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In this work, we analyze a mathematical problem for dynamic contact between two electro-viscoelastic bodies with adhesion, normal compliance, and damage. An inclusion of the parabolic type describes the evolution of damage. A first order differential equation explains the development of the bonding field. We create a variational formulation for the model and demonstrate the existence and uniqueness of the weak solution. Parabolic inequalities, variational inequalities, and the Banach fixed point theorem form the foundation for the proof. [ABSTRACT FROM AUTHOR]

This study follows a novel path toward alarming the dangerous conditions of the buildings by means of piezoelectricity. piezoelectric materials have the ability to translate electrical voltage and displacement to each other interchangeably. This feature is employed in this research to define a critical threshold for the displacements. The case study of this research is a graphene-platelets reinforced functionally-graded piezoelectric (GPLR-FGP) rectangular wall with one free edged at its top. The voltage would be gradually increased until the natural frequency approaches to zero. This circumstance puts the wall in the direct danger of failing its stability. Accordingly, displacements of the wall at this condition can be considered as the critical deflections of the system. The wall's governing equations are established in the background of higher-order shear deformation theory (HOSDT). Differential quadrature approach (DQA) is employed to obtain the natural frequency of the wall. Deep-learning is utilized to accelerate the computation process by means of training a deep network of neurons through the instances determined by the explained numerical approach. Efficiency of the innovative implemented solution in this research is verified through a comparative analysis with the results of the published articles. This research can be considered as the main stone of developing innovative solutions for alarming safety issues in the smart cities of near future. [ABSTRACT FROM AUTHOR]

There is a diverse and well-constructed application of energy harvesting systems due to their innovate technology to provide the necessary power for low-energy electronics. In this regard, the prime objective of the current study is to analyze the size-dependent nonlinear dynamic performance of piezoelectric beam-type energy harvesters at nanoscale subjected to a time-dependent mechanical uniform load. A laminated structure containing an agglomerated nanocomposite core integrated with top and bottom piezoelectric surface layers is considered for the nanoscale bridge-type energy harvesters. To take the size dependency into account, the nonlocal strain gradient continuum elasticity is formulated based upon a quasi-3D beam theory incorporating the both features of size effects. Thereafter, the size-dependent nonlinear problem is then solved numerically relevant to simply supported and clamped end conditions via employing the meshless collocation technique. Accordingly, the numerical solving procedure is established without any background meshes as well as eliminating the integration and singularity by using proper multiquadric radial basis functions. [ABSTRACT FROM AUTHOR]

The piezoelectric property was found by Curie brothers in quartz and Rachel salt (1881). This property is a complicated phenomenon that makes it challenging to study. In 1935, the piezoelectric properties of potassium-dehydrogenated phosphate, the first famous piezoelectric material, were determined. Study about these properties of materials was developed by USA, Russia, and Japan during the Second World War, resulting in some piezoelectric materials such as barium titanate (BT) and lead zirconate titanate (PZT) in 1940 and 1950, respectively. Pure and doped PZT families have been widely studied in ceramics and nanostructured forms to enhance their piezoelectric properties. Because of the lead, the PZT materials are harmful to the environment. Therefore, it has been tried to replace it with suitable lead-free materials for practical purposes. The first lead-free piezoelectric material investigated in this respect is BT. However, the piezoelectric properties of BT are not as good as PZT, so a new generation of lead-free piezoelectric materials has been developed. These new lead-free piezoelectric materials are divided into two categories: (1) the lead-free piezoelectric material based on BNT (bismuth niobium titanate) and (2) the lead-free piezoelectric material based on KNN (potassium sodium niobite). The most significant advantage of these materials is that they are environmentally friendly, but their piezoelectric properties are less than PZT. In this chapter review, lead-based and lead-free piezoelectric materials such as PZT, BT, BZT, KNN, BNT, and ZnO are studied. The synthesized methods of piezoelectric materials in ceramic and nanostructure forms are presented. The applications of piezoelectric ceramics and nanostructures are discussed. [ABSTRACT FROM AUTHOR]

The present work presents the investigation of the dynamics and influence of chaotic behavior on energy capture for a U-shaped structure (portal frame) that contains shape memory alloy (SMA), piezoelectric material (PZT), a nonlinear energy sink (NES) and a non-ideal excitation source represented by an unbalanced electric motor coupled to the U-structure. The mathematical model presents nonlinearities arising from the nonlinear stiffness of the U-structure, the NES system, the SMA, and the PZT material. Chaotic behavior is assessed through time history, bifurcation diagrams, phase diagrams, and the 0–1 test. Energy capture is carried out through a piezoelectric material (PZT), represented by a non-linear electromechanical coupling model, and electromagnetic induction generated by the non-linear electromagnetic energy sink coupled to the structure (NES). Dynamic analysis is performed through parametric analysis of parameters related to piezoelectric coupling and NES parameters. Numerical simulations demonstrate that the system has chaotic behavior for specific parameters and that its energy capture is influenced by parametric variation. It is shown numerically that the parameters of the SMA material, the PZT material, and the NES significantly influence the chaotic behavior and energy capture of the investigated electromechanical system. [ABSTRACT FROM AUTHOR]

Dense (Pb0.92Ba0.08)Nb2O6‐xmol% MnO2 with 0.25 wt% TiO2 ceramics with a single orthorhombic phase were synthesized through a conventional solid‐state reaction method. Excellent piezoelectric performance (d33 = 90 pC/N) and low dielectric loss (tan δ = 0.5%) are achieved in Mn‐doped samples. Interestingly, the dielectric anomalies are observed in the temperature range of 300–400°C, which could be completely suppressed through Mn doping. The dielectric anomalies are associated with thermally activated domain wall motion, which could be constrained by the defect dipoles produced by Mn doping. More importantly, all samples experience about 12% performance degradation below 300°C, attributed to an accelerated aging process at elevated temperatures. After thermal aging, the samples exhibit excellent performance stability within the temperature range of 25–450°C, showing no further degradation. The results indicate that the PbNb2O6‐based ceramics are promising high‐temperature piezoelectric materials for piezoelectric devices operating at temperatures up to 450°C. [ABSTRACT FROM AUTHOR]

