Performance Of Piezoelectric Sensors Research Articles

Arrayed multi-layer piezoelectric sensor based on electrospun P(VDF-TrFE)/ZnO with enhanced piezoelectricity

Flexible pressure sensors can maintain good pressure sensing capabilities even under arbitrary degrees of deformation, which are widely used in fields such as robotic perception, physiological signal detection and wearable electronics. Currently, piezoelectric-based flexible pressure sensors face significant limitations in terms of large-area, high-sensitivity, and high-resolution pressure detection. Targeted research efforts primarily focus on enhancing the performance of piezoelectric sensors by optimizing the properties of the sensitive layer piezoelectric material and modulating device structural design. This study introduces a novel multilayer array design for flexible composite piezoelectric sensors. A high-voltage electrospinning selective deposition process is proposed to fabricate arrayed nanofiber mats. Patterned electrospun films can be automatically patterned by patterned AgNW electrodes, which allows manual alignment of patterns for subsequent stacking. Compared to sensor based on P(VDF-TrFE) prepared under the same conditions, the sensitivity of the multi-layer P(VDF-TrFE)/ZnO sensor increased from 2.82 mV/kPa to 8.30 mV/kPa, providing an effective approach for highly sensitivity wearable devices with short response time (∼5 ms).

Enhancing the performance of molecule-based piezoelectric sensors by optimizing their microstructures.

By combining the rigidity of inorganic components with the flexibility of organic components, molecule-based ferroelectrics emerge as promising candidates for flexible, self-powered piezoelectric sensors. While it is well known that the performance of piezoelectric sensor devices depends not only on the materials' piezoelectric properties but also on the device architecture, research into enhancing molecule-based piezoelectric sensor performance through microstructure optimization has never been investigated. Here, we report the synthesis of a molecule-based ferroelectric, [(2-bromoethyl) trimethylammonium][GaBr4] ([(CH3)3NCH2CH2Br][GaBr4]) (1), which exhibits a piezoelectric coefficient (d 33) of up to 331 pC N-1. Our investigation reveals that the power density of a composite piezoelectric sensor device made from 1@S-PDMS(800#) (with microstructures) is twelve times that of 1-Flat-PDMS (without microstructures), due to a synergistic combination of piezoelectric and triboelectric effects. Interestingly, this flexible piezoelectric sensor can effectively detect human physiological signals, such as finger bending, breathing, and speech recognition, without the need for an external power supply.

Finite element modeling and analysis of adhesive layer effects in surface-bonded piezoelectric sensors and actuators including non-uniform thickness

A finite element model for multi-functional structures containing surface-bonded piezoelectric patches is proposed with two main objectives: to reduce the computational cost of detailed and accurate analyses; and to fully account for the adhesive layer between structure and patches, including non-uniform thickness. The proposed model is verified and used to assess the effect of adhesive layer properties on the performance of piezoelectric sensors and actuators, based on frequency responses and effective electromechanical coupling coefficient. Results indicate that increases of bonding layer thickness and thickness non-uniformity are not always detrimental to the actuation/sensing performance and could be explored as design parameters.

An Integrated Piezoelectric Sensor Based Energy Efficient Transmission Using Base-Station Controlled Dynamic Clustering Protocol

A piezoelectric sensor based energy efficient transmission using base station controlled dynamic clustering protocol (BSCDCP) is proposed in this work. The piezoelectric sensor design and simulation is analyzed with the help of COMSOL finite element modeling and location based energy efficient routing is estimated by BSCDCP hierarchical routing techniques. The sensor voltage 5.2 V–1 g acceleration and electrical load impedance 12 Ω is distributed uniform voltage to all the nodes and analyze piezoelectric sensor performance based on BSCDCP protocol. The number of iterations the life time of sensor node is increasing with the help of piezoelectric sensor. The numerical results show that 95% accuracy when increase the distance and number of nodes also it suggest to improve the life time of piezoelectric sensor. By using BSCDCP protocol, the optimize piezoelectric sensor frequency and generated voltage is enhance and time duration 0.5 µs is achieved and simulation done with number of nodes, which is very fast compared to existing protocol techniques. The overall protocol is best suitable for energy efficient routing for large volume with less latency and accuracy.

