Piezoelectric Research Articles

Micro-Movement Measured by Laser Heterodyne Interferometer Based on Acousto-Optic Effect

In this experiment, the stable output of a dual-frequency laser source is obtained by an acousto-optic modulator due to the Bragg diffraction effect. Furthermore, the non-polarized dual-laser heterodyne interferometer is designed to measure the micro-movement of stacked piezoelectric (PZT) ceramic. This micro-movement can be dynamically determined by comparing the phase difference between the conference beam and measuring beam. The results indicate that the micro-movement of PZT ceramic changes linearly with the driven-voltage in the range of 0–30 V and the sensitivity of movement to voltage is 58.3 nm/V, which is very close to the theoretical value and this laser heterodyne interferometer can be applied for calibrating parameters of PZT ceramic.

Equivalent pin-forces or equivalent moments for the modelling of piezoelectric patches: a parametric study

Many piezoelectric (PZ) actuation or sensing systems consist of PZ patches bonded on elastic beams or blades. In order to optimise the design of such systems, Finite Element Analysis (FEA) can be used. However, this option is relatively time consuming and not necessarily appropriate to the first steps of the design process. The replacement of FEA by simple analytical tools is desirable in the early design stages in order to explore the optimal configurations for the device (beam dimensions, patch position and properties). Two main modelling approaches can be found in the literature, based on the Solid Mechanics beam theory. The first approach consists in replacing the PZ patch by two opposite forces positioned at the surface of the beam, each at one extremity of the PZ patch. The second approach consists in replacing the PZ patch by two opposite moments positioned at the neutral axis of the beam, each at one extremity of the PZ patch. The object of this paper is to detail these options, and to evaluate their range of validity. For this purpose, a parametric study is conducted on a cantilever beam structure to compare the different approaches for standard dimensions and material properties. The results of corresponding FEA simulations are taken as reference. It is shown that the validity of analytical models is restricted to a narrow range of material properties and dimensions. This range is chosen when the error between the normalised displacements obtained analytically and those obtained by numerical calculation does not exceed 6%. Within this range, the two-moment model is revealed a more precise choice than two pin-forces. As a consequence, its validity range is larger compared to other analytical approaches. This is due to the introduction of the flexural stiffness of the PZ patch and of a realistic strain profile across the section of the structure. These results can be used to obtain analytical expressions of stress and strains in PZ actuation and sensing devices.

Study of Drain Access Resistance in Saturation Region of AlGaN/GaN Heterostructure Field-Effect Transistors

A method is proposed to determine drain access resistance in saturation region of AlGaN/GaN heterostructure field-effect transistors (HFETs). The variation of drain access resistance is analyzed qualitatively and quantificationally. Comparing with source access resistance, the difference is attributed to the asymmetry of additional polarization charge distribution at AlGaN/GaN interface. Interaction strength between additional polarization charge and gate–drain channel electron is stronger than that of gate–source channel electron. The drain access resistance components corresponding to polarization Coulomb field (PCF) scattering, polar-optical-phonon (POP) scattering, piezoelectric (PE) scattering, and interface roughness (IFR) scattering are obtained quantificationally. POP scattering dominates drain access resistance with the increase of drain–source current, because of hot-electron and hot-POP effect. Moreover, PCF scattering also plays an important role, especially under low drain–source current, because of stronger PCF scattering potential and lower hot-POP temperature.

KAJIAN PUSTAKA KOMPOSIT LIMBAH PLASTIK SEBAGAI PAVING BLOK PENGHASIL ENERGI BERKELANJUTAN TERINTEGRASI PIEZOELEKTRIK DAN PHOTOVOLTAIC (VIZO)

This work aims to improve pedestrian functions, improve the welfare of waste banks and scavengers, and fulfil electricity needs for the surrounding community towards Society 5.0. The method of writing is done with secondary data through the latest literature study. The literature study focused on the development of technology for processing plastic waste, photovoltaic (PV), and piezoelectric (PZT) and their use in road construction. The results of the discussion show the potential of plastic waste as a composite material for paving. Similarly, PV and PZT can be integrated together as a producer of renewable electrical energy. With this innovation, VIZO is expected to be able to reduce plastic waste and provide welfare for the community, scavengers, waste banks, and help local government energy-saving programs.

