Piezoelectric Patches Research Articles

Dual-Function Cloak of Edge Target in Metamaterial Plate with Active Intelligent Control

Wave invisibility has attracted great attention because of its significant influences on mechanical, acoustic, and many other fields, and it has a great potential application to practical engineering. In this work, a dual-function cloak is proposed in which there is an edge object with an intelligent control system in an elastic wave metamaterial plate. Based on the image and scattering cancellation methods, the scattering mode coefficients are derived. The effects of material and structural parameters on dynamic stress concentration and scattering amplitude are investigated. The cloaking configuration consists of concentric layers of piezoelectric (lead–zirconate–titanate [PZT]) patches, which are connected with the intelligent control system. The theoretical and experiment results show that the dual-function cloak can effectively reduce the dynamic stress concentration and scattering amplitude. Compared to the range from 100 to 450 Hz for the original structure without a control system, the effective frequency range of the intelligent cloak can be extended from 100 to 500 Hz. The present design with both strength enhancement and invisibility of the edge target is expected to provide new ideas for the development of mechanical metamaterials and novel structures.

Analysis of damage control of thin plate with piezoelectric actuators using finite element and machine learning approach

In recent studies, piezoelectric actuators have been recognized as a practical and effective material for repairing cracks in thin-walled structures, such as plates that are adhesively bonded with piezoelectric patches due to their electromechanical effects. In this study, we used the finite element method through the ANSYS commercial code to determine the stress intensity factor (SIF) at the crack tip of a cracked plate bonded with a piezoelectric actuator under a plane stress model. By running various simulations, we were able to examine the impact of different aspects that affect this component, such as the size and characteristics of the plate, actuator, and adhesive bond. To optimize performance, we utilized machine learning algorithms to examine how these characteristics affect the repair process. This study represents the first-time machine learning has been used to examine bonded PZT actuators in damaged structures, and we found that it had a significant impact on the current problem. As a result, we were able to determine which of these parameters were most helpful in achieving our goal and which ones should be adjusted to improve the actuator's quality and reduce significant time and costs.

Study of Electrospun PVDF/GO Nanofibers as a Conductive Piezoelectric Heart Patch for Potential Support of Myocardial Regeneration

AbstractHeart patches are currently being utilized to repair damaged myocardium and are a promising way to address the limitations of current therapeutic strategies. Given the electromechanical nature of cardiac tissue, conductive or piezoelectric materials are of interest to researchers. An electrospinning method is used to synthesize and evaluate polyvinylidene fluoride/graphene oxide (PVDF/GO) nanocomposites. Effects of GO concentration (0, 0.1, 0.3, 0.5, 0.7, and 1 wt%) on the main physical‐mechanical characteristics of the patch are studied. Results show nanofibers containing 0.7 wt% GO with a diameter of 857 ± 168 nm, provide excellent tensile strength (0.51 ± 10.34 MPa). Fourier transform infrared and X‐ray diffraction analysis confirm the increase of the β‐polymer phase by adding 1 wt% of GO from 63% to 86%. However, the highest output voltage in the piezoelectric shock test is recorded at 9.44 V for a concentration of 0.5 wt%, which is increased by 8.2 times compared to the neat PVDF. In addition, human umbilical vein endothelial cell culture on the electrospun patches confirmed no toxicity as well as increased cell growth and proliferation (3.4 times) over 7 d. The developed material has the potential to be utilized as a heart patch due to its promising characteristics.

Advances in Tunable Bandgaps of Piezoelectric Phononic Crystals.

Bandgaps of traditional phononic crystals (PCs) are determined using structural geometric parameters and material properties, and they are difficult to tune in practical applications. Piezoelectric PCs with lead zirconium titanate piezoelectric ceramics (abbreviated to piezoelectric PCs) have multi-physics coupling effects and their bandgaps can be tuned through external circuits to expand the application range of the PCs. First, the typical structures of piezoelectric PCs are summarized and analyzed. According to the structure, common tunable piezoelectric PCs can be roughly divided into three categories: PCs that only contain piezoelectric materials (single piezoelectric PCs), PCs composed of embedded piezoelectric materials in elastic materials (composite piezoelectric PCs), and PCs that are composed of an elastic base structure and attached piezoelectric patches (patch-type piezoelectric PCs). Second, the tuning methods of bandgaps for piezoelectric PCs are summarized and analyzed. Then, the calculation methods of the bandgaps of piezoelectric PCs are reviewed and analyzed. Finally, conclusions are drawn on the research status of piezoelectric PCs, shortcomings of the existing research are discussed, and future development directions are proposed.

