Piezoelectric Resonance Frequency Research Articles

A Hybrid Actuator Model for Efficient Guided Wave based Structural Health Monitoring Simulations

Abstract Simulation has been recognized as a promising option to reduce the time and costs associated with determining Probability of Detection (POD) curves to demonstrate the performance of Guided Wave based Structural Health Monitoring (GW-SHM) systems. Time domain transient spectral finite element schemes have been used for large GW-SHM simulation campaigns, but the most common piezoelectric transducer model used for actuation, the pin force model, has limitations in terms of its range of validity. This is because the excitation frequency for the pin force model has only been validated far below the first electromechanical resonance frequency of the piezoelectric transducer mainly due to not considering the normal stress and dynamics of the transducer. As a result, the value of simulation tools for performance demonstrations may be limited. To address this limitation, this paper introduces a Hybrid Actuator Model that integrates frequency-dependent complex interfacial stresses in both the shear and normal directions, computed using finite elements. These surface stresses are compatible with time domain transient spectral finite element schemes, enabling their seamless integration without compromising the required performance for conducting intensive simulation campaigns. The proposed hybrid actuator model undergoes validation through a combination of simulation and experimental studies. Additionally, a comprehensive parametric study is conducted to assess the model's validity across a wide range of excitation frequencies. The results demonstrate the accurate representation of the transduction signal above the piezoelectric transducer's first free electromechanical resonance frequency.

RF oscillator circuit for absorption coefficient measurement of piezoelectric materials.

We have introduced an approach for low optical absorption coefficient measurement of piezoelectric materials based on the piezoelectric resonance laser calorimetry (PRLC) method. An RF oscillator circuit provides a convenient way to track the piezoelectric resonance frequency during laser irradiation. In this work, the optical absorption coefficient of lithium triborate crystal under high-power IR laser irradiation was measured using the oscillator circuit and the conventional PRLC technique.

Sound Transmission Loss of Metamaterial Honeycomb Core Sandwich Plate Elastically Connected with Periodic Subwavelength Arrays of Shunted Piezoelectric Patches.

Honeycomb core sandwich plates are widely used as a lightweight, high-strength sound insulation material. However, they do not perform well in specific frequency bands. Acoustic metamaterials can break the law of mass in specific frequency bands and have high sound transmission loss (STL); however, the resonance frequency is difficult to regulate. To solve this problem, this paper first proposes an infinitely large metamaterial honeycomb core sandwich plate, which can generate newly tuned piezoelectric resonance frequencies, and we study its STL. The structure has piezoelectric patches arranged in sub-wavelength arrays with inductance shunting circuits that are elastically connected to both sides of the honeycomb core sandwich plate. The effective dynamic mass density and effective dynamic bending stiffness of the metamaterial plates were obtained using the effective medium (EM) method. A theoretical model for the numerical calculation of oblique STL and diffuse-field STL was established by the structural bending wave method. The finite element simulation method was used to verify that the metamaterial plates can generate three peaks at 1147 Hz, 1481 Hz and 1849 Hz in oblique or diffuse-field STL curves, which reached 57 dB, 86 dB and 63 dB, respectively, and are significantly better than the plate rigidly connected with piezoelectric sheets and the bare plate with the same mass. In order to better understand the characteristics of STL, the explicit functions of the resonance frequencies were derived. Key influencing factors were analyzed, and the regulation law of new piezoelectric resonance frequencies was clarified.

Temperature dependence of the piezoelectric resonance frequency in relation to the anomalous strain near the incommensurate phase of quartz

The temperature dependence of the piezoelectric resonance frequency is analyzed by the power-law formula in the vicinity of the critical temperature of the incommensurate (INC) phase in quartz using the experimental data from the literature. By considering the piezoelectric resonance frequency as an order parameter of the INC phase, correlation between the piezoelectric resonance frequency and the strain is constructed, which both decrease linearly with increasing temperature toward Tc in quartz. Our results can explain dynamics of the ordering mechanism in the INC phase (within a very narrow temperature interval between the α and β phases of quartz) and suggest a second order transition from INC to the β phase in quartz.

Modeling and Analysis of Multiple Attached Masses Tuning a Piezoelectric Cantilever Beam Resonant Frequency

Mechanical vibrations have been an important sustainable energy source, and piezoelectric cantilevers operating at the resonant frequency are regarded as one of the effective mechanisms for converting vibration energy to electricity. This paper focuses on model and experimental investigations of multiple attached masses on tuning a piezoelectric cantilever resonant frequency. A discrete model is developed to estimate the resonant frequencies’ change of a cantilever caused by multiple masses’ distribution on it. A mechanism consisted of a piezoelectric cantilever with a 0.3 g and a 0.6 g movable mass along it, respectively, is used to verify the accuracy of the proposed model experimentally. And another mechanism including a piezoelectric cantilever with two 0.3 g attached masses on it is also measured in the designed experiment to verify the discrete model. Meanwhile, the results from the second mechanism were compared with the results from the first one in which the single attached mass is 0.6 g. Two mechanisms have wildly different frequency bandwidths and sensitivities although the total weight of attached masses is the same, 0.6 g. The model and experimental results showed that frequency bandwidth and sensitivity of a piezoelectric cantilever beam can be adjusted effectively by changing the weight, location, and quantity of attached masses.

