PZT Plate Research Articles

A centipede-inspired bonded-type ultrasonic actuator with high thrust force density driven by dual-torsional-vibration-induced flexural traveling waves

This paper presents an ultrasonic actuator with high thrust force density driven by dual-torsional-vibration-induced flexural traveling waves. Here, the PZT plates are bonded onto a duralumin vibrating body in a block shape to accomplish a compact configuration and they operate in the 2nd torsional vibrations, whose strong electromechanical coupling effect facilitates the enhancement of the driving force. Interestingly, the operating principle somewhat imitates the movement pattern of the centipede’s feet. To test the validity, first, by using a Mason-equivalent-circuit-based dynamic model, several key dimensions were tuned to increase the driving-force-to-weight ratio. Meanwhile, the driving feet’s configurations are adjusted based on a kinetic model to make the elliptical motion shape close to a circle. Then, an actuator prototype with the size of 48 × 47 × 6 mm3 and the weight of 29 g was fabricated and the moving/loading/positioning performance was evaluated. When the actuator adopts a continuous operation, its maximal sliding speed reached 630 mm/s at the frequency of 24.95 kHz. Moreover, it yielded the maximal thrust force and the maximal output power of 4.38 N and 527.8 mW, corresponding to the thrust force density and the power density of 151.2 N/kg and 18.2 W/kg, respectively. In a stepping operation, the minimal step displacement was 0.91 μm. These results demonstrate that the dual-torsional-vibrations-induced traveling wave allows the actuator to produce the high thrust force density and provides a new actuating principle to design powerful ultrasonic actuators.

An Influence of Actuator Gluing on Elastic Wave Excited in the Structure.

In this article, the practical issues connected with guided wave measurement are studied: (1) the influence of gluing of PZT plate actuators (NAC2013) on generated elastic wave propagation, (2) the repeatability of PZT transducers attachment, and (3) the assessment of the possibility of comparing the results of Laser Doppler Vibrometry (LDV) measurement performed on different 2D samples. The consideration of these questions is crucial in the context of the assessment of the possibility of the application of the guided wave phenomenon to structural health-monitoring systems, e.g., in civil engineering. In the examination, laboratory tests on the web of steel I-section specimens were conducted. The size and shape of the specimens were developed in such a way that they were similar to the elements typically used in civil engineering structures. It was proved that the highest amplitude of the generated wave was obtained when the exciters were glued using wax. The repeatability and durability of this connection type were the weakest. Due to this reason, it was not suitable for practical use outside the laboratory. The permanent glue application gave a stable connection between the exciter and the specimen, but the generated signal had the lowest amplitude. In the paper, the new procedure dedicated to objective analysis and comparison of the elastic waves propagating on the surface of different specimens was proposed. In this procedure, the genetic algorithms help with the determination of a new coordinate system, in which the assessment of the quality of wave propagation in different directions is possible.

Piezoelectric 1D MEMS scanning micromirror fabricated with bulk PZT laminated on stainless steel plate

In this research, a piezoelectric metal scanning micromirror with a large reflective surface area is presented. Unlike conventional scanning micromirrors fabricated with single-crystal silicon, stainless steel plate is used as the structural layer material. Two distinct device models, varying in cantilever and connector geometry, were conceptualized and experimentally assessed. These fabricated devices utilized the strain induced in bulk PZT (lead zirconate titanate) plates affixed to the cantilevers on opposing sides of the reflective surface. A 5 mm-diameter gold-coated silicon mirror plate served as the reflective surface. We evaluated the performance of two bulk PZT plates, PZT-5H and PZT-8. Our experimental results reveal that model #1, driven by PZT-5H with a sinusoidal input voltage of 200 Vpp, achieved a maximum optical scan angle of 26°, while model #2 exhibited a more substantial maximum scan angle of 44°. The average resonant frequency of the PZT-5H samples was 1264 Hz for model #1 and 995 Hz for model #2. These findings underscore the viability of stainless steel plates as a robust structural layer for piezoelectric scanning micromirrors. The proposed design holds potential for integration into a 3D LiDAR system when combined with an additional slow vertical scanner.