Advancing the development of high‐temperature piezoelectric sensors requires high‐performance piezoelectric materials with high Curie temperatures, wherein the charge signals can be efficiently collected at elevated temperatures. The bismuth layer‐structured ferroelectric (BLSF) bismuth titanate‐ferrite (Bi5Ti3FeO15, BTF) has recently attracted considerable attention because of its high Curie temperature (TC) of ∼761°C. However, the piezoelectric properties of BTF‐based compounds have not been extensively investigated because of their extremely poor piezoelectric performances and low electrical resistivities at elevated temperatures. Herein, tungsten‐substituted BTF (BTF‐100xW) ceramics were synthesized using a solid‐state reaction method. X‐ray diffraction refinement results confirmed the lattice distortion of the BO6 octahedron, while piezoelectric force microscopy images verified an increase in the domain wall density with tungsten modification, both of which contribute to significant enhancement of the piezoelectric properties of BTF‐100xW as intrinsic and extrinsic contributions, respectively. Remarkably, BTF‐3W exhibits a high TC of 793°C and a large piezoelectric constant (d33) of 24.3 pC/N, which is over three times that of BTF (7.1 pC/N). Importantly, the substitution of tungsten decreases the concentration of oxygen vacancies, increases the direct current electrical resistivity, and improves the electrical homogeneity at high temperatures, resulting in extremely stable piezoelectric and electromechanical properties at high temperatures, with a high in‐situ relative d33 of >90% at 400°C and a small variation in the electromechanical coupling factor (kp) of <8% at temperatures up to 450°C. These results suggest that the tungsten‐substituted BTF is a potential candidate for high‐temperature piezoelectric ceramics, and is a promising material for applications in high‐temperature piezoelectric sensors. [ABSTRACT FROM AUTHOR]

The full matrix parameters of a piezoelectric material are crucial for designing and evaluating piezoelectric devices. However, due to their inverse problematic nature, commonly used single‐sample characterization methods heavily depend on the accuracy of initial values and mode matching. In this paper, we propose a quasi‐31‐vibrator method to directly evaluate these parameters by designing the sample geometry and establishing the relationship equation between the parameters. This approach completely bypasses the need for characteristic spectrum simulation and mode identification processes. Subsequently, we tested the full matrix parameters of PZT‐5H ceramics and compared the simulated impedance spectra with the measured ones. The presence of well‐fitting spectra validates the feasibility of the method. This method will contribute to characterize the parameters of new piezoelectric materials and advance the intelligent implementation of measuring full matrix parameters. [ABSTRACT FROM AUTHOR]

Piezoelectric materials can develop mechanical strain upon applying electric voltage and vice-versa. A piezoelectric bimorph, widely used in various sensors and actuator applications, essentially behaves like a beam and consists of a nonpiezoelectric material substrate layer glued between two piezoelectric layers. The application of an electric field alone can induce the bending of such a beam. Studies on the modeling of the piezoelectric bimorph are mostly restricted to the small deflection regime. In the present work, a simple numerical method is proposed to obtain the large deflection response of any piezoelectric bimorph. To begin with, the governing equation of a cantilever bimorph under electric field and end load is obtained. The nonlinear governing equation is then linearized with respect to the current time step. Subsequently, the linearized equation is solved using the RK4 method. From the numerical results, it is found that the response of the key design parameter, namely free displacement is considerably different from that predicted from small deflection analysis. Also, as the entities involved are suitably nondimensionalized, the results are directly relatable to all classes of piezoelectric materials. The nondimensionalization has also paved the way for better insight into the physical problem by rendering a simple mathematical representation. [ABSTRACT FROM AUTHOR]

High-temperature piezoelectric vibration sensors play a crucial role in the accurate monitoring of the dynamic mechanical conditions in aerospace, automotive, and energy generation systems. However, the use of conventional piezoelectric materials in high-temperature environments is restricted owing to their limited Curie temperatures. In this study, we grew a piezoelectric crystal Bi12SiO20 (BSO) with the crystal cut optimized for high longitudinal piezoelectric coefficient and low piezoelectric crosstalk behaviors. Subsequently, a compression-type piezoelectric vibration sensor utilizing the BSO bulk crystal was developed and fabricated for structural health monitoring under high temperatures. The impact of pre-tightening torques on the sensor performance was investigated. Moreover, the sensor performance was analyzed under temperatures up to 650 °C. The BSO-based sensor exhibited an average sensitivity of ∼3.89 pC/g between 25 and 650 °C under 160 Hz frequency, with a variation of 5.5%. Additionally, the BSO-based sensor demonstrated ultra-stable sensitivity at 600 °C, highlighting its strong sensing capabilities and reliability under high temperatures. Thus, the BSO-based vibration sensor is a promising option for structural health monitoring applications under high temperatures. [ABSTRACT FROM AUTHOR]

