Piezoelectric Composite Sensors Research Articles

Experimentation and simulation study of electromechanical response characteristics of a 2-2 type cement-based piezoelectric composite sensor

In the manuscript, the piezoelectric functional element was prepared by slicing and adding method using piezoelectric ceramic PZT-5H and ordinary silicate cement 42.5 was as base materials, and then a 2-2 type cement-based piezoelectric composite sensor was prepared by an encapsulated epoxy resin. The experimental and simulation analysis was carried out to obtain the quasi-static linear sensitivity of the electromechanical response of the sample under conditions of compressive loading. The development process of the sample from local failure to overall fragmentation was observed using a high-speed camera. Found that the electrical nonlinear threshold of 35 MPa appeared before the mechanical nonlinear threshold. Further, the results showed that when the loading frequency was increased from 5 to 15 Hz under equal amplitude, the response waveform remained unchanged, however, the electrical displacement was attenuated by 19.7%. Packaging schemes using various lengths and thicknesses of an epoxy layer were conducted by using simulation. It is indicated that, under the premise of ensuring the protection package and considering the manufacturing process, the length of the package side could increase appropriately, and the single-side package side length is set to 4 mm. When the thickness of the package layer becomes less, it would be better.

Flexible piezoelectric composite sensor for impact monitoring of curved structures

Flexible piezoelectric composite sensor for impact monitoring of curved structures

Characterization of UV Light Curable Piezoelectric 0-0-3 Composites Filled with Lead-Free Ceramics and Conductive Nanoparticles

Lead-free piezoelectric materials are essential for our healthy future but offer lower performance than lead-based materials. Different material combinations are explored to improve the performance of lead-free materials. By filling the UV light curable photopolymer resin with 30 vol.% lead-free piezoelectric ceramics and with up to 0.4 wt.% conductive nanofillers, thin and flexible piezoelectric 0-0-3 composites are formed. Two particle sizes of Potassium Sodium Niobate (KNN) and Barium Titanate (BTO) ceramics were used with four conductive nanofillers: Graphene Nanoplatelets (GNPs), Multi-Walled Carbon Nanotubes (MWCNTs), and two types of Graphene Oxide (GO). Resulting high viscosity suspensions are tape-cast in a mold as thin layers and subsequently exposing them to UV light, piezoelectric composite sensors are formed in 80 s. Even low nanofiller concentrations increase relative permittivities, however, they strongly reduce curing depth and increase undesirable dielectric losses. Non-homogeneous dispersion of nanofillers is observed. In total, 36 different compositions were mixed and characterized. Only six selected material compositions were investigated further by measuring mechanical, dielectric, and piezoelectric properties. Results show KNN composite performance as piezoelectric sensors is almost six times higher than BTO composite performance.

Multi-material freeform 3D printing of flexible piezoelectric composite sensors using a supporting fluid

Three-dimensional (3D) printed flexible piezoelectric devices featuring conformal or freeform geometries show great potential for being fabricated into wireless sensors and energy harvesters with tailorable mechanical stiffness and piezoelectric response. In our work, supporting fluid-assisted multi-material extrusion-based 3D printing technology has been successfully utilized to fabricate flexible conformal or freeform piezoelectric composite sensors with integrated electrodes. The printing technique relies on the extrusion of two paste-like materials: piezoelectric and conductive composite inks. A comprehensive characterization of the inks (i.e., piezoelectric or conductive behaviors, rheological and mechanical properties) and the rheological behavior of the supporting fluid are performed. Polydimethylsiloxane (PDMS)/30 vol% lead zirconate titanate (PZT), PDMS/25 vol% silver (Ag) and mineral oil/6% (w/v) fumed silica are the formulations for piezoelectric ink, conductive ink and supporting fluid, respectively. Three types of piezoelectric composite demonstrators which are a multi-layer planar film, a conformal non-planar hemisphere and a 3D structure composed of six spirals printed vertically between two hexagon layers (freeform spiral-hexagon), are fabricated and tested under tension or compression tests. The piezoelectric performance is consistent with the applied stress in all the tests. For example, the freeform spiral-hexagon piezoelectric sensor has a peak-to-peak voltage output of 86.39 ± 1.145 mV when it is subjected to a cyclic compression force at 8 Hz for more than 800 cycles. The dimensional accuracy measurements using an optical microscope and the microstructure images taken using a scanning electron microscope (SEM) show that the fabricated 3D structures have good shape fidelity (with a maximum relative error of ~3.5%) when compared to the designed models. Our fabrication approach opens a new way to fabricate conformal and freeform piezoelectric structures with integrated electrodes from flexible composites for sensing and energy harvesting applications.