Analytical model of z-piezoelectric energy harvester for power generation from human physical activities

Human physical activities, viz., walking, jogging, jumping, etc on piezoelectric energy harvesters (PEH) have a great potential for the generation of free and clean energy. In the present work, an analytical model is developed to study the performance of a z-PEH, and the results were validated with numerical and experimental results. The distinctive features of the z-PEH are (a) it can be installed in a very small pavement/road surface area, (b) it results in very less damage to the road during installation, and (c) the repair and maintenance works can be carried out relatively easily. The power generation of the harvester can be enormously increased by increasing the number of unimorphs in the vertical (z) direction without increasing in the surface (x-y) directions, hence termed z-PEH. The harvester studied has four unimorphs. Each unimorph has a PZT-5A plate and an Aluminum substrate. The analytical and numerical studies resulted in a harvester with optimum dimensions for the PZT plate and Aluminum substrate of 20 × 20 × 0.4 mm3 and 65.1 × 20 × 1 mm3 respectively. Experiments were carried out on the optimum structure. The z-PEH, for an input deflection of 1 mm generated a maximum power of 0.84 mW, 0.88 mW and 0.80 mW from the proposed analytical model, numerical work and experiments respectively. The percentage of error between analytical and numerical results is 4.55% and between analytical and experimental results is 4.76%. An average human can generate a force of 490 N while walking, thereby allowing the use of 88 unimorphs in the z-PEH. From the analytical model, the resulted DC power of this harvester is 18.39 mW and the power density is 10.09 W m−3.

Distributed-parameter modeling and dynamic analysis of rotational compressive-mode energy harvesters

This paper presents a modeling and dynamic analysis of a rotational high-efficiency compressive-mode piezoelectric energy harvester (HC-PEH) with partially thickened bow-shaped beams. Based on the Euler–Bernoulli beam theory and the extended Hamilton’s principle, the governing equations of the rotational HC-PEH system are formulated. The nonlinear electromechanical coupling partial differential equations of the system are transformed into ordinary differential equations in the truncated modal coordinates. The developed distributed-parameter model is validated against experimental data, and a good agreement is achieved. The stability and the nonlinear dynamic behavior of the rotational HC-PEH system in conditions of different offset distances and preloaded axial forces are investigated by numerical simulation results. A parametric study of the parameters directly related to the system design is also performed to provide fundamental guidance for understanding the electrical output performance and modulating the voltage–rotation speed responses of the harvester. The result shows that the design parameters of the bow-shaped beam and the PZT plate have apparent effects on the electrical output of the harvester system.

Hybrid magnetoelectric converter

The article is devoted to the study of a hybrid magnetoelectric voltage converter. The article deals with the magnetoelectric structure of the converter with its design features. The measuring stand with the calculation of the converter parameters is also described and the measurement results are given. In the manufacture of the ME element, materials such as piezoelectric PZT and magnetostrictive amorphous alloy Metglas were used. ME is a layered element, which consists of a PZT plate with electrodes applied to the lateral surfaces and one or more Metglas layers. The Metglas plates are connected to the piezoelectric using an adhesive bond. In experimental studies, the number of Metglas layers varied from one to three. The article discusses the design of the converter and the choice of the most optimal of the ones under study. As a result of the study, the lowest indicators were found for a converter without a core, the more Metglas layers, the better the characteristics of the converter. The ME element at the resonant frequency converts energy much better (the conversion power was about 130 μW) than the design of a conventional converter, and also a hybrid converter based on a series switching circuit gives an even greater gain in energy conversion (the conversion power was about 180 μW).

A Micro Piezoelectric Motor With Multiple Excitation Modes and Methods

To widen the performance of piezoelectric motors, this paper demonstrates a micro piezoelectric motor having multiple driving ways. The stator includes a hollow polygon bar and two groups of PZT plates. PZT plates are symmetrically bonded onto a brass base, and used to actuate the vibration modes of the stator. The symmetrical design enables the motor to operate in two types of vibration modes. The working modes are the second/third-order in-plane bending modes, and can be excited by different ways. Elliptical motion of stator surface points is generated by superposition of two bending modes with the same order. To investigate the feasibility of multi-mode and multi-motivation mechanisms, vibration behaviors of stator driving particles are simulated using ANSYS software. The structural parameters of the stator are strictly designed to harmonize the eigenfrequencies of the vibration modes. The calculated results reveal that the motor performance can be adjusted by selecting different operating modes and excitation ways. The motor performances under various excitation ways and driving modes are also investigated experimentally to validate the proposed design. The dimension of the fabricated prototype motor is 8.3 mm$\times 7.2$ mm$\times 15.0$ mm. The maximum torques are respectively 8.3 cN$\cdot \text{m}$ and 13.3 cN$\cdot \text{m}$ under single-phase and two-phase excitation voltages, when the motor operates in the second-order bending modes. The corresponding no-load speeds are respectively 40 rpm and 47 rpm. The maximum torque and speed under the third-order bending modes are much smaller than that under the second-order bending modes.

