scholarly journals Analysis of a Cascaded Piezoelectric Ultrasonic Transducer with Three Sets of Piezoelectric Ceramic Stacks

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 580 ◽  
Author(s):  
Xiangdi Meng ◽  
Shuyu Lin

To increase the ultrasonic intensity and power of a piezoelectric transducer, a cascaded piezoelectric ultrasonic transducer with the three sets of piezoelectric ceramic stacks is analyzed. The cascaded piezoelectric ultrasonic transducer consists of four metal cylinders and three sets of piezoelectric ceramic stacks in the longitudinal direction. In analysis, the electromechanical equivalent circuit of the cascaded piezoelectric ultrasonic transducer is obtained, as well as the resonance/anti-resonance frequencies equations. By means of an analytical method, when the position of piezoelectric ceramic stacks PZT-2/PZT-3 changes, the resonance/anti-resonance frequencies and the effective electromechanical coupling coefficient of the cascaded piezoelectric ultrasonic transducer have certain characteristics. Several prototypes of the cascaded piezoelectric ultrasonic transducer are manufactured. The experimentally measured resonance frequencies are in good agreement with the theoretical and simulated results. The cascaded piezoelectric ultrasonic transducer with three sets of piezoelectric ceramic stacks presented in this paper is expected to be used in the field of high power ultrasound.

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4785
Author(s):  
Xiaoyu Wang ◽  
Shuyu Lin

The radial vibration of a radial composite tubular transducer with a large radiation range and power capacity is studied. The transducer is composed of a longitudinally polarized piezoelectric ceramic tube and a coaxial outer metal tube. Assuming that the longitudinal length is much larger than the radius, the electromechanical equivalent circuits of the radial vibration of a piezoelectric ceramic long tube and a metal long tube are derived and obtained for the first time following the plane strain theory. As per the condition of the continuous forces and displacements of two contact surfaces, the electromechanical equivalent circuit of the tubular transducer is obtained. The radial resonance/anti-resonance frequency equation and the expression of the effective electromechanical coupling coefficient are obtained. Then, the effects of the radial geometry dimension of the transducer on the vibration characteristics are analyzed. The theoretical resonance frequencies, anti-resonance frequencies, and the effective electromechanical coupling coefficients at the fundamental mode and the second mode are in good agreement with the finite element analysis (FEA) results. The study shows that when the overall size of the transducer is unchanged, as the proportion of piezoelectric ceramic increases, the radial resonance/anti-resonance frequency and the effective electromechanical coupling coefficient of the transducer at the fundamental mode and the second mode have certain characteristics. The radial composite tubular transducer is expected to be used in high-power ultrasonic wastewater treatment, ultrasonic degradation, and underwater acoustics, as well as other high-power ultrasonic fields.


Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1952 ◽  
Author(s):  
Jinhyuk Kim ◽  
Jungwoo Lee

We recently proposed a numerical model using equivalent circuit models to analyze the resonance characteristics of Langevin transducers and design them in a systematic manner. However, no pre-load torque biased by a metal bolt was considered in the model. Here, a parametric study is, therefore, carried out to reveal how model parameters are adapted to incorporate the pre-compression effect into our existing model. Analytical results are compared with corresponding experimental data, particularly regarding the input electrical impedance and effective electromechanical coupling coefficient for the transducer at resonance modes. The frequency response of input impedance is presented as a function of torque, both theoretically and experimentally. For 10.0 N·m bias, for instance, both resonance and anti-resonance frequencies are calculated as 38.64 kHz and 39.78 kHz, while these are measured as 38.62 kHz and 39.77 kHz by the impedance analyzer. The impedance difference between these cases is 14 Ω at resonance and 9 kΩ at anti-resonance, while the coupling coefficients in both cases become 0.238 and 0.239, respectively. Hence, these test results are closely matched with their theoretical values. Consequently, this study provides a quantitative guideline that specifies the pre-loading condition of bolt clamps with proper parameter settings to predict the intended resonance characteristics of Langevin transducers.