Contactless excitation of ZnO based piezoelectric device

In this paper the design and evaluation of performance of a contactless electric field transmission framework for excitation of piezoelectric/piezo-electric component using lead free piezoelectric material Zinc Oxide (ZnO) is described. In the proposed strategy, a parallel-plate capacitor structure is planned with two aluminium electrodes equidistantly placed with lead (Pb) free piezoelectric component aligned along the central axis of the electrodes gap. It has been seen that piezoelectric component is contactless energized as a result of both electric plus piezoelectric resonance. They are widely used in modern industries because of their atypical electromechanical coupling properties, quick response, and compact size. The electromechanical coupling (k332)factor is the numerical measure of conversion capacity of piezoelectric material from electrical to vibration and vice-versa. When the operating frequency of the parallel plate electric field (Efield) generator matches with the piezoelectric plate mechanical resonance frequency (fm) then maximum vibrational displacement is obtained across the piezoelectric plate. The maximal output power obtained across the contactless excited piezo-electric component depends upon operating frequency, and gap between the electrodes. The maximal output power (Pout) of 0.49 mW is obtained across piezoelectric plates at resonance frequency of 700 KHz with input voltage of 50 V input and 4 mm live and ground electrodes gap.

Conditions of application of LiNbO3 based piezoelectric resonators at high temperatures

We have researched piezoelectric, dielectric properties and ion conductivity in near-stoichiometric LiNbO3 crystals (NSLN) in order to establish conditions for application of LiNbO3 based piezoelectric resonators in the high-temperature region (∼300–850 K) which implies high conductivity. NSLN crystals have been grown from a congruent melt (R=Li/Nb≈0.946) with 5.5 wt% K2O flux. We have revealed that piezoelectric resonance in NSLN crystals appears in a certain temperature range ΔT and resonance frequencies ΔωR provided that τV−1≪ωR. The temperature range ΔT corresponds to certain values of conductivity (Δσ) and relaxation time (ΔτV) range. We have concluded that application of high-temperature piezoelectric resonators based on crystal NSLN is possible at certain kinetic parameters of charge transport in a temperature range ΔT and at piezoelectric resonance frequencies corresponding to the temperature range.

Use of Flat Ribbon like Electrode Geometry to Pole PVDF Piezoelectrics in Solution Processing

We study how ribbons of fluids subjected to electric fields can serve applications in energy harvesting. In particular the emphasis is on how the geometry (i.e. 2-D ribbons) can influence functionality. For applications related to energy harvesting, we consider the use of polymer Piezo-electric Polyvinylidene Fluoride (PVDF). Corona poling, photo-induced, photo-thermal and electron beam poling are the different conventional techniques used for PVDF poling. The parallel plate capacitor structure made for poling the PVDF material while the PVDF is being cured. One key advantage of preparing PVDF is the ability of solution processing. Normally, the liquid is then spin coated on a substrate and left to dry. Either during the process of spin coating, or after drying - the film of PVDF is poled so as to align the dipoles and make a piezoelectric. We propose the use of a metal-insulator ribbon like electrode geometry to combine the process of fabrication and poling thereby making the process more efficient. On the application of a voltage across the electrodes, the voltage of Vs is developed across the fluid. This result in a field of Vs/d across the PVDF fills aiding the process of poling while the film is in liquid phase. Therefore the ribbon like geometry aids the use of PVDF piezo-electrics in two ways. Firstly, it makes the fabrication process efficient by combining the poling with the structure development. Secondly, the control of width (w) and length (l) aids the setup of the PVDF piezoelectric resonant frequency for a given thickness (d). This helps match the resonant frequency of the ribbon with the incoming low frequency vibration to improve the energy harvesting levels. Piezo-electrics can be used in submerged applications, large area PVDF energy scavengers, mechanical filters and sensors, rural electrification, and charging circuits for hand-held devices.