Design and verification of a micro piezoelectric motor with energy harvesting characteristic for capsule endoscope

Wireless capsule endoscopy has the distinctive advantage of providing trustworthy results without substantial discomforts to patients. However, lack of capsule active motion control and energy supply have been significant obstacles preventing wider applications of this technology. To overcome these problems, this paper presents a micro piezoelectric motor with energy harvesting feature. The motor is driven by a single-phase voltage and can be used in capsule endoscopy. The stator was constructed by bonding two PZT plates (PZT1 and PZT2) onto the adjacent outer surfaces of a metal base. PZT1 and PZT2 can both be used to excite the in-plane bending modes of the stator to generate a traveling wave in the stator. The PZT plate supplied with no-exciting voltage source can be used to convert the superfluous vibration energy of stator body into electric energy to power small electronic devices. The elliptical trajectories of points on the stator surface result from a superposition of the two bending modes. The vibration and energy conversion characteristics of the stator were analyzed by using the finite element analysis software ANSYS. The structure parameters of the stator were adjusted until the mode mixture of the stator disappeared. A prototype motor was fabricated and tested to explore its mechanical and electric energy output abilities. The size of the prototype motor is about 9.8×9.2×22.0 mm3. The tested resonance frequencies of the operating modes are 15.305 kHz and 15.815 kHz, respectively. The maximum no-load speed is 85 rpm. The applied single-phase driving voltage is 100 Vo-p (peak voltage) at frequency of 15.54 kHz. The stall torque is 0.98 mN·m, and the maximum output power of the harvesting PZT plate is 127 mW under an optimal equivalent load resistance of 5.16 kΩ.

Electric-field-controlled frequency tunability enhancement by samarium light doping in PZT/Ni–Zn ferrite/PZT magnetoelectric composites

Electric-field-controlled resonance tuning in tri-layer magnetoelectric laminate consisting of Ni–Zn ferrites (with/without Sm-doped) and PZT plates has been performed and systemically characterized. By applying the DC voltage on PZT plate, modulus of the sample will change in ferrite which is caused by mediated pre-stress from PZT plate, resulting in a resonance shifting without a sacrifice of MEVC decay. For the purpose of tuning range improvement, light doping of samarium was employed in spinel nickel–zinc ferrites to modify frequency responses properties. Experimental results showed that a nearly linear variation of resonance frequency with applied voltage varied from 0 to 6 kV/cm was obtained. Consequently, the resonance frequency can be precisely controlled by the pre-stress generated from DC electric field. In addition, the tunability of resonance frequency exhibits an approximately 3.68 times enhancement by samarium doping in the Ni–Zn ferrites. The pathway for resonance frequency tunable realization by applied DC voltage provides an accurate tuning method for the tunable resonator, which can be deployed extensively in signal generators, phase shifters and other electronic devices.

Optimization of molecular delivery to red blood cells using an ultrasound-integrated microfluidic system

The shelf-life of donated red blood cells (RBCs) for transfusions is currently limited to six weeks when stored under refrigeration. This causes supply shortages worldwide and prevents transfusions in locations that lack access to cold-chain storage. Recently, a new approach to store RBCs as a dried powder at ambient temperature was developed. This method utilizes an ultrasound-integrated microfluidic platform to induce intracellular delivery of compounds that protect cells during desiccation and rehydration. The objective of this study was to detect cavitation emissions in order to optimize parameters for molecular delivery to RBCs in this system. Ultrasound was continuously generated in the microfluidic channels using an 8-MHz PZT plate and acoustic emissions were passively detected with an identical PZT plate aligned coaxially. Fluorescein and lipid-coated microbubbles were added to RBC solutions in order to nucleate cavitation and enhance intracellular molecular uptake as measured by flow cytometry. Increased levels of broadband emissions were detected at microfluidic flow rates associated with higher fluorescein delivery to RBCs. These results suggest that inertial cavitation plays an important role in enhancing molecular delivery to RBCs in the microfluidic channels. Optimization of this system may enhance delivery of protective compounds for long-term preservation of blood.

