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Measurement of Parameters of Piezoelectric Active Elements for Acoustic Emission Sensors
Fialka, Jiří ; Erhart,, Jiří (referee) ; Sedlák, Petr (referee) ; Beneš, Petr (advisor)
The doctoral thesis discusses the measurement of parameters of piezoelectric (PZT) materials and the influence of temperature on their stability. In the introductory sections, the author briefly explains the piezoelectric effect and its use; simultaneously, methods for the preparation of piezoelectric materials and the measurement of their properties are presented to illustrate the analyzed problem. The experimental part of the thesis describes the procedure of measuring and calculating the complete matrix of material coefficients from samples of PZT ceramics. The applied set of piezoelectric samples complying with relevant European and world standards was made in the form of thin plates, thin discs and cylinders, via gradual modification of the large disc. The NCE51 and/or the older PCM51 ceramics obtained from the company Noliac Ceramics were used in determining the complete matrix and describing the measurement method. Both these types are soft piezoceramics composed from a solid solution of lead zirconate and lead titanate with the general chemical formula of Pb(Zr1-x,Tix)O3. The real crystallographic structure and chemical composition of the samples were confirmed by X-ray diffraction spectroscopy and energy dispersive spectroscopy (EDS), respectively. The frequency method was used for the measurement and calculation of all material coefficients. An Agilent 4294A impedance analyzer and a set of measuring tweezers marketed as “Tweezers Contact Test Fixture 16334A” were used in the process. Fast determination of the entire matrix of coefficients without any special requirement for the preparation of the samples to be measured was tested and verified. The charge coefficients of the piezoelectric material were confirmed by direct methods including the laser interferometer technique, the vibrometric method, and the procedure utilizing changes of the force applied to the sample. The advantages and disadvantages of the methods were compared and defined based on measurements and their results. The main part of thesis was focused on the behavior of piezoelectric material at high temperatures near the Curie point. Depolarization performed by means of a high temperature approaching the Curie point constitutes a significant yet hardly measurable material property of PZT ceramics. Commonly available vibrometric methods (d33-meters) do not appear to be suitable for the measurement of temperature dependencies, and for that reason the frequency technique was used. The piezoelectric charge coefficient, whose value can be effectively measured via the above-discussed frequency method, was selected as the indicator showing the depolarization state in the applied piezoelectric ceramics. The accuracy of the procedure was verified via comparison of the vibrometric method in cylinders of the NCE51 ceramics with different sizes, which are designed for the longitudinal length mode. The result is an optimized measurement methodology which facilitates accurate determination of the Curie temperature, namely phase transition to the cubic crystallographic structure. The experiment also proved the applicability of progressive, controlled depolarization of PZT ceramics via high temperature, and it also enabled us to define the temperature limits at which there occur irreversible changes of the piezoelectric properties of piezoceramics. In the measured NCE51 and PCM51 materials, the limit for the irreversible changes was equal to 95% of the Curie temperature.
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Proposal of Microactuator Based on SMART Material
Hradil, Aleš ; Houška, Pavel (referee) ; Hadaš, Zdeněk (advisor)
The master’s thesis deals with the proposal of microactuator based on SMART material. The thesis opens with the comparison of SMART materials which are suitable for actuator construction from the point of view of a reaction on stimulation in form of deformation. Subsequent part of the thesis is the report theory of piezoelectric effect, it also describes direct and indirect effects and it concerns about the description of piezoelectric materials. The thesis focuses on several principles of piezoactuators and motors. The last part of the thesis includes modeling and simulation of piezoelectric material in program ANSYS 13.0 and dimensioning geometric of actuator with evaluation of impact of parameters on final motion.
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The Hefaistos System
Mancl, Vlastimil ; Beneš, Petr (referee) ; Pikula, Stanislav (advisor)
This master's thesis describes functionality and principle of the Hefaistos measurement system, which is fully automated and modular. Its purpose is to measure frequency responses of materials and its temperature dependence. The thesis describes all the necessary parts of the modular measurement system. Main part of this system is the control application programmed in LabVIEW software environment. Another necessary parts are impedance analyzers for acquiring frequency dependencies and heating chambers for heating measured materials. The control application ensures hardware synchronization between impedance analyzers and heating chambers. Together they create the Hefaistos system. Modularity of the system means that a user may choose which instrument combination will be used. The system offers choice between three impedance analyzers Agilent 4294A, Wayne Kerr 6520B and HIOKI 3532 LCR Hi-Tester and two heating chambers AOIP GEMINI 700 LRI and AOIP HYPERION. Possibilities of the Hefaistos system are demonstrated on the results of an example measurement.