The realistic modeling of vibratory energy harvesters is necessary to ensure their reliable performance when subjected to random excitation. However, the hysteretic behavior of piezoelectric materials and the nonlocality of fractional electrical components make the numerical estimation of their stochastic response computationally challenging. This paper proposes an iterative method based on equivalent linearization and stochastic averaging for estimating the stationary probability density function of the output voltage amplitude of vibratory energy harvesters modeled as a hysteretic oscillator with fractional electrical components subject to a broadband stochastic process. By estimating the average of hysteretic terms, one can find an amplitude-dependent linear governing equation for the output voltage, from which one can determine a stochastic differential equation governing the evolution of the output voltage amplitude. We obtain the stationary solution of the corresponding Fokker–Planck equation in a semianalytical form, and we include comparisons with pertinent Monte Carlo simulation data to show that the estimated probability density functions are accurate and obtained at a minimal computational cost. [ABSTRACT FROM AUTHOR]

[Display omitted] Piezoelectric catalysis, which converts mechanical energy into chemical activity, has important applications in environmental remediation. However, the piezo-catalytic activity of various piezoelectric materials is limited by the weak piezoelectricity as well as the mismatched band-gap, leading to inefficient electron-hole pair generation and difficult carrier migration. Here, a simple strategy combining phase boundary and energy band structure modulation was innovatively proposed to enhance the piezo-catalytic activity of BaTiO 3 ferroelectric by Ce ions selecting different doping sites. Thanks to the coexistence of tetragonal (P 4 mm) and orthorhombic (Amm 2) phases effectively flattened the Gibbs free-energy and thus enhanced the piezoelectric activity, as well as suitable energy bandwidth facilitating the carrier migration were realized in the B-sites doped Ba(Ti 0.95 Ce 0.05)O 3. The degradation rate constant k of tetracycline (TC) was high to 30.56 × 10-3 min−1, which was 2.03 times higher than that of pure BaTiO 3 and superior to most representative lead-free perovskite piezoelectric materials. Theoretical calculations validated that the charge density and high O 2 and OH– adsorption energy on the Ba(Ti 0.95 Ce 0.05)O 3 surface promoted more efficient •O 2 – and •OH radicals conversion and bettered response to piezo-catalytic reaction. This work is important to design high-performance piezo-catalysts by synergistic regulation of phase boundary and energy band structure in perovskite materials for long-term antibiotic tetracycline removal. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT) has attracted great attention due to the recognition of its impact on extensive applications in high-resolution force sensing. However, its brittleness and the preparation challenges of ultrahigh aspect ratio nanostructures have hindered their practical application. Here, we present a nanoscale electrohydrodynamic jet 3D printing method capable of tailoring ultrahigh aspect ratio hierarchical PZT nanostructures with controllability, fast, and inexpensive. Thermally in situ curing and vertical shear stress of high viscous jet avoid introducing defects in the post-treatment sintering process and minimize internal defects providing a relatively smooth surface. The printed ultrahigh aspect ratio PZT structure exhibits Young's modulus of 99.4 GPa, which was smaller than the block PZT, greatly improving its flexibility. The experimental results show that it can detect forces in the nano-Newton scale. This finding provides a generally applicable strategy for preparing high-performance ultrahigh aspect ratio nanoscale piezoelectric materials for MEMS devices. • A novel E-Jet 3D nanoprinting method was proposed. • Various ultrahigh aspect ratio hierarchical PZT nanostructures were fabricated. • The printed ultrahigh aspect ratio PZT structure showed ultralarge elastic deformation. The printed force sensor could detect nanoscale Newton loading. [ABSTRACT FROM AUTHOR]

The Bi 0.5 Na 0.5 TiO 3 -based system is one of the most competitive candidates for lead-free piezoelectric materials. However, the relatively low thermal depolarization temperature (T d) hinders the practical application of the materials, making effectively improving T d an urgent challenge to be overcome. Herein, excellent thermal stability with ultrahigh T d value (251 ℃) is obtained in Mn-doped 0.79Bi 0.5 Na 0.5 TiO 3 -0.14Bi 0.5 K 0.5 TiO 3 -0.07BaTiO 3 (79BNT-14BKT-7BT:Mn) ternary ceramics by quenching strategy. It is found that the quenching treatment increases the phase proportion and enhances the lattice distortion of tetragonal structure. By utilizing piezoelectric force microscopy (PFM) and autocorrelation function method, it is revealed that the quenching process can induce an increase in the length of correlation polarization, ferroelectric long-range ordering and domain size. The domain switching is significantly suppressed, which contributes to the improvement of T d. This study provides a feasible avenue to achieve BNT-based piezoelectric ceramics with high thermal stability and facilitates their development and application. • Excellent thermal stability and good piezoelectric properties (T d=251 ℃, d33=150 pC/N) were obtained in BNT-BKT-BT:Mn piezoceramics by quenching method. • The ultrahigh Td derives from enhanced tetragonal distortion and a more stable domain structure caused by quenching. • The quenching increases the correlation length of the polar regions and enhances ferroelectric long-range ordering. [ABSTRACT FROM AUTHOR]

Piezoelectric temperature stability is often a very important item for piezoelectric materials when putting them into practical applications like filters and ultrasonic transducers. Phase transitions of (K,Na)NbO 3 -based compositions that contain neither toxic Pb nor Sb elements were tailored to simultaneously acquire enhanced piezoelectric properties and good piezoelectric temperature stability in this study. Specifically, dense 0.94(K 0.48 Na 0.52)NbO 3 -0.03BaZrO 3 -0.01BaSnO 3 -0.02(Bi 0.5 Na 0.5)ZrO 3 ceramic and its further compositionally modified one by 1 wt% MnO 2 were prepared. Both of these two ceramics display quite weak piezoelectric temperature dependence in the usage temperature range between −30 °C–100 °C, but the one modified by MnO 2 has the significantly improved piezoelectric properties with a high piezoelectric coefficient d 33 of 310 pC/N and large electromechanical coupling factors k p and k 33 of 0.57 and 0.73 at room temperature. The obtained excellent piezoelectric performance is considered to be associated closely with the stable piezoelectric characteristic of the orthorhombic phase and the diffused rhombohedral-orthorhombic and orthorhombic-tetragonal phase transitions. [ABSTRACT FROM AUTHOR]