Flow-induced reconfiguration and cross-flow vibrations of an elastic plate and implications to energy harvesting

We numerically study flow-induced vibrations (FIV) of an elastic cantilevered plate in a cross-flow configuration. The plate is kept upright in an open domain with a fixed bottom end. Such a configuration eliminates energy losses in the wall boundary. Due to allowed vortex shedding from its bottom end, the resulting novel dynamics of the fluid-structure interaction (FSI) system is explored. An in-house sharp-interface immersed boundary method-based flow solver, coupled with a Saint-Venant Kirchhoff material model-based open-source finite element solver, is employed. Two sets of simulations were carried out in two-dimensional Cartesian coordinates at Reynolds number of 100 for a wide range of reduced velocity (UR), by performing a parametric sweep of dimensionless Young’s modulus (E) and mass ratio (M). In general, FIV characteristics of the plate are similar to the transverse vortex-induced vibration of an elastically-mounted cylinder. The plate deforms to a curved mean position depending on E and M and exhibits angular oscillations. In particular, the following FIV regimes are obtained with increasing UR: initial excitation, lock-in with the first mode, desynchronization after the first lock-in, lock-in with the second mode, and desynchronization after the second lock-in. During lock-in, the plate oscillation and vortex shedding frequency are closer to the first or second mode natural frequency of plate. A larger angular amplitude and increased energy exchange between the structure and fluid characterize the lock-in. We quantify the modal contributions of Euler-Bernoulli modes in the plate’s vibration response with a curved mean position. The spatiotemporal variation of energy exchange between the fluid and plate is analyzed to understand the observed plate dynamics. The flow physics of the wake is discussed using wake patterns, vortex formation length, and vortex strength. Drag over the plate reduces due to flow-induced reconfiguration and strongly correlates with these parameters. Lastly, based on the spatial distribution of strain energy density over the plate, we present a potential design for an ambient fluid energy harvester to harness the plate’s vibration energy with optimized piezoelectric patching. The optimum location and height of a piezoelectric patch on the plate for different cases are reported.

Piezoelectric power generation from tyres

The piezoelectric effect enables the conversion of mechanical energy, resulting from the contact between a vehicle's wheel and the road, into electrical energy. Piezoelectricity refers to the accumulation of electric charge in specific solid materials, such as ceramics, human bone, and DNA, in response to mechanical stress. The objective of this project is to enhance electricity generation in an environmentally friendly manner. By utilizing technological advancements, it becomes possible to convert wasted vibrational mechanical energy from the vehicle's tire into electrical energy, leading to both cost-effectiveness and environmental sustainability. To achieve this, piezoelectric patches are strategically positioned within the wheel rim. When these patches come into contact with the road and are subjected to the weight of the vehicle, electricity is generated. In our project, we will employ polyurethane foam to safeguard the piezoelectric patches, which will be situated inside the bicycle's tire. This setup aims to generate sufficient energy to charge a battery. Consequently, the electrical energy stored in the wheels will be transformed into light energy through the utilization of the piezoelectric patches.

An experimental and theoretical piezoelectric energy harvesting from a simply supported beam with moving mass