Elastic properties and frequency performance of a novel 3–0-type three-component composite

A three-component 3–0-type composite based on the ferroelectric PZT-type ceramic is studied to show the elastic properties and their links to the piezoelectric properties and resonance frequencies. The corundum ceramic is used as a component with a large elastic stiffness, and in the presence of this component, almost equal volume fractions of corundum mc and air pores mp are achieved at 0.05 < mc < 0.18. This influences the elastic and other properties of the studied composite. Experimental results on its performance are interpreted in terms of a model wherein an interaction between the 3–0 ferroelectric ceramic/corundum and 3–0 ferroelectric ceramic/air regions plays the important role. A correlation between the elastic and piezoelectric anisotropy factors is observed, and the anisotropy of the piezoelectric coefficients / ≈ −4 is stated at mc > 0.10. The studied composite is of interest as an active element of piezoelectric transducers and sensors.

Equivalent Surface Temperature of Optical Elements Interacting with Laser Irradiation

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Piezoelectric Unimorphs Dynamic Response Measurement

The paper deals with the experimental methods of determination of piezoelectric unimorph resonant frequencies essential for a design of acoustical systems. The characterization of piezoelectric unimorphs and their significant properties are brought in. Three broadband methods of determination of unimorph frequency response based on measurement of electrical impedance, acoustic pressure and vibration velocity are presented. The supposed methodology is verified by measurement of three unimorph samples. The efficiency and practical applicability of each method are further discussed.

Piezoelectric Resonance in KH2PO4 Type Crystals Revisited

Within the framework of proton model with taking into account the piezoelectric interaction with the shear strain , a dynamic dielectric response of KH2PO4 family ferroelectrics and anti­fer­roelectrics is considered. Piezoelectric resonance frequencies of rectangular thin plates of the crystals cut in the (001) plane (0 Z-cut) are calculated, which are found to be in a good agreement with experiment.

Sensitivity and Noise Evaluation of a Bonded Magneto(elasto) Electric Laminated Sensor Based on In-Plane Magnetocapacitance Effect for Quasi-Static Magnetic Field Sensing

The quasi-static magnetic field detection of a layer-bonded magneto(elasto) electric (ME) laminate has been investigated by measuring the in-plane electric capacitance via its interdigital electrodes close to the piezoelectric resonant frequency. The ME-layered composite is considered as a stress-induced dielectric effect because there is practically no direct response of the electric capacitance to an external magnetic field. The sensitivity is dominated by the magnetoelastic coupling in the magnetic layer and on the stress induced by the permittivity change in the piezoelectric layer. The low-frequency magnetocapacitance effect is sensitive to an external magnetic bias which can modulate the electric permittivity by producing a stress. The magnetoelastic coupling is another important parameter for this magnetic field detection mode. For a given magnetic field, the amplitude of the magnetostriction is directly related to this parameter as well. Therefore, an optimal magnetic bias can maximize the induced strain or stress which is coupled into the piezoelectric layer through the change of the electric permittivity in this layer. To evaluate the sensitivity and the noise performance by the magnetocapacitance effect, we have used the piezoelectric and magnetic constitutive equations to predict the permittivity dependence. Experimentally, this sensor achieved an equivalent magnetic noise spectral density, presently still limited, by the noise of the detection electronics, ~100 pT/√Hz at 1 Hz and offered a dc detection capability. With the model and experimental nonlinear factors, an equivalent sensor noise spectral density close to the pT/√Hz can be ultimately predicted considering the mechanical loss limitation of the sensor.

Novel method for identification of intrinsic vibration modes in piezoelectric crystals

Novel method for identification of intrinsic vibration modes in piezoelectric crystals is introduced. This method is based on recently proposed theoretical model of piezoelectric resonance frequencies dependence on temperature. Calculation of crystal sample eigenmodes is based on Lagrange-Hamilton variation principle. Comparison of temperature dependencies of calculated resonance frequencies with measured ones reveals reliable method for identification of vast majority of the experimentally observed resonances. Influence of sample sizes variation on eigenmode frequencies is also considered.

Origin of temperature independent piezoelectric coefficient in Pb(Mg1/3Nb2/3)O3-BaTiO3-PbTiO3 ceramics

The temperature dependence of piezoelectric resonance frequency, dielectric, and piezoelectric properties of (65-x)[Pb(Mg1/3Nb2/3)O3]–xBaTiO3-35PbTiO3 (x = 0, 1, 2, 3) ceramics has been investigated. Sample compositions with x = 2 and 3 were found to exhibit a large piezoelectric response. Particularly, d31 value was nearly a constant over a temperature range from 150 to 325 K. A broad ferroelectric phase transition tuned by BaTiO3 ratio in the sample was deduced from the dielectric constant, piezoelectric resonance frequency, and Raman spectra. The temperature dependence of the Raman modes wavenumber positions and intensities provides a clear evidence for the occurrence of the phase transition. The temperature-stable piezoelectric response was attributed to the counter-balance of contributions from the dielectric and elastic responses.

