Search Results (921)

Printable piezoelectric materials are emerging as a cornerstone of next-generation sensing, actuation, and energy harvesting technologies, driven by the need for lightweight, flexible, and digitally manufactured transducers. Conventional ceramic piezoelectrics offer exceptional electromechanical performance but require high-temperature sintering and exhibit intrinsic brittleness, limiting their integration with soft or unconventional substrates. Polymeric piezoelectrics, in contrast, provide mechanical compliance and low-temperature processability yet suffer from lower crystallinity, reduced piezoelectric coefficients, and limited thermal stability. These contrasting characteristics have catalyzed the development of functional piezoelectric inks—ceramic, polymeric, and hybrid formulations engineered for additive manufacturing techniques such as direct ink writing, stereolithography, screen printing, and inkjet printing. This review systematically examines the material compositions, dispersion chemistries, printing requirements, thermal treatment pathways, and poling strategies that govern the performance of printed piezoelectric transducers. By comparing ceramic-based, polymer-based, and hybrid systems, we reveal the fundamental trade-offs between printability, crystallinity, mechanical compliance, and electromechanical response, and map how these trade-offs shape device design across wearable electronics, soft robotics, and structural health monitoring. Finally, we highlight emerging approaches—including surface functionalization, low-temperature crystallization, liquid-phase sintering, and engineered ceramic–polymer interfaces—that offer promising routes to bridge the gap between printability and high piezoelectric performance. Full article

Piezoelectric actuators enable ultra-fast switching due to their microsecond-scale response and high acceleration capability. This study experimentally investigates arc behavior in air, vacuum, and nitrogen using round and flat contacts driven by an amplified piezoelectric actuator. Unlike prior work focused mainly on actuation dynamics, this study provides a multi-medium comparison and investigates the coupled effects of drive operating time and contact geometry on arc characteristics. Arc tests were conducted using a capacitor discharge platform, with synchronized electrical measurements and high-speed imaging. In air (140 V, 350 A), arc voltage increased with rise time, reaching 800 V, 840 V, and 1080 V at 0.5 ms, 1 ms, and 2 ms, respectively, while shorter rise times reduced arc duration but promoted reignition. In vacuum (140–200 V), arc voltage stabilized at 80–90 V, with longer rise times extending arc duration; round contacts exhibited faster voltage rise and higher peaks. In nitrogen (140–200 V), higher voltages were obtained at shorter rise times, reaching 2680 V, 2600 V, and 2320 V at 0.5 ms, 1 ms, and 2 ms, respectively, with reduced arc duration. Across all media, round contacts consistently produced higher arc voltages than flat contacts. These results demonstrate that drive dynamics and contact geometry critically influence arc voltage and duration, providing practical guidelines for the design of high-speed piezoelectric-based switching devices. Full article

Resonant electromechanical de-icing uses piezoelectric actuators to generate stresses high enough to fracture and shed ice, offering an energy-efficient alternative to conventional systems. This work focuses on prestressed piezoelectric actuators composed of a ceramic stack clamped between two brackets, addressing limitations of previous designs such as mechanical losses and screw fatigue. A new architecture is proposed, featuring a variable-cross-section screw that concentrates deformation in a thinned central region and brackets bonded to the structure to reduce losses. An analytical sizing method is developed using multi-beam longitudinal vibration modelling and two de-icing criteria, including a newly introduced one. The analysis shows how actuator geometry and modal shapes influence de-icing performance, required voltage, and mechanical stresses, highlighting key trade-offs. A dedicated prototype is designed and experimentally tested, with results in good agreement with the analytical predictions. Full article