Multiresolution Dynamic Mode Decomposition (mrDMD) of Elastic Waves for Damage Localisation in Piezoelectric Ceramic

The performance of piezoelectric sensors deteriorated due to the presence of defect, delamination, and corrosion that needed to be diagnosed for the effective implementation of the structural health monitoring (SHM) framework. A novel experimental approach based on Coulomb coupling is devised to visualise the interaction of ultrasonic waves with microscale defects in the Lead Zirconate Titanate (PZT). Multiresolution dynamic mode decomposition (mrDMD) technique in conjunction with image registration, and Kullback Leibler (KL) divergence is utilised to diagnose and localise the surface defect in the PZT. The mrDMD technique extracts the spatiotemporal coherent mode and provides an equation-free architecture to reconstruct underlying system dynamics. Additionally, due to the strong connection between mrDMD and Koopman operator theory, the proposed technique is well suited to resolve the nonlinear and dispersive interaction of elastic waves with boundaries and defects. The mrDMD sequentially decomposes the three-dimensional spatiotemporal data into low and high frequency modes. The spectral modes are sensitive to defects based on the scaling of wavelength with the size of the defect. The error due to offset and distortion was minimised with ad hoc image registration technique. Further, localisation and quantification of defect are performed by evaluating the distance metric of the probability distribution of coherent data of mrDMD acquired from healthy and defected samples. In the arena of big-data that is ubiquitous in SHM, the paper demonstrates an efficient damage localisation algorithm that explores the nonlinear system dynamics using spectral multi-mode resolution techniques by sensitising the damage features.

Effect of Adhesive and Its Aging on the Performance of Piezoelectric Sensors in Structural Health Monitoring Systems

Adhesive and its aging can have influence on the Piezoelectric (PZT) elements in structural health monitoring (SHM) systems. However, the current research pays little attention to the effect of adhesives in SHM systems, and the mechanism of adhesive aging on monitoring signals is still unclear. In the present study, the relationship between types of adhesives, adhesive thickness, accelerated aging, and monitoring signal was analyzed in detail. The study was carried out with three kinds of epoxy resin AB adhesive (AW106, E-30CL, and E-120HP) and bonding thicknesses (0.01, 0.05, and 0.12 mm), and the elevated temperature was 100 °C for 45 days. The signal-based monitoring method was used to extract the characteristic parameters. The experimental results indicated that the standard shear strength and thickness of the adhesive may have a combined effect on the monitoring signal. Increasing the thickness may enhance the shear strength between PZT and the matrix. For the effectiveness of monitoring the signal propagation, however, increase in thickness may have a negative influence. Moreover, the elevated temperature will bring the signal amplitude to a peak in the first period of aging, and the highest point appears in 10 to 15 days. Nevertheless, with the increase of aging time, the adhesive will finally be degraded, resulting in the decrease of the signal amplitude. The experimental results may provide useful information for practical monitoring in the SHM field.

Innovation Strategy Selection Facilitates High-Performance Flexible Piezoelectric Sensors

Piezoelectric sensors with high performance and low-to-zero power consumption meet the growing demand in the flexible microelectronic system with small size and low power consumption, which are promising in robotics and prosthetics, wearable devices and electronic skin. In this review, the development process, application scenarios and typical cases are discussed. In addition, several strategies to improve the performance of piezoelectric sensors are summed up: (1) material innovation: from piezoelectric semiconductor materials, inorganic piezoceramic materials, organic piezoelectric polymer, nanocomposite materials, to emerging and promising molecular ferroelectric materials. (2) designing microstructures on the surface of the piezoelectric materials to enlarge the contact area of piezoelectric materials under the applied force. (3) addition of dopants such as chemical elements and graphene in conventional piezoelectric materials. (4) developing piezoelectric transistors based on piezotronic effect. In addition, the principle, advantages, disadvantages and challenges of every strategy are discussed. Apart from that, the prospects and directions of piezoelectric sensors are predicted. In the future, the electronic sensors need to be embedded in the microelectronic systems to play the full part. Therefore, a strategy based on peripheral circuits to improve the performance of piezoelectric sensors is proposed in the final part of this review.

