Showing papers on "Lead zirconate titanate published in 2022"

Efficacy and Damage Diagnosis of Reinforced Concrete Columns and Joints Strengthened with FRP Ropes Using Piezoelectric Transducers

Abstract: Recent research has indicated that the implantation of a network of piezoelectric transducer patches in element regions of potential damage development, such as the beam–column joint (BCJ) area, substantially increases the efficacy and accuracy of the structural health monitoring (SHM) methods to identify damage level, providing a reliable diagnosis. The use of piezoelectric lead zirconate titanate (PZT) transducers for the examination of the efficiency of an innovative strengthening technique of reinforced concrete (RC) columns and BCJs is presented and commented on. Two real-scale RC BCJ subassemblages were constructed for this investigation. The columns and the joint panel of the second subassemblage were externally strengthened with carbon fiber-reinforced polymer (C-FRP) ropes. To examine the efficiency of this strengthening technique we used the following transducers: (a) PZT sensors on the ropes and the concrete; (b) tSring linear variable displacement transducers (SLVDTs), diagonally installed on the BCJ, to measure the shear deformations of the BCJ panel; (c) Strain gauges on the internal steel bars. From the experimental results, it became apparent that the PZT transducers successfully diagnosed the loading step at which the primary damage occurred in the first BCJ subassemblage and the damage state of the strengthened BCJ during the loading procedure. Further, data acquired from the diagonal SLVDTs and the strain gauges provided insight into the damage state of the two tested specimens at each step of the loading procedure and confirmed the diagnosis provided by the PZT transducers. Furthermore, data acquired by the PZT transducers, SLVDTs and strain gauges proved the effectiveness of the applied strengthening technique with C-FRP ropes externally mounted on the column and the conjunction area of the examined BCJ subassemblages.

Structural Damage Detection through EMI and Wave Propagation Techniques Using Embedded PZT Smart Sensing Units

Abstract: Lead Zirconate Titanate (PZT) sensors have become popular in structural health monitoring (SHM) using the electromechanical impedance (EMI) technique for damage identification. The vibrations generated during the casting process in concrete structures substantially impact the conductance signature’s (real part of admittance) magnitude and sensitivity. The concept of smart sensing units (SSU) is presented, composed of a PZT patch, an adhesive layer, and a steel plate. It is embedded in the concrete structure to study the impact of damage since it has high sensitivity to detect any structural changes, resulting in a high electrical conductance signature. The conductance signatures are obtained from the EMI technique at the damage state in the 10–500 kHz high-frequency range. The wave propagation technique proposes implementing the novel embedded SSUs to detect damage in the host structure. The numerical simulation is carried out with COMSOL multiphysics, and the received voltage signal is compared between the damaged and undamaged concrete beam with the applied actuation signal. A five-cycle sine burst modulated by a Hanning window is employed as the transient excitation signal. For numerical investigation, six cases are explored to better understand how the wave travels when a structural discontinuity is accounted for. The changes in the received signal during actuator–receiver mode in the damage state of the host structure are quantified using time of flight (TOF). Furthermore, the numerical studies are carried out by combining the EMI-WP technique, which implies synchronous activation of EMI-based measurements and wave stimulation. The fundamental idea is to implement EMI-WP to improve the effectiveness of SSU patches in detecting both near-field and far-field damage in structures. One SSU is used as an EMI admittance sensor for local damage identification. Meanwhile, the same EMI admittance sensor is used to acquire elastic waves generated by another SSU to monitor damages outside the EMI admittance sensor’s sensing area. Finally, the experimental validation is carried out to verify the proposed methodology. The results show that combining both techniques is an effective SHM method for detecting damage in concrete structures.

High Sensitivity MEMS Accelerometer Using PZT-Based Four L-Shaped Beam Structure

Abstract: Piezoelectric accelerometers present higher sensitivities and better signal-to-noise ratios in comparison with piezoresistive and capacitive accelerometers. A micro-electromechanical system (MEMS) piezoelectric accelerometer was designed and manufactured with four L-shaped beams covered by Lead Zirconate Titanate (PZT) thin film with $1~\mu \text{m}$ in thickness which was deposited using sol-gel methods. The micro devices, whose size and the optimized PZT distribution were determined by theoretical and simulation analysis, were fabricated on the silicon substrate using PZT films working in the ${d}_{31}$ mode. Different from the conventional vertical crossbeam accelerometers, the designed structure devotes to the larger area piezoelectric film laid on L-shaped supporting beams with higher energy transferring efficiency for sensing. Then the chips of accelerometer were fabricated, and the proposed sensor was packaged on the printed circuit board (PCB). In addition, the microsphere was integrated in the center of the beams. Finally, the properties of the accelerometer were measured by vibration measurement system. The measuring results show that the initial sensitivity of the accelerometer is 28.14mV/g at 500Hz. The proposed piezoelectric accelerometer has high sensitivity and low resonance frequency, and the frequency response on each beam is consistent, providing a new structure for high-performance accelerometer.

