Design Of Piezoelectric Transducers Research Articles

Textured BiScO3-PbTiO3 piezoelectric ceramics with both high electromechanical coupling factor and high curie temperature

High-temperature piezoelectric devices require piezoelectric ceramics with high Curie temperatures and high-temperature stability of piezoelectric properties to avoid the depolarization of piezoelectric ceramics during application. However, piezoelectric materials with high Curie temperatures usually have restrained piezoelectric properties. Crystallographic orientation via texture engineering is a practicable way to improve piezoelectric performance. Here, we propose a sintering-aid-assisted template grain growth strategy to texture BiScO3-PbTiO3 ceramics to overcome the low orientation issue that challenges the texturing of BS-PT for decades. By judiciously selecting B2O3-CuO as sintering aids, we fabricated highly ⟨001⟩-textured 0.43BS-0.57PT ceramics with Logtering factors >99.0% that possess high piezoelectric coefficients d33 of 474–612 pC/N while maintaining relatively high Curie temperatures of 370–402 °C. Importantly, this work addresses a long-standing issue presented in BS-PT ceramics, i.e., the low electromechanical coupling property of BS-PT ceramics (k33 < 0.70) by improving the electromechanical coupling factor k33 to 81.2%. The newly designed textured BS-PT ceramics are thought to be promising candidates for the design of high-temperature piezoelectric transducers and actuators.

The Modeling Design and Analysis of Spherical-Cymbal Piezoelectric Transducer

The paper proposes a model and analysis of spherical-cymbal piezoelectric transducer. First, we select materials for force-sensitive element, the metal end cap and ring and epoxy resin. The load transfer law of the spherical-cymbal piezoelectric transducer is analyzed. Then, resonant frequency test, axial vibration displacement test and ultimate static pressure test are implemented in experiment. The experimental results show that the spherical-cymbal piezoelectric transducer outperforms the traditional cymbal piezoelectric transducer. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P _max</i> value can increase up to 10% under different geometric parameters. This paper is conducted to provide new insight into the design of cymbal piezoelectric transducer.

Time domain response of a piezoelectric layer

A number of one-dimensional models have been developed to inform the design of piezoelectric transducers. The majority of these models are in the frequency domain. In this paper, we develop a one-dimensional time-domain model for the mechanical response of a piezoelectric layer. Secondary effects, resulting from feedback between the acoustic and electric variables, are included in the model. Our approach utilizes Green's function for the Helmholtz equation with radiation boundary conditions and the methods of complex analysis. The model predictions are validated by comparison with a finite-difference time-domain numerical simulation of the governing acoustic equations in and outside the layer. This time-domain model enables efficient calculation of the secondary piezoelectric action effects and provides the mechanical response to an arbitrary electrical source.

Time domain response of a piezoelectric layer

A number of one-dimensional models have been developed to inform the design of piezoelectric transducers. The majority of these models are in the frequency domain. In this paper, we develop a one-dimensional time-domain model for the mechanical response of a piezoelectric layer. Secondary effects, resulting from feedback between the acoustic and electric variables, are included in the model. Our approach utilizes the Green's function for the Helmholtz equation with radiation boundary conditions and the methods of complex analysis. The model predictions are validated by comparison with a finite-difference time-domain numerical simulation of the governing acoustic equations in and outside the layer. This time-domain model enables efficient calculation of the secondary piezoelectric action effects and provides the mechanical response to an arbitrary electrical source.

Design of Piezoelectric Acoustic Transducers for Underwater Applications.

Interest in underwater transducers has persisted since the mid-1900s. Underwater transducers are designed in various shapes using various materials depending on the purpose of use, such as to achieve high power, improve broadband, and enhance beam steering. Therefore, in this study, an analysis is conducted according to the structural shape of the transducer, exterior material, and active material. By classifying transducers by structure, the transducer design trends and possible design issues can be identified. Researchers have constantly attempted new methods to improve the performance of transducers. In addition, a methodology to overcome this problem is presented. Finally, this review covers old and new research, and will serve as a reference for designers of underwater transducer.

Design and 3D FEM Analysis of a Flexible Piezoelectric Micromechanical Ultrasonic Transducer Based on Sc-Doped AlN Film.

