Piezoelectric Material Layer Research Articles

Innovative method to estimate state of charge of the hydride hydrogen tank: application of fuel cell electric vehicles

ABSTRACT Significant attention has been paid to metal hydrides (MH) as an environmentally friendly and safe way to store hydrogen. This technology has considerable potential for the application of embedded hydrogen storage in fuel cell electric vehicles, but its widespread application faces a major problem in terms of estimating the remaining hydrogen amount in the tank. In this work, a new method is proposed for estimating the state of charge (SoC) of the hydrogen hydride tank (HHT) by application of piezoelectric material. The idea is to cover the entire inner wall of the metal-hydride tank with a layer of piezoelectric material. During the process of hydrogen absorption, the pressure inside the tank increases, resulting in an increase in the mechanical stress applied to the piezoelectric layer, thus generating a voltage. This effect can therefore be used as an effective means of estimating the amount of hydrogen absorbed. The COMSOL Multiphysics software was used to implement the model and solve the differential equation of energy, mass, and moment. The simulation results showed that the voltage evolution as a function of hydrogen concentration follows the same behavior as the variation of the Pressure Concentration Isotherm (PCI).

Comparative study of micro-scale size effects on mechanical coupling factors and SH-wave propagation in functionally graded piezoelectric/piezomagnetic structures

The present paper delves the propagation behavior of horizontally polarized shear waves (SH-wave) influenced by micro-scale size effects in two distinct models i.e. functionally graded piezomagnetic material (FGPMM) layer overlying micropolar substrate (Model I) and functionally graded piezoelectric material (FGPEM) layer overlying micropolar substrate (Model II). The dispersion equations of SH-wave propagating in Model I and II have been deduced for open and short circuit conditions in distinct cases. The results are observed to be in well-agreement with the classical case of dispersion equation of Love wave. Emphatic influence of affecting parameters, viz. material gradient factors, characteristic length, micropolarity, and thickness of piezo material layers on the phase velocities of SH-waves has been analyzed through graphical illustrations. The graphs for mechanical coupling factors and group velocity of SH-wave propagating in the considered composite structures are also scrutinized. The novelty of this article is the comparative study of Model I and Model II on the propagation behavior of SH-wave and mechanical coupling factors.

Response analysis of hybrid functionally graded material plate subjected to thermo-electro-mechanical loading

Static and free vibration response analysis of a functionally graded piezoelectric material plate under thermal, electric, and mechanical loads is done in this study. The displacement field is acquired using the first-order shear deformation theory, and the Hamilton principle is applied to deduce the motion equations. Temperature-dependent material properties of the functionally graded material plate are used, and these properties follow the power-law distributions along the thickness direction. However, the properties of piezoelectric material layers are assumed to be independent of the electric field and temperature. Finite element formulation for the functionally graded piezoelectric material plate is done using the combined effect of mechanical and electrical loads. The effects of parameters like electrical loading, volume fraction exponent N, and temperature distribution on the static and free vibration characteristics of the functionally graded piezoelectric material square plate are analyzed and presented. Responses are obtained in terms of the centerline deflection, axial stress and the nondimensional natural frequency with various boundary conditions. It is observed that the centerline deflection and nondimensional natural frequency increases as exponent N increases. At the same time, the axial stress decreases with an increase in exponent N. The findings of the static and the free vibration analysis suggest the potential application of the functionally graded piezoelectric material plate in the piezoelectric actuator as well as for sensing deflection in bimorph.

Propagation characteristic of Love-type wave in different types of functionally graded piezoelectric layered structure

A mathematical model has been proposed for the analytical study of the propagation of Love-type wave in an initially stressed functionally graded piezoelectric material (FGPM) layer overlying an orthotropic fluid-saturated porous half-space. The expression of dispersion equation is derived in closed form for both electrically open and electrically short conditions. The impact of various affecting parameters viz. wave number, gradient parameter, tensile initial stress on the dispersion curve of Love-type wave has been revealed by means of graphical illustrations. Some remarkable observation has been made through numerical computation for different piezoelectric ceramics of BaTiO, PZT-4 and PZT-5A, respectively. The outcomes of the present study are momentous for both theoretical and practical implication for the surface acoustic wave (SAW) devices.