In this study the electromechanical response of a cantilever composite beam with surface-bonded piezoelectric patches is examined, focusing on interface stresses that may initiate delamination. A thermodynamically consistent electroelastic framework was specialized to the linear piezoelectric law used in finite element software, and a two-dimensional (2D) finite element model was developed and validated under static actuation. The predicted tip displacement was compared against the analytical Euler–Bernoulli solution across all seven mesh levels of the convergence study; findings indicated that the converged ANSYS 17.1 result (h = 5 × 10⁻⁵ m) differed from the analytical value by 5.8%, a discrepancy attributed to the plane-strain assumption and the neglect of shear deformation in the Euler–Bernoulli formulation. To resolve the delamination-critical behavior, three-dimensional (3D) models were built using SOLID185/SOLID5 and SOLID186/SOLID226 elements. Interfacial peel σ_y and shear τ_xy stresses were evaluated along lengthwise (PATH1) and transverse (PATH2) paths at the patch–core interface, with maximum interface stresses occurring along the transverse PATH2 near the free end, where strong three-dimensional edge effects developed. Both element sets predicted a similar tip displacement, but the SOLID186/SOLID226 elements yielded peak interface stresses approximately 19% higher in peel and 87% higher in shear along the critical transverse PATH2. These findings demonstrate that element choice minimally affects global stiffness but significantly influences local interface stress prediction, providing practical guidance for the selection of appropriate models when assessing the delamination risk in piezoelectric-actuated composite beams. Full article

Reinforced Concrete (RC) structures experience progressive degradation over their service life due to mechanical loading and environmental exposure, leading to reduced bearing capacity and compromised structural safety. Incorporating discrete fibers into concrete mitigates crack propagation and enhances ductility, resulting in fiber-reinforced concrete (FRC) with superior fracture energy, durability, and sustainability characteristics. Despite these advantages, research on Structural Health Monitoring (SHM) techniques for FRC elements remains limited. The Electromechanical Impedance (EMI) method, which exploits piezoelectric transducers as both actuators and sensors, offers high sensitivity for detecting early-stage damage by monitoring variations in local mechanical impedance. This study investigates the effectiveness of a deep learning-enabled EMI framework for assessing the structural condition of FRC beams under flexural loading. A one-dimensional convolutional neural network (1D-CNN) is proposed to automatically extract salient features from high-frequency EMI signatures and classify structural health into three predefined states. The model is rigorously evaluated using specimen-invariant validation to ensure generalization across different FRC specimens, addressing a critical limitation of conventional cross-validation approaches in SHM research. Experimental tests on FRC beams instrumented with surface-bonded PZT transducers provide a dataset of 264 EMI responses for training and validation, enabling direct comparison between common and specimen-invariant validation schemes. The results demonstrate the superior robustness of the specimen-invariant approach and confirm the capability of the proposed 1D-CNN to identify flexural damage progression in FRC elements accurately. An ablation study further highlights the contribution of each architectural component to overall model performance. The findings underscore the potential of integrating EMI-based sensing with advanced deep learning models for reliable, automated, and scalable SHM of next-generation resilient concrete infrastructures. Full article

Reliable detection of internal defects in pressure vessel structures remains essential for structural safety and condition-based maintenance. This study presents a low-complexity structural health monitoring framework based on fiber Bragg grating (FBG) sensing and multiresolution wavelet analysis for void detection in curved pressure vessel structures under guided wave excitation. Guided waves are introduced using piezoelectric actuators, while the FBG sensors capture the resulting strain-induced wavelength variations. Due to the limited bandwidth of the optical interrogator, the recorded signals represent the strain envelope response associated with guided wave interaction rather than the resolved ultrasonic carrier waveform. To characterize defect-induced changes, the acquired signals are analyzed using continuous wavelet transform (CWT) for time–frequency interpretation, and discrete wavelet transform (DWT) and wavelet packet transform (WPT) for energy-based multiresolution feature extraction. Experimental results show that void defects lead to consistent redistribution of wavelet-domain energy and increased non-stationarity in the measured strain responses. These trends are further supported by finite-element simulations, which reproduce similar energy redistribution patterns between intact and damaged cases. The proposed framework provides a physically interpretable and computationally efficient approach for defect detection using low-bandwidth FBG sensing, without reliance on high-speed acquisition or data-intensive learning models. The results demonstrate the feasibility of using energy-based multiresolution analysis of FBG strain signals for practical and scalable structural health monitoring of pressure vessel systems. Full article

