Piezoelectric Ceramic Patches Research Articles

Sound isolation via temporal modulation material based on piezoelectric elements

The temporal modulation material is investigated to be used as lightweight sound isolation material. This smart composite material consists of a lightweight structure attached with shunted piezoelectric ceramic (PZT) patches. The shunt circuits are connected to the two poles of PZT patches to act as some local electrical resonators to improve the sound isolation. The circuit is composed of operational amplifiers and passive analog circuit elements, so the system is always stable, and the power consumption is low. The metal-oxide-semiconductor field-effect-transistor (MOSFET) is added in the shunt circuit connected to the PZT patches, so the time sequence of the working circuit is controlled with the MOSFET devices in each resonant shunt. The motivation of this study is to improve the sound isolation in the low-to-middle frequency range. The temporal modulation material proposed in this study has many potential applications in environmental acoustics, precise instrument, automotive sector, and aerospace technologies.

Evaluation and validation of a multiphysics finite element model for a piezoelectric energy harvester

This study explores the applicability of the multiphysics finite element method to model a piezoelectric energy harvester. The piezoelectric energy harvester under consideration consists of a stainless-steel cantilever beam attached to a piezoelectric ceramic patch. Two configurations were considered: one without a proof mass and one with a proof mass. COMSOL Multiphysics software is used to simultaneously model three physics: solid mechanics, electrostatics, and electrical circuit physics. Several key relationships were investigated to predict the behaviour of the piezoelectric energy harvester. The effects of the electrical load resistance and proof mass on the performance of a piezoelectric energy harvester were evaluated. Experimental testing was conducted to validate the results obtained using the finite element model. Overall, the results from the finite element model closely matched those from the experimental testing. It was found that increasing the load resistance of the piezoelectric energy harvester caused an increase in voltage across the load resistor, and matching the impedance yielded the maximum power output. Increasing the proof mass reduces the fundamental frequency, which results in an increase in the displacement transmissibility and impedance-matched resistance. The study shows that the multiphysics finite element method is effective for modelling piezoelectric energy harvesters.

Parametric Analysis of a Rotational Piezoelectric-Coupled Tapered-Bimorph Structure with Various Boundary Conditions Under Transient Axial Loading

The steady-state parametric analysis of a piezoelectric-coupled rotating tapered-bimorph system consists of a central host beam and two piezoelectric ceramic patches above and below it, tapering along positive X-direction and rotating in the X–Y plane, subjected to axial dynamic as well as static loading at its one end is done. The influence of three boundary conditions and various system parameters are also studied. The mathematical modeling of the rotating tapered-bimorph system is formulated with the help of Hamilton's equation. The parametric analysis of the axially loaded system is done for clamped-free (C-F), pinned-pinned (P-P), and clamped-pinned (C-P) boundary conditions. A number of parametric instability regions along with static buckling load plots are obtained and analyzed for various values of the piezoelectric patches to the host beam thickness ratio, taper parameter, and rotational frequency using MATLAB software and depicted through a series of diagrams. The results illustrate that the principal modal frequencies of the tapered-bimorph rotating system are increased rapidly with an increase in the thickness ratio, whereas increase less significantly with a rise in taper parameter and spinning speed for both the static and dynamic loading conditions. The lowest first modal frequency is observed for the P-P system under any given system configurations and operating conditions, which can be used for low-frequency rotational vibration energy harvester over the orthodoxly used C-F system. Designing low-frequency rotational vibration energy harvester and rotor blades can be done by selecting appropriate dimensions and parameters presented in this article.

Monitoring and Imaging of Bolted Steel Plate Joints Using Ultrasonic Guided Waves

Abstract Steel structures with bolted joints are easily dismantled and repurposed. However, maintaining joint integrity is a challenge. This paper reports a non-destructive methodology to monitor steel bolted joints. Piezoelectric ceramic patches have been surface bonded in the joint for transmission and reception of guided ultrasonic waves. Both single and multiple bolted joints have been investigated. It has been demonstrated that the variation in acoustic impedance due at the bolt interface can be discerned and calibrated with bolt torque level. The recorded reflections from interfaces are used as inputs for a newly developed imaging algorithm. The proposed method has the potential to be a reference-free and fully automated method.