The feasibility of harvesting electrical energy from mechanical vibration is demonstrated in the thesis. In the technique, energy is harvested from simply supported beam vibration under a moving mass using a thin piezoelectric material.The structure is represented by a basic beam of length L that is supported at both ends and traversed by a moving mass M travelling at a constant velocity v. The Euler-Bernoulli differential equation describes its behaviour. The dynamic analysis of a beam is performed by using three moving masses of (35.61, 65.81, and 79.41) gr each travelling three uniform speeds of (1.6, 2 and 2.4) m/s. A differential equation of the electromechanical system is obtained by transforming the piezoelectric constitutive equation and solved numerically by MATLAB.The results indicate that the numerical and experimental values for the midpoint deflection of the beam and the piezoelectric voltage are very close.Using the COMSOL programme, the proposed approach is checked by comparing results with data obtained by the finite element method (FEM). An experimental setup was also built and constructed to determine the voltage created by the piezoelectric patch and the beam response as a result of the mass travelling along the beam.The results show that the dynamic deflection, piezoelectric voltage, and piezoelectric energy harvesting all increase as the speed and magnitude of the moving mass increase. The harvesting power vs. load resistance curve begins at zero, increases to a maximum value, and then remains almost constant as the resistance is increased further. The optimal length of the piezoelectric patch was obtained to be 0.63 m. When the length of the beam increases, the resonant frequency decreases, and at the same time the harvested energy increases. However, increasing the beam thickness has the opposite effect; whereas raising the beam width does not affect the resonant frequency but decreases energy harvesting.The most essential point here is the need to have correctly built scale models. They can provide a substantial amount of information at a low cost, accommodate a variety of test settings, and aid in the selection and verification of the most effective analytical model to resolve the actual issue.

Enhancing Electrical Generation Efficiency through Parametrical Excitation and Slapping Force in Nonlinear Elastic Beams for Vibration Energy Harvesting.

This study aims to enhance conventional vibration energy harvesting systems (VEHs) by repositioning the piezoelectric patch (PZT) in the middle of a fixed-fixed elastic steel sheet instead of the root, as is commonly the case. The system is subjected to an axial simple harmonic force at one end to induce transversal vibration and deformation. To further improve power conversion, a baffle is strategically installed at the point of maximum deflection, introducing a slapping force to augment electrical energy harvesting. Employing the theory of nonlinear beams, the equation of motion for this nonlinear elastic beam is derived, and the method of multiple scales (MOMS) is used to analyze the phenomenon of parametric excitation. This study demonstrates through experiments and theoretical analysis that the second mode yields better power generation benefits than the first mode. Additionally, the voltage generation benefits of the enhanced system with the added baffle (slapping force) surpass those of traditional VEH systems. Overall, the proposed model proves feasible and holds promising potential for efficient vibration energy harvesting applications in various industrial sectors.

Multi-Damage Detection in Composite Space Structures via Deep Learning.

The diagnostics of environmentally induced damages in composite structures plays a critical role for ensuring the operational safety of space platforms. Recently, spacecraft have been equipped with lightweight and very large substructures, such as antennas and solar panels, to meet the performance demands of modern payloads and scientific instruments. Due to their large surface, these components are more susceptible to impacts from orbital debris compared to other satellite locations. However, the detection of debris-induced damages still proves challenging in large structures due to minimal alterations in the spacecraft global dynamics and calls for advanced structural health monitoring solutions. To address this issue, a data-driven methodology using Long Short-Term Memory (LSTM) networks is applied here to the case of damaged solar arrays. Finite element models of the solar panels are used to reproduce damage locations, which are selected based on the most critical risk areas in the structures. The modal parameters of the healthy and damaged arrays are extracted to build the governing equations of the flexible spacecraft. Standard attitude manoeuvres are simulated to generate two datasets, one including local accelerations and the other consisting of piezoelectric voltages, both measured in specific locations of the structure. The LSTM architecture is then trained by associating each sensed time series with the corresponding damage label. The performance of the deep learning approach is assessed, and a comparison is presented between the accuracy of the two distinct sets of sensors: accelerometers and piezoelectric patches. In both cases, the framework proved effective in promptly identifying the location of damaged elements within limited measured time samples.

Sensing and control the static deflection of a cantilever beam by using piezoelectric patches

Abstract Different mechanical structures when comes under static and dynamic loadings then they respond. It is very important to sense it so that the dynamic behavior of the structure in terms of natural frequencies, its mode shapes, and viscous damping coefficients can be successfully predicted or measured. The accurate prediction of the dynamic response of the oscillating structure always plays an important role to design its physical parameters. However, in this paper, the simulated and experimental study is conducted to accurately sense the static deflection of the cantilever beam by using piezoelectric patches. The accurate prediction of the static deflection of the beam and its control through piezoelectric patches is the novelty of the present work. Mostly, the finite element model of the beam is developed to predict its dynamic behavior. The finite element modeling provides an approximate solution. In this regard, the finite element model updating technique such as the direct updating algorithm is used in this study to correct the simulated finite element model of the beam. The updated simulated finite element model is then used to predict the accurate value of the static deflection. It is observed that the maximum percentage error between the predicted and measured static deflection is 29.1%. The updated simulated finite element model is also used to design the controller. The direct output feedback controller is developed and it is found that the static deflection of the beam has been reduced by 46.65%.