Exploring Physics of Ferroelectric Domain Walls in Real Time: Deep Learning Enabled Scanning Probe Microscopy

Abstract: The functionality of ferroelastic domain walls in ferroelectric materials is explored in real‐time via the in situ implementation of computer vision algorithms in scanning probe microscopy (SPM) experiment. The robust deep convolutional neural network (DCNN) is implemented based on a deep residual learning framework (Res) and holistically nested edge detection (Hed), and ensembled to minimize the out‐of‐distribution drift effects. The DCNN is implemented for real‐time operations on SPM, converting the data stream into the semantically segmented image of domain walls and the corresponding uncertainty. Further the pre‐defined experimental workflows perform piezoresponse spectroscopy measurement on thus discovered domain walls, and alternating high‐ and low‐polarization dynamic (out‐of‐plane) ferroelastic domain walls in a PbTiO3 (PTO) thin film and high polarization dynamic (out‐of‐plane) at short ferroelastic walls (compared with long ferroelastic walls) in a lead zirconate titanate (PZT) thin film is reported. This work establishes the framework for real‐time DCNN analysis of data streams in scanning probe and other microscopies and highlights the role of out‐of‐distribution effects and strategies to ameliorate them in real time analytics.

Crack healing in concrete by microbially induced calcium carbonate precipitation as assessed through electromechanical impedance technique

Abstract: Abstract In the present study, Electromechanical Impedance (EMI) technique is utilized to assess the application of the microbially induced calcium carbonate precipitation (MICCP) to restore the integrity of cracked concrete. The artificial crack width of approximately 0.5 mm is healed autonomously using a bacteria-based healing agent, using flyash (FA) as a carrier material. Lead Zirconate Titanate sensors were bonded on the cracked specimen to monitor the continuous healing process. The EMI signatures were captured over the healing period using an impedance analyser in the frequency range of 100 to 250 kHz. Statistical crack healing indicator, root mean square deviation (RMSD) was employed for evaluating crack efficiency based on extracted signatures. Results revealed that the RMSD values were effective in quantifying the progressive healing achieved due to MICCP precipitation. This is the first study with a successful implementation of the EMI technique to monitor the crack sealing in concrete through MICCP. Healing capacity was also correlated with the crack width reduction that was evaluated by optical imaging of repaired cracked surface. Also, the bacterial mineralization products were analyzed by FESEM, EDX, XRD and TGA. The results give clear proof that the FA-based carrier material can be effectively used in healing the cracks. Graphical Abstract

3D interpenetrating piezoceramic-polymer composites with high damping and piezoelectricity for impact energy-absorbing and perception

Abstract: Materials and structures with enhanced energy-absorbing and impact perception capabilities are widely deployed for crash mitigation, protective packaging of sensitive elements, and personal impact protection. However, conventional lightweight structures with a monolithic constitutive material cannot simultaneously achieve exceptional energy-absorbing capacity and electromechanical sensitivity. Here we proposed a new class of architected ceramic-polymer composites with improved energy-absorbing capacity and piezoelectric performance. An interconnected porous lead zirconate titanate ([Pb(Zr0.52Ti0.48)O3], PZT) skeleton with uniformly distributed cellular-like pores in the transverse section and directionally aligned porous structure in the longitudinal section was fabricated using a facial camphene-templated freeze-casting method. Subsequently, the polymeric polydimethylsiloxane (PDMS) was impregnated into the skeleton to form the three-dimensional (3-D) interpenetrating-phase piezoelectric composite (IP3C). The as-fabricated interpenetrating architecture with each phase interconnected has endowed the proposed IP3C with an unprecedented combination of mechanical-damping (energy-absorption efficiency ∼ 7.71 MJ m−3) and electromechanical-conversion (piezoelectric constant d33 ∼ 146 pC N−1) properties, which are 9 times and 7 times higher than the conventional counterpart 0–3 piezoelectric composite, respectively. As evidenced by numerical simulations, this remarkable enhancement is attributed to the high stress transfer efficiency within the IP3C, which is intrinsically controlled by the rationally designed interpenetrating architecture. The findings reported here demonstrate that multifunction, e.g., exceptional energy absorption and high sensitivity, can be achieved in one composite with architecture design, thereby driving forward and expanding the fundamental understanding in the area of multifunctional materials in hostile loading environments.