Low-velocity impact source localization in a composite sandwich structure using a broadband piezoelectric sensor network

An online structural health monitoring strategy for real-time impact source localisation in composite sandwich structure (CSS) is presented in this paper. A broadband piezoelectric (PZT) sensor-network based laboratory experiments and finite element method based numerical simulations of low-velocity steel-ball drop impacts at different locations on a CSS have been carried out. It is observed that the arrival-time of the impact-induced elastic wave signals increases with the increase in source-to-sensor distance. Further, the influence of impactor drop-height variations is studied by conducting a series of numerical simulations in ABAQUS. An arrival-time difference calculation based impact source localisation strategy is proposed to locate the impact regions in the CSS. The proposed monitoring strategy uses the registered impact signals (time-domain) at the PZTs to predict impact locations in real-time. Eventually, a study on the estimation of localisation error has been carried out to check the effectiveness of the proposed SHM strategy.

Electro-Mechanical Impedance Technique for Assessing the Setting Time of Steel-Fiber-Reinforced Mortar Using Embedded Piezoelectric Sensor

The electro-mechanical impedance (EMI) change in Piezoelectric (PZT) sensors embedded in steel-fiber-reinforced mortar (SFRM) was investigated to assess the material setting time. The EMI was continuously monitored for 12 h by the PZT sensor embedded in SFRM having fiber volume fraction of 0.5%, 1.5%, and 2.0%. The initial and final setting time of the SFRM were estimated using EMI signal change. The penetration resistance test, a conventional test method for the setting time of cement mortar, was also conducted. In the penetration resistance test, it was observed that the initial and the final setting time of SFRM accelerated as the volume fraction of the steel fiber increased. On the other hand, in the EMI sensing technique, the initial and the final setting time of the SFRM were consistent regardless of the fiber volume fraction.

Design of Reconfigurable Spin-Wave Nanochannels Based on Strain-Mediated Multiferroic Heterostructures and Logic Device Applications

A method based on the magnetoelectric effect present in multiferroic heterostructures was used to design a reconfigurable waveguide (WG) channel for spin wave (SW) transmission. The multiferroic heterostructures consisted of a piezoelectric (PZT) layer and an adjacent ferromagnetic (CoFeB) layer within the WG region. By applying voltage to the PZT layer, a piezostrain would be generated and transferred to the ferromagnetic layer, leading to a magnetoelastic field in the latter, which could modulate SW dispersion, including propagation frequency and SW vector. Two applications based on these piezostrain-modulated SW dispersion parameters were explored. A piezostrain-modulated, multiple-shaped WG channel was first proposed to allow specific-frequency SW propagation via control of the applied strain. Then, piezostrain was used to perform a phase shift modulation in the multiferroic SW channel. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\pi }$ </tex-math></inline-formula> -phase shift in the propagation of SW was obtained by customizing the length of strain operation for a given frequency. A phase shifter was designed to build an interferometer to fulfill the destruct and construct logic functions based on strain-controlled SWs. These simulation results highlight the considerable potential of strain engineering to control logical and computational reconfigurable SW devices.

Electromechanical modeling of energy harvesting for FRP composite structures coupled with piezoelectric transducers

Supplanting of metals by composites is on the rise for the last three decades in the aerospace, marine and automotive industry following the trend of electrification and indigenous design approaches. In parallel, piezoelectric (PZT) sensors and energy harvesters have gained significant attention due to their applicability and efficacy for microscale power generation systems. From a new perspective, embedding PZT sensors into composite structures will be beneficial in many aspects. Condition monitoring can be performed by using the sensing capability of PZTs while vibration can be controlled by means of its excitation capability. Besides, energy harvesting can be employed due to the mechanical forces exerted on the coupled structure. It is critical to create an accurate numerical modeling of electromechanical coupling for the investigation of efficiency of PZT sensors. In this paper, electromechanical modeling of a Fiber Reinforced Polymer (FRP) composite structure with an embedded PZT patch is presented and validated with an experimental setup. Afterwards, the energy harvesting capability of a PZT patch embedded in the FRP structure is investigated.