Overlap of the intrinsic and extrinsic magnetoelectric effects in BiFeO3-PbTiO3 compounds: Potentialities for magnetic-sensing applications

The potentialities of BiFeO3-PbTiO3 multiferroic compounds for magnetic-field sensing applications is investigated by characterizing the dynamical magnetoelectric response of La doped (0.6)BiFeO3-(0.4)PbTiO3 piezoceramics. The results are compared with those obtained in Nb doped (1 wt. %) PbZr0.53Ti0.47O3 (PZT-5A) piezoceramics and the observed non-linearity of the oscillating voltage response of (0.6)BiFeO3-(0.4)PbTiO3 piezoceramics is attributed to the overlapping of the intrinsic and extrinsic magnetoelectric effects that were successfully decoupled by analyzing the in-phase and out-of-phase voltage components relative to applied oscillating magnetic field. For an alternating cosine-like magnetic field of 0.32 Oe, at the piezoelectric resonance frequency (184.2 kHz), the alternating voltage response decreases from 7.77 mV, at −10 kOe, to 2.71 mV, at 1.8 kOe, to subsequently increases until 5.97 mV at 10 kOe. This non-linear voltage response, which can be easily converted into a linear signal by using the phase difference, can be used for static magnetic field sensing in a wide range of magnetic fields.

Electro-optic effect of lithium niobate in piezoelectric resonance

The electro-optic (EO) effect of a lithium niobate (LN) single crystal was analyzed around a piezoelectric resonance frequency. The EO-coefficient of the LN resonator was measured as a function of frequency. The EO-coefficient around piezoelectric resonance frequency varied with a maximum and a minimum in the frequency dependence. To explain the frequency dependence of the EO-coefficient, three effects were considered: (1) the intrinsic EO-effect excluding the effect of piezoelectric resonance, (2) the change of optical pass length due to piezoelectric displacement, and (3) the photo-elastic effect due to piezoelectric strain. The maximum of the EO-coefficient corresponded to the maximum of piezoelectric displacement at the resonance frequency, while the minimum was caused by the phase-lag between applied sinusoidal electric field and piezoelectric displacement. A new equation including the three effects as well as the phase-lag was formulated to represent the EO-effect of piezoelectric crystals. The equation gave a good agreement in the fitting of calculation to the observation.

Quadratic electro-optic properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 transparent ceramics under both DC and AC bias

The basic quadratic electro-optic properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) transparent ceramics have been studied under both DC and AC electric field bias. The contribution of piezoelectric resonance to electro-optic effect for this quadratic electro-optic ceramics material has been experimentally demonstrated and theoretically analyzed. It is found that, at the piezoelectric resonance frequencies, the piezoelectric induced electro-optic effect dominates and leads to a dramatically high sensitivity for weak electric signal detection. About 20 dB signal-to-noise ratio is attained when detecting AC electric field strength of 1 V/m with optimized DC bias. Besides, the effects of AC frequency and amplitude on halfwave voltage V(π) of PMN-PT are investigated.

Magnetic field dependence of piezoelectric resonance frequency in CoFe2O4–BaTiO3 composites

The particulate and the multilayer CoFe2O4(CFO)–BaTiO3(BT) composites were prepared by the conventional solid state reaction method and the tape casting method, respectively. Both the prepared composites were simultaneously ferroelectric and ferromagnetic at room temperature. For the multilayer composite sample, a piezoelectric resonance frequency remarkably depended on the applied DC magnetic field, while no remarkable magnetic field dependence was observed for the particulate composite samples. An uniform magnetostriction of the CFO phase in the multilayer composite contributes to piezoelectric effect of the BT phases, resulting in the modulation of the piezoelectric resonance frequency.

Acoustic spin pumping: Direct generation of spin currents from sound waves in Pt/Y3Fe5O12 hybrid structures

Using a Pt/Y3Fe5O12 (YIG) hybrid structure attached to a piezoelectric actuator, we demonstrate the generation of spin currents from sound waves. This “acoustic spin pumping” (ASP) is caused by the sound wave generated by the piezoelectric actuator, which then modulates the distribution function of magnons in the YIG layer and results in a pure-spin-current injection into the Pt layer across the Pt/YIG interface. In the Pt layer, this injected spin current is converted into an electric voltage due to the inverse spin-Hall effect (ISHE). The ISHE induced by the ASP is detected by measuring a voltage in the Pt layer at the piezoelectric resonance frequency of the actuator coupled with the Pt/YIG system. The frequency-dependent measurements enable us to separate the ASP-induced signals from extrinsic heating effects. Our model calculation based on the linear response theory provides us with a qualitative and quantitative understanding of the ASP in the Pt/YIG system.