Design and Experimental Analysis of Composite Material with Piezoelectric Layer

The main objective of this work is to analyze the active vibration control using smart sensors and actuators in a laminated E-Glass/epoxy cyanate composite beam. The cantilevered composite beam has piezoelectric ceramic patches as smart sensors and actuators. Hand layup technique for vibration suppression is done on the fabricated E-Glass/Epoxy-cyanate composite laminated beam. Experimental modal testing is performed to achieve vibration suppression on the flexible composite beam bonded with seven circular type piezoelectric actuator elements and seven circular type sensor elements. The complete vibration suppression utilizes a data acquisition system, a real-time control system, and a functional generator, in addition to the composite beam with PZT sensor and actuator. The data acquisition hardware consists of model NI 9233 (4 channel +5 V 24 Bit IEPE Analog input I2VA 1-to earth ground).

Development and evaluation of an external reusable piezo-based concrete hydration-monitoring sensor

Hydration of concrete is a very complicated and multiphase process, where the cement gel transforms into a hardened state from plastic/semiplastic phase. Proper progression of the hydration process ensures the development of targeted mechanical properties such as the elastic modulus, the coefficient of thermal expansion, the Poisson’s ratio, and finally, the characteristic strength of concrete. Concrete experiences large thermal variations during the early phase of hydration due to the heat generated during the formation of cement hydration compounds, which contributes to shrinkage and cracking, somewhat making ground for the ultimate failure in the long run. Therefore, it is utmost important to monitor the progression of hydration for enhancing performance during the curing and the early service life. This article presents a new reusable external configuration of piezo-impedance transducers to monitor the hydration process in concrete structures using the electro-mechanical impedance technique. The proposed configuration consists of a thin metal foil instrumented with piezoelectric ceramic patch at the free end with the other end of the foil embedded inside the concrete. This configuration is compared against a piezoelectric ceramic patch directly bonded on the rebar used for reinforcement and another one embedded in the concrete surrounding the rebar. The sensing capability of the proposed metal foil configuration is clearly evident from the coupled admittance signature quantitatively vis-à-vis the other configurations. As a preliminary analysis, root mean square deviation values are employed to monitor the hydration process quantitatively. A piezo-equivalent mechanical model is also developed wherein the piezo-identified mass, stiffness and damping parameters are investigated for the cement hydration process so as to chalk out rigorous quantifiers of hydration progression. The employability of the proposed configuration is further proven by explanation of the physio-chemical products developed during various stage of hydration with step-by-step explanation along with corelation of the piezo-identified mass, stiffness and damping parameters. Overall, the proposed reusable configuration carries a high potential for field deployment in concrete industry for early detection of physio-chemical changes.

New design of piezoelectric plate-type vibrator based on quasi-traveling wave

This paper proposes a novel piezoelectric vibrator using a two-layer rectangular plate with the sizes of 90 × 50 × 20 mm3, to produce quasi-traveling wave in a compact structure. The excited quasi-traveling waves propagate along the surface of a rectangular plate, depending on the superposition of two orthogonal flexural vibration modes with a spatial phase difference of 90°. Piezoelectric ceramic patches are used to excite two working modes of the vibrator. In the study, we first design a mass-block type vibrator (M-type) and a tail type vibrator (T-type), and demonstrate the excitation of quasi-traveling wave on the plate. Second, we design the piezoelectric vibrator and use finite element method (FEM) to perform eigen-frequency degeneration. After that, the designed vibrators, consisting of a two-layer aluminum plate structure with blocks at both ends and eight piezoelectric patches bonded on back surface of the plate, are manufactured and tested. Then experimental characterization of two types of vibrators is carried out, and results are revealed. The excitation and propagation of quasi-traveling wave are also proved by laser vibration test. Our experimental results show that maximum driving amplitude of this piezoelectric plate-type vibrator is 10 μm, the excitation frequency is about 3–18 kHz, and voltage is 50–80 Vpp.

Monitoring early hydration of reinforced concrete structures using structural parameters identified by piezo sensors via electromechanical impedance technique

Abstract Concrete is the most widely used material in civil engineering construction. Its life begins when the hydration process is activated after mixing the cement granulates with water. In this paper, a non-dimensional hydration parameter, obtained from piezoelectric ceramic (PZT) patches bonded to rebars embedded inside concrete, is employed to monitor the early age hydration of concrete. The non-dimensional hydration parameter is derived from the equivalent stiffness determined from the piezo-impedance transducers using the electro-mechanical impedance (EMI) technique. The focus of the study is to monitor the hydration process of cementitious materials commencing from the early hours and continue till 28 days using single non-dimensional parameter. The experimental results show that the proposed piezo-based non-dimensional hydration parameter is very effective in monitoring the early age hydration, as it has been derived from the refined structural impedance parameters, obtained by eliminating the PZT contribution, and using both the real and imaginary components of the admittance signature.