3D-Printable Piezoelectric Composite Sensors for Acoustically Adapted Guided Ultrasonic Wave Detection.

Commercially available photopolymer resins can be combined with lead zirconate titanate (PZT) micrometer size piezoelectric particles to form 3D-printable suspensions that solidify under UV light. This in turn makes it possible to realize various non-standard sensor geometries which might bring benefits, such as increased piezoelectric output in specific conditions and less interference with incoming waves due to better acoustical adaptation compared to solid PZT ceramics. However, it is unclear whether piezoelectric composite materials are suitable for guided ultrasonic wave (GUW) detection, which is crucial for structural health monitoring (SHM) in different applications. In this study, thin piezoelectric composite sensors are tape casted, solidified under UV light, covered with electrodes, polarized in a high electric field and adhesively bonded onto an isotropic aluminum waveguide. This approach helps to demonstrate the capabilities of tape casting’s freedom to manufacture geometrically differently shaped, thin piezoelectric composite sensors for GUW detection. In an experimental study, thin two-dimensional piezoelectric composite sensors demonstrate successful detection of GUW for frequency-thickness products of up to 0.5 MHz mm. An analytical calculation of the maximum and minimum amplitudes for the ratio of the wavelength and the sensor length in wave propagation direction shows good agreement with the sensor-recorded signals. The output of the piezoelectric composite sensors and occurring reflections as measure for wave interactions are compared to commercial piezoelectric discs to evaluate their performance.

Properties of novel 0–3 PZT/silicone resin flexible piezoelectric composites for ultrasonic guided wave sensor applications

Ultrasonic guided wave (UGW) technology based on piezoelectric sensors is considered a very promising technology for aircraft structural damage detection. Traditional piezoelectric sensors are made of lead zirconate titanate (PZT) ceramics, but their brittleness and hardness make them difficult to apply to curved structure surfaces. In this study, a novel 0–3 flexible piezoelectric composite was fabricated by dispersing PZT particles in silicone resin, and its performance for potential applications in UGW sensors was studied. The effects of polarization conditions, PZT volume fraction, and PZT powder size on the performance of the composite were investigated. The influence of ambient temperature on composite performance was discussed, and temperature adaptability experiments were conducted. The results show that the optimal poling process of 0–3 PZT/silicone resin piezoelectric composite has a poling time of 25 min, a poling electric field of 4 kV/mm, and a poling temperature of 100°C. When the sensor is required to meet the test strain range of 8,000 με, the composite should be fabricated with a PZT volume fraction of 50% and a powder size of 170∼212 μm to obtain optimal sensing sensitivity. At an ambient temperature range of -55–75°C, the fabricated piezoelectric composite sensor has good flexibility and sensitivity in detecting the guide wave signals. These research results provide a new flexible piezoelectric sensing technology for aircraft structural damage detection.