Electric field-induced nonlinear behavior of lead zirconate titanate piezoceramic actuators in bending mode

Abstract: Abstract In this article, analytical solutions of piezoelectric bimorph and unimorph actuator in cantilever configurations are developed using the second-order constitutive equation. Tip deflection ratio (TDR), a dimensionless parameter, is defined to analyze the effect of second-order coefficients of piezoelectric materials on the response of bimorph and unimorph actuators. Four piezoelectric unimorphs of varying geometries are fabricated and tested to verify the nonlinear response under applied electric field. Furthermore, second-order coefficients of lead zirconate titanate (PZT; APC 850) are derived by fitting the experimental data with nonlinear analytical solution. The nonlinear response of all the piezoelectric unimorphs compares well with the experimental results.

A Comparative Simulation Study of the Different Variations of PZT Piezoelectric Material by Using A MEMS Vibration Energy Harvester

Abstract: In this article, the presented work aims to scavenge maximum electrical outputs by using the novel microelectromechanical system flared-U shaped spring based piezoelectric vibration energy harvester (PVEH). The performance studies were carried out by employing four different variations of lead zirconate titanate (PZT) piezoelectric material namely PZT-4, PZT-5A, PZT-5H, and PZT-8 in the same size and shape of the proposed device. The maximum output powers employing PZT-4, PZT-5A, PZT-5H, and PZT-8 piezoelectric materials are 7.156 nW, 8.657 nW, 10.738 nW, 5.701 nW over 30 Hz, 28.4 Hz, 28.6 Hz, and 30.2 Hz, resonant frequency, respectively, at input acceleration of 0.07 g. From the finite element method simulator COMSOL Multiphysics 5.4 (licensed version) simulation-based outcomes, it is inferred that PZT-5H piezoelectric material performs better than other variations of PZT, such as PZT-4, PZT-5A, and PZT-8 piezoelectric materials.

Singular spectrum analysis and fuzzy entropy-based damage detection on a thin aluminium plate by using PZTs

Abstract: Abstract In this research, a new method based on singular spectrum analysis (SSA) and fuzzy entropy is developed for damage detection on thin wall-like structures, and the normalized fuzzy entropy is employed as an indicator to identify the severity of the damage. The lead zirconate titanate (PZT) transducers are used in this research to generate and detect the Lamb waves. During the detection, the collected signals from the PZT sensors are firstly decomposed and reconstructed by SSA to extract the feature of the damage, and then the reconstructed signals with the feature of the damage are processed to obtain the normalized fuzzy entropy. An experimental setup of an aluminium plate with added magnets is fabricated to validate the proposed method. The experimental results show that when magnets are attached on the aluminium plate, the normalized fuzzy entropy is smaller than that when there are no magnets. That is because when magnets are placed on the plate, the movement and some vibration modes of Lamb waves are disturbed by the added magnets and this disturbing effect can be enhanced by increasing the number and locations of the added magnets, and eventually the complexity and nonlinearity of the waves are weakened. The experimental results of a single damage with different number of magnets indicate that the normalized fuzzy entropy decreases linearly as the number of the added magnets increases, which demonstrates that the proposed method can be used to detect the severity of the damage. Moreover, the experimental results of multi-damage on different locations indicate that the normalized fuzzy entropy is relevant with both the total number and locations of the added magnets. The normalized fuzzy entropy decreases linearly as the total number of the magnets increases, and the entropy of a single damage is smaller than that of the multi-damage with the same total number of magnets, which demonstrates that the proposed method also can be used for multi-damage detection on a thin plate. This study provides us a new approach to identifying a single or multiple damages on thin wall-like structures.

High performance piezoelectric composite fabricated at ultra low temperature

Abstract: This work presents the next leap in piezoelectric all-ceramic composites fabricated at ultra low temperatures. The “Upside-down” composite method is further developed and instead of the water-soluble lithium molybdate used in our earlier study, an organotitanate based precursor gel is used as a binder. Utilizing heat and pressure the precursor transforms into titanium oxide which, together with lead zirconate titanate particles, forms a high-performance piezoelectric composite. The two-step fabrication method is based only on mixing and uniaxial hot-pressing sequences. The all-ceramic samples are fabricated at ultra low temperatures 275–350 °C with exceptionally high fractions of filler (filler to matrix 84:16 vol ratio) resulting in low porosity and showing excellent dielectric and piezoelectric properties. The charge coefficient d33 ∼150 pC N−1 and the voltage coefficient, g33 ∼52 mVm N−1 obtained with the developed composite outperforms many other known composites (80% and 70% higher than achieved with lithium molybdate bound upside-down composite, respectively) and are comparable even to some bulk piezoceramics and low permittivity polymer-ceramic piezocomposites. The sensor properties of the developed composite and the feasibility of the material from the application point of view are successfully demonstrated by utilizing sample elements in a charge mode acceleration sensor and sensitivities comparable to commercial devices are achieved.