A piezoelectric-based micro motion actuator is typically used in micro-scale movement technologies, with the actuator developed to deliver very small movements and high resolution for motion within several micrometer ranges. However, a significant challenge from the strong, nonlinear hysteresis arises affects the piezoelectric materials joining input voltage to output movement, which deteriorates the accuracy of the actuator and causes instability in a closed-loop system. To obtain high precision, accuracy and reduced nonlinear effects, piezoelectric actuators must be controlled with hysteresis compensation. Therefore, this research developed a piezoelectric-based microactuator system with a control scheme based on PID (proportionalintegral-derivative) combined with the inverse hysteresis model implemented to compensate for the actuator's hysteresis. Furthermore, a Modified Prandtl-Ishlinskii (MPI) model was used to capture the hysteresis phenomenon, where its parameters were obtained through a system identification process. The inverse model of the hysteresis was then used to generate feedforward signals in the control system. The results showed that the control scheme is able to provide an accurate motion due to the decrease in hysteresis compensation signals from 4.87 µm to 0.97 µm. The closed loop control system consisting of the PID control and hysteresis compensation further improved the accuracy of the piezoelectric actuator and reduced the error down to 0.41 µm. [ABSTRACT FROM AUTHOR]

Piezoelectric composites, which consist of piezoelectric materials and polymers, are widely employed in various applications such as underwater sonar transducers and medical diagnostic ultrasonic transducers. Acoustic transducers based on piezoelectric composites can have high sensitivity with broad bandwidth. In recent studies, it is demonstrated that 2-2 composites based on single crystals provide further increased sensitivity and wide bandwidth. In order to utilize a 2-2 composite in acoustic sensors, it is required to demonstrate the full material coefficients of the 2-2 composite. In this study, we investigated an analytic solution for determining equivalent material coefficients of a 2-2 composite. Impedance spectrums of the single-phase resonators with equivalent material coefficients and 2-2 composite resonators were compared by the finite element method in order to verify the analytic solutions. Furthermore, the equivalent material coefficients derived from the analytic solution were also verified by comparing the measured and the simulated impedance spectrums. The difference in resonance and anti-resonance frequencies between the measured and simulated impedance spectrums was around 0.5% and 1.2%. By utilizing the analytic solutions in this study, it is possible to accurately derive full equivalent material coefficients of a 2-2 composite, which are essential for the development of acoustic sensors. [ABSTRACT FROM AUTHOR]

A frequency up-conversion piezoelectric energy harvester (FUC-PEH) consists of a force amplifier, a piezoelectric stack, a low-frequency oscillator (LFO), and a stop limiter. The force amplifier generates the amplification of stress on the piezoelectric stack. The LFO, comprising a spring and a mass block, impacts the stop limiter during vibration to induce high-frequency oscillations within the piezoelectric stack. In this paper, we represent and simplify the FUC-PEH as a lumped-parameter model based on piezoelectric material constitutive equations and structural dynamic theories. Using the electromechanical analogy, we developed an equivalent circuit model (ECM) of the FUC-PEH. A parametric study was performed to investigate the impact of system parameters, such as spring stiffness and concentrated mass, on the FUC-PEH performance. The collision-induced amplitude truncation (AT) effect enlarges the operation bandwidth. ECM simulations show that low-frequency input excitation is converted into a high-frequency output response, enhancing the energy conversion efficiency. Furthermore, we aimed to improve the FUC-PEH's performance using a synchronous electric charge extraction (SECE) circuit. Using the ECM approach, we established a system-level model that considers the electromechanical coupling behavior. The simulation results provide insights into the performance of FUC harvesters with SECE circuits and offer valuable design guidance. [ABSTRACT FROM AUTHOR]

Antimony sulfoiodide (SbSI) is a highly efficient energy conversion piezoelectric material. We obtained SbSI doped with tin (II) ions according to the formula Sb[Formula: see text]SnxSI[Formula: see text] ([Formula: see text]–0.1). This heterovalent doping has been performed by the novel method of synthesis in an aqueous solution. The introduction of tin cations leads to a material Curie point increase of more than 10[Formula: see text]K. The samples containing 5[Formula: see text]mol.% of the dopant possess the best piezoelectric properties: piezomodule [Formula: see text][Formula: see text]pC/N, dielectric constant at a frequency of 1[Formula: see text]kHz — 1758, dielectric loss tangent — 0.054, and piezosensitivity — 50[Formula: see text]mV[Formula: see text]×[Formula: see text]m/N. Thus, tin-doped SbSI is a promising material for highly efficient electromechanical transducers and sensors.

Electrophoretic deposition (EPD) is a widely accepted, cost-effective and simple method to obtain conformal coatings of dense nanoparticles via application of a DC voltage. This paper reports the physical and mechanical properties of nanostructured barium titanate/hydroxyapatite (BT/HA) ceramic composites coated onto Ti-6Al-4V alloy via cathodic EPD in various ratios of 40:60, 50:50 and 60:40 (HB4, HB5 and HB6) respectively. Homogenous BT/HA coatings were obtained at a notably low voltage of 10 V. The crystallinity and phase analysis confirmed the formation of tetragonal phase of BT indicating the piezoelectric property. HB6 exhibits maximum piezoelectric coefficient (d33) of 159 pC/N and Vicker's hardness of 242.31 HV. The cross-sectional electron micrographs show well connected and homogeneous coatings with increasing amounts of BT. Human mesenchymal stem cell lines were utilized in biocompatibility experiments, which revealed that HB composites had greater viability of HW-MSCs cells than pure BT, with HB6 exhibiting a maximum cell viability of more than 90 %.