In this paper, a flexible piezoelectric micromachined ultrasonic transducer (PMUT) based on Scandium (Sc)-doped Aluminum Nitride (AlN) film was designed and modeled by the three-dimensional finite element method (3D-FEM). The resonant frequency of 218.1 kHz was reported. It was noticeable that a high effective electromechanical coupling coefficient (k2eff) of 1.45% was obtained when a combination of a flexible PI and a thin Si layer was used as the PMUT supporting structure layer. Compared with a pure Si supporting layer counterpart, the coupling coefficient had been improved by 110.68%. Additionally, the increase of Sc doping concentration in AlN film further enhanced the device electromechanical coupling coefficient and resulted in an improvement for transmitting/receiving sensitivity of the proposed flexible PMUT. When the doping concentration of Sc reached 30%, the emission sensitivity was as large as 1.721 μm/V, which was 2.86 times greater than that of conventional AlN film-based PMUT. The receiving sensitivity was found to be 2.11 V/KPa, which was as high as 1.23 times the performance of an undoped device. Furthermore, the bending simulation result showed that the proposed flexible PMUT device can maintain a good mechanical stability when the bending radius is greater than 1.5 mm. The simulation of sound field characteristics demonstrated that the flexible PMUT based on AlScN could receive stable sound pressure signals under the bending radius of 1.5 cm.

Clinical Performance, Safety, and Patient-Reported Outcomes of an Active Osseointegrated Steady-State Implant System.

ObjectiveTo investigate the clinical performance, safety, and patient-reported outcomes of an active osseointegrated steady-state implant system that uses piezoelectric technology.Study DesignA prospective, multicenter, open-label, single-arm, within-subject clinical investigation.SettingThree tertiary referral clinical centers located in Melbourne, Sydney, and Hong Kong.PatientsTwenty-nine adult subjects, 24 with mixed hearing loss or conductive hearing loss and 5 with single-sided sensorineural deafness.InterventionImplantation with the Cochlear Osia 2 System.Main Outcome MeasuresAudiological threshold evaluation and speech recognition in quiet and in noise. Patient satisfaction and safety.ResultsAt 6-month follow-up after surgery, a mean improvement in pure-tone average of 26.0 dB hearing level and a mean improvement of 8.8 dB signal-to-noise ratio in speech reception threshold in noise was achieved with the investigational device as compared with the unaided situation. Usability of the investigational device was rated 71.4/100 mm for sound processor retention and 81.4/100 mm for overall comfort using a visual analog scale.ConclusionThese outcomes confirm the clinical safety, performance, and benefit of an innovative active transcutaneous bone conduction implant using a piezoelectric transducer design in subjects with conductive hearing loss, mixed hearing loss, or single-sided sensorineural deafness.

Piezoelectric transducer design for simultaneous ultrasonic power transfer and backscatter communication

Ultrasonic waves can transfer power and data to sensors and devices deployed to traditionally inaccessible locations, such as inside the human body or deep in the ocean, eliminating the need for battery replacement. In ultrasonic power and data transfer systems, a piezoelectric transducer converts incident ultrasonic waves to useful electric power while transmitting data by modulating its reflected signal through backscatter communication. Existing approaches rely on reflecting a portion of the incident power to communicate, reducing the harvested power. This work realizes uninterrupted power harvesting with simultaneous backscatter communication through frequency multiplexing. A piezoelectric transducer is first designed and tested experimentally for high sensitivity and high bandwidth operation through low-loss broadband acoustic and electrical impedance matching. The transducer achieved 70% bandwidth at 1 MHz with a 10 dB difference between reflecting and absorbing incident ultrasonic waves. A frequency multiplexing technique is then developed to separate power and data into different frequency bands achieving simultaneous operation. The technique extends the range and bandwidth of ultrasonically powered devices such as biomedical implants and ocean monitoring sensors.

Enhanced Piezoelectric Properties and Improved Property Uniformity in Nd‐Doped PMN‐PT Relaxor Ferroelectric Single Crystals

AbstractRelaxor‐PbTiO3 crystals exhibit excellent piezoelectric properties (d33 &gt; 2000 pC N−1 and k33 &gt; 90%) and thus attractes widespread attention in the past two decades. However, the inevitable segregation of components during the crystal growth results in relatively low‐performance consistency of Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) crystals, which seriously affects their practical applications. In this work, Nd3+ as A‐site substitution is introduced to improve the uniformity of electromechanical performance of PMN‐PT crystal. The results show that the crystal exhibits a high piezoelectric coefficient of 3000 pC N−1 in rhombohedral phase with a variation of 36%. The electron probe X‐ray microanalyzer indicates that the opposite separation characteristics of Nd3+ and Ti4+ lead to improved uniformity of piezoelectric performance along the crystal boule. The giant piezoelectricity in Nd‐doped PMN‐PT is attributed to the enhanced local structural heterogeneity introduced by doping Nd. Furthermore, the Nd‐doped PMN‐PT crystal shows the rhombohedral‐tetragonal phase transition temperature in the range of 74–87 °C, which indicates that Nd‐doped PMN‐PT crystal can be a promising candidate for the design of advanced piezoelectric transducers.