Influence functions for a hysteretic deformable mirror with a high-density 2D array of actuators.

We present modeling and analysis of a hysteretic deformable mirror where the facesheet interacts with a continuous layer of piezoelectric material that can be actuated distributively by a matrix of electrodes through multiplexing. Moreover, a method to calculate the actuator influence functions is described considering the particular arrangement of electrodes. The results are presented in a semi-analytical model to describe the facesheet's deformation caused by a high-density array of actuators, and validated in a simulation. The proposed modeling of an interconnection layout of electrodes is used to determine the optimal pressures the actuators must exert to achieve a desired surface deformation.

Mathematical analysis of surface wave transference through imperfect interface in FGPM bedded structure

In the present article, a theoretical investigation has been carried out to analyze the propagation of shear horizontal surface waves (SH-waves) in a structure consisting of a functionally graded piezoelectric material (FGPM) layer lying over an FGPM half-space. The material properties of FGPM layer are assumed to have exponential function distribution along the thickness direction whereas those of FGPM half-space are presumed to have quadratic variation. The interface between the FGPM layer and the FGPM half-space has been considered to be imperfect. At the surface, two cases are considered, electrically open case and electrically short case. Moreover two types of imperfections at the interface are taken into account (one as mechanically compliant and dielectrically weakly conducting and other as mechanically compliant and dielectrically highly conducting). Variable separable method is used for the wave solution. In particular, the solutions for mechanical displacement and electric potential function for FGPM half-space has been obtained in the form of modified Bessel function. The dispersion relation for each case is obtained in determinant form using suitable boundary conditions. Numerical example is given and graphs are plotted. The numerical results show that the surface wave velocity is affected by the layer width, gradient coefficient of the two FGPM media, and the degree of mechanical and dielectrical imperfections at the interface between the covering layer and the substrate. This study finds its application in optimization of SAW devices.

Smart control of large amplitude vibration of porous piezoelectric conical sandwich panels resting on nonlinear elastic foundation

In this paper, a nonuniform electric field model is proposed for the smart control of large amplitude vibration of porous piezoelectric conical sandwich panels resting on nonlinear elastic foundation within the framework of von Kármán type of geometrical nonlinearity and the first order shear deformation theory. The conical sandwich panel consists of a viscoelastic core and two porous piezoelectric material layers. By employing Hamilton’s principle, the nonlinear governing equations of porous piezoelectric conical sandwich panels are derived. Then, the semi-analytical solutions are given for the current system by utilizing the harmonic balance method to solve those coupled governing equations. Through numerical results, the influences of the control gain, uniform and nonuniform electric field models, type of porosity distribution, total porosity volume fraction, aspect ratio, linear and nonlinear foundation stiffnesses on the vibration control of porous piezoelectric conical sandwich panels are discussed in details. It is found that the uniform electric field model overrates the damping characteristic of the system with a great total porosity volume fraction when compared with the nonuniform electric field model.

Dynamic control of Euler Bernoulli FG porous beam under thermal loading with bonded piezoelectric materials

In order to develop a mathematical modeling of the smart structure, the study consists of using, in first time, the finite element method and Euler-Bernoulli theory applied to a flexible beam divided into a finite number of elements. For this purpose, we define the beam represented by the imperfect FG material, partially bonded on both surfaces, four thin layers of piezoelectric materials used as sensors/actuators. The effects of temperature and porosity on the dynamics and the active control are studied and discussed. The equations of motion are obtained via Hamilton principle. The structure is modeled analytically and numerically and the optimal LQG control with Kalman filtering is applied. The results of the simulation are presented to visualize the states of the dynamics of the several cases.