Peculiarities of Performance of Piezoelectric Sensors under a Linear Increase in Pressure

The electric response and processes occurring in piezoelectric elements subjected to pulsed pressure are usually described for two extreme cases: when the time of pressure variation is much longer than the time of propagation of an acoustic wave through a piezoelectric element, when the pressure in the piezoelectric element can be treated as constant (thin sensor regime), and under loading by a rectangular shock wave, when the shock front divides the piezoelectric element into the compressed and uncompressed zones (thick sensor regime). In the former case, the voltage across the piezoelectric element and electric fields emerging in it directly depend on the electric load, and the induced charge is proportional to the applied pressure (in the linear region). In the latter case, the current generated by the piezoelectric element is proportional to the shock load pressure, and the fields in the bulk of the piezoelectric element appear even in the case of short-circuiting of its electrodes. In this study, we consider the electric response of piezoelectrics to the action of pressure, which noticeably varies during the time commensurate with the time of propagation of the shock wave through the piezoelectric element. Such a situation takes place, for example, when a high-velocity particle flow formed when the shock wave emerging on the free surface of the metal plate (dusting) [1–4] is incident on the piezoelectric sensor. The calculations based on the constructed mathematical model show that under an increasing pressure on the piezoelectric element, electric fields with magnitudes depending on the rate of pressure increase and nonuniform over the piezoelectric element thickness appear in its bulk, and the induced electric charge is proportional to the average pressure in the piezoelectric element. Under certain conditions, these fields can attain values leading to the emergence of breakdown in the piezoelectric element and to distortion of generated signals. We consider experimentally observed cases of manifestation of breakdown effects under the action of rapidly increasing pressures in piezoelectric elements.

Two-Dimensional Layered Perovskite Ferroelectric with Giant Piezoelectric Voltage Coefficient.

Piezoelectric sensors that can work under various conditions with superior performance are highly desirable with the arrival of the Internet of Things. For practical applications, a large piezoelectric voltage coefficient g and a high Curie temperature Tc are critical to the performance of piezoelectric sensors. Here, we report a two-dimensional perovskite ferroelectric (4-aminotetrahydropyran)2PbBr4 [(ATHP)2PbBr4] with a saturated polarization of 5.6 μC cm-2, high Tc of 503 K [above that of BaTiO3 (BTO, 393 K)], and extremely large g33 of 660.3 × 10-3 V m N-1 [much beyond that of Pb(Zr,Ti)O3 (PZT) ceramics (20 to 40 × 10-3 V m N-1), more than 2 times higher than that of poly(vinylidene fluoride) (PVDF, about 286.7 × 10-3 V m N-1)]. Combined with the advantages of molecular ferroelectrics, such as light weight, easy and environmentally friendly processing, and mechanical flexibility, (ATHP)2PbBr4 would be a competitive candidate for next-generation smart piezoelectric sensors in flexible devices, soft robotics, and biomedical devices.

Effect of Adhesive Debonding on the Performance of Piezoelectric Sensors in Structural Health Monitoring Systems.

Piezoelectric (PZT) ceramic elements are often subjected to complex loads during in- service lifetime in structural health monitoring (SHM) systems, and debonding of both excitation actuators and receiving sensors have a negative effect on the monitoring signals. A first systematic investigation of debonding behaviors by considering actuators and sensors simultaneously was performed in this paper. The debonding areas of actuators were set in different percentage range from 0% to 70%, and sensors in 0%, 20%, 40% and 60%. The signal-based monitoring method was used to extract the characteristic parameters of both the amplitudes and phases of received signals. Experimental results revealed that as the debonding areas of the actuators increase, the normalized amplitude appears a quick decrease before 35% debonding area of actuators and then a slow rise until 60% of debonding reached. This may be explained that the 35% debonding turning point correspond to the coincidence of the excitation frequencies of peripheral actuators with the inherent frequency of the central piezoelectric sensor, and the 60% be the result of the maximum ability of piezoelectric sensor. The degrees of debonding of actuators and sensors also have significant influence on the phase angle offset, with large debonding of actuators increases the phase offset sharply. The research work may provide useful information for practical monitoring of SHM systems.

Improvement of the Vibratory Diagnostic Method by Evolution of the Piezoelectric Sensor Performances

Vibration analysis is an important means in the industrial field to monitor electromechanical systems; their evolution can provide the correct information on vibration. For this purpose; it is necessary to focus the study on improving the piezoelectric sensor performance to progress the vibration analysis method. In industry, the piezoelectric accelerometer is the instrument often used to monitor rotating machines and detect their defects in an early stage. In this paper, piezoelectric detection is studied to understand the operating principle of the piezoelectric accelerometer and translate it into a mathematical model. Validation of the model developed of measurement accuracy and measurement error as a function of relative vibration movement by simulation and experimental tests is performed. Using this validated model, the improvement of the characteristics and performance of this sensor can be achieved as well as a new conception of the latter can be proposed. This new design of piezoelectric sensor aims to obtain more accurate results and to provide correct information’s on the vibratory level. A comparative study is made to show the importance of our results compared to literature, these results have showed that a suitable and appropriate choice of damping ratio develops the accelerometer parameters and enhances the vibratory analysis technique.

