Smart Piezoelectric Materials Research Articles

Study on stable configurations and snap through of the rectangular VS bi-stable laminates with curvilinear fiber alignment

With advances in fiber placement technology, variable stiffness bistable laminates (VSBL) composited by curvilinear fiber format become a subject of intense interest for morphing structures due to their lower weight, adjustable stiffness and a richer range of stable configurations compared to straight fiber bistable laminate. Merely conducting research on square laminates is not enough allowing for practical application scenarios. This article investigates the influence of geometrical parameters of VSBL on the stable state configuration and static snap through actuated by MFC systematically. A quadratic variable curvature polynomial is used to fit the transverse displacement according to classical laminate theory. By means of von-Karman geometrical relationship and the Rayleigh-Ritz method, stable configurations of the VS bistable laminate are solved. By comparing with finite element results, the reliability and precision of the current results are verified. It shows that changing fiber orientation leads to significant effects on the steady state configuration and critical bifurcation points. Theoretical analysis of VS bistable laminates containing the smart piezoelectric material MFC is followed by analytical modeling. The voltage threshold required for actuating snap through of two stable states is acquired by smart material layer MFC. The specific reasons for the differences in the configurations of VS bistable laminates are illustrated by analyzing distribution of the stiffness of VSBL in the plane.

Study on the monitoring method of debonding between concrete beams and reinforced steel plates based on piezoelectric smart materials

Concrete reinforcement is essential for ensuring the safety and durability of concrete structures. Bonding steel plates to reinforce concrete is widely used to renovate or strengthen concrete beam structures. Due to construction quality and the influence of factors such as environment and fatigue, debonding often occurs between the steel plate and concrete, making monitoring and early warning after concrete structure reinforcement challenging. This paper proposes a novel approach to monitor the degree of debonding between the steel plate and concrete beam using active sensing technology. The method uses lead zirconate titanate (PZT) as an actuator to generate stress waves. It prepares strip sensors with polyvinylidene fluoride as the sensing element to monitor stress waves passing through the steel plate and concrete beam. The monitoring system detects the degree of debonding between the steel plate and the concrete beam by monitoring the change in surface voltage of the sensor. Experiments show that the degree of debonding significantly correlates with the received voltage signal; the higher the debonding, the larger the received voltage signal. It is also observed that, at the same degree of debonding, the actuator and sensor attachment position have a particular impact on the received voltage signal. Through experiments and numerical simulation analysis, it is found that when the sensor is attached to the left side of the steel plate, that is, the bonded section of the steel plate, the amplitude of the voltage signal collected by the dynamic information acquisition system is the smallest, i.e., V_debonded section > V_middle > V_bonded section. Based on the above research, the active sensing technology proposed in this paper has good sensitivity to the degree of debonding between the steel plate and concrete. It is expected to become an effective monitoring and evaluation method for the degree of debonding between steel plates and concrete.

Properties of PSN-PZT piezoelectric ceramic powder prepared by fast solid-phase reaction method

Piezoelectric smart materials have been developed from piezoelectric ceramics in various fields, and thus piezoelectric ceramics play a vital role in new materials. However, the complex process involved in the preparation of piezoelectric ceramic powder is expensive, making it difficult to achieve large-scale production. Therefore, in this study, we propose a fast solid-phase method for preparing a piezoelectric ceramic powder (PSN-PZT). The method optimises two procedures in the conventional solid-phase method, saving 43.9% and 34.7% in power cost and time, respectively, and saving 34.8% in total cost. Optimisation of the process did not significantly reduce the piezoelectric and ferroelectric properties of PSN-PZT. The optimal polarisation conditions were a polarisation temperature of 40 ℃, a polarisation time of 25 min, and a polarisation voltage of 3.5 kV. Under these conditions, the piezoelectric constant (d33), dielectric constant εr, and depolarisation rate at 7 days were 895 pC/N, 4340, and 0.34%, respectively. In this paper, the preparation process of the piezoelectric ceramic powder used in the preparation process of piezoelectric composites is optimized, and the preparation of piezoelectric ceramics by the fast solid-phase method provides technical support for the mass production of piezoelectric composites.