Energy harvesting performance of a full-pressure piezoelectric transducer applied in pavement structures

Using piezoelectric materials to convert mechanical energy into electrical energy provides ideas for energy self-consistency of road infrastructure. Since some 3–3 form piezoelectric transducers underutilize vehicle loads, which weaken the energy conversion potential, the full-pressure concept was proposed and novel piezoelectric transducers were designed. Furthermore, studies on the piezoelectric response and long-term performance of piezoelectric transducers after being applied to pavements are insufficient. Therefore, referencing pavement-related specifications small piezoelectric pavements were first prepared. Then the direct and potential factors that affect energy harvesting were elaborated. The instantaneous and long-term piezoelectric properties were finally evaluated through acceleration loading tests. Results show that the piezoelectric output has a significant linear relationship with the load, indicating that the new piezoelectric transducer has a good electrical response after being applied to the pavement structure. An increase in the loading speed leads to an increase in the output voltage and output power but not necessarily an increase in energy output. The high-temperature environment contributed to the energy output. Pavements with larger particle sizes can boost the output voltage. After 500,000 cycles of loading, the long-term performances of piezoelectric pavements were verified. This study could provide references for the design of piezoelectric transducers and their applications.

Origin of the thickness-dependent electric properties of BiScO3-PbTiO3 piezoceramics near the morphotropic phase boundary

The mechanism of thickness dependence electric properties for BiScO3-PbTiO3 ceramics with morphotropic phase boundary has been investigated. With increasing the sample thickness from 0.2 mm to 1.0 mm, the dielectric constant and piezoelectric coefficient increase by 39% and 36%, respectively, and then become stable with further increase of the sample thickness up to 2.0 mm. Both XRD patterns and Raman spectra show the lattice distortion of tetragonal phase decreases with the thickness. Quantitative analysis of XRD patterns of ceramics with different thicknesses reveal that enhanced electric properties with sample thickness are owing to the improved contributions from lattice distortion, irreversible domain switching and irreversible phase transition from tetragonal to rhombohedral phase with the increases of thickness, which is quite different from the decreased domain size in PMN-PT single crystal. These results not only provide a new mechanism, but also give an important basis for piezoelectric transducer design based on BiScO3-PbTiO3 ceramics.

Weighted differential evolution heuristics for improved multilayer piezoelectric transducer design

Piezoelectric transducers are designed for wide applications of underwater sonar, energy harvesting, biomedical and nondestructive testing in terms of higher sensitivity and broad bandwidth. Multilayer transducers have well-known advantages of higher sensitivity and thus can be optimized by varying layer thicknesses of active material. The present study deals with mathematical optimization of multilayer transducers exploiting weighted differential evolution (WDE) based computational heuristics for optimized piezoelectric transducer design while satisfying the constraint of constant total thickness. Fitness evaluation is carried out on the basis of one dimensional model (ODM) for simple multilayer, multilayer with bondlines and transducer with bondlines and matching for piezoelectric materials including PZT5h, PMN-PT and piezocomposite with PMN-PT for different loading media. WDE exploited along with ODM for the transducer models has demonstrated the efficacy, reliability and applicability of the proposed scheme. Comparative study of the proposed WDE-ODM with its counterparts including simulated annealing, genetic algorithms, and particle swarm optimization, reveal better performance in terms of accuracy, complexity and convergence metrics for different number of layers for simple transducers. Applicability of WDE-ODM on piezoelectric structures with bondlines, and matching layers has also been accessed and validated.

Energy conversion models and characteristics under various inner connections of a novel packaged piezoelectric transducer for pavements