Development of a resonant type piezoelectric stepping motor using longitudinal and bending hybrid bolt-clamped transducer

A resonant type piezoelectric stepping motor using a bolt-clamped transducer is proposed and its novel driving method for stepping motion is discussed in this study. The exciting signals used in the driving method consist of several sinusoidal signals and a pause in one driving period, and the two exciting signals applied to the longitudinal PZT plates and bending PZT plates have a phase shift of π/2. The first longitudinal vibration and second bending vibration of the motor are excited and two intermittent reciprocating vibrations along two orthogonal directions are generated on the driving tip to press and drive a linear runner step-by-step, respectively. The proposed motor is designed and its driving method is described. The operating principle of the motor is illustrated by finite element method. A prototype is fabricated and its impedance characteristics are tested to obtain the resonance frequencies. An experimental system is established to test mechanical output characteristics. The results state that the proposed stepping motor outputs a velocity and thrust force of 11.73 mm/s and 18 N under voltage of 200 Vp-p. The displacement resolution is tested as 0.26 μm when the voltage and number of sinusoidal signal in one period are 200 Vp-p and 1.

A three-dimensional piezoelectric nanopositioner using a sandwich transducer

This work presents a three-dimensional piezoelectric nanopositioner based on a sandwich transducer is fabricated and tested. The proposed piezoelectric positioner mainly consists of five parts: driving tip, horn, sheet copper, PZT plates and end cap, and the size of the positioner is 60 mm × 60 mm × 90 mm. The positioner utilizes the operating principle of composite mode to accomplish different driving purposes. The operating principle of the piezoelectric positioner is discussed detailly and simulated by the finite element method. The working ranges of the proposed positioner in X, Y, Z direction are tested as 9.18 µm, 9.06 µm and 1.55 µm, respectively. Meanwhile, the positioner shows the characters of the resolution of 13 nm, working frequency up to 800 Hz and small location error (less than 1%).

Thermal Pulse Studies of Integrated Piezoceramics

Integrated piezoceramics enable smart structures which interact with their environment. Their polarization state can be probed by thermal methods based on the pyroelectric effect. In this work, single PZT plates and PZT plates embedded into low temperature co‐fired ceramics (LTCC) are heated by thermal pulses and the pyroelectric current is measured in time domain. Analytical and numerical models to describe the mean temperature of the sample and derive the pyroelectric current are presented by the authors. Single‐layer and two‐layer models are used and the effects of a finite pulse width, the electrode, and heat losses are investigated. The goal is to find a suitable model characterizing the pyroelectric current in time domain as basis to derive information on the corresponding polarization state.

Optimizing piezoelectric receivers for acoustic power transfer applications

In this paper, we aim to optimize piezoelectric plate receivers for acoustic power transfer applications by analyzing the influence of the losses and of the acoustic boundary conditions. We derive the analytic expressions of the efficiency of the receiver with the optimal electric loads attached, and analyze the maximum efficiency value and its frequency with different loss and acoustic boundary conditions. To validate the analytical expressions that we have derived, we perform experiments in water with composite transducers of different filling fractions, and see that a lower acoustic impedance mismatch can compensate the influence of large dielectric and acoustic losses to achieve a good performance. Finally, we briefly compare the advantages and drawbacks of composite transducers and pure PZT (lead zirconate titanate) plates as acoustic power receivers, and conclude that 1–3 composites can achieve similar efficiency values in low power applications due to their adjustable acoustic impedance.

Experimental results for active control of multimodal vibrations by optimally placed piezoelectric actuators

Vibration damping is an effective strategy to enhance the life-cycle and performance of mechanical components. In this regard passive control systems involve lower costs and are easier to implement but their bandwidth is limited, whereas active systems provide larger bandwidth and higher adaptability to dynamic loads but higher costs and complexity are required. The recent advances in smart materials promoted the development of smart structures suitable for vibration damping and control. Between them the piezoelectric systems seem to be the most promising, however their efficiency relies on their placement. In a previous work the authors proposed and validated an analytical method to detect the optimal location of piezoelectric plates to control the multi-modal vibrations of a cantilever beam. Recent findings show that, if all actuators are activated simultaneously, the optimization problem can be traced back to the determination of the optimal potential distribution on all the piezoelectric actuators. In this paper the above method is taken into account and applied to a cantilever beam with 13 pairs of surface mounted PZT plates under the excitation provided by an electrodynamic shaker. The experimental damping of two flexural modes combinations has been performed by means of a special-purpose workbench and the assessment of the damping efficiency has been measured by means of a micro I.C.P. accelerometer. The results showed that the multimode vibrations of the cantilever beam can be efficiently damped if the potential distribution on all the PZT plates is optimized.