Study on the Actuating Performance of an Embedded Macro Fiber Composite Considering the Shear Lag Effect.

Macro fiber composite (MFC), which are new ultrathin piezoelectric smart materials, are mostly applied in the fields of shell structure deformation and vibration control. Among others, the application of embedded MFCs in sandwich structures has received wide attention. Currently, its actuating force formula is primarily acquired based on the Bernoulli–Euler Model, which does not consider the shear lag effect and actuating force of MFC ends. To study the actuating performance of an MFC in a sandwich structure, according to its action characteristics, the MFC is divided into upper and lower actuating units without any interaction between to two under the condition of plane strain, and the shear lag effect is considered between the units and the top and bottom of the sandwich structure. The actuating force of the MFC ends is obtained by considering its influence on the bending deformation of the sandwich structure, which deduces the actuating force formula of the embedded MFC. In contrast to ANSYS piezoelectric simulation, the distribution of the MFC interior normal stress is similar to the result from ANSYS piezoelectric simulation, and there is a very small deviation between the MFC end and central normal stress and the result from ANSYS piezoelectric simulation. Taking the end deflection of the sandwich structure with an embedded MFC as an example, the actuating force simulation of the MFC considering the shear lag effect is compared with the ANSYS piezoelectric simulation and actuating force simulation based on the Bernoulli–Euler model. The result indicates that the actuating force simulation of the MFC considering the shear lag effect is closer to the ANSYS piezoelectric simulation, which proves the rationality and necessity of considering the shear lag effect and end actuating force of the MFC.

Smart Piezo-bonded carbon fibre/epoxy composite structure: experiments and finite element simulation

Smart sensors patched to composite structures assist in the prediction of the mechanical behaviour of the structures. The present paper used finite element modelling and experimental procedures to conduct a detailed study on the response of composite laminate bonded with smart piezoelectric material. Fibre reinforced epoxy composite laminate was fabricated using the vacuum assisted resin transfer method. Test coupons in accordance with ASTM standards were prepared using high-speed and high-pressure abrasive water jet cutting. The mechanical properties of the composites were obtained through material characterization and the material properties were incorporated into the Finite element model. The layer-wise strain rate was computed with the ANSYS® Composite Prep Post module. A finite element model of a composite with piezoelectric sensor patch was created in ANSYS® APDL and harmonic analysis was conducted to determine the optimal frequency range for the applied load. An attempt was made to measure the strain by affixing lead zirconate titanate to a carbon fibre reinforced polymer laminate for cantilever configuration, and the LabVIEW® VI software module was integrated with the NI myDAQ system to detect the corresponding voltage for the excited frequency. The values of the generated voltage through numerical simulations were verified and validated using experimental counterparts.

Acoustic Biosensors and Microfluidic Devices in the Decennium: Principles and Applications.

Lab-on-a-chip (LOC) technology has gained primary attention in the past decade, where label-free biosensors and microfluidic actuation platforms are integrated to realize such LOC devices. Among the multitude of technologies that enables the successful integration of these two features, the piezoelectric acoustic wave method is best suited for handling biological samples due to biocompatibility, label-free and non-invasive properties. In this review paper, we present a study on the use of acoustic waves generated by piezoelectric materials in the area of label-free biosensors and microfluidic actuation towards the realization of LOC and POC devices. The categorization of acoustic wave technology into the bulk acoustic wave and surface acoustic wave has been considered with the inclusion of biological sample sensing and manipulation applications. This paper presents an approach with a comprehensive study on the fundamental operating principles of acoustic waves in biosensing and microfluidic actuation, acoustic wave modes suitable for sensing and actuation, piezoelectric materials used for acoustic wave generation, fabrication methods, and challenges in the use of acoustic wave modes in biosensing. Recent developments in the past decade, in various sensing potentialities of acoustic waves in a myriad of applications, including sensing of proteins, disease biomarkers, DNA, pathogenic microorganisms, acoustofluidic manipulation, and the sorting of biological samples such as cells, have been given primary focus. An insight into the future perspectives of real-time, label-free, and portable LOC devices utilizing acoustic waves is also presented. The developments in the field of thin-film piezoelectric materials, with the possibility of integrating sensing and actuation on a single platform utilizing the reversible property of smart piezoelectric materials, provide a step forward in the realization of monolithic integrated LOC and POC devices. Finally, the present paper highlights the key benefits and challenges in terms of commercialization, in the field of acoustic wave-based biosensors and actuation platforms.