Optimisation of active SHM system based on optimal number and placement of piezoelectric transducers

This paper concerns optimal placement and number of discrete piezoelectric macro fibre composite (MFC) sensors to optimise SHM systems. Its novelty lies in a two-stage placement methodology for discrete piezoelectric transducers, with fitness and objective functions to optimise the location and number of discrete piezoelectric sensors in order to reduce the cost and complexity of data processing and increase the effectiveness in damage detection. The maximisation of sensor voltage amplitude at multiple modes of vibration and the average of sensor normal damage index [Formula: see text] measured for several plates artificially cracked at different positions and orientations are proposed as objective functions to optimise the locations and the number of efficient piezoelectric sensors. A non-normalised root-mean-square deviation [Formula: see text] is introduced in this study in place of the conventional normalised [Formula: see text] to assess the degree of damage and sensor effectiveness. Furthermore, normal damage indices [Formula: see text] and [Formula: see text] normalised to 100% are proposed as the fitness functions. The placement methodology is utilised and verified for stiffened and unstiffened plates; stiffeners are used to break the dynamic symmetry and increase plate complexity. The performance of the placement methodology is tested for a healthy and 12 damaged plates to optimise SHM system based on the maximisation of sensor voltage and average normal damage index [Formula: see text] as objective functions. The results show that the placement methodology is efficient in determining the optimum number and placement of piezoelectric sensors at a low computational effort. The optimum placement of two piezoelectric sensors can efficiently monitor the crack’s initiation at different positions and multiple modes of vibration. The optimal placement and number of sensors have a positive impact on the cost, data acquisition and processing of the active SHM system

Multi-Material Freeform 3d Printing of Flexible Piezoelectric Composite Sensors Using a Supporting Fluid

Multi-Material Freeform 3d Printing of Flexible Piezoelectric Composite Sensors Using a Supporting Fluid

Comparison of sensor output because base plate thickness and shape change of piezoelectric composite sensor for long-term measurement

After the huge earthquake many steel structures were constructed using frame welded joints of welded construction and welded base. Steel structures are considered earthquake resistance structures however, many steel structures are constructed using frame-welded joints of fillet welded construction and welded column bases. These weld joints could result to have low capacity to absorb energy during earthquakes. In this paper, we have proposed the development method for sensor measuring displacement by using composite piezoelectric film and glass. We are investigated relationship between the displacement of the structure and the output voltage from the piezoelectric joint sensor to recorded the sensor characteristics.

Kinetic motion sensors based on flexible and lead-free hybrid piezoelectric composite energy harvesters with nanowires-embedded electrodes for detecting articular movements

Self-powered motion sensors have drawn many attentions for the last decade because it can be usefully applied to not only smart clothing and biomedical applications but also future remote controlling robotics systems. In this study, we develop a ceramic–polymer hybrid lead-free piezoelectric composite-based device to fabricate excellent flexible energy harvesters and kinetic motion sensing gloves. With the use of a composite composed of (K,Na)NbO3 (KNN) piezoelectric particles and poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] matrix, the fabricated flexible energy harvester generates an open-circuit voltage of ~5 V and short-circuit current of ~1 μA under mechanical bending deformations. Moreover, the advantages of the P(VDF-TrFE) matrix for piezoelectric composite-based devices are validated by the results of the finite element method (FEM) simulation. Based on the hybrid piezoelectric composite, stable and reliable self-powered kinetic motion sensors are fabricated to monitor tiny biomechanical motions, i.e., the angles of finger hinges and various hand gestures. Our development successfully indicates that the hybrid lead-free piezoelectric composite can be applied to the active component of self-powered kinetic sensors for future low-power electronic motion detector.

Liquid Property Identification by Electro-Mechanical Impedance Method Using a 1-3 Piezoelectric Composite Sensor

Electro-mechanical impedance (EMI) method utilizing smart materials is an effective way for liquid property identification. In this article, we report on a 1-3 piezoelectric composite sensor used for identifying liquid property based on EMI method. To understand the operation mechanism of the sensor immersed in liquid, a fluid-structure interaction model was established. An analytical solution to govern the electrical impedance of the 1-3 piezoelectric composite sensor coupled with a liquid was derived. Based on the model, the influence of the acoustic impedance of a liquid on electrical impedance of piezoelectric materials is clearly revealed. The experimental results show that the measured acoustic impedance of 3 liquids using the fluid-structure interaction model agrees well with the reference values. The maximum relative error in the experiments is merely 2.4%, much less than that obtained by equivalent circuit model, confirming the accuracy of the model we built. Moreover, the 1-3 piezoelectric composite sensor based on EMI method exhibits a higher resolution than frequency drift method. The method presented provides a simple, cost-effective, and convenient way in liquid property identification.