Application of the Lock-In Technique in Magnetoelectric Coupling Measurements of the PZT/Terfenol-D Composite

This paper presents a study of magnetoelectric (ME) properties of the PZT/Terfenol-D composite with a varying number of layers. The composite consists of piezoelectric and magnetostrictive phases that are mechanically coupled. The purpose of this setup is to gain control over the electric polarization of a material via an external magnetic field. Unlike most similar composites, our samples utilize a commercial piezoelectric patch instead of pure PZT. At present, researchers face two main problems regarding magnetoelectric materials: (i) the effect is observed far below room temperature for single-phase materials, and (ii) the ME coupling is too weak to be commercially viable. Our research was carried out via the lock-in technique on two PZT/Terfenol-D samples we synthesized. Relatively strong room-temperature magnetoelectric coupling between piezoelectric and magnetostrictive phases was observed for both samples. Two types of characteristics were investigated: (i) ME voltage versus magnetic AC field frequency, and (ii) ME voltage versus magnetic DC field. We detected multiple, grouped signal peaks ascribed to different resonance modes. Uniquely, the peaks form band-like characteristics which might be an important step in bringing the materials closer to wider commercial use.

Energy Harvesting by V‐Shape Bluff Bodies with Various Apical Angles Attached to a Revolute Joint

This study parametrically investigates the efficiency of an integrated energy harvesting system that consists of a piezoelectric patch attached to a cantilever beam and V‐shape bluff bodies with various apical angles. V‐shape bluff bodies are connected to a cantilever beam with a revolute joint that represents a two degrees‐of‐freedom configuration. The mechanical energy of the galloping and fluttering motions, resulting from the vortex shedding that appears downstream of the bluff bodies, is converted into electricity by means of a piezoelectric patch. The apical angle of the V‐shape geometries, that varies between 0° and 180°, is the main parameter where the generated voltages and the related power curves are the major results for the evaluation of the efficiency of this harvesting system. Based on the experimental examinations, the maximum output power of 0.295 mW is produced at a wind speed of 10 m s−1 for the apical angle of 180° and the electrical resistance of 230 kΩ. Moreover, the proposed energy harvester system can still produce usable output power for the apical angles ranges from 0° to 20° and from 170° to 180°.

Experimental Studies on the Vibration Control of Epoxy Clay Nanocomposites

Fabrication of nanocomposites for different-clay (alumino-silicate) concentrations (1, 3, 5 and 10 wt%) with the matrix (epoxy) is done by using shear mixer. This paper presents the experimental study of free vibration and damping characteristics. The work also involves vibration control of nanocomposite laminates by reinforcing organically modified montmorillonite clay in the epoxy matrix by resin casting technique. Theoretical study is also carried out to study the vibration and damping characteristics of epoxy clay nanocomposites. Dynamic result shows that the second phase nanoscale dispersion in the matrix significantly enhances the internal damping of nanocomposites. This work also presents the active vibration control of nanocomposite beams. Piezoelectric patches are bonded on the surface of beam and control algorithms are applied to the system. Feed forward (open loop) control algorithms are used to control the vibration. Maximum control is obtained for sample with 3 wt.%OC.

Effectiveness of Discrete Piezo-patch Locations in Clamped-simply Supported Plates

Present study investigates the problem of determining the control effectiveness of piezoelectric patches for controlling vibration in higher modes of clamped-simply supported plates. A modal analysis approach is used to identify high average strain (or curvature) locations, as desired patch locations and represented in the form of geometrical parameters. The 9-patch configuration is used and modal analysis of integrated structure is carried out, which clearly shows that the initial patch configuration yields better effectiveness for square plates. In case of rectangular plates, the above strategy provides mixed results for the patch distribution effectiveness, for the modes considered here. Next, a concept of ‘stretching’ the patch distribution is applied for improving the effectiveness of the patch distribution and a Fig. of Merit (FOM), based on modal strains, is defined for quantifying the effectiveness. The results show that particular patch distribution geometry is suitable only for a specific group of modes. In view of this, a combined Fig. of Merit, based on the concept of modal weights, is also introduced, which has the potential to help in determining a suitable patch distribution through a formal optimization methodology. The control effectiveness comparison study of the initial and stretched patch configuration of plates also supports the quantification of control effectiveness of patch configuration through the FOM.