2010 ◽  
Vol 123-125 ◽  
pp. 161-164
Author(s):  
Dong Yu Xu ◽  
Shi Feng Huang ◽  
Chao Ju ◽  
Zong Zhen Zhang ◽  
Xin Cheng ◽  
...  

Periodic and non-periodic 1-3 type cement based piezoelectric composites were fabricated by cut and filling technique, using P(MN)ZT ceramic as functional material and cement as matrix. The influences of periodicity of piezoelectric ceramic rods in the composites on electrical properties of all the composites were discussed. The results show that the non-periodic composites have larger dielectric factor and piezoelectric strain constant than those of the periodic composite. The impedance-frequency spectra analysis indicates that the non-periodic arrangement of ceramic rods can effectively restrict the lateral structural mode of the composite, accordingly reduces the coupling resonant between the thickness resonant mode and lateral resonant mode. The thickness electromechanical coupling coefficient of non-periodic composites is larger than that of the periodic composite. With increasing the non-periodic level of P(MN)ZT ceramic in the composites, the mechanical quality factor of the composites increases gradually. Therefore, 1-3 type cement based piezoelectric composites with different special abilities can be obtained by varying the periodic arrangement of P(MN)ZT ceramic rods in the composites.


Author(s):  
S. H. Chang ◽  
T. W. Yang

Abstract The parts feeder provides both horizontal and vertical forces to transfer the small parts between stations in automated manufacturing processes. In this paper, the dynamic characteristics of a piezoelectrically actuated rotating parts feeder was evaluated. The model of the piezoelectric bimorph, the key component of the parts feeder, is formulated under DC and AC excitation. Experiments using laser interferometer, impedance analyzer and spectrum analyzer were conducted to measure displacement sensitivity, resonance frequencies and antiresonance frequencies of the electrical/mechanical system. Relations between driving frequencies and vibration amplitudes under various driving voltages were reported. From experimental results, the resonance frequencies of the mechanical system were identified at 176.6 Hz and 535 Hz. The first resonance and anti-resonance frequencies of the electrical system were found at 176.0 Hz and 177.5 Hz. The electromechanical coupling coefficient for piezoelectric actuator using Mason formula is 13%. Operating at the first resonance frequency, the parts feeder feeds at 17.66 mm/sec with a vertical vibration amplitude of 14.2 μ m.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4115 ◽  
Author(s):  
Myeongcheol Kang ◽  
Lae-Hyong Kang

In this study, we investigate the piezoelectric characteristics of 0.55Pb(Ni1/3Nb2/3)O3-0.45Pb(Zr,Ti)O3 (PNN-PZT) with MnO2 additive (0, 0.25, 0.5, 1, 2, and 3 mol%). We focus on the fabrication of a piezoelectric ceramic for use as both actuator and sensor for ultrasound transducers. The actuator and sensor properties of a piezoelectric ceramic depend on the piezoelectric strain coefficient d and piezoelectric voltage coefficient g, related as g = d/εT. To increase g, the dielectric constant εT must be decreased. PNN-PZT with MnO2 doping is synthesized using the conventional solid-state reaction method. The electrical properties are determined based on the resonant frequencies and vibration modes measured by using an impedance analyzer. The MnO2 addition initially improves the tetragonality of the PNN-PZT ceramic, which then saturates at a MnO2 content of 1 mol%. Therefore, the dielectric constant and piezoelectric coefficient d33 steadily decrease, while the mechanical properties (Qm, Young’s modulus), tanδ, electromechanical coupling coefficient k, and piezoelectric voltage coefficient g were improved at 0.5–1 mol% MnO2 content.


1996 ◽  
Vol 18 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Wenkang Qi ◽  
Wenwu Cao

Finite element method (FEA) has been used to calculate the thickness resonance frequency and electromechanical coupling coefficient kt for 2–2 piezocomposite transducers. The results are compared with that of the effective medium theory and also verified by experiments. It is shown that the predicted resonance frequencies from the effective medium theory and the unit cell modeling using FEA deviate from the experimental observations for composite systems with a ceramic aspect ratio (width/length) more than 0.4. For such systems, full size FEA modeling is required which can provide accurate predictions of the resonance frequency and thickness coupling constant kt.


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