The piezoelectric effect in piezoelectric transducers converts the mechanical energy into electrical energy to supply power to road facilities. The piezoelectric transducer designed in the 3–3 piezoelectric mode has been widely studied due to the consideration of power generation performance and load-bearing requirements. However, the conservative design of some external packages and the lack of theory in the internal connection design are two deficiencies of existing research on 3–3 piezoelectric mode transducers. Given the shortcoming of packages cannot make full use of the compressive properties of piezoelectric ceramics which weakens the energy conversion ability of the piezoelectric transducers, a novel piezoelectric transducer with full-pressure packaging was designed. For the lack of theoretical and systematic research on the spatial arrangement and electrical connection of piezoelectric materials inside piezoelectric transducers, from a theoretical point of view, the energy conversion models of piezoelectric transducers in four connection modes: stacked series, stacked parallel, array series, and array parallel were derived. Subsequently, through model verification tests, the influence of the four connection modes on the energy conversion characteristics of the piezoelectric transducer was systematically studied. Finally, the effect of connection mode on energy conversion was explained in a unified manner. Five methods of promoting the energy conversion of piezoelectric transducers were proposed. The study indicated that the connection mode affected the energy conversion of the piezoelectric transducer. Specifically, the maximum energy conversion potential of the piezoelectric transducer is only affected by the spatial arrangement. The electrical connection method determines the matching resistance, which can facilitate the piezoelectric transducer to exert the maximum energy conversion potential. In the stacked type, the peak energy conversion monotonously increases with the number of stacked layers, whereas the array type exhibits the opposite trend. Regardless of the spatial arrangement of the piezoelectric materials, when piezoelectric ceramics are connected in series, the optimal value of resistance increases with the number of piezoelectric ceramics, and the opposite is true when the connection is made in parallel. The normalization analysis pointed out that the connection mode affects the energy conversion of the piezoelectric transducer can be summarized as the volume index of the piezoelectric ceramic group affects its energy conversion. A larger ratio of height to diameter of the piezoelectric ceramic group can improve the energy conversion of the transducer. This article provides ideas for the packaging design of piezoelectric transducers and a theoretical reference for the design of internal piezoelectric ceramic connection methods.

Axial guided wave characteristics in functionally graded one-dimensional hexagonal piezoelectric quasi-crystal cylinders

In one-dimensional hexagonal piezoelectric quasi-crystals, there exist the phonon–phason, electro–phonon, and electro–phason couplings. Therefore, the phonon–phason coupling and piezoelectric effects on axial guided wave characteristics in one-dimensional hexagonal functionally graded piezoelectric quasi-crystal (FGPQC) cylinders are investigated by utilizing the Legendre polynomial series method. The dispersion curves and cut-off frequencies are illustrated. Wave characteristics in three hollow cylinders with different quasi-periodic directions are comparatively studied. Some new wave phenomena are revealed: the phonon–phason coupling and piezoelectric effects on the longitudinal and torsional phonon modes (N = 0) vary as the quasi-periodic direction changes; the phonon–phason coupling effect on flexural–torsional modes in the r-, z-FGPQC hollow cylinders, and on flexural–longitudinal modes in ϑ-FGPQC hollow cylinders increases as N increases. The corresponding results obtained in this work lay the theoretical foundation for the design and manufacture of piezoelectric transducers with high resolution and energy-conversion efficiency.

МОДИФІКАЦІЯ ТА ПРАКТИЧНЕ ЗАСТОСУВАННЯ П’ЄЗОЕЛЕКТРИЧНИХ ПЕРЕТВОРЮВАЧІВ З РОЗДІЛЕНИМИ ЕЛЕКТРОДАМИ

В роботі наводяться результати удосконалення технології формування струмопровідних електродів п’єзоелектричних елементів та розробка пристроїв з п’єзоелектричної кераміки з розділеними електродами методом, що базується на технології комбінованої електронно-променевої модифікації. Показано перспективу використання методу термовакуумного напилення при отриманні покриттів електродів на виробах з п’єзоелектричної кераміки сорту ЦТС. Особливістю такого комбінованого методу є здійснення його в одному технологічному циклі «термовакуумне осадження – електронно-променева модифікація покриття» за незмінних умов робочого середовища, що виключає утворення хімічних сполук в осаджуваному покритті на проміжному етапі формування наноструктурних утворень. Встановлено, що утворені за запропонованою технологією срібні покриття на п’єзоелектричних елементах є більш рівномірними та однорідними порівняно з покриттями, отриманими у традиційний (промисловий) спосіб. Як практичний результат реалізації запропонованої в статті технології розроблено конструкції пристроїв п’єзоелектроніки на основі елементів із п’єзоелектричної кераміки зі сформованими на їх поверхні розділеними електродами, зокрема багатосекційного п’єзоелектричного перетворювача. Найбільш цікавим у цьому випадку є те, що п’єзоелемент (пружне монолітне тверде тіло) може одночасно мати різні властивості внаслідок технологічних можливостей методу термовакуумного напилення. Зміна розмірів електродів, їх взаємне розташування дають змогу впливати на параметри вихідних сигналів і відкривають широкі можливості для створення п’єзоелектричних перетворювачів для комп’ютерних систем критичного застосування. Основна перевага використання перетворювачів з п’єзокерамічних матеріалів у комп’ютерних системах пов’язана з їх особливою конструкцією, що дає можливість реалізувати принципово різні схеми в одному такому елементі.