A comparative analysis on wave characteristics of viscoelastic rods coated with piezoelectric layer

In this study, longitudinal stress waves of viscoelastic rods bonded with piezoelectric layer are tackled comparatively. The analysis is based on one-dimensional wave theory and various rheological models are considered. The new viscoelastic wave equations that include the effect of piezoelectric material layer are developed. The numerical illustrations of the wave characteristics are presented in detail. Especially, the attenuation illustrations can be regarded as significant novelties of this study for the present literature. This study can be helpful in modelling laminated piezoelectric structures having viscoelastic core as suitable to desired operating conditions.

Analysis of wave scattering in 3-layer piezo composite structure [Pb[Zr x Ti1- x ]O3-ALN-Pb[Zr x Ti1- x ]O3

An analytical model has been considered to study the scattering phenomenon of the quasi-plane wave in functionally graded piezoelectric material (FGPM) layer sandwiched between two similar piezoelectric (PE) media. In more contrast, the effect of material gradient factor on amplitude ratios of various reflected and transmitted waves has been investigated. The composite structure consists of an FGPM layer bonded between two similar transversely isotropic PE half-spaces. It has been shown that incident quasi-longitudinal wave (qP-mode) at lower interface generates reflected and transmitted waves namely qP and quasi-shear vertical waves (qSV-mode). These transmitted waves further give rise to reflected and transmitted waves at the upper interface. At the interfaces of the FGPM layer, the stresses, displacements and electric potential functions are continuous. Due to the scattering of waves, 12 independent amplitude ratios of displacement components are obtained. Amplitude ratios of various reflected and transmitted waves (for the electrically short case) have been obtained by solving a set of linear algebraic equations (using Crammer’s rule). The impact of gradient factor has been examined on amplitude ratios against the angle of incidence and presented graphically. The plot of the slowness section is also demonstrated through graph. In addition, deduced results are compared with the earlier studies and found to be in agreement with the findings.

Anti-plane fracture mechanics analysis of a piezoelectric material layer with strain and electric field gradient effects

The problem of an anti-plane crack in a polarized ceramic layer with both the strain and electric field gradient effects is studied. This model includes two characteristic length parameters l and m which describes the strain gradient and the electric field gradient effects, respectively. The analysis demonstrates that the near-tip asymptotic stress and electric displacement are governed by r−3/2 singularities. Due to stain gradient effect, stresses ahead of the crack tip are significantly higher than those in the classical linear piezoelectricity fracture mechanics. When the strain and electric field gradient parameters decrease to sufficiently small, the solutions reduce to the conventional linear elastic fracture mechanics results. The new contribution of this research is that it includes the effects of the strain gradient and electric field gradient simultaneously for a finite crack in a finite piezoelectric layer.

Characterization of Polarized Shear Waves in FGPM Composite Structure with Imperfect Boundary: WKB Method

Propagation behavior of horizontally polarized shear waves (SH-waves) in a piezo-composite structure is discussed, using the Wentzel–Kramers–Brillouin (WKB) method. The considered model is made by combining the Functionally Graded Piezoelectric Material (FGPM) layer and piezoelectric orthotropic substrate. The linear form spring model is considered to delineate the imperfection of interface. Moreover, the material properties of FGPM layer are varying linearly along the thickness direction. Dispersion relation is obtained for both electrically open and short cases. Numerical example and graphical representation have been provided to illustrate the effect of different parameters on the phase velocity of SH-waves. As a special case, dispersion relation has been obtained when the boundary is perfect. Results are compared for different orthotropic materials to add more specific observations. Finally, the outcome of this study is validated by matching it with classical Love wave result. Observations will be helpful in optimization of Love wave sensors and Surface Acoustic Wave (SAW) devices.