Nonlinear damping of auxetic sandwich plates with functionally graded magneto-electro-elastic facings under multiphysics loads and electromagnetic circuits

This work addresses the damped transient response of smart sandwich plates subjected to coupled/multiphysics loads. The plate is made of an auxetic core with magneto-electro-elastic functionally graded (MEEFG) facesheets. The well known active constrained layer damping (ACLD) technique making use of the piezoelectric (PE) patch also known as1-3 PZC layer embedded on the viscoelastic (VE) layer is adopted to attenuate the vibrations. A finite element (FE) based approach has been adopted in order to derive the governing equations. Further, the solutions to the considered problem are obtained by adopting the direct iterative method. The primary focus of this work is to evaluate the effects of the auxetic core's rib-length ratio, inclination angle on the damped structural response, which has been carried out for the first time in the literature. Also, parametric studies on the geometric and material properties such as thickness configuration of core and facesheets, ACLD patch positions, PE fiber orientation angle, control gain, functional gradation pattern, and gradient index have been carried out. Emphasize has been made to understand the impact of applying open and closed circuits associated with the rest of the parameters, on the controlled nonlinear behaviour of smart sandwich plates. The numerical results of this work make some major revelation about the implementation of auxetic cores in the smart structures, which make this work interesting.

Longitudinal piezoelectric, elastic, and dielectric properties of rare-earth aluminum nitride alloys determined by density-functional perturbation theory

The superior piezoelectric (PE) performance of devices based on thin-films of wurtzite (w) w-${\mathrm{Sc}}_{x}{\mathrm{Al}}_{1\ensuremath{-}x}\mathrm{N}$ alloys has motivated research efforts to determine the material properties of other alloys of aluminum nitride and rare-earth nitride (w-${\mathrm{RE}}_{x}{\mathrm{Al}}_{1\ensuremath{-}x}\mathrm{N}$). The longitudinal PE, elastic and dielectric properties of substitutional w-${\mathrm{RE}}_{x}{\mathrm{Al}}_{1\ensuremath{-}x}\mathrm{N}$ alloys have been calculated with density-functional perturbation theory. The rare-earth elements in the simulations stand for scandium, yttrium and seven lanthanides: lanthanum, neodymium, gadolinium, dysprosium, erbium, ytterbium, and lutetium. The structure of the investigated alloys is modeled with special quasirandom $2\ifmmode\times\else\texttimes\fi{}2\ifmmode\times\else\texttimes\fi{}2$ supercells at rare-earth nitride fractions $x$ of 0.0625 and 0.25. The $4f$ electrons of the lanthanides are incorporated in the pseudopotential core, an approach supported by the standard model of lanthanide chemistry. An increase of the PE stress coefficient ${e}_{33}$ and a softening of the stiffness coefficient ${c}_{33}^{E}$ are found for all investigated alloys for $x$ = 0.25, when compared to w-AlN. This leads to significant improvements of the PE strain effective coefficient ${d}_{33,f}$ of films of these alloys. For w-${\mathrm{Lu}}_{0.25}{\mathrm{Al}}_{0.75}\mathrm{N}$, the ${d}_{33,f}$ increases by $\ensuremath{\sim}100%$ compared to pure w-AlN. Increased displacement-response internal-strains and Born effective charges are demonstrated for all alloys at $x$ = 0.25, in a manner consistent with the behavior of w-${\mathrm{Sc}}_{x}{\mathrm{Al}}_{1\ensuremath{-}x}\mathrm{N}$ alloys, suggesting shared intrinsic properties for the entire w-${\mathrm{RE}}_{x}{\mathrm{Al}}_{1\ensuremath{-}x}\mathrm{N}$ alloy family. Distortions of the alloy structure, correlated with the ionic radius of the rare earths, negatively affect their PE properties. At a small fraction $x$ = 0.0625, the alloys incorporating Sc, Y, Er, Yb, and Lu possess PE coupling coefficients ${k}_{33,f}^{2}$ greater than for w-AlN.