In this study, the sintering behavior and electrical properties of 0.7Pb(Zr_0.46Ti_0.54)O₃ (PZT)–0.1Pb(Zn₁/₃Nb₂/₃)O₃ (PZN)–0.2Pb(Ni₁/₃Nb₂/₃)O₃ (PNN) piezoelectric ceramics with different Pb(Fe₂/₃W₁/₃)O₃ (PFW) doping contents were investigated to obtain a formulation that can be co-fired with silver (Ag) electrodes below 900 °C for multilayer ceramics. PFW was introduced as a sintering aid, which effectively reduced the sintering temperature of the ceramics from 1200 °C to 850 °C. The sample with x = 0.12 exhibited the largest average grain size of 1.72 μm, achieving excellent comprehensive properties with piezoelectric constant (d₃₃) = 477 pC/N, planar electromechanical coupling factor (k_p) = 0.68, dielectric loss tangent (tanδ) = 0.0154, and relative density of 98.2%. Furthermore, the feasibility of fabricating piezoelectric actuators based on this optimized composition was verified. Multilayer piezoelectric devices were prepared via screen printing combined with a carbon-based sacrificial layer method. No obvious interdiffusion was observed at the interface between the Ag internal electrodes and the ceramic matrix. The 9-layer device attained a high d₃₃ = 1470 pC/N and produced a large displacement of 5.5 μm (corresponding to a strain = 1.83%) with a voltage of 500 V. The thickness of the multilayer piezoelectric film was approximately 0.3 mm. Through this, the feasibility of manufacturing a multilayered actuator with an Ag electrode was confirmed through the composition of 0.58PZT–0.1PZN–0.2PNN–0.12PFW. Full article

Lead zirconate titanate (PZT) is a widely used material for applications in microsensors, actuators, and transducers. Due to its high piezoelectric coefficient, large dielectric constant, and strong polarization capability near the morphotropic phase boundary (Zr/Ti ≈ 52/48), it is considered one of the most attractive materials for micro-electromechanical systems (MEMS). These advantageous material properties strongly depend on the PZT layer’s microstructure and crystallinity, which are primarily determined by the choice of seed layer, deposition conditions, and the post-deposition annealing treatment that promotes the formation of the PZT’s perovskite phase. In this contribution, sputter-deposited PZT thin films were crystallized by conventional furnace annealing (CFA) to evaluate the effect of heating/cooling rates (1 °C·min⁻¹–7 °C·min⁻¹) within a temperature range of 450 °C to 700 °C on structural, electrical, and ferroelectric properties, with consideration of the seed layer preparation. We characterized the materials’ properties by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and measurements of the ferroelectric hysteresis, capacitance, and leakage current. All samples annealed at temperatures of at least 500 °C fully crystallized into the perovskite phase, independently of the heating/cooling rate. The best ferroelectric performance was achieved at 550 °C with a 1 °C·min⁻¹ heating/cooling rate, yielding a saturation polarization of 82.8 µC·cm⁻² and a remnant polarization of 36.9 µC·cm⁻² under a maximum applied field of 300 kV·cm⁻¹. Full article

This study examines the bending of cross-ply laminated composite nanoplates coupled to a piezoelectric fiber-reinforced composite layer via the nonlocal strain gradient theory. The aim is to accurately capture size-dependent impacts and electromechanical interaction in nanoscale composite structures. The mechanical response is modeled utilizing a refined four-variable shear deformation theory, with the governing equilibrium equations developed using the virtual work assumption. The nanoplate is examined under simply supported boundary conditions exposed to both mechanical loading and applied electric voltage. A detailed parametric investigation is done to assess the contribution of non-local and strain gradient factors, imposed voltage, and geometric ratios on the bending behavior. The results show that the nonlocal parameter generates a softening result, increasing deflection, whereas the strain gradient parameter raises stiffness and minimizes deformation. Moreover, the applied voltage successfully controls the bending response by electromechanical actuation, underlining the potential of PFRC-integrated nanoplates in smart nanoscale systems. Full article