Influence of Anisotropy and Transverse-Shear Strains on the Performance of Piezoelectric Sensors and Actuators

The effect of anisotropy and shear strains on the performance of piezoelectric sensors and actuators in active damping of the resonance vibrations of a hinged rectangular plate is studied. To model the vibrations of the plate, Timoshenko’s hypotheses are used. The analytical solution of the problem is obtained by Fourier’s method. Formulas for the voltage that should be applied to the actuators to balance the mechanical load are derived. Similar formulas are obtained for the sensor voltage. Formulas for the damping coefficient for the case of using both sensors and actuators for active damping of the resonant vibrations of the plate are presented.

An experimental study: Integration device of Fiber Bragg grating and reinforced concrete beam for measuring debris flow impact force

The impact effect of boulder within debris flow is the key factor contributing to peak impact as well as to the failure of debris flow control work. So accurate measuring and calculating the impact force of debris flow can ensure the engineering design strength. However, limited to the existing laboratory conditions and piezoelectric sensor performance, it is impossible, based on the conventional measurements, to devise a computing method for expressing a reliable boulder impact force. This paper has therefore designed a new measurement device according to the method of integrating Fiber Bragg grating (FBG) and reinforced concrete composite beam (RCB) for measuring the impact force of debris flows, i.e. mounting FBG on the axially stressed steel bar in the composite beam at regular intervals to monitor the steel strain. RCB plays the role of contacting debris flow and protecting FBG sensors. Taking this new device as the experimental object, drop testing is designed for simulating and reflecting the boulder impact force. In a series of impacting tests, the relationship between the peak dynamic strain value of the steel bar and the impact force is analyzed, and based on which, an inversion model that uses the steel bar strain as the independent variable is established for calculating the boulder impact force. The experimental results show that this new inversion model can determine the impact force value and its acting position with a system error of 18.1%, which can provide an experimental foundation for measuring the impact force of boulders within the debris flow by the new FBG-based device.

Research on Planetary Gear Reducer with Dynamic Torque Measurement

Torque is a main parameter of mechanical transmission system, while the dynamic torque measurement is a technical difficulty in mechanical test system. In order to improve the level of dynamic torque measurement technique, the authors synthetically analyzed the existing problems of the existing torque sensor, studied on the principle of planetary gear transmission, researched piezoelectric sensor performance, and then put forward the planetary gear reducer with torque self-inspection. To improve the design of planetary gear reducer and use piezoelectric force sensor in measuring the gear ring of torque, then calculate the torque of input shaft and output shaft, and transfer torque measurement and dynamic transmission into one, change the complex torque measurement into simple pressure measurement, simplify the torque measuring system, improve the dynamic performance of the torque measurement. The study indicates that the planetary gear reducer with torque self-inspection has such advantages as the simple principle of measurement, high sensitivity, high signal-to-noise ratio, reliable work, small impact by environmental factors, convenient maintenance and so on. It can greatly improve the detection accuracy and efficiency of torque measurement, and be widely used in all kinds of torque measurement field.

Failure investigation of top-hat composite stiffened panels

This paper presents a study on failure investigation of top-hat composite stiffened panels using a combination of techniques. Acoustic emission technique is used to discriminate between the various failure modes using piezoelectric sensors. In addition, an attempt is made to investigate the possibility of using a state of the art surfaced bonded fibre-optic sensor as an acoustic sensor. A strain insensitive fibre Bragg grating (FBG) sensor is used to compare the performance of piezoelectric sensors for composite structures. On the other hand, fibre-optic sensors have some beneficial properties such as low specific weight, small size and good compatibility with polymeric composites compared to traditional sensing mechanisms. FBG sensors are expected to provide a replacement for traditional electric sensors as FBGs are not susceptible to electromagnetic signature, have multi-functionality and enable multiplexing. Fibre-optic sensors are embedded in the composite specimen to measure the non-linear strain at the bend and to analyse the progressive failure with strain anomalies.

Acoustic emission techniques for failure characterisation in composite top-hat stiffeners

Modern day aerospace, automotive, marine, mechanical and civil structures rely on the advanced composites for their added benefits over conventional metallic structures. The complex damage process in composites involves various failure modes such as matrix cracking, fibre-matrix debonding, fibre fracture and delamination. This paper presents an acoustic emission technique for the failure characterisation of top-hat stiffener specimens using conventional piezoelectric acoustic emission sensors and modern fibre Bragg Gratings. Strain insensitive fibre Bragg Grating sensors are used in this experimental investigation to compare the performance of piezoelectric sensors for composite structures. This work has contributed to the development of an acoustic emission sensing system based on fibre Bragg Gratings. Main objectives of this work are to compare the sensing characteristics simultaneously in a composite structure with a surface-bonded acoustic emission–fibre Bragg Grating sensor and acoustic emission–piezoelectric sensor. The feasibility of the system is demonstrated in typical applications of in-situ structural health monitoring based on acoustic emission techniques.