Piezoelectric Materials Under Natural and Man-Made Radiation: The Potential for Direct Radiation Detection

Radiation detection systems used for monitoring long term waste storage need to be compact, rugged, and have low or no power requirements. By using piezoelectric materials it may be possible to create a reliable self-powered radiation detection system. To determine the feasibility of this approach, the electrical signal response of the piezoelectric materials to radiation must be characterized. To do so, an experimental geometry has been designed and a neutron source has been chosen as described in this paper, which will be used to irradiate a uranium foil for producing fission fragments. These future experiments will be aimed at finding the threshold of exposure of lead zirconate titanate (PZT) plates needed to produce and electrical signal. Based on the proposed experimental geometry the thermal neutron beam-line at the Breazeale Reactor at The Pennsylvania State University will be used as the neutron source. The uranium foil and neutron source will be able to supply a maximum flux of 1.5e5 fission fragments/second*cm2 to each of the PZT plates.

Elution of lead from lead zirconate titanate ceramics to acid rain

The amount of lead that eluted from lead zirconate titanate (PZT) ceramics to artificial acid rain was evaluated. Four kinds of PZT ceramics, namely, pure PZT at MPB composition, CuO-added PZT, PZT with 10 mol % substitution of Ba for Pb, and CuO-added PZT with 10 mol % substitution of Ba for Pb, were used as samples of the elution test. These PZT ceramics of 8 mm2 and 1.1–1.2 mm thickness were suspended in 300 ml of H2SO4 solution of pH 4.0. The concentration of lead eluted from PZT was in the range from 0.2 to 0.8 ppm. It was found that both liquid phase formation by the addition of CuO and the substitution of Ba for Pb were effective to reduce the amount of lead that eluted. By fitting the leaching out curve with a classical equation, a master curve assuming no sampling effect was obtained. The lead concentration evaluated from the amount of lead that eluted from a commercial PZT plate to H2SO4 solution of pH 5.3 was almost the same as the limit in city water. It is concluded that PZT is not harmful to health and the environment and the amount of lead that eluted from PZT can be controlled by modifying PZT composition.

Influence of Electrode Layers on the Fracture Strength of PZT Ceramics

A newly developed process chain enables the production of active structural components. Thereby lead zirconate titanate (PZT) fibres are integrated in metal sheets by joining by forming. For the further development of the process chain to a high volume production the fracture strength of PZT should be increased. This paper pursues the approach to increase the strength by selected electrode layers. For this purpose, various electrode layers are tested on PZT plates in strength tests with the ball on three balls test (B3B-test). The evaluation of the recorded values is carried out according to statistically methods. The results show that the strength of PZT can be increased by electrode layers up to 30%. In addition, it was established that a high tensile strength and a high Young’s modulus of the electrode layers do not have a positive effect on the strength of PZT.

A piezoelectric motor driven by a single-phase signal

This paper aims to present a proof-of-concept for a novel piezoelectric motor using a single-phase driving signal. The stator is constructed by bonding a Terfenol-D plate and a piezoelectric ceramic (PZT) plate onto the outer surface of a metal base. The PZT plate based on d31 effect is used to simultaneously excite two in-plane bending modes of the stator. Similarly, the Terfenol-D plate can also be used to excite the two bending modes. By superposition of the two bending modes, elliptical motions of the stator surface points are generated. The working modes and vibration characteristics of the motor are analyzed by finite element analysis software. The resonance frequencies of the two bending modes are tuned to be close by additional mass. The dimensions of the stator are optimized to maximize the output displacement. To confirm the feasibility of the proposed design, a prototype motor is fabricated and tested. The size of the prototype motor is about 11.2×10.7×28.0 mm3. The tested resonance frequencies of the two bending modes are 16.0820 kHz and 16.3476 kHz respectively. The maximum no-load speed is 85 rpm. The applied driving voltage is 100 Vo-p (peak voltage) at a frequency of 16.34 kHz.

An inertial piezoelectric plate type rotary motor

Investigation of a novel design inertial type piezoelectric motor is presented in the paper. Research was performed to validate operation principle and to investigate dynamic characteristics of the motor. Motor has simple design and consist of rectangular bronze stator, clamping frame, eight lead zirconate titanate (PZT) plates and a conical rotor. PZT plates are glued on the stator from both sides and are used to excite second in-plane bending mode. Excitation of the motor is carried out by two saw-tooth signals with phases shifted by π. Rotor is located at the center of the stator. Rotation motion of the rotor is based on stick-slip operation principle. Proposed piezoelectric motor is flat and can be used for the applications where space and mounting volume are critical. Numerical investigation of the piezoelectric motor based on finite elements method was performed in order to obtain natural frequency and modal shape of the stator, to investigate dynamic characteristics and to validate operation principle of the motor. Proper geometric parameters of the stator were obtained by solving optimization problem. A prototype of the motor was made and investigations of the mechanical, thermal and electrical characteristics were performed. The results of the numerical and experimental investigations are discussed.