High performance piezoelectric composite fabricated at ultra low temperature

Abstract: This work presents the next leap in piezoelectric all-ceramic composites fabricated at ultra low temperatures. The “Upside-down” composite method is further developed and instead of the water-soluble lithium molybdate used in our earlier study, an organotitanate based precursor gel is used as a binder. Utilizing heat and pressure the precursor transforms into titanium oxide which, together with lead zirconate titanate particles, forms a high-performance piezoelectric composite. The two-step fabrication method is based only on mixing and uniaxial hot-pressing sequences. The all-ceramic samples are fabricated at ultra low temperatures 275–350 °C with exceptionally high fractions of filler (filler to matrix 84:16 vol ratio) resulting in low porosity and showing excellent dielectric and piezoelectric properties. The charge coefficient d33 ∼150 pC N−1 and the voltage coefficient, g33 ∼52 mVm N−1 obtained with the developed composite outperforms many other known composites (80% and 70% higher than achieved with lithium molybdate bound upside-down composite, respectively) and are comparable even to some bulk piezoceramics and low permittivity polymer-ceramic piezocomposites. The sensor properties of the developed composite and the feasibility of the material from the application point of view are successfully demonstrated by utilizing sample elements in a charge mode acceleration sensor and sensitivities comparable to commercial devices are achieved.

A plantar wearable pressure sensor based on hybrid lead zirconate-titanate/microfibrillated cellulose piezoelectric composite films for human health monitoring.

Abstract: Flexible and wearable electronic sensors hold great promise for improving the quality of life, especially in the field of healthcare monitoring, owing to their low cost, flexibility, high electromechanical coupling performance, high sensitivity, and biocompatibility. To achieve high piezoelectric performance similar to that of rigid materials while satisfying the flexible requirements for wearable sensors, we propose novel hybrid films based on lead zirconate titanate powder and microfibrillated cellulose (PZT/MFC) for plantar pressure measurements. The flexible films made using the polarization process are tested. It was found that the maximum piezoelectric coefficient was 31 pC N-1 and the maximum tensile force of the flexible films was 26 N. A wide range of bending angles between 15° and 180° proves the flexibility capability of the films. In addition, the charge density shows a proportional relation with the applied mechanical force, and it could sense stress of 1 kPa. Finally, plantar pressure sensors are arranged and packaged with a film array followed by connection with the detection module. Then, the pressure curves of each point on the plantar are obtained. Through analysis of the curve, several parameters of human body motions that are important in the rehabilitation of diabetic patients and the detection of sports injury can be performed, including stride frequency, length and speed. Overall, the proposed PZT/MFC wearable plantar pressure sensor has broad application prospects in the field of sports injury detection and medical rehabilitation training.

Improving dielectric properties of composites thin films with polylactic acid and PZT microparticles induced by interfacial polarization

Abstract: Although polylactic acid (PLA) is widely identified as a biodegradable polymer, its use is limited due to the inherently poor mechanical properties. Therefore, the strengthening of PLA with microscale particles like lead zirconate titanate (PZT) is a promising field of research that has only just begun to be explored. Piezoelectric polymer-PZT films are encouraging materials for modern applications. PLA/PZT composites have been elaborated with diverse content of PZT employing a solvent casting technique. The mechanical characteristics and dielectric properties of the considered films were investigated. X-ray Diffraction (XRD). Fourier Transform Infrared (FTIR) Spectroscopy and Scanning Electron Microscopy (SEM) were used to examine the influence of these fillers at the molecular level, crystal structural change, micro charges dispersion inside the polymer matrix, and Thermogravimetric Analysis (TGA) was used to examine the stability and thermal degradation of the films. The change in these properties as a function of content (0.1–1 wt. %) of PZT has also been investigated. It is found that the PZT incorporation induces a considerable influence on the transformation of the α→β phase. The result can lead to a significant improvement in the dielectric and piezoelectric properties of PLA/PZT composite.