Abstract Painless, needleless delivery of drugs through the skin can be realized through aphenomenon called sonophoresis by applying an ultrasound field to the biological tissue. Development of wearable embodiments of such systems demands comprehensive characterization of both the physical mechanism of sonophoresisas well as wearability parameters. Here, we present a framework for analyzing disk‐type piezoelectric transducers in a polymeric substrate to create acoustic cavitation in a fluid coupling medium for sonophoresis applications. The device design and operating parameters such as the working frequency, applied voltage range, acoustic pressure distribution, and transducer spacing were determine dusing a finite element methods (FEM),and verified with experimental measurements. The influence of the surrounding water and tank reflections on the acoustic pressure field, and the interaction between the elements in the array structure were also studied.Finally, the impact of skin and the substrate geometry on the acoustic pressure fields was characterized to simulate the invivo use‐case of the system. These analytical models can be used to guide critical parameters for device design such as the separation distance of the piezoelectric transducer from the skin boundary. We envision that this tool boxwill support rapid design iteration for realization of wearable ultrasound systems.

The (K , Na) Nb O 3 (KNN)-based ceramics have been deemed one of the most promising lead-free piezoelectric materials replacing lead-containing ones. In our study, we have prepared both undoped and Mn-doped KNN nanofibers via the electrospinning method and investigated how the thermal annealing process affects their structural, crystallographic, and piezoelectric properties. X-ray diffraction measurements suggest that the crystallization occurs around 450 ° C in these fibers, and with increasing annealing temperature, both undoped and Mn-doped nanofibers become granular with small grains forming along the fiber, accompanying the crystallization. Both exhibit increasing piezoelectric properties with annealing temperature based on the piezoresponse force microscopy measurements with Mn-doping, leading to a higher piezoelectric response. [ABSTRACT FROM AUTHOR]

BaTiO3 is a well-known piezoelectric material with commercial uses. The ferroelectric state of BaTiO3 generally comprises electrically polarized domains separated by domain walls (DWs). The DW alters local polarization vectors by an angle of 90° for 90° DW or 180° for 180° DW. The DW is crucial to piezoelectric properties such as response time and fatigue. Furthermore, the DW structure and its dynamics in BaTiO3 are not well understood. Hence, for the first time, we theoretically obtained the atomistic structure of the 90° DW via molecular dynamics simulations at 300 K with the core–shell interatomic potential, using a large-scale system with a side length of 2.8 × 10 3 Å. The width of the 90° DW thereby obtained was approximately 30 Å, which was 20 Å wider than that of the 180° DW. Under the external electric field E → ext parallel to the DW, we observed an extension of a domain having a polarization vector with a positive component along the E → ext -direction. The migration velocity of the 90° DW was approximately two times that of the 180° DW at the same E ext in the range 7 – 20 MV / m. For E ext ≥ 15 MV / m , the migration velocity of the 90° DW in the direction with a positive component along the polarization vector of the extending domain was substantially higher than that in the opposite direction. The physical causes of the difference in the migration velocities of the 90° DW in the two directions were analyzed. [ABSTRACT FROM AUTHOR]

There is a growing interest in BiFeO3-based alloys because of the possibility it offers for developing high-temperature high-performance piezoelectric materials and for their interesting multiferroic properties. Often such ceramics are synthesized with additives either to reduce/suppress leakage current that the system inherits from the parent compound BiFeO3 or to promote sintering via formation of the liquid phase. We demonstrate here the propensity for stabilizing ferromagnetism in the ferroelectric solid solution BiFeO3–PbTiO3 (BF–PT) when synthesized with additive MnO2. Detailed investigation revealed that the ferromagnetic property of the ceramic is extrinsic and caused by the additive enabled precipitation of trace amount of the ferrimagnetic Pb-hexaferrite phase, not easily detected in conventional x-ray diffraction measurements. We also show that the ferromagnetic property is induced in Co-modified BF–PT. However, in this case, the additive stabilizes the CoFe2O4 spinel ferrite phase. While our findings offer a strategy to develop particulate magnetoelectric multiferroic composites using additive assisted precipitation of the ferrimagnetic phase(s) in BiFeO3-based ferroelectric alloys, it also helps in better understanding of the electromechanical response in BFO-based alloys. [ABSTRACT FROM AUTHOR]

The properties of most III–V semiconductor materials in the wurtzite structure are not known because of their metastable character. However, recent advances in the growth of III–V wurtzite nanorods open new perspectives for applications. In this work, we present a systematic computational study of bulk wurtzite III–V semiconductors, using predictive ab initio methods, to provide a necessary base knowledge for studying the nanostructures. The most important physical properties of bulk systems, i.e., lattice constants, elasticity, spontaneous polarization, piezoelectricity, band structures, deformation potentials, and band offsets, have been studied. Comparison with the available experimental and theoretical data shows the high credibility of our results. Moreover, we provide a complete set of parameters for a six-band k ⋅ p model, which is widely used for simulating devices based on semiconductor heterostructures. [ABSTRACT FROM AUTHOR]

A method for simulating coupled electromagnetic and mechanical vibrations on arbitrarily shaped piezoelectric structures is presented. This method is based on weak forms and can be implemented in any finite-element-method software, allowing editable access to their definitions. No quasi-static approximation is imposed, meaning that magnetic fields generated by displacement currents within piezoelectric materials are captured, enabling the flow of electromagnetic energy inside and around structures containing such material to be accurately simulated. The method is particularly relevant to the design of piezoelectric antennas, resonators, and waveguides exploiting either bulk or surface-acoustic waves. The accuracy and capabilities of the method are demonstrated by simulating, in COMSOL Multiphysics, (i) a Rayleigh mode on the surface of Z-cut lithium niobate crystal and (ii) a torsional mode of a cylinder of lead zirconium titanate (PZT-5H) ceramic functioning as a micro-antenna. [ABSTRACT FROM AUTHOR]