Piezoelectric actuators are core components in precision motion control due to their unique electromechanical coupling properties. This paper establishes a dynamic model for a partially laminated piezoelectric–metal–piezoelectric beam actuator based on the Euler–Bernoulli beam theory. The model comprises symmetrically bonded piezoelectric layers on both sides of a central metal substrate, with the piezoelectric material partially distributed along the beam length. The structure is analyzed segment-wise along the beam’s longitudinal length direction. By applying continuity conditions at the interfaces of varying cross-sections and leveraging the structural symmetry, analytical solutions for both the natural frequency and output displacement are derived. The analytical predictions are validated against finite-element results, and experiments also verify the accuracy of the analytical solution of the analytical voltage–displacement response. In addition, the effects of key geometric parameters on the dynamic performance are systematically investigated. The proposed model provides theoretical guidance for tuning the resonance characteristics and drive displacement design of the PMP actuators. Full article

Piezoelectric thin films have been widely used in micro-electromechanical systems (MEMSs), such as sensors, actuators, and resonant devices. Electromechanically driven fractures can severely degrade device performance and reliability. In this work, a phase-field damage model is developed for MEMS piezoelectric thin films under coupled electromechanical loading, incorporating pre-existing defects via an equivalent local fracture toughness. Microcracks and micro-voids arising from manufacturing defects are integrated into the model through an effective local fracture toughness, enabling a unified description of their roles in crack initiation and propagation. The proposed model is implemented in ABAQUS by means of a user-defined element (UEL) subroutine and solved using a staggered scheme. Numerical results show that the level of pre-existing defects, the applied electric potential, and the polarization direction all exert significant effects on fracture behavior. As the defect parameter D_c increases from 0 to 0.10, the reaction force decreases from 87.8 N to 86.3 N, indicating reduced fracture resistance due to manufacturing-induced defects. In addition, the reaction force changes from 90.3 N at −500 V to 86.3 N at +500 V, while it decreases from 102.9 N to 87.1 N as the polarization angle β increases from 0° to 90°. These results demonstrate that pre-existing defects and electromechanical loading jointly govern crack evolution in MEMS piezoelectric thin films. The present study provides a useful numerical tool for fracture analysis, reliability assessment, and structural design of MEMS piezoelectric devices containing manufacturing defects. Full article

Surface Acoustic Wave (SAW) technology, long central to analog signal processing and RF filtering, is undergoing a major renewal. Driven by advances that decouple SAWs from traditional piezoelectric materials and fixed-function devices, the field is gaining unprecedented control over acoustic, optical, and electronic interactions at the micro and nanoscale. This review synthesizes these developments across four fronts: new physical mechanisms for SAW manipulation, emerging material platforms, ranging from thin films to 2D systems, along with reconfigurable device architectures and circuits, and the expanding landscape of applications they enable. Optical methods are reshaping how SAWs are generated and controlled, bypassing the limits of conventional electromechanical coupling. Coherent optical excitation of high-Q SAW cavities via Brillouin-like optomechanical interactions now grants access to modes in non-piezoelectric substrates such as diamond and silicon, while on-chip SAW excitation in photonic waveguides through backward stimulated Brillouin scattering opens new integrated sensing routes. In parallel, magneto-acoustic experiments have revealed nonreciprocal SAW diffraction from resonant scattering in magnetoelastic gratings. On the device side, ZnO thin-film transistors integrated on LiNbO₃ exploit acoustoelectric coupling to realize voltage-tunable phase shifters; UHF Z-shaped delay lines achieve high sensitivity in a compact footprint; and parametric synthesis of wideband, multi-stage lattice filters targets 5G-class performance. Atomistic simulations show that SAW propagation in 2D MXene films can be engineered via surface terminations, while aerosol jet printing and SAW-assisted particle patterning provide agile, cleanroom-light fabrication of microfluidic and magnetic components. These advances enable applications ranging from hybrid quantum systems and quantum links to lab-on-a-chip particle control, SBS-based and UHF sensing, reconfigurable RF front-ends, and soft robotic actuators based on patterned magnetic composites. At the same time, optical techniques offer non-contact probes of dissipation, and MXenes and other emerging materials open new regimes of acoustic control. Conclusively, they are transforming SAW technology into a versatile, programmable platform for mediating complex interactions in next-generation electronic, photonic, and quantum systems. Full article