A Comprehensive Review on Piezoelectric Polymeric and Ceramic Nanogenerators

Abstract: Piezoelectric nanogenerators (PNGs) have recently received significant attention because of their great potential for harvesting electricity from wasted mechanical energy resources. In spite of many studies on piezoelectric energy harvesters, a comprehensive review that summarizes alternative types of piezoelectric materials is yet to be reported. This article categorizes piezoelectric materials into two types: piezoelectric perovskite and wurtzite micro-/nanostructures ceramics and ferroelectric polymers and compares their energy harvesting capabilities and piezoelectric properties. Piezoelectric inorganic materials with a perovskite structure, such as lead magnesium niobate−lead titanate (PMN−PT, d33 = 2500 pCN−1) and lead zirconate titanate, d33 = 500–600 pCN−1) PNGs, generate the highest output voltage and current density among all piezoelectric materials. However, the piezoelectric coefficient d31 (−28 to ≈−69 pC N−1) of PMN−PT is lower than PZT (−175 pC N−1) and its toxicity and expensive fabrication process have limited its utilization. Cellular polypropylene (PP) as a ferroelectret polymer offers a high piezoelectric coefficient d33 (250−1400 pC N−1), although their d31 is lower than piezoelectric poly(vinylidene fluoride) (PVDF) polymer. Piezoelectric natural polymers such as cellulose (d33 ≈ 8−28 pC/N, silk (d33 ≈ 0.3−0.8 pC/N, and collagen (d33 ≈ 22 pC/N are also introduced for bio-PNG applications to tackle environmental problems. There is still a research gap on rationally designed self-powered, wearable, stretchable, and biocompatible PNGs with high and controllable energy conversion efficiency.

Inkjet‐Printed Piezoelectric Thin Films for Transparent Haptics

Abstract: Transparent thin‐film piezoelectric transducers are attractive for haptic displays. However, for their widespread use in consumer electronics, innovative and cost‐effective processing methods need to be developed. In this contribution the effectiveness of the deposition of lead zirconate titanate thin films by inkjet printing for the fabrication of haptic devices is demonstrated. The 1,3‐propanediol solvent is used to prepare effective inkjet‐printing inks from chemical solution deposition solutions. The printed thin‐film structures on fused silica glass substrates are 900 nm thick and strongly {100} oriented perovskite phase is detected in X‐ray diffraction patterns. To fabricate devices, interdigitated capacitors and SU‐8 insulation layers are deposited on top of the printed lead zirconate titanate. Dimensions of the final device are 15.7 × 3.4 mm2. A standing antisymmetric Lamb wave is observed at 63.3 kHz, with out‐of‐plane displacement reaching 2 µm at an applied voltage of 100 V. This value exceeds the limit at which the texture rendering function can be induced in the device. Good functional performance of the device is linked with good electromechanical properties of the printed piezoelectric, with permittivity ε ′ and piezoelectric coefficient e33,f values of 1000 and 7.7 C m−2, respectively, which are comparable to films prepared by standard spin‐coating process.

Magnetoelectric effects in stripe- and periodic heterostructures based on nickel–lead zirconate titanate bilayers

Abstract: Objectives. A topical task in the design of magnetoelectric (ME) devices based on composite ferromagnetic– piezoelectric heterostructures involves reducing their dimensions to increase their operating frequencies and optimize their integration in modern electronics. The study set out to investigate the influence of in-plane dimensions on the characteristics of ME effects in stripe and periodic nickel–lead zirconate titanate heterostructures manufactured via electrolytic deposition.Methods. Lead zirconate titanate disks with Ag-electrodes were used for manufacturing the ME heterostructures; Ni was deposited on one Ag-electrode only.Results. While a reduction in stripe size leads to an increase in the frequency of the resonant ME effect, it is followed by a decrease in ME conversion efficiency. The ME coefficient for the periodic heterostructures is about ~1 V/(Oe·cm). By increasing the angle between the magnetic field H and the Ni-stripe axis from 0° to 90°, a 2.5-fold increase in the optimal field Hm and a 4-fold drop in the maximum amplitude of ME voltage umax(Hm) was achieved.Conclusions. In periodic heterostructures, the frequency of the resonant ME effect is determined by the substrate’s size, while ME conversion efficiency depends on the width of the Ni stripes and the distance between them. The observed anisotropy of the ME effects in the investigated heterostructures is explained in terms of demagnetization effects. In the future, the anisotropic ME effect in the periodic heterostructures could be used to develop magnetic field sensors that are sensitive to field orientation.