One of the important requirements for piezoelectric materials for use as high strain actuators is that they exhibit large unipolar electrostrain with minimum hysteresis. While large unipolar electrostrain >1% is generally achievable in good quality single crystals, most polycrystalline piezoelectric show low values < 0.4%. Unipolar electrostrain 0.5%–0.7% in polycrystalline piezoelectrics has often been reported in Na0.5Bi0.5TiO3-based compositions at the non-ergodic ergodic boundary. Not amenable to poling, such materials exhibit almost nearly zero direct piezoelectric coefficient (d33 ∼ 0 pC/N) and cannot be simultaneously used as a sensor. In this paper, we report a combination of large unipolar electrostrain of ∼0.6% with small strain hysteresis of 25% in a Sn-modified relaxor ferroelectric system PbTiO3–Bi(Ni1/2Zr1/2)O3. It exhibits d33 ∼ 340 pC/N, which is stable up to 130 °C, and large signal converse piezoelectric coefficient d33* ∼ 1200 pm/V. A combination of large d33 and d33* in the same material makes it an important candidate for simultaneous use as a sensor and high strain actuators. X-ray diffraction study in situ with the electric field suggests that large electrostrain with low strain hysteresis in this system is because of the increased reversible switching of the field stabilized tetragonal ferroelastic domains. [ABSTRACT FROM AUTHOR]

A novel elastomer-based composite material with enhanced piezoelectric performances is proposed in this paper, which is composed of the top and bottom polytetrafluoroethylene (PTFE) solid films with the middle PTFE nanoparticle–polydimethylsiloxane (PDMS) sponge layer. To enhance the charge retention capability of elastomers, PTFE nanoparticles are introduced to form PTFE–PDMS interfaces, which can trap charges with longevity. Besides, PTFE solid films take on the role of the charge blocking layers to further improve the piezoelectric performances. As a result, the PTFE–PDMS sandwich structure shows the advantages of remarkable sensitivity (1053 pC/N), high stability, and flexibility. After a 6 h of annealing treatment at the temperature of 100 °C, no significant deterioration of the piezoelectric properties can be observed, which reveals the great thermal stability of the sandwich structure. In addition, the sandwich structure can be immersed in water for 24 h without any loss of piezoelectric activity. Finally, the experiment of lighting one LED by hand pressing successfully demonstrates that the sandwich structure has good applicability in the field of energy harvesting. Considering the excellent electrical and mechanical features, the PTFE–PDMS sandwich structure has promising applications in sensing, energy harvesting, and actuation. [ABSTRACT FROM AUTHOR]

The focus of this study is on the Fe2O3-doped Bi0.5Na0.5TiO3-SrTiO3 piezoelectric material. This is important to find ecologically acceptable piezoelectric materials. This research aims to obtain a leadfree piezoelectric material because lead is a material that is not environmentally friendly. An alternative solution is a piezoelectric material based on BNT-ST, which in this case is doped with Fe2O3 material. The study of Fe2O3 doped Bi0.5Na0.5TiO3-SrTiO3 piezoelectric material prepared by the solid-state reaction method was carried out to determine the optimum composition of the material formed. Doping variations are 0; 2.5; 5; 7.5; and 10 in mol %. The examinations were performed using X-ray diffraction (XRD) spectroscopy, a Scanning Electron Microscope (SEM), and an LCR meter. The Fe2O3 doped Bi0.5Na0.5TiO3-SrTiO3 produced a new compound in the form of FeBi5Ti3O15-Na2Ti3O7-SrTiO3 with the crystal structure of cubic, orthorhombic, and monoclinic, as well as the increasing crystalline size with the addition of dopants, exclude at 5 mol % and 7.5 mol %. FeBi5Ti3O15-Na2Ti3O7-SrTiO3 also produces varying particle sizes, which are between 0.88–8.23 µm. From the obtained data, the optimum composition of Fe2O3 doped Bi0.5Na0.5TiO3-SrTiO3 was the 2.5 mol % of Fe2O3 due to it having the highest dielectric constant (εr) and temperature Curie (Tc), and also the lowest material impedance (Z) with the εr of 12.037 at Tc of 400 °C and Z of 135 kΩ. The high piezoelectricity, which is indicated by the high value of the dielectric constant and Curie temperature, is possible due to the presence of a greater number of sodium ions in the Na2Ti3O7 phase. Sodium ions are ions with good electrical storage capabilities. The increase in dielectric constant in the BNT-ST piezoelectric obtained by the addition of Fe2O3 shows that this material can be used as a substitute for lead-based piezoelectric materials so that it is secure for the environment. The piezoelectric material of BNT-ST doped with Fe2O3 earned from this research can be applied to obtain electricity with a optimal value when given mechanical pressure. [ABSTRACT FROM AUTHOR]