Assessment of human bones encompassing physiological decay and damage using piezo sensors in non-bonded configuration

In the recent years, several biomedical applications of lead zirconate titanate piezo-electric ceramic patches based on the electro-mechanical impedance technique have been reported in the literature. However, practical application of the technique on live subjects is severely hampered due to the requirement of bonding the patch with bone or cartilage with an adhesive. In addition, live subjects have skin cover over the bone. This article proposes and evaluates the feasibility of employing lead zirconate titanate patches as biomedical sensors in non-bonded configuration for assessing the physiological conditions of bones. For this purpose, a special design is proposed where the lead zirconate titanate patch is first bonded on a thin aluminum strip, which is in turn clamped securely on the biomedical subject. The proposed configuration is investigated both in vitro and in vivo. The non-bonded piezo sensors are first investigated to identify dynamic parameters of the bone through lab-based experimental study involving artificial bones. Thereafter, physiological damage and decay conditions are artificially simulated in the experimental bones and the same are correlated with changes in conductance signatures from the non-bonded piezo sensor as well as the lead zirconate titanate patch in the conventional adhesively bonded (direct bonding to the subject) configuration. The trend of the conductance signatures in the healthy and the damaged conditions from the non-bonded piezo sensor is found to correlate well with the corresponding signatures from the directly bonded piezo sensor. At the same time, the repeatability of the signatures is also found to be satisfactory. After success in bare bones, the non-bonded piezo sensor configuration is extended to monitor the condition of bones covered with skin and tissue, simulated in the lab with the aid of silicone-based coating. Finally, a proof-of-concept experiment on a live human subject is successfully demonstrated. The overall results of the study demonstrate very good prospects of employing lead zirconate titanate patches in non-bonded piezo sensor mode for monitoring the condition of human bones and other related biomedical subjects.

Investigation of aggregate size effects on the compressive behavior of concrete by electromechanical and mechanical impedance spectroscopy

Concrete is a composite material that is composed of cement mortar and aggregate. The size of the aggregates in the internal structure of concrete affects the mechanical properties and compressive strength of the concrete. In this study, three-dimensional concrete models are created by idealizing the material properties such as modulus of elasticity and mass density which were experimentally acquired in order to investigate the effect of varying size of the aggregates on the compressive strength of concrete cubes in the age of 28 days. Piezoelectric ceramic patches (PZT) are embedded in the core of the concrete cube models with aggregates in fine, medium, and coarse sizes and the harmonic analyses are simulated in commercial software, ABAQUS® using the multi-physics finite element method (MP-FEA). Eventually, electromechanical impedance spectroscopy (EMIS) results as well as mechanical impedance spectroscopy (MIS) results are obtained to highlight the relative changes in the impedance results depending on the aggregate sizes. Thus, EMIS and MIS simulation results are employed in order to predict the effects of varying aggregate sizes on the compressive strengths of the concrete models.

Experimental mode shape determination of a cantilevered hydrofoil under different flow conditions

The first three mode shapes of a cantilevered NACA0009 hydrofoil were experimentally investigated in air and under different flow conditions in a cavitation tunnel. First and second bending modes and first torsion mode were determined in resonance conditions with the hydrofoil vibrating in air, in still water, in flowing water, or with leading edge sheet cavitation. The hydrofoil was excited with embedded piezoelectric ceramic patches, and the response was measured along the surface at selected positions by means of a laser Doppler vibrometer. The modes of vibration obtained from a cross correlation analysis of the signals were compared for the different conditions, and the most significant differences were identified. In particular, it was found that the mode shape deformation and the location of the nodal lines are dependent on the fluid conditions.

Numerical investigations on energy harvesting potential of thin PZT patches adhesively bonded on RC structures

The reinforced concrete (RC) structures, such as bridges and flyovers, provide a viable platform for ambient vibration energy harvesting. Adhesively bonded thin piezoelectric ceramic (PZT) patches, operating in d31 mode, have recently been demonstrated capable of energy harvesting from ambient vibrations in RC structures in addition to structural health monitoring (SHM). Optimization of energy harvesting warrants detailed parametric investigations, which are, however, infeasible analytically or through experimentation, due to the complex piezo-structure interaction through the bond layer and the sheer large number of the parameters involved. This article investigates the effect of the adhesive bond and the related parameters on the energy harvesting capability of thin PZT patches operating in surface-bonded/embedded configurations bonded onto RC structures. Towards this end, a numerical model is generated for a real-life sized simply supported RC beam instrumented with (a) surface bonded piezo-sensor (SBPS), and (b) embedded PZT patch. Coupled field analysis is performed for both the configurations. Before employing for parametric study, the numerical model is validated with the previously developed analytical model as well as the experimental observations. The numerical model is utilized to investigate the effect of the varying load resistance, the piezo and the bond thicknesses, the patch’s plan dimensions, the shear modulus of the adhesive layer and the presence of the adhesive covering on the voltage/close circuit power generated by the patch. The results of the study show that whereas the surface bonded condition generates higher voltage, the embedded configuration is more desirable from the point of view of dependence on piezo parameters, especially larger thickness, which promises definite beneficial effects. Further, covering the surface bonded patch with an adhesive layer not only offers protection to the patch but also aids in higher voltage and higher power output from it. The results of the study are crucial for practical deployment of PZT patches on RC structures for energy harvesting in addition to SHM.