Size-dependent electromechanical responses of a bilayer piezoelectric microbeam

On the basis of the couple stress piezoelectric theory including flexoelectric effects, a size-dependent model of a bilayer microbeam consisting of a piezoelectric material layer and an elastic layer has been established. The governing equations along with the boundary conditions of the microbeam model have been obtained from variation principle. The microbeam bending problems have been solved to analyse the electromechanical coupling responses to the applied concentrated force and voltage. Numerical results show that whether under the concentrated force or the voltage, the influence of flexoelectric effects on the equivalent piezoelectric response is larger than that of rotation gradient elastic effects when the size of the microbeam is much larger than the material length scale parameters. However, with the continuous decrease of the beam characteristic size scale, rotation gradient elastic effects have a stronger impact on the electromechanical responses than flexoelectric effects, which leads to a rapid decrease of the equivalent piezoelectric responses. The result also shows that the contribution of flexoelectric effects on the equivalent piezoelectric response increases when the beam size diminishes, which leads to a significant surge of the electromechanical responses compared to the model under the classical piezoelectric theory.

Effect of interfacial imperfection on shear wave propagation in a piezoelectric composite structure: Wentzel–Kramers–Brillouin asymptotic approach

The primary objective of this article is to investigate the behaviour of horizontally polarized shear (SH) wave propagation in piezoelectric composite structure consisting of functionally graded piezoelectric material layer imperfectly bonded to functionally graded porous piezoelectric material half-space. The linear form of functional gradedness varying continuously along with depth is considered in both functionally graded piezoelectric material layer and functionally graded porous piezoelectric material half-space. The interface of the composite structure is considered to be damaged mechanically and/or electrically. Wentzel–Kramers–Brillouin asymptotic approach is adopted to solve the coupled electromechanical field differential equations of both functionally graded piezoelectric material layer and functionally graded porous piezoelectric material half-space. An analytical treatment has been employed to determine the dispersion relations of propagating SH-wave for both electrically short and electrically open conditions, which further reduced to the pre-established and classical results as special case of the problem. The effect of various affecting parameters, namely, functional gradedness, wave number, mechanical/electrical imperfection parameters in the presence and absence of porosity on the phase velocity of SH-wave, has been reported through numerical computation and graphical demonstration. In addition, the variation of the coupled electromechanical factor with dimensionless wave number and cut-off frequency with different modes of propagation of wave for electrically short and electrically open cases has also been discussed.

Active vibration control of a smart functionally graded piezoelectric material plate using an adaptive fuzzy controller strategy

In this article, the active vibration control of a smart structure made out of a single functionally graded piezoelectric material layer, equipped with a network of discrete electrodes, is studied. The material properties vary continuously across the direction of thickness, so that top and bottom surfaces consist of pure PZT4 and the mid surface is composed of pure aluminium. The percolation phenomenon is taken into account. A functionally graded piezoelectric material plate finite element based on the first-order shear deformation theory hypothesis and layer-wise approximation for electric potential is implemented. An optimization procedure is considered to define the relevant electrodes for actuators and sensors, based on controllable and observable criteria. An adaptative fuzzy controller system is used, activating with relevance the actuators according to the most excited eigenmodes. Simulations show the effectiveness of this kind of concept.

Characterization of a PiezoMUMPs Microsensor for Contactless Measurements of DC Electrical Current

This paper presents an integrated sensor able to perform contactless measurements of dc electrical current. The microsensor conceived is based on the PiezoMUMPs technology which embeds a layer of piezoelectric material thus offering a mechanoelectric transduction of the measurand: the dc electrical current flowing into a wire external to the microsensor is here converted into a voltage signal without the need of auxiliary polarization signals or integrated inductors/coils as in the case electrostatic and electromagnetic devices, respectively. A prototype of the MEMS device has been designed, modeled, numerically simulated, and then fabricated. A measurement campaign allowed validating the sensor and to characterize its performances.