Design and evaluation of a magnetically coupled piezoelectric energy harvester with parallel connection.

This work proposed a magnetically coupled piezoelectric energy harvester with parallel connections. The rectangular piezoelectric patch in the upper part of the device generates regular vibrations due to the nonlinear forces caused by magnetic coupling. The lower rectangular piezoelectric patch is deformed by contact collision excitation. The parallel connection effectively connects the two sets of piezoelectric patches together and fully exploits the performance of the piezoelectric energy harvester. The intrinsic frequency of the rectangular piezoelectric patch was simulated and verified experimentally. The rectangular piezoelectric patch generates a large vibration amplitude in high-speed operation due to its elasticity property. From the experimental results, it can be seen that the piezoelectric energy harvester can work well in different frequency bands. The parallel piezoelectric energy harvester with a three-contact rotor has a peak-to-peak voltage of 252V at a speed of 120 r/min and 200V at a speed of 240 r/min. The maximum voltage achieved by the piezoelectric energy harvester in parallel is 266V at a speed of 180 r/min with a resistance of 1000 kΩ. The maximum voltage reached by a series-connected piezoelectric energy harvester is 256V at a speed of 180 r/min and a resistance of 100 kΩ. The peak-to-peak power of the piezoelectric energy harvester connected in parallel is 0.313W under a resistance of 100 kΩ and a speed of 180 r/min. Besides, the developed piezoelectric energy harvester can light up to 60 light-emitting diodes. Accordingly, the energy can be effectively harvested by the piezoelectric energy harvester and then supplied to the microelectronic device.

Dynamic buckling of active sandwich panels

In this work, a laminated sandwich plate model with external piezoelectric layers is extended for buckling and dynamic stability analysis. In-plane harmonic uniformly distributed loads are considered in the dynamic stability problem, and the Mathieu-type equilibrium equations are solved using Bolotin’s method to obtain the regions of dynamic instability. The model is validated to begin with, using available results in the literature for static and dynamic buckling of laminated soft core sandwich panels. Ultimately, the model is used to simulate the behaviour of laminated composite and sandwich plates with piezoelectric patches, controlled using a closed loop law with proportional and derivative gains, for buckling and dynamic stability analysis. This control system is used to postpone buckling, increase fundamental frequencies and reshape the regions of dynamic instability.

Energy harvesting and dynamic response of SMA nano conical panels with nanocomposite piezoelectric patch under moving load

Nowadays, the application of advanced and intelligent materials such as piezoelectric, shape memory alloys (SMA), and multi-phase materials, are highly demanded, especially in self-powered energy structures. Therefore, to obtain maximum efficiency, it is crucial to study and analysis the mechanical behavior of the energy production rate of the employed materials. This research theoretically evaluated the impacts of moving load and the use of a piezoelectric patch on the level of energy harvesting and dynamic behavior of a Nano Conical Panel (NCP) made from SMA located on a frictional substrate using the First-order Shear Deformation Theory (FSDT). Based on mixture rule, boron nitride nanotubes (BNNTs) with smart properties are used to reinforce the piezoelectric patch. A two-phase nonlocal method was adopted to take nano-scale effects into account. Mechanical behaviors such as friction and torsional viscoelastic were considered for the foundation layer. To reproduce the pseudo-elastic characteristics of SMA, the Hernandez-Lagoudas model was employed. In addition to these, Integral Quadrature (IQ), Differential Quadrature (DQ), and Newmark methods were coupled together to solve the equations regarding the output voltage, electric power and dynamic deflection. The computational outcomes showed that by applying a positive voltage to a piezoelectric patch, the maximum strain, as well as the energy harvesting capacity of NCP, were increased. Placing the NCP on a frictional viscoelastic-torsional layer led to deteriorated peak values of dimensionless dynamic displacement and dimensionless voltage by about 50.3% and 44.5%, respectively, compared with those of the system without the medium. At load resistance of 400 nano ohm, increasing the moving load velocity to 6.5 nm/ns, piezoelectric patch length to NCP length ratio up to 0.5, and applying CFCF boundary conditions led to enhancement of maximum output power by 30%, 88.3%, and 377%, respectively. Also, increasing the weight fraction of Boron Nitride Nanotubes (BNNT) up to 0.4% in the piezoelectric layer was found to be a suitable strategy to simultaneously decrease the dimensionless dynamic displacement and enhance dimensionless voltage by 23.4% and 21%, respectively.