Interfacial crack-induced debonding identification in FRP-strengthened RC beams from PZT signatures using hierarchical clustering analysis

The Electromechanical Impedance Method (EMI), based on the use of piezoelectric ceramic patches (PZT) constitutes one of the most promising methods for damage detection and location in the Structural Health Monitoring (SHM) field, more particularly for monitoring structures reinforced with novel FRP strengthening techniques. Many efforts have been made to obtain robust and reliable procedures that lead to a successful damage identification of experimental structures in general, but reliable data analysis and rational data interpretation are still challenges to be overcome in the case of debonding detection in strengthened structures, an approach being necessary that allows direct assessment of these experimental structures without the use of numerical models to compare with. In that way, clustering methods are a useful tool since they provide a classification of the data, based on some kind of similarity after a direct comparison between experimental results. With that purpose, in this study an innovative hierarchical clustering analysis has been proposed in order not only to obtain a set of clusters based on damage patterns found in experimental data obtained with PZT sensors, but also to achieve a graphical representation of this information so that the damage identification can be done qualitatively and quantitatively in an intuitive manner. The performance of the proposed approach has been investigated using three experimental tests including a full-scale reinforced concrete beam strengthened with FRP strip.

Non-Destructive Assessment of Rebar Corrosion Based on Equivalent Structural Parameters Using Peizo-Transducers

Occurrence of corrosion in rebars of reinforced concrete (RC) structures is a common problem faced by the ageing infrastructure across the world. This article presents a newly developed approach for detecting and quantifying corrosion of steel bars utilizing a piezoelectric ceramic (PZT) patch surfacebonded on the rebars employing equivalent structural parameters using the electro-mechanical impedance (EMI) technique. This technique utilizes the electromechanical coupling property of piezoelectric materials for a damage diagnosis. Through tests on three steel rebars, empherical relations are derived to relate the corrosion-induced mass and stiffness loss to the loss in the equivalent mass and stiffness identified by the PZT patch. The equivalent mass loss and stiffness loss correlate well with the actual mass loss and stiffness loss and, provide an alternative corrosion assessment paradigm suitable for diagnosing corrosion in steel rebars. The model-based corrosion assessment presented can be utilized for real-life steel structures.

Combined Energy Harvesting and Structural Health Monitoring Potential of Embedded Piezo-Concrete Vibration Sensors

AbstractPiezoelectric materials have proven their efficacy for both energy harvesting and structural health monitoring (SHM) individually. Piezoelectric ceramic (PZT) patches, operating in d31-mode, are considered best for SHM. However, for energy harvesting, built up configurations such as stack actuators are more preferred. The proposed study in this paper provides a proof-of-concept experimental demonstration of achieving both energy harvesting and structural health monitoring from the same PZT patch in the form of concrete vibration sensor (CVS), designed specifically for RC structures. This packaged sensor (CVS), composite in nature, has better compatibility with surrounding concrete and can withstand the harsh conditions encountered during construction. The paper covers experiments carried out in the laboratory environment to measure the voltage and the power generated by a CVS embedded in a life-sized simply-supported RC beam subjected to harmonic excitations. An analytical model is developed to co...

Point load actuation on plate structures based on triangular piezoelectric patches

This paper investigates the design of a perfect point load actuator based on flat triangular piezoelectric patches. Applying a difference of electric potential between the electrodes of a triangular patch leads to point loads at the tips and distributed moments along the edges of the electrodes. The previously derived analytical expressions of these forces show that they depend on two factors: the width over height (b/l) ratio of the triangle, and the ratio of the in-plane piezoelectric properties (e31/e32) of the active layer of the piezoelectric patch. In this paper, it is shown that by a proper choice of b/l and of the piezoelectric properties, the moments can be cancelled, so that if one side of the triangle is clamped, a perfect point load actuation can be achieved. This requires e31/e32 to be negative, which imposes the use of interdigitated electrodes instead of continuous ones. The design of two transducers with interdigitated electrodes for perfect point load actuation on a clamped plate is verified with finite element calculations. The first design is based on a full piezoelectric ceramic patch and shows superior actuation performance than the second design based on a piezocomposite patch with a volume fraction of fibres of 86%. The results show that both designs lead to perfect point load actuation while the use of an isotropic PZT patch with continuous electrodes gives significantly different results.Copyright © 2014 Techno-Press, Ltd.