Dispersion of Love waves in size-dependent substrate containing finite piezoelectric and viscoelastic layers

The dispersion properties of Love waves are utilized for the fabrication of sensor devices in the different material environments. This study involves the propagation of Love wave in a double-layered structure consisting of two finite layers of viscoelastic and piezoelectric material lying over the semi-infinite size-dependent micropolar substrate. The bottom substrate of the structure is modeled as, the material with microstructural properties. The real and damping dispersion relations are obtained analytically in closed form expression under both the cases of electrically open and short conditions. The coupling constant and characteristic length that describe the effect of the microstructure of the micropolar substrate, are studied graphically on Love wave propagation. The effects of piezoelectric layer are shown by considering two different materials of a piezoelectric layer, i.e., $$PZT-5H$$ or $$BaTiO_3$$ , along with the internal friction and heterogeneity parameter associated with a viscoelastic layer. The numerical computation and the graphs are given for aluminium-epoxy (substrate), viscoelastic material and $$PZT-5H$$ or $$BaTiO_3$$ (piezoelectric layer). Some of the particular cases are derived from the study by using different relevant conditions.

Propagation of SH waves in corrugated FGPM layer lying over a piezomagnetic half-space

Present article aims to study the propagation of horizontally polarized shear waves (SH waves) in Functionally Graded Piezoelectric Material (FGPM) layer. The considered FGPM layer is lying over a piezomagnetic half-space with corrugated interface. The material properties of FGPM layer are assumed to have exponential function distribution along the -axis. Two cases are considered - electrically and magnetically open case and electrically and magnetically short case. Dispersion relations are obtained in determinant form. Numerical example has been provided for graphical representation of findings. This study provides a theoretical foundation for optimization of Surface Acoustic Wave (SAW) devices.

Dynamic stability and nonlinear vibration of rotating sandwich cylindrical shell with considering FG core integrated with sensor and actuator

In this research, the dynamic stability and nonlinear vibration behavior of a smart rotating sandwich cylindrical shell is studied. The core of the structure is a functionally graded material (FGM) which is integrated by functionally graded piezoelectric material (FGPM) layers subjected to electric field. The piezoelectric layers at the inner and outer surfaces used as actuator and sensor, respectively. By applying the energy method and Hamilton\'s principle, the governing equations of sandwich cylindrical shell derived based on first-order shear deformation theory (FSDT). The Galerkin method is used to discriminate the motion equations and the equations are converted to the form of the ordinary differential equations in terms of time. The perturbation method is employed to find the relation between nonlinear frequency and the amplitude of vibration. The main objective of this research is to determine the nonlinear frequencies and nonlinear vibration control by using sensor and actuator layers. The effects of geometrical parameters, power law index of core, sensor and actuator layers, angular velocity and scale transformation parameter on nonlinear frequency-amplitude response diagram and dynamic stability of sandwich cylindrical shell are investigated. The results of this research can be used to design and vibration control of rotating systems in various industries such as aircraft, biomechanics and automobile manufacturing.

Approximation of surface wave velocity in smart composite structure using Wentzel–Kramers–Brillouin method

In mathematical physics, the Wentzel–Kramers–Brillouin approximation or Wentzel–Kramers–Brillouin method is a technique for finding approximate solutions to linear differential equations with spatially varying coefficients. An attempt has been made to approximate the velocity of surface seismic wave in a piezo-composite structure. In particular, this article studies the dispersion behaviour of Love-type seismic waves in functionally graded piezoelectric material layer bonded between initially stressed piezoelectric layer and pre-stressed piezoelectric half-space. In functionally graded piezoelectric material stratum, theoretical derivations are obtained by the Wentzel–Kramers–Brillouin method where variations in material gradient are taken exponentially. In the upper layer and lower half-space, the displacement components are obtained by employing separation of variables method. Dispersion equations are obtained for both electrically open and short cases. Numerical example and graphical manifestation have been provided to illustrate the effect of influencing parameters on the phase velocity of considered surface wave. Obtained relation has been deduced to some existing results, as particular case of this study. Variation in cut-off frequency and group velocity against the wave number are shown graphically. This study provides a theoretical basis and practical utilization for the development and construction of surface acoustics wave devices.