An investigation of the tertiary coupling effect under the longitudinal mode of a piezoelectric crystal

In this article, multiple piezoelectric effects are investigated on the basis of the classical piezoelectric theory. The objective reality of multiple piezoelectric effects is elucidated from theoretical analysis first. Based on four kinds of piezoelectric equations, the relationship between the generation of multiple piezoelectric effects and boundary conditions is analysed, the process of their generation is elaborated, and the formulae of the tertiary piezoelectric effect are deduced. Then, the experimental results of the tertiary coupling effect are obtained under the longitudinal mode of a PZT-5 stack by the methods that are equivalent to changing boundary conditions. Experimental data show that the output of the tertiary direct and converse piezoelectric effect is also linear with the applied force and voltage, respectively. However, the output directions are opposite to that of the primary piezoelectric effect. The theoretical analysis is justified by experimental results and the experimental methods presented are proved to be scientific and feasible. Moreover, the influence of the tertiary piezoelectric effect on the piezoelectric coefficient and the performance of sensors and actuators is further analysed. The study of multiple piezoelectric effects provides a new method for the improvement of the performance of piezoelectric sensors and actuators.

Investigation of the reliability of piezoelectric chemical sensors

The aim of the research was to study the functional change of sensitivity, selectivity and overall stability of piezoelectric chemical sensors. A test device was built and experiments have been carried out to estimate the degradation of the piezoelectric sensor performance. Sensing materials were inspected by a scanning electron microscope (SEM) to investigate the surface structures. Strong correlation was found between the reliability and the quality of the sensing material surface. The surface formation depended upon the physical and chemical properties of the sensing materials. Both the electrostatic and structural features influenced the interactions between the sensor surface and the analytes. Interactions during the adsorption and desorption of volatile compounds could not only be estimated by the van der Waals interactions. The contact area of interactions, where the secondary chemical forces play a significant role, was determined by the surface structure and the molecular structure of the sensing material. Polarity and different surface formation were found to be the most important factors to improve the discrimination capability of piezoelectric chemical sensors. The same investigations were repeated after 3 months. The most remarkable comparison was the appearance of the SEM images. A relationship was also recognized between the elapsed time and the degradation of the selectivity of the detectors. The method developed can be used to estimate the applicability of a piezoelectric chemical sensor.

Fundamental Understanding of Piezoelectric Strain Sensors

This paper investigates the behavior of piezoelectric elements as strain sensors. Strain is measured in terms of the charge generated by the element as a result of the direct piezoelectric effect. Strains from piezoceramic (PZT) and piezofilm (PVDF) sensors are compared with strains from a conventional foil strain gage and the advantages of each type of sensor are discussed, along with their limitations. The sensors are surface bonded and are calibrated by means of a dynamic beam bending setup over a frequency range of 5-500 Hz. Correction factors to account for transverse strain and shear lag effects due to the bond layer are analytically derived and validated experimentally. Additionally, design of signal conditioning electronics to collect the signals from the piezoelectric sensors is addressed. The superior performance of piezoelectric sensors compared to conventional strain gages in terms of sensitivity and signal to noise ratio is demonstrated.

Fundamental Understanding of Piezoelectric Strain Sensors

This paper investigates the behavior of piezoelectric elements as strain sensors. Strain is measured in terms of the charge generated by the element as a result of the direct piezoelectric effect. Strain measurements from piezoceramic (PZT) and piezofilm (PVDF) sensors are compared with strains from a conventional foil strain gage and the advantages of each type of sensor are discussed, along with their limitations. The sensors are surface bonded to a beam and are calibrated over a frequency range of 5-500 Hz. Correction factors to account for transverse strain and shear lag effects due to the bond layer are analytically derived and experimentally validated. The effect of temperature on the output of PZT strain sensors is investigated. Additionally, design of signal conditioning electronics to collect the signals from the piezoelectric sensors is addressed. The superior performance of piezoelectric sensors compared to conventional strain gages in terms of sensitivity and signal to noise ratio is demonstrated.