This research work explores the innovative use of mechanical energy generated by human walking and its conversion into usable electrical energy. By harnessing this often-overlooked energy source, we address the growing demand for sustainable energy solutions. Utilizing simple mechanisms such as piezoelectric materials and mechanical footfall pressure plates, the project demonstrates how everyday human movement can contribute to renewable energy generation. This dual-purpose approach promotes walking for transportation and exercise while simultaneously serving as a renewable energy resource. By integrating these technologies into common surfaces like floors and pavements, we envision sustainable urban environments where human activity directly powers infrastructure. This project highlights the potential of human-powered energy, emphasizing its role in fostering environmental sustainability and public health, and showcases innovative thinking in the pursuit of a greener future. The Footstep Futura project explores innovative solutions to harness human kinetic energy for sustainable power generation. By integrating advanced piezoelectric materials and efficient mechanical systems, the project converts the mechanical energy generated by walking into usable electrical power. This energy can be stored in batteries and used to power small electronic devices, demonstrating a practical application of human-powered energy. Designed for user-friendliness and portability, Footstep Futura offers a convenient and eco-friendly energy solution for everyday use. The project aims to contribute to greener urban environments and promote the adoption of sustainable technologies in daily life. Index Terms— Footstep Futura, human-powered energy, piezoelectric materials, kinetic energy, electrical power, energy storage, portable energy solution, sustainable technology, green energy, pedestrian power, energy generation, user-friendly design, eco-friendly innovation, renewable energy, everyday convenience. [ABSTRACT FROM AUTHOR]

Piezoelectric materials, which exhibit a charge distribution across the surfaces in reaction to mechanical strain, find significant utility in actuation and sensing applications. Apart from actuation applications like acoustic devices, motors, and vibration damping, an emerging domain for ultrasonic actuators lies in additive manufacturing processes. Ultrasonic waves applied during solidification aim to modulate grain structure and minimize defects. This research focuses on a fixture designed to facilitate and optimize ultrasonic wave propagation through the build plate in laser powder bed fusion additive manufacturing by utilizing a piezoelectric transducer. Three implementations of piezoelectric transducers were evaluated based on their out-of-plane ultrasonic velocity transmissions. It was determined that a thin plate adhered to the surface of the piezoelectric transducer yielded the most favorable outcomes for implementation, achieving 100% transmission of velocity and energy. Preliminary analysis of melt pool morphology and defects in single-track laser scanning experiments demonstrated the impact of ultrasound on solidification, hinting at a novel approach to enhancing the printability of alloys in laser powder bed fusion additive manufacturing processes. The optimal fixture and the explored transducing efficiency could further guide advanced ultrasound testing to enable in situ defect and texture detection during the additive manufacturing processes. [ABSTRACT FROM AUTHOR]

In this article, an L-shaped three-dimensional (3D) braided piezoelectric composite energy harvester (BPCEH) is established, which consists of an elastic layer composed of a 3D braided composite, flanked by upper and lower layers of piezoelectric material and two tuning mass blocks. Glass fiber and epoxy resin are used to produce a 3D braided composite. This L-shaped 3D BPCEH is mechanically designable and can be adapted to different work requirements by varying the braided angle of the 3D braided composite layer. The material parameters of 3D braided composites are predicted for different braided angles by means of a representative volume element (RVE). Electro-mechanical coupled vibration equations for the L-shaped 3D BPCEH are established. The impact of braided angles on voltage and power output is discussed in this article. Simulations using finite element method are conducted to analyze the voltage and power output responses at various braided angles. In addition, the effects of the mass of mass block B and the length of the beam on the output performance of the L-shaped 3D BPCEH are analyzed. [ABSTRACT FROM AUTHOR]

Piezoelectricity, one of the most desirable properties of non-centrosymmetric crystalline materials, has long been blooming in academic research, industrial manufacturing, and daily applications owing to its unique electromechanical transformation capability. Compared with inorganic piezoelectric ceramics dominating the market, molecule-based piezoelectric materials exhibit advantages of light weight, mechanical flexibility, and environment friendliness and have attracted widespread interest recently. However, investigations on molecular materials with large piezoelectric coefficients are mainly focused on organic–inorganic hybrids, while pure organic homochiral piezoelectrics holding large piezoelectric coefficients remain scarce. Herein, by precise molecular modification on (S)-2-methylpiperazin-1-ium perchlorate ([(S)-MPP][ClO4]) with polar cyanomethyl groups, a homochiral pure organic compound (3S)-3-methyl-1,4-di(cyanomethyl)piperazin-1-ium perchlorate [DCM-(S)-MPP][ClO4] with large d22 of 18 pC/N was achieved, along with changes in the space group from nonpolar to polar, giving rise to second harmonic generation and phase transition behaviors. The modification strategy proposed here will benefit piezoelectricity enhancement in more chiral compounds, promoting their application potential in biological medicine, flexible devices, and green chemistry. [ABSTRACT FROM AUTHOR]

The paper investigates the possibilities of purposefully changing the properties and lowering the sintering temperatures of piezoelectric materials used in multilayer converters. The aim of the work was to correct the basic properties of piezoelectric ceramics at the stage of its manufacture, due to changes in technological modes with unchanged chemical composition. At the most important technological stage—the sintering of piezoelectric ceramics, a ceramic frame is formed, as well as mechanical properties—density, hardness, strength, affecting electrophysical properties. Consequently, by correcting the conditions for the formation of the microstructure of piezoelectric ceramics, it is possible to purposefully change its functional parameters. Consolidated sintering of piezoelectric ceramics by methods of hot pressing and spark plasma sintering, provides an opportunity to effectively control the process of microstructure formation. The objective of the study was to practically test these sintering methods in the manufacture of piezoelectric ceramics of various functional groups and variations of their parameters. The model objects of the study were: a relaxation piezoelectric material based on the lead zirconate-titanate system, a ferroalloy material of the PMN-PT system and a multicomponent piezoelectric material with a sintering temperature of less than 1000°C. In the course of the study it was found that the sintering of piezoelectric ceramics by hot pressing and spark plasma sintering contributes to the formation of a homogeneous defect–free microstructure that provides an increase in the basic mechanical and electrophysical properties by 10–16%. Also, these methods help to reduce sintering temperatures by 150–300°C. The spark plasma sintering method, characterized by its high speed, reduces the duration of isothermal exposure by 36 times, which has a positive effect on energy saving. As part of the study, batch multilayer converters were manufactured using consolidated sintering methods. The efficiency of consolidated sintering has been experimentally established and confirmed for purposefully changing the functional parameters of piezoelectric ceramics with the possibility of lowering the sintering temperature. [ABSTRACT FROM AUTHOR]

