Mechanical Impedance Technique". Materials 14, n.º 23 (25 de noviembre de 2021): 7168. http://dx.doi.org/10.3390/ma14237168.

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Many methods have been used in the past two decades to detect crack damage in steel joints of the offshore structures, but the electromechanical impedance (EMI) method is a comparatively recent non-destructive method that can be used for quality monitoring of the weld in structural steel joints. The EMI method ensures the direct assessment, analysis and particularly the recognition of structural dynamics by acquiring its EM admittance signatures. This research paper first briefly introduces the theoretical background of the EMI method, followed by carrying out the experimental work in which damage in the form of a crack is simulated by using an impedance analyser at different distances. The EMI technique is used to identify the existence of damage in the welded steel joints of offshore steel jacket structures, and Q345B steel was chosen as the material for test in the present study. Sub-millimetre cracks were found in four typical welded steel joints on the jacket platform under circulating loads, and root average variance was used to assess the extent of the crack damage.

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