Influence of adhesive bond layer on power and energy transduction efficiency of piezo-impedance transducer

This article deals with the analysis of the power consumption in the piezoelectric ceramic patch of lead zirconate titanate and the losses arising from the adhesive bonding with the host structure. When a lead zirconate titanate patch is utilized as an impedance transducer in the electromechanical impedance technique, it acts both as a sensor and as an actuator (dual effect) for the range of frequency. Power consumption occurs in two forms. First part of the energy is used to actuate the lead zirconate titanate patch and produce deformations. The other part of the energy is dissipated within the piezo-mechanical system due to the internal mechanical loss and the associated heat generation. The determination of the power consumption characteristics for an active piezo-system is very important for designing an efficient intelligent structure with optimized mass and energy combination. Adhesive bond itself acts as an added stiffness, mass and damper and plays an important role in mechanical and electrical energy conversion. Hence, a detailed investigation is needed to characterize the power consumption and energy issues associated with bond layer driven by lead zirconate titanate patch, which is the main aim of this article.

A continuum based modelling approach for adhesively bonded piezo-transducers for EMI technique

In the electro-mechanical impedance (EMI) technique, which is based on induced strain actuation through piezoelectric ceramic (PZT) patch, the knowledge of shear stress distribution in the adhesive bond layer between the patch and the host structure is very pertinent for reliable health monitoring of structures. The analytical derivation of continuum based shear lag model covered in this paper aims to provide an improved and more accurate model for shear force interaction between the host structure and the PZT patch (assumed square for simplicity) through the adhesive bond layer, taking care of all the piezo, structural and adhesive effects rigorously and simultaneously. Further, it eliminates the hassle of determining the equivalent impedance of the structure and the actuator separately, as required in the previous models, which was approximate in nature. The results are compared with the previous models to highlight the higher accuracy of the new approach. Based on the new model, a continuum based interaction term has been derived for quantification of the shear lag and inertia effects.

Modeling and experimental analysis of the linear ultrasonic motor with in-plane bending and longitudinal mode

A novel linear ultrasonic motor based on in-plane longitudinal and bending mode vibration is presented in this paper. The stator of the motor is composed of a metal plate and eight piezoelectric ceramic patches. There are four long holes in the plate, designed for consideration of the longitudinal and bending mode coupling. The corresponding model is developed to optimize the mechanical and electrical coupling of the stator, which causes an ellipse motion at the contact tip of the stator when the composite vibrations with longitudinal and bending are excited. Its harmonic and transient responses are simulated and inspected. A prototype based on the model is fabricated and used to conduct experiments. Results show that the amplitude of the stator’s contact tips is significantly increased, which helps to amplify the driving force and speed of the motor. It is therefore feasible to implement effective linear movement using the developed prototype.

Feasibility of energy harvesting from thin piezo patches via axial strain (d 31) actuation mode

Energy harvesting and structural health monitoring (SHM) are individually very active research fields in themselves. Piezoelectric materials have the necessary capability to perform both the tasks. Surface bonded plate-type piezoelectric ceramic (PZT) patches operating in d31-mode are considered best for SHM. However, for energy harvesting, built-up configurations such as stack actuators are conventionally preferred. The main objective of this study was to explore the possibility of energy harvesting from thin PZT patches operating in d31-mode, so that the patches can serve for SHM as well as energy harvesting. The voltage and the power generated by a PZT patch bonded in the d31-mode on a simply supported laboratory beam are measured experimentally. A coupled PZT-bond-structure electro-mechanical model is developed for predicting the voltage output across the patch under harmonic vibrations. The losses associated with the PZT patch, namely mechanical damping, electrical damping and the shear lag are included and rigorously quantified. Experimental observations are found to match closely with the theoretical predictions. After laboratory verification, a real life flyover (span 25 m) is modelled using finite element model to estimate the power generated by a plate-type PZT patch surface bonded on a typical city flyover. The power output is found to be in the microwatt range. This energy can possibly be harvested during the idle time of the sensor and utilised later for driving the same patch for SHM.