Cement-based piezoelectric composite sensor designed for charactering the three-dimensional stress state in concrete

We reported a sensor, designed based on the specific working modes of piezoelectric, to characterize the three-dimensional (3-D) stress state in concrete. The sensor contains 6 piezoelectric elements: 3 elements working in normal mode to measure the normal stress, and 3 elements working in shear mode to measure the shear stress. Cement-based piezoelectric composite, fabricated by cutting-filling method, was used to fabricate the sensor, as it has better mechanical compatibility with concrete than piezoelectric ceramics. By embedding the sensor into a cement mortar column, we systematically characterized its performance under dynamic uniaxial load from 3.0 MPa to 7.5 MPa with frequency from 1 Hz to 20 Hz. Results demonstrate that the sensor can measure the 3-D stress state in concrete well, and has good linearity, high sensitively, and excellent working bandwidth. The cross sensitivities of the sensor were also calculated and discussed.

Active vibration control of smart laminated beams using PFRC patches as sensors and actuators

Abstract The aim of this paper is to present the performance of piezoelectric fiber-reinforced composite (PFRC) sensors and actuators in active vibration suppression of smart laminated beams. Finite element based on an efficient layerwise theory has been selected for the kinematic modelling of smart beam. Both classical (CGVF) and optimal (LQR and LQG) feedback control systems are employed to actively suppress the vibration. The effects of fiber volume fraction and fiber direction of PFRC on the settling time, active damping ratios, peak tip deflection and peak control voltage are studied. The effectiveness of control strategies in terms of minimum control voltage for a given settling time is presented

A cement-based 1−3 piezoelectric composite sensor working in d15 mode for the characterization of shear stress in civil engineering structures

This paper reports a cement-based 1−3 piezoelectric composite sensor for the characterization of shear stress in civil engineering structures. The sensor was fabricated using a cutting−filling method, in which the piezoelectric elements work in d15 shear mode. Its properties—such as piezoelectric constant, dielectric constant, electromechanical coupling coefficient, and density—have been systematically tested. By embedding two sensors into a concrete beam, we have further characterized its performance with a three point bending test technique. Results show that both sensors have very good accuracy, linearity, and frequency bandwidth. For instance, under a dynamic load of 2000 N at 10 HZ, the shear stresses measured by the two embedded sensors were 12.07 kPa and 12.01 kPa, slightly smaller than the calculated value of 12.5 kPa. Furthermore, the potential application of the sensor in monitoring acoustic signals in concrete was validated by knocking three arbitrary points of the beam.

Flexible and active self-powered pressure, shear sensors based on freeze casting ceramic-polymer composites.

Self-powered flexible electronics are of particular interest and important for next generation electronics due to their light weight, flexible and self-sustainable properties. Many self-powered sensors made from piezoelectric composite materials are either inflexible or possess low piezoelectricity. In this work, we demonstrate self-powered flexible and highly active pressure and shear sensors based on freeze casting ceramic-polymer structures. A lamellar lead zirconate titanate (PZT) structure is initially developed via freeze-casting and the piezoelectric composites are formed by impregnating a polydimethylsiloxane (PDMS) matrix into the aligned pore channels. The structured PZT-PDMS composites exhibited a high effective longitudinal piezoelectric coefficient (d 33*) of 750 pC N-1, which is higher than that of the monolithic ceramic due to the combination of bending and flexural effects. The use of freeze casting enables the manufacture of complex and arbitrary shaped 3D piezoelectric architectures, along with the unique advantages of low-cost and ease of fabrication. A 14 × 14 mm2 PZT-PDMS pressure sensor was able to bend to a small radius of 8 mm and maintain a high d 33. Furthermore, the manufactured self-powered sensors are demonstrated in a range of applications, such as acceleration, strain and touch sensors that use the d 33, d 31 and d 15 coefficients to detect longitudinal, transverse and shear loads. This work expands on the potential applications of freeze casting and provides new opportunities for the manufacture of future electronic sensors.

