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Measurement system for determination of the piezoelectric charge coefficient
Kašpárek, Ondřej ; Skalský, Michal (referee) ; Fialka, Jiří (advisor)
The master's thesis deals with methods of measuring material coefficients of piezoelectric materials with a focus on direct methods of measuring piezoelectric charge constant. The first chapters of this paper focus on the theory of the piezoelectric effect, the description of piezoelectric material coefficients, and the theory of direct measurements of piezoelectric charge constant, where is the generated charge, which corresponds to the mechanical load, measured. The next part of this thesis deals with designing and creating advanced measuring systems based on the quasi-static method, which are measuring the electrical response of the material to a step-change in force or a harmonic force signal straining the testing sample. In the last part, the influences on the measurement results, such as the use of electromagnetic shielding, are investigated using the created measurement systems.
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Characterization of lead-free piezoelectric ceramics
Šťastná, Magdaléna ; Holcman, Vladimír (referee) ; Tofel, Pavel (advisor)
This project is focused on lead-free piezoelectric ceramics which are meda in CEITEC. Behaviour of these ceramics is quite different from the lead one. The first part is dedicated to dielectrics and its polarisation techniques. These techniques also include the piezoelectric effect which occurs only in crystals without central symmetry. The following part is focused on piezoelectric materials, piezoelectric polymers and piezoelectric ceramics respectively. The next section of the project is dedicated to the design of an experimental workplace for direct measurement of the piezoelectric charge coefficient đť‘‘33. The experimental part of the work is focused on electric characterisation of lead-free piezoceramics.
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Measurement system for determination of the piezoelectric charge coefficient
Kašpárek, Ondřej ; Skalský, Michal (referee) ; Fialka, Jiří (advisor)
The master's thesis deals with methods of measuring material coefficients of piezoelectric materials with a focus on direct methods of measuring piezoelectric charge constant. The first chapters of this paper focus on the theory of the piezoelectric effect, the description of piezoelectric material coefficients, and the theory of direct measurements of piezoelectric charge constant, where is the generated charge, which corresponds to the mechanical load, measured. The next part of this thesis deals with designing and creating advanced measuring systems based on the quasi-static method, which are measuring the electrical response of the material to a step-change in force or a harmonic force signal straining the testing sample. In the last part, the influences on the measurement results, such as the use of electromagnetic shielding, are investigated using the created measurement systems.
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Characterization of lead-free piezoelectric ceramics
Šťastná, Magdaléna ; Holcman, Vladimír (referee) ; Tofel, Pavel (advisor)
This project is focused on lead-free piezoelectric ceramics which are meda in CEITEC. Behaviour of these ceramics is quite different from the lead one. The first part is dedicated to dielectrics and its polarisation techniques. These techniques also include the piezoelectric effect which occurs only in crystals without central symmetry. The following part is focused on piezoelectric materials, piezoelectric polymers and piezoelectric ceramics respectively. The next section of the project is dedicated to the design of an experimental workplace for direct measurement of the piezoelectric charge coefficient đť‘‘33. The experimental part of the work is focused on electric characterisation of lead-free piezoceramics.
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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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Determination of the coefficient of linear thermal expansion of sintered PZT ceramics
Šašek, Petr
Působením teploty dochází v materiálech ke změnám velikosti. Toto může být problém v případě, že se jedná o vrstevnatý materiál, kdy jednotlivé vrstvy mají rozdílné vlastnosti. Cílem této studie bylo zjistit součinitel teplotní roztažnosti piezoelektrické keramiky s tenkou stříbrnou vrstvou. Teplotní rozsah byl od -20 do 60 °C, resp. od -30 do 160 °C. Rychlost ohřevu byla 1°C/min. Celkem byly měřeny 3 vzorky. Srovnání tepelné roztažnosti nám ukazuje, že jeden vzorek se liší od dvou vzorků, které mají podobné vlastnosti.
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