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Electronic noise temperature characteristics of piezoceramic sensors
Shromáždil, Petr ; Rampl, Ivan (referee) ; Majzner, Jiří (advisor)
The main objective of the thesis „Electronic noise temperature dependence of piezoceramic sensors“ is to design the measuring set-up for the measurement of the piezoceramic sensor noise temperature dependence. The application for the control of the measurement process is realized. The theoretic chapter is focused on the properties of materials for the production of piezoceramic sensors. The basic effects related to the piezoceramic properties and the material structure is described in this part. Next chapter is focused on the technology of production of used piezoceramic. The properties of solid solutions as PbZrO3 – PbTiO3, and the non-destructive methods of the material testing are discussed. Our attention is concentrated to methods of acoustic emission. The next chapter is concerned on the realization of the measuring set-up and program equipment. The tested sample is the acoustic emission sensor made of piezoceramic material PCM-51. It is placed in the cylinder chest which is heated by the DC current source. The temperature measurement is realized by the data acquisition switch unit. The results of measurements are saved in PC and they are analyzed using MATLAB program. As a result we receive the frequency spectra of the electric noise voltage spectral density SU. The temperature dependencies of resonant peak value and frequency are determined from these spectra.
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The Hefaistos System
Mancl, Vlastimil
This paper describes functionality and principle of Hefaistos system. This system is fully automated and modular. Its purpose is for measurement of frequency responses of materials and its temperature dependence. Article describes all of the parts of modular measurement system, which main part is control application, programmed in LabVIEW software enviroment. Application is used for synchronization of hardware i.e. synchronization of frequency analyzer with heating chamber. Final aplication is user friendly and offers frequncy measurement with or without heating chamber. Possibilities of Hefaistos system are demonstrated on results of an example measurement.
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The Hefaistos System
Mancl, Vlastimil ; Beneš, Petr (referee) ; Pikula, Stanislav (advisor)
This master's thesis describes functionality and principle of the Hefaistos measurement system, which is fully automated and modular. Its purpose is to measure frequency responses of materials and its temperature dependence. The thesis describes all the necessary parts of the modular measurement system. Main part of this system is the control application programmed in LabVIEW software environment. Another necessary parts are impedance analyzers for acquiring frequency dependencies and heating chambers for heating measured materials. The control application ensures hardware synchronization between impedance analyzers and heating chambers. Together they create the Hefaistos system. Modularity of the system means that a user may choose which instrument combination will be used. The system offers choice between three impedance analyzers Agilent 4294A, Wayne Kerr 6520B and HIOKI 3532 LCR Hi-Tester and two heating chambers AOIP GEMINI 700 LRI and AOIP HYPERION. Possibilities of the Hefaistos system are demonstrated on the results of an example measurement.
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Measurement of Parameters of Piezoelectric Active Elements for Acoustic Emission Sensors
Fialka, Jiří ; Erhart,, Jiří (referee) ; Sedlák, Petr (referee) ; Beneš, Petr (advisor)
The doctoral thesis discusses the measurement of parameters of piezoelectric (PZT) materials and the influence of temperature on their stability. In the introductory sections, the author briefly explains the piezoelectric effect and its use; simultaneously, methods for the preparation of piezoelectric materials and the measurement of their properties are presented to illustrate the analyzed problem. The experimental part of the thesis describes the procedure of measuring and calculating the complete matrix of material coefficients from samples of PZT ceramics. The applied set of piezoelectric samples complying with relevant European and world standards was made in the form of thin plates, thin discs and cylinders, via gradual modification of the large disc. The NCE51 and/or the older PCM51 ceramics obtained from the company Noliac Ceramics were used in determining the complete matrix and describing the measurement method. Both these types are soft piezoceramics composed from a solid solution of lead zirconate and lead titanate with the general chemical formula of Pb(Zr1-x,Tix)O3. The real crystallographic structure and chemical composition of the samples were confirmed by X-ray diffraction spectroscopy and energy dispersive spectroscopy (EDS), respectively. The frequency method was used for the measurement and calculation of all material coefficients. An Agilent 4294A impedance analyzer and a set of measuring tweezers marketed as “Tweezers Contact Test Fixture 16334A” were used in the process. Fast determination of the entire matrix of coefficients without any special requirement for the preparation of the samples to be measured was tested and verified. The charge coefficients of the piezoelectric material were confirmed by direct methods including the laser interferometer technique, the vibrometric method, and the procedure utilizing changes of the force applied to the sample. The advantages and disadvantages of the methods were compared and defined based on measurements and their results. The main part of thesis was focused on the behavior of piezoelectric material at high temperatures near the Curie point. Depolarization performed by means of a high temperature approaching the Curie point constitutes a significant yet hardly measurable material property of PZT ceramics. Commonly available vibrometric methods (d33-meters) do not appear to be suitable for the measurement of temperature dependencies, and for that reason the frequency technique was used. The piezoelectric charge coefficient, whose value can be effectively measured via the above-discussed frequency method, was selected as the indicator showing the depolarization state in the applied piezoelectric ceramics. The accuracy of the procedure was verified via comparison of the vibrometric method in cylinders of the NCE51 ceramics with different sizes, which are designed for the longitudinal length mode. The result is an optimized measurement methodology which facilitates accurate determination of the Curie temperature, namely phase transition to the cubic crystallographic structure. The experiment also proved the applicability of progressive, controlled depolarization of PZT ceramics via high temperature, and it also enabled us to define the temperature limits at which there occur irreversible changes of the piezoelectric properties of piezoceramics. In the measured NCE51 and PCM51 materials, the limit for the irreversible changes was equal to 95% of the Curie temperature.