Enhancement of Bone Regeneration Through the Converse Piezoelectric Effect, A Novel Approach for Applying Mechanical Stimulation.

Serious bone injuries have devastating effects on the lives of patients including limiting working ability and high cost. Orthopedic implants can aid in healing injuries to an extent that exceeds the natural regenerative capabilities of bone to repair fractures or large bone defects. Autografts and allografts are the standard implants used, but disadvantages such as donor site complications, a limited quantity of transplantable bone, and high costs have led to an increased demand for synthetic bone graft substitutes. However, replicating the complex physiological properties of biological bone, much less recapitulating its complex tissue functions, is challenging. Extensive efforts to design biocompatible implants that mimic the natural healing processes in bone have led to the investigation of piezoelectric smart materials because the bone has natural piezoelectric properties. Piezoelectric materials facilitate bone regeneration either by accumulating electric charge in response to mechanical stress, which mimics bioelectric signals through the direct piezoelectric effect or by providing mechanical stimulation in response to electrical stimulation through the converse piezoelectric effect. Although both effects are beneficial, the converse piezoelectric effect can address bone atrophy from stress shielding and immobility by improving the mechanical response of a healing defect. Mechanical stimulation has a positive impact on bone regeneration by activating cellular pathways that increase bone formation and decrease bone resorption. This review will highlight the potential of the converse piezoelectric effect to enhance bone regeneration by discussing the activation of beneficial cellular pathways, the properties of piezoelectric biomaterials, and the potential for the more effective administration of the converse piezoelectric effect using wireless control.

Large deformations of piezoelectric laminated beams based on the absolute nodal coordinate formulation

Piezoelectric beams can be deformed into many patterns and have potential application prospect in the field of smart foldable structures. Knowing the large deformation actuation mechanism of such structures is the basis in the soft machine design. In this paper, using the Equivalent Single-layer model, a new flexible piezoelectric laminated beam element based on the Absolute Nodal Coordinate Formulation (ANCF) is established. This beam element contains three layers, in which the base layer is made of linear elastic material, and the top and bottom layers are both made of piezoelectric materials. The constitutive equation of the piezoelectric material is introduced to derive the elastic force and the piezoelectric force. The correctness of the new beam element are validated by comparing with the analytical solution and the results from the equivalent bending moment equation. A group of large deformation patterns of the laminated beam are given to prove the applicability of the proposed element. Results show that when various voltages are applied to the piezoelectric actuators that located in arbitrary positions of the base beam, the flexible beam can achieve the desired shape smoothly. Dynamic responses of a highly flexible pendulum with and without piezoelectric layers are also investigated. Research in this work can be helpful to the understanding of complicated coupled nonlinear mechanics of flexible or soft structures with covered smart piezoelectric materials.