The present study investigates the influence of geometric parameters on the vibro-acoustic performance of piezoelectric speakers, with the objective of establishing quantitative design guidelines for resonance tuning and sound pressure level (SPL) enhancement. Understanding the dimension-dependent behavior of such devices is essential for the development of compact and efficient acoustic transducers. To this end, a fully coupled electromechanical–acoustic finite element model is developed in the frequency domain, incorporating linear piezoelectric constitutive relations, structural dynamics, and an external acoustic air domain. The model systematically examines the effects of variations in piezoelectric disc thickness, brass diaphragm thickness, and diaphragm radius. The results demonstrate that increasing the piezoelectric disc thickness leads to a noticeable increase in resonance frequency and a measurable enhancement in SPL due to strengthened electromechanical coupling. In contrast, reducing the brass membrane thickness primarily shifts the resonance frequency to lower values, while producing negligible changes in SPL amplitude. Furthermore, enlarging the diaphragm radius significantly decreases the fundamental resonance frequency, confirming its dominant influence on stiffness-controlled vibration behavior. These findings quantitatively establish the relationship between geometric design parameters and acoustic response, providing a predictive framework for performance optimization. The proposed modeling approach offers an effective and reliable tool for the design and refinement of high-performance piezoelectric speaker systems. Full article

Multifrequency operation in micromachined ultrasonic transducers, enabled by targeted excitation of specific vibrational modes, has emerged as an attractive approach for achieving tunable performance and configurability, well-suited for advanced ultrasound imaging and therapeutic applications. This paper presents a dual-electrode rectangular piezoelectric micromachined ultrasonic transducer (PMUT) designed for efficient dual-frequency operation through mode-selective actuation. The proposed architecture employs segmented electrodes that are spatially aligned with the strain distributions of two distinct flexural modes, enabling selective excitation of Mode 1 (fundamental) and Mode 3 (higher order) through appropriate electrode actuation. Finite element simulations and impedance analysis were used to guide the electrode configuration and validate the mode-selective behavior. The dual-mode PMUT was fabricated alongside a conventional single-electrode PMUT using identical membrane dimensions and material stack for direct comparison. Comprehensive electrical and underwater acoustic characterization confirmed that the conventional PMUT is limited to single-frequency operation at the fundamental resonance. In contrast, the proposed design achieved a substantial improvement in higher-order performance, with a threefold increase in acoustic pressure at Mode 3 compared to the conventional device. These results demonstrate that mode-aligned electrode segmentation enables efficient dual-mode operation without added fabrication complexity, making the design highly suitable for multifrequency ultrasonic applications such as biomedical imaging and sensing. Full article

Microinjection is one of the most established and effective techniques for introducing foreign substances into cells. However, issues such as cumbersome procedures, low success rates, and poor repeatability in manual cell microinjection have seriously restricted its practical applications in biomedical research and engineering. Responding to such problems, this paper designs an automated microinjection system that combines deep learning visual positioning and adaptive neural network sliding-mode motion control. The machine vision solution based on the deep learning YOLOv8 target detection algorithm is utilized by the system to provide positional prerequisites for automated microinjection. Then, stable and fast puncture is completed by controlling the end effector (composed of a piezoelectric actuator and a displacement amplification mechanism). Since the piezoelectric actuator has strong nonlinearity, the motion control of the end effector adopts the control strategy combining sliding mode variable structure and adaptive neural networks to meet the requirements of precise displacement output of microinjection. At the same time, a host computer control system is developed to integrate hardware equipment, visual positioning algorithms and motion control algorithms to achieve corresponding automated microinjection tasks. Finally, the effectiveness of the designed automated microinjection system is successfully verified on zebrafish embryos. Full article