Damage detecting roller device based on electromechanical impedance technique for debonding detection in glass fiber epoxy composite structures

Maintaining structural safety for the public is one of the most utmost importance to avoid catastrophic events involving human casualty. For this reason, vast amount of research is being conducted around the globe to create an efficient system to detect structure damage. In this study, a local damage detection method known as the electromechanical impedance method is improved with the new concept introduced in this study. The idea allows one to detect of composite structures at a reduced cost. Since the electromechanical impedance requires one to permanently attach the piezoelectric (PZT) transducer onto the target structure, a moving device was made which creates temporarily contact with the target structure to investigate the possibility of replacing hundreds of PZT transducers into a single device. The experiment involves using two different glass fiber epoxy composite plates with different thicknesses to evaluate the performance of the roller PZT device. The findings from the experiments show possibility of detecting of composite plate using the proposed idea.

Vibration Excitation and Suppression of a Composite Laminate Plate Using Piezoelectric Actuators.

Piezoelectric (PZT) actuators bonded on a structure can be used to generate deformation and excite vibration for the shape control and vibration suppression, respectively. This article proposes a theoretical model for predicting vibrational response of a composite laminate plate with PZT actuators. The bending moment induced by the PZT actuator was obtained and applied on the composite laminate plate. Utilizing composite mechanics and plate theory, an analytical solution of the vibrational response of a composite laminate plate excited by the PZT actuator with oscillating voltage was derived. Furthermore, the finite element analysis using ANSYS software (2019 version) was carried out to compare with the proposed model with a good agreement. A parametric study was performed to investigate the influences of PZT location and frequency on the vibration. Numerical results illustrate that mode can be selectively excited provided the PZT actuator is placed in an appropriate location. Moreover, the proposed model was employed to predict the effectiveness of vibration suppression by distributed PZT actuators. The novelty of this work is that a complicated coupling problem between the composite plate and bonded PZT actuator is resolved into two simple problems, leading to a simple analytical solution for the vibrational response of a composite plate induced by PZT actuators. The proposed model has been successfully demonstrated its applications on the vibration excitation and suppression of a composite laminate plate.

Analysis of wake induced vibration of a coupled circular cylinder-piezoelectric using two-way fluid structural interaction

A wake-induced vibration of a self-excitation thin Piezoelectric (PZT) actuator is being studied to explore some aspects of energy harvesting using vortices energy. The PZT is under the effect of vortices at different longitudinal spacing ratios in the wake of the cylinder, which is defined as the distance between the center of the upstream cylinder and the tip edge of the PZT (L* = L/D = 3.0–6.0). The Reynolds number is set at 200. The upstream cylinder is stationary, while the flexible PZT in the wake of the cylinder is considered a cantilever beam. The influence of spacing ratio on downstream wake is first investigated by modeling flow around a stationary coupled cylinder-PZT. Initially, the PZT is rigid and has no flexibility. Considering the numerical results, a key spacing ratio is discovered and introduced for the second part of the simulation with a flexible PZT. Then, the dynamic response of a flexible PZT is explored in the second part. The output power is calculated based on the deformation of the PZT. Two-Way Fluid Structural Interaction (TW-FSI) is used to conduct numerical investigations, and all required equations, including fluidic and structural equations, are formulated and discussed in detail. The frequency and tip displacement of the vortices are found to be directly related to the highest power production.