Electric energy output model of a piezoelectric transducer for pavement application under vehicle load excitation

Piezoelectric transducers convert mechanical energy in the pavement into electrical energy, providing a new energy supply for road auxiliary facilities. To quantify the relationship between vehicle loads and the electrical energy output of a piezoelectric transducer, the rolling process of a vehicle on the piezoelectric transducer is analyzed. Two output models considering the moving load are established. New piezoelectric transducers are fabricated to verify the models, and differences between the models and the test values are compared in five areas. The loading process was affected by the shape of the piezoelectric transducer and the grounding area of the tire. Although the two models are similar in form, the results show that Model 2 can better represent the electrical energy output because the percentage differences from test results for Model 1 are unstable. Materials with a high strain constant and a low equivalent capacitance can help the transducer achieve higher output voltage and power. Heavy-duty high-speed traffic loads can increase the piezoelectric output of the transducer. The output voltage increases continuously with resistance, whereas the output power has a peak value at a matched resistance. This study can provide a reference for the design of piezoelectric transducers and piezoelectric pavements.

Mechanistic Modeling and Economic Analysis of Piezoelectric Energy Harvesting Potential in Airport Pavements

This study investigated the feasibility of applying piezoelectric energy harvesting technology in airfield pavements through mechanistic modeling and economic analysis. The energy harvesting performance of piezoelectric transducers was evaluated based on mechanical energy induced by multi-wheel aircraft loading on flexible airfield pavements. A three-dimensional finite element model was used to estimate the stress pulse and magnitude under moving aircraft tire loading. A stack piezoelectric transducer design was used to estimate the power output of a piezoelectric harvester embedded at different locations and depths in the pavement. The aircraft load and speed were found to be vital factors affecting the power output, along with the installation depth and horizontal locations of the energy harvester. On the other hand, the installation of the energy module had a negligible influence on the horizontal tensile strains at the bottom of the asphalt layer and compressive strains on the top of the subgrade. However, the near-surface pavement strains increased when the edge ribs of the tire were loaded on the energy module. Feasibility analysis results showed that the calculated levelized cost of electricity was high in general, although it varies depending on the airport traffic levels and the service life of the energy module. With the development of piezoelectric materials and technology, further evaluation of energy harvesting applications at airports needs to be conducted.

Design of piezoelectric micro-machined ultrasonic transducer for wideband ultasonic radiation in air

Design of piezoelectric micro-machined ultrasonic transducer for wideband ultasonic radiation in air

Design and simulation of a flat cap mushroom shape microelectromechanical systems piezoelectric transducer with the application as hydrophone

A microelectromechanical systems piezoelectric transducer capable of measuring static accelerations and acoustic vibrations has been designed and proposed. The transducer is composed of a circular plate on a pillar, which is fixed at the centre and free at the rim so that it resembles a flat cap mushroom. An annular piezoelectric layer has been employed to convert the vibration-induced stress of the plate to a potential difference. The proposed structure has been compared with diaphragm piezoelectric transducers and hydrophones and its superior performance has been verified. Analytical models for both static and dynamic accelerations have been developed, discussed and the output voltage has been formulated, which is in a very good agreement with the finite element analysis. Results show that the maximum sensitivity is achieved when there is an annular piezoelectric layer on the plate around the pillar perimeter. The effect of different geometrical parameters on the transducer performance has been studied. The proposed flat cap mushroom shape piezoelectric transducer could achieve −186.5 dB sensitivity and a very wide bandwidth. Another important advantage of the proposed structure is that by controlling the pillar radius and without changing the plate size, the sensitivity can be enhanced.

Linear Phase Design of Piezoelectric Transducers for Acousto-Optic Dispersion Delay Lines Using Differential Evolution for Matching Circuit Optimization.

A numerical method for providing linear phase response of bulk acoustic wave (BAW) piezoelectric transducers (PTs) of acousto-optic devices is developed. Our approach is based on the analytic approximation of the phase response of the PT with the matching electrical circuit and optimization with a differential evolution genetic algorithm. Simulations and experiments were performed for two typical BAW excitation schemes: direct and reflective. Variance of the group delay in the specified frequency range was reduced by an order of magnitude for reflective excitation of BAWs.