Wide band underwater acoustic transducer for stacked 2-2 piezoelectric composite material tube

ABSTRACTA kind of high frequency wideband underwater acoustic transducer is developed, this transducer is formed by 2-2 type piezoelectric composite tube which is composed of double ring stacked along the axial direction. Through the radial cutting piezoelectric ceramic ring, filled with epoxy resin, samples polished, coated electrode and a series of process, the piezoelectric composite ring is prepared, then, the ring with the same outer diameter and different wall thickness is stacked in the axial direction. A double ring stack piezoelectric composite sensor is prepared, after pouring waterproof permeable layer, the transducer is made. Underwater performance test results show that the resonant frequency of transducer is 410 kHz, the maximum transmit voltage response is 150 dB, the -3dB bandwidth reaches 60 kHz, The bandwidth of the transducer is expanded by the method of composite and dual mode coupling.

Impact Mechanical Response of a 2-2 Cement-Based Piezoelectric Sensor Considering the Electrode Layer Effect.

Cement-based piezoelectric composite, has been widely used as a kind of smart material in structural health monitoring and active vibration control. However, transient dynamic loads such as impact loads may cause serious damage to the composite. Considering the electrode layer effect, this paper aimed to investigate the theoretical response of a 2-2 cement-based piezoelectric composite sensor subjected to an impact load. The vibration behaviors are analyzed by using the mode summation method and the virtual work principle. To simulate the impact load, transient haversine wave loads are assumed in the numerical simulation. Close agreements between theoretical and numerical solutions are found for peak transient haversine wave loads larger than 500 kPa, therefore proving the validity of the theory. Moreover, the influence of the electrode material and geometrical parameters on the dynamic characteristics of this sensor are considered. The present work should be beneficial to the design of this kind of sensor by taking into account the electrode layer effect.

Design and Validation of an Orthotropic Piezoelectric Composite Material Phased Array Sensor Used to Nondestructive Detection

Design and Validation of an Orthotropic Piezoelectric Composite Material Phased Array Sensor Used to Nondestructive Detection

Piezoelectric Lead Zirconium Titanate Composite Touch Sensors for Integration with Flexible OLED Technology

To enable the design of more intuitive product user interfaces, the prospects of matching piezoelectric touch sensors with flexible organic light emitting diode (OLED) technology are investigated. Low stiffness piezoelectric composite sensors, combining piezoelectric Pb(Zr,Ti)O3 powder with a polymer matrix, are prepared and compared to existing ceramic and polymer sensors. The piezoelectric sensitivity per stiffness of these piezoelectric composites can be tailored by adapting the polymer matrix to the stiffness required by the OLED, while retaining a relatively high sensitivity. Concurrently, the relatively low energy output of these flexible piezoelectric sensors can be increased through optimized sensor design.

Smart thin-film piezoelectric composite sensors based on high lead zirconate titanate content

Piezoelectric composites are hybrid materials primarily consisting of polymer matrices and micro-sized particles of ferroelectric ceramic. While incorporating high-fraction ceramic particles into composites is indispensable to meet the ever increasing requirement of sensitivity, it is a great challenge to achieve such a high concentration due to processing difficulties. In this study, we developed piezoelectric composites of 0-3 geometry containing 95 wt% (∼73 vol%) lead zirconate titanate particles by modifying the surface of lead zirconate titanate particles with isophorone diisocyanate and polyoxyalkyleneamine (J2000) and compounding them with epoxy resin. The functional groups of J2000 molecules covalently grafted onto the particle surface can react with the matrix, thus creating a robust linkage between the matrix and the particles. This improved the particle dispersion and the interface, enabling the development of a superior composite film with high lead zirconate titanate fractions. Modified piezocomposites can save up to 75% poling time at 75% lower voltage in comparison with the unmodified sample as well as previous studies. The remarkable improvement is indebted to the two-stage interface modification process and the layer-by-layer fabrication method.