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Proposal of Microactuator Based on SMART Material
Hradil, Aleš ; Houška, Pavel (referee) ; Hadaš, Zdeněk (advisor)
The master’s thesis deals with the proposal of microactuator based on SMART material. The thesis opens with the comparison of SMART materials which are suitable for actuator construction from the point of view of a reaction on stimulation in form of deformation. Subsequent part of the thesis is the report theory of piezoelectric effect, it also describes direct and indirect effects and it concerns about the description of piezoelectric materials. The thesis focuses on several principles of piezoactuators and motors. The last part of the thesis includes modeling and simulation of piezoelectric material in program ANSYS 13.0 and dimensioning geometric of actuator with evaluation of impact of parameters on final motion.
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Electronic noise temperature characteristics of piezoceramic sensors
Shromáždil, Petr ; Rampl, Ivan (referee) ; Majzner, Jiří (advisor)
The main objective of the thesis „Electronic noise temperature dependence of piezoceramic sensors“ is to design the measuring set-up for the measurement of the piezoceramic sensor noise temperature dependence. The application for the control of the measurement process is realized. The theoretic chapter is focused on the properties of materials for the production of piezoceramic sensors. The basic effects related to the piezoceramic properties and the material structure is described in this part. Next chapter is focused on the technology of production of used piezoceramic. The properties of solid solutions as PbZrO3 – PbTiO3, and the non-destructive methods of the material testing are discussed. Our attention is concentrated to methods of acoustic emission. The next chapter is concerned on the realization of the measuring set-up and program equipment. The tested sample is the acoustic emission sensor made of piezoceramic material PCM-51. It is placed in the cylinder chest which is heated by the DC current source. The temperature measurement is realized by the data acquisition switch unit. The results of measurements are saved in PC and they are analyzed using MATLAB program. As a result we receive the frequency spectra of the electric noise voltage spectral density SU. The temperature dependencies of resonant peak value and frequency are determined from these spectra.
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Piezoceramics Measurements
Fialka, Jiří ; Fidler, Petr (referee) ; Beneš, Petr (advisor)
The master’s thesis deals with the piezoelectric coefficients, the resonance frequency and especially the piezoelectric constants verification. With the assistance of several devices, for instance LCR-meter HIOKI 3532, impedance analyzer Agilent 4294A and LCR-meter Agilent E4980A, the resonance and the anti-resonance frequencies as well as impedance and capacitance of samples are measured. The paper opens with the theory of the piezoelectric phenomenon and the difference between direct and indirect piezoelectric phenomenon, it also describes the basic behaviour of a piezoelectric ceramic element during mechanical straining or applied voltage. Further, the paper concerns the description of various piezoelectric constants and their calculations. Subsequent part of the paper is devoted to the temperature dependence of the main piezoelectric parameters of PZT ceramics. The materials coefficients are delineated as a function of temperature of the piezoelectric charge coefficients dij, relative permittivity r, electromechanical coupling factor kij and frequency constants Ni. One of the chapters also determines the piezoelectric charge constant d33 of PZT ceramics by laser interferometer and compares it with the value measured by resonance methods. The surface displacement was measured by a single-beam interferometer Polytec OFV-5000. The results of measurements of piezoelectric charge coefficients d33 acquired by the first and the second method are identical. The last section of the paper is focused on different methods of experimental studies on the characteristics of heat transfer by diffusing heat through conduction between the silver-plated surface of cylinder made of PZT ceramics. The effect on the resonance and the anti-resonance frequencies is monitored. There after, the real heat, determined by thermo camera and the physical model of heat transfer created in program COMSOL Multiphysics, is analysed.
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