The evaluation of electrical circuits for adjusting sound transmission properties of piezoelectric metamaterials

In rods and beams, piezoelectric patches with external circuits have been extensively studied to dampen structural vibrations at the sound source. This work uses a large flat-layer type of piezoelectric acoustic metamaterial (AM) model for noise attenuation in the sound transmission stage rather than at the sound source. This could be directly implemented as a large space sound transmission barrier at the interface of diverse media including gas, liquid, and solid materials. The general analytical model to derive acoustic properties of the piezoelectric acoustic metamaterial is established by the equivalent transfer matrix approach for normal incidence waves. This has been validated numerically using the finite element method and experimentally in the solid medium propagation for the first time. Moreover, a parametric study of sound transmission properties in air, water, and steel is conducted by adjusting external circuit parameters, flat-layer structures, and piezoelectric materials. The findings demonstrate the ability to control sound resonance frequency and bandwidth through the propagation process over a wide range using external circuit parameters alone. This endows the piezoelectric acoustic metamaterial with great versatility relative to conventional, fixed structure, metamaterials used as sound barriers at the interface of diverse media. In addition, the size of the piezoelectric AM can reach a deeply sub-wavelength level, less than 10−3 of the resonance wavelength in both water and solid media, which goes far beyond the wavelength-to-thickness ratio of classical acoustic metamaterials. The layer-type piezoelectric AM thus shows excellent performance in tunability and compactness for space-sensitive applications as well as great potential in combining metamaterials with electronic control.

Aeroelastic flutter of actively controlled nanocomposite beams with an open edge crack

Active control of aeroelastic flutter in composite structures is vital for improving the performance and safety of aerospace systems. Understanding the impact of cracks on flutter behavior of active controlled structures is of importance for early crack detection and accident prevention. The present work investigates the aeroelastic flutter of functionally graded (FG) graphene nanoplatelet (GNP)-reinforced nanocomposite (GNPRC) beams containing an edge crack under active control with an attached piezoelectric patch. The governing differential equations are derived using Hamilton's principle together with the Ritz method, based on the first order shear deformation theory (FSDT) and a rotational spring model. The flutter velocities of the system are determined by numerically solving the eigenvalue problem. Through a comprehensive parametric study, the effects of crack length and location, GNP parameters, and different control actions on the flutter velocities of the FG-GNPRC beams with different end supports are discussed. The results reveal that the presence of a crack reduces the flutter velocities of GNPRC beams, with the extent of reduction depending on the GNP distribution pattern, crack location and support ends. Additionally, the cracked GNPRC beams can be enhanced by attaching piezoelectric actuators with feedback gains at appropriate locations on the beam's surface.

Piezoelectric-shunt-based approach for multi-mode adaptive tuned mass dampers

This paper deals with the design and development of a multi-frequency adaptive tuned mass damper based on a cantilever beam equipped with shunted piezoelectric elements. It is demonstrated that the device is able to independently shift a number of eigenfrequencies equal to the number of piezoelectric elements and that the use of negative capacitances is able to strongly improve the adaptation capability of the device. Mathematical formulations are provided for linking the values of the capacitances used for shunting the piezoelectric elements and the resulting shifts of the eigenfrequencies, and vice versa. Furthermore, being the negative capacitances based on operational amplifiers, the stability of the electro-mechanical system is investigated, giving rules about the tuning of these negative capacitances. The resulting adaptive tuned mass damper can be fruitfully employed for lowering vibrations of a primary system whose eigenfrequencies undergo different frequency shifts, improving the robustness to possible mistuning of non-adaptive classical tuned mass dampers. All the theoretical outcomes are validated through an experimental campaign with a cantilever beam equipped with two piezoelectric patches.