PbTiO3‐based ferroelectric solid‐solution ceramics have been widely used for electromechanical devices. However, it is still challenging to separate and control the contributions to the electromechanical functionalities, mainly as a function of temperature, where thermal anomalies and phase transitions can be observed. This study investigates the ultrasonic velocity and attenuation and the dielectric, ferroelectric and structural features of Pb0.55Ca0.45TiO3 ceramics from low temperatures (10 or 115 K) up to room temperature as an example of A‐site isovalent substitution in PbTiO3. Such a combination of information makes possible the phenomenological deconvolution of the effects of ferroelectric domain wall pinning and structural features on spontaneous electric polarization. The room‐temperature symmetry was determined as Pna21. The results show that this model refined by the Rietveld method for synchrotron X‐ray diffraction patterns from 115 K to room temperature can explain the polarization extension features of these materials during heating. This study shows a correlation between structural thermal anomalies and low‐temperature electric polarization in PbTiO3‐based ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

Piezoelectric material-based devices have garnered considerable attention from scientists and engineers due to their unique physical characteristics, resulting in numerous intriguing and practical applications. Among these, flexural-mode piezoelectric resonators (FMPRs) are progressively gaining prominence due to their compact, precise, and efficient performance in diverse applications. FMPRs, resonators that utilize one- or two-dimensional piezoelectric materials as their resonant structure, vibrate in a flexural mode. The resonant properties of the resonator directly influence its performance, making in-depth research into the resonant characteristics of FMPRs practically significant for optimizing their design and enhancing their performance. With the swift advancement of micro-nano electronic technology, the application range of FMPRs continues to broaden. These resonators, representing a domain of piezoelectric material application in micro-nanoelectromechanical systems, have found extensive use in the field of physical sensing and are starting to be used in micropower systems and biomedicine. This paper reviews the structure, working principle, resonance characteristics, applications, and future prospects of FMPRs. [ABSTRACT FROM AUTHOR]

A porous microplate embedded with two nanocomposite piezoelectric layers is investigated in the current work. All three layers are functionally graded and completely attached to each other, and the microstructure lies on a bi-parameter elastic foundation that withstands shear and normal forces simultaneously. Also, an external voltage is subjected to the piezoelectric patches. The mentioned patches are reinforced with carbon nanotubes to enhance their electro-mechanical performance. A higher-order shear deformation theory and von Karman's assumptions are hired to demonstrate the kinematic relations. Next, applying Hamilton's principle and variational technique, the governing motion equations are derived with the help of the modified couple stress theory to capture the scale influence. To solve the system of differential equations, a closed-form Navier method is employed, and by ensuring the correctness of the results, then it turns to investigate the impact of different factors including porosity percentage and also pores' distribution patterns, nanotubes dispersion patterns, and other important factors on the natural frequencies of the model. Obtained results show that symmetric and uniform porosity distributions have the maximum and minimum amounts of natural frequencies. Moreover, the maximum difference between natural frequencies of three different porosity distribution occurs in e0 = 0.95 and is approximately 32%. The current study results may consider to design and produce smart structures and devices with improved performance. [ABSTRACT FROM AUTHOR]

This article explores the characteristics of Love wave in a piezoelectric layer imperfectly bonded over a heterogeneous fluid-saturated cracked dual porous half-space. The governing equations of the piezoelectric layer are solved analytically to determine mechanical displacement and electrical potential. Dispersion equations have been established using suitable boundary conditions for electrically open and electrically short conditions. In a particular case, the dispersion equation is reduced to the classical Love wave equation, which validates the present mathematical model. The effect of different parameters (like imperfection, dielectric constant, piezoelectric, and inhomogeneity) on phase velocity has been discussed theoretically and graphically, along with a comparative study by considering two piezoelectric materials, namely, PZT-4 and BaTiO3. [ABSTRACT FROM AUTHOR]

Excellent mechanical and electric properties enable the piezoelectric materials to be widely and dynamic aero-mechanical-electric coupling properties of the piezoelectric plate structures can significantly affect performance of aircrafts flying in high speed. This paper is focused on the flutter behaviors of the functionally graded piezoelectric material (FGPM) plate in supersonic airflow. The first-order shear deformation theory (FSDT) is employed to formulate the energy functional of the FGPM plate with general boundary conditions. The supersonic air flow is taken into account using the supersonic piston theory. The governing equations for the aero-mechanical-electric coupling system are deduced on basis of the Hamilton's principle. To address the limitation of intricate boundary conditions to the admissible functions, a modified Fourier series is introduced to yield the unified solutions of the FGPM plate subject to supersonic airflow and with arbitrary boundary conditions. Flutter properties of series of FGPM plates are investigated to demonstrate robust ability of the proposed method to accurately yet consistency include the aero-elastic-electric coupling, inhomogeneous material and arbitrary boundary conditions. The influences of the boundary condition, material constituent, external voltage and yawed flow angle on the vibration, and flutter behaviors of the FGPM plate are examined. Adjusting corresponding parameters accordingly can significantly improve the stability of the plate structures subject to supersonic airflow, which provides physical insights into dynamic optimal design of the plate structures. [ABSTRACT FROM AUTHOR]