Strain-driven magnetic domain wall dynamics controlled by voltage in multiferroic heterostructures

Magnetic domain walls (DWs) have significants application potential as information carriers in the construction of novel high-density, high-speed spintronics devices. In this study, the fully coupled micro-magnetic-mechanical finite element method (FEM) was used to demonstrate the behaviour of DW dynamics under voltage-modulated magnetoelastic anisotropy via piezostrain transfer in ferromagnetic (FM)/piezoelectric (PE) multiferroic heterostructures. Continuous and long-distance high-speed DW-motion could be realized in the ferromagnetic layer by utilizing a voltage switching on the piezoelectric layer without applying magnetic fields or spin-polarization currents. Numerical simulations demonstrate that this system has low energy consumption of 1.215fJ for every shift operation and high speed with an average velocity of 234.4m/s when applying a 0.5volts under continuous and long-distance DW motion. This performance can be further improved by optimizing the structural design and material selection. The design and analysis results in this study provide a new and effective method to realize low-power consumption and high-speed spin logic devices based on magnetic DWs.

Piezoresistive Versus Piezoelectric Position Sensing in MEMS Micromirrors: A Noise and Temperature Drift Comparison

This letter presents a comparative study concerning the characterization of piezoresistive (PZR) and piezoelectric (PZT) tilt-angle sensing in MEMS micromirrors. Position tracking is mandatory in such devices, so to achieve high-resolution displays, and the control system must be accurate against noise sources and stable against drifts of physical parameters, such as ambient temperature. This letter presents the performance results achieved on PZR and PZT sensors integrated on the same micromirror, showing that, at the cost of a larger area occupation, the latter achieves ten times larger sensitivity (with improvements in the signal-to-noise ratio and thus in position accuracy), and a five times lower overall transduction variation under temperature changes.

An analytical study of sound transmission loss of functionally graded sandwich cylindrical nanoshell integrated with piezoelectric layers

The multidisciplinary nature of piezoelectric (PZ) structures necessitates precise and efficient methods to express their behavior under different conditions. This article extends the general usage of PZ materials by introducing acoustic and fluid loading effects in a way that an unfilled multilayer cylindrical nanoshell with a functionally graded (FG) material core and PZ layers is subjected to preliminary external electric load, acoustic waves and external flow motion. As the properties of a functionally graded material changes along the shell thickness, a power law model is assumed to be governing such variations of desired characteristics. Evidently, this system includes different types of couplings and a comprehensive approach is required to describe the structural response. To this aim, the first-order shear deformation theory (FSDT) is used to define different displacement components. Next, the coupled size-dependent vibroacoustic equations are derived based on in conjunction with nonlocal strain gradient theory (NSGT) with the aid of Hamilton’s variational principle and fluid/structure compatibility conditions. NSGT is complemented with hardening and softening material effects which can greatly enhance the precision of results. It is expected to use the findings of this paper in the optimization of similar systems by selecting suitable FG index, incident angle of sound waves, flow Mach number, nonlocal and strain gradient parameters, starting electric potential and geometric features. One of the important findings of this study is that increasing the electric voltage can obtain better sound insulation at small frequencies, specially prior to the ring frequency.

Coexistence of Semiconducting Ferromagnetics and Piezoelectrics down 2D Limit from Non van der Waals Antiferromagnetic LiNbO3-Type FeTiO3.

Stable two-dimensional (2D) ferromagnetic semiconductors (FMSs) with multifunctional properties have attracted extensive attention in device applications. Non van der Waals (vdW) transition-metal oxides with excellent environmental stability, if ferromagnetic (FM), may open up an unconventional and promising avenue for this subject, but they are usually antiferromagnetic or ferrimagnetic. Herein, we predict an FMS, monolayer Fe2Ti2O9, which can be obtained from LiNbO3-type FeTiO3 antiferromagnetic bulk, has a moderate band gap of 0.87 eV, large perpendicular magnetization (6 μB/fu) and a Curie temperature up to 110 K. The intriguing magnetic properties are derived from the double exchange and negative charge transfer between O_p orbitals and Fe_d orbitals. In addition, a large in-plane piezoelectric (PE) coefficient d11 of 5.0 pm/V is observed. This work offers a competitive candidate for multifunctional spintronics and may stimulate further experimental exploration of 2D non-vdW magnets.

Damage Classification Using Supervised Self-Organizing Maps in Structural Health Monitoring.

Improvements in computing capacity have allowed computers today to execute increasingly complex tasks. One of the main benefits of these improvements is the possibility of developing machine learning algorithms, of which the fields of application are extensive and varied. However, an area in which this type of algorithms acquires an increasing relevance is structural health monitoring (SHM), where inspection strategies and guided wave-based approaches make the evaluation of the structural conditions of an aircraft, vessel or building among others possible, by detecting and classifying existing damages. The use of sensors, data acquisition systems (DAQ) and computation has also allowed these damage detection and classification tasks to be carried out automatically. Despite today’s advances, it is still necessary to continue with the development of more robust, reliable, and low-cost structural health monitoring systems. For this reason, this work contemplates three key points: (i) the configuration of a data acquisition system for signal gathering from an an active piezoelectric (PZT) sensor network; (ii) the development of a damage classification methodology based on signal processing techniques (normalization and PCA), from which the models that describe the structural conditions of the plate are built; and (iii) the use of machine learning algorithms, more specifically, three variants of the self-organizing maps called CPANN (counterpropagation artificial neural network), SKN (supervised Kohonen) and XYF (X–Y fused Kohonen). The data obtained allowed one to carry out an experimental validation of the damage classification methodology, to determine the presence of damages in two aluminum plates of different sizes, where masses were added to change the vibrational responses captured by the sensor network and a composite (CFRP) plate with real damages, such as delamination and cracks. This classification methodology allowed one to obtain excellent results by validating the usefulness of the SKN and XYF networks in damage classification tasks, showing overall accuracies of 73.75% and 72.5%, respectively, according to the cross-validation process. These percentages are higher than those obtained in comparison with other neural networks such as: kNN, discriminant analysis, classification trees, partial least square discriminant analysis, and backpropagation neural networks, when the cross-validation process was applied.

A non-time division multiplexing single inductor solar and piezoelectric energy multi-input harvesting interface circuit

Due to time-varying and instability, single environmental energy cannot provide reliable energy for wireless sensor network nodes. Therefore, researchers propose to use multi-source synergy to provide power. Still, these circuits take time-division multiplexing or setting priority, which can only harvest one kind of environment energy at a particular moment, resulting in low energy harvesting efficiency and complex circuit structure. Also, a single vibration source is configured with multiple piezoelectric (PZT) harvesters to obtain more power. For the above questions, this paper proposes a non-time-division multiplexing single-inductor synchronous electric charge extraction circuit (NTD-SECE), which is mainly composed of rectifier bridge, peak detection circuit, control circuit, input comparison circuit, and buck-boost circuit. Theoretical analysis and experiments verify the effectiveness of the interface circuit. The results show that NTD-SECE can extract energy from photovoltaic (PV) and multi-PZTs by non-time division multiplexing, the maximum power is 450 mW. It has broad application prospects in the energy supply of low-power equipment.

Influence of dispersant concentration toward enhancing printing precision and surface quality of vat photopolymerization 3D printed ceramics

The primary objective of this study is to develop an optimal dispersant concentration for high-precision PZT ceramic components with a high surface quality via a digital light processing (DLP) based vat photopolymerization method. Here, the ceramic suspension formulations composed of PZT ceramics (80 wt%), photoinitiator (1 wt%), dispersant (1,2,3 wt%), and monomer (18,17,16 wt%) were prepared to characterize the influences of dispersant concentrations on 1) the rheological properties and 2) the dispersion stability of ceramic suspensions as well as 3) the curing properties and 4) the surface quality of the DLP printed ceramic components. Interestingly, the optimal dispersant concentration (2 wt%) determined by FTIR spectroscopy induced the lowest viscosity, the lowest sedimentation rate, and the highest dispersion stability, which are considered desirable for the DLP printing process. Furthermore, 2 wt% dispersant significantly improved not only the printing precision by 43% but also the surface quality by 56% compared to the results obtained from the non-optimal dispersant concentration. This work proposes a novel perspective that the dispersant concentration affects the rheological properties as well as the printing results such as the printing precision and surface quality, which can contribute to the advancement of vat photopolymerization based ceramic 3D printing technology.