Damage Propagation Prediction of Adhesion Failure in Composite T-joint Structure and Improvement using PZT Patch

In this paper, a three dimensional finite element simulation model has been developed for the prediction, propagation and improvement of adhesion failure in an adhesively bonded laminated T-joint structure using the smart piezoelectric material. Initially, the three-dimensional stresses (normal and shear) and failure locations in the composite T-joint (all the layers of the web and flange) are evaluated. At the identified failure location, virtual crack closure technique (VCCT) of fracture mechanics has been employed to compute the strain energy release rate (SERR) values for different pre-embedded adhesion failure lengths. The developed coupling analysis model is used to evaluate the SERR responses for the laminated composite T-joint with single/multiple piezoelectric layers. The efficacy and improved performance (resistance to adhesion failure) of the laminated smart T-joint structure have been analysed in details by considering the different influencing parameters i.e. orientation schemes, material types, piezoelectric layers, thickness, number of layers of the laminate.

Impact of microstructures and viscous liquid loading on electromechanical coupling factor and surface wave transference in a prestressed piezoelectric smart material layered structure

The electromechanical coupling factor (K 2) is a key parameter in acoustic devices that acquaints the affect of piezoelectricity on the phase velocity of elastic waves. For conventional engineering applications, greater electromechanical coupling factor (K 2) are expected in surface acoustic wave (SAW) devices. This present study investigates the impact of microstructures and viscous liquid loading on transference of Love-type surface wave in a prestressed piezoelectric smart material layered structure. A micropolar material as substrate is employed for capturing the microstructural influence. The study involves the extraction of dispersion equations for both electrically open and short conditions depicting explicitly the effects of viscosity and density of viscous liquid, microstructural parameters of the substrate, electromechanical coupling factor and material parameters of the prestressed piezoelectric layer. Some particular cases of the problem are derived and the obtained results are matched with the classical Love wave equation. PZT − 5H ceramic material as piezoelectric material and Aluminium-Epoxy as micropolar material, are considered for the investigation. The present study is meaningful in intensifying the performance of chemical and biochemical sensors working in a liquid environment.

Shape control of hybrid functionally graded plate through smart application of piezoelectric material using simple plate theory

The present study takes its inspiration from notable work in the literature related to the flexural analysis of functionally graded material (FGM) plate along with a smart application of piezoelectric material but maintains its novelty in terms of simple approach, an analytical solution with a wide scope of application. Coupling the plate element with piezoelectric smart material can control deflection, vibration thereby increasing the safety, stability, and life of these elements. Plates made up of functionally graded material further enhances the applicability as two different materials are fused. Analysis of such a system is challenging especially for a closed form mathematical solution along with complex boundary conditions. In the present study, it is proposed to develop a simple analytical model for bending analysis of FGM plate coupled with piezoelectric layers. Polynomial based shear deformation function taken from literature is applied to develop a simple mathematical model. A complete flexural analysis is performed for FGM plate to validate the governing simple mathematical model. Through the smart application of piezoelectric material, the deflection of the FGM plate is controlled in as closed loop feedback system. Analytical solution valid over the entire plate domain is obtained incorporating fixed and simple support types of boundary conditions. The initial part of the study details complete mathematical formulation for the plate under consideration, followed by numerical validation in which results of the present model are compared with notable studies in the literature. Lastly, the smart application through shape control of the FGM plate is demonstrated graphically and numerically. The development and application of the discussed mathematical model presented in this study are complete in all aspects of its mathematical form, solution, and numerical validation.

Progress in the Applications of Smart Piezoelectric Materials for Medical Devices.

Smart piezoelectric materials are of great interest due to their unique properties. Piezoelectric materials can transform mechanical energy into electricity and vice versa. There are mono and polycrystals (piezoceramics), polymers, and composites in the group of piezoelectric materials. Recent years show progress in the applications of piezoelectric materials in biomedical devices due to their biocompatibility and biodegradability. Medical devices such as actuators and sensors, energy harvesting devices, and active scaffolds for neural tissue engineering are continually explored. Sensors and actuators from piezoelectric materials can convert flow rate, pressure, etc., to generate energy or consume it. This paper consists of using smart materials to design medical devices and provide a greater understanding of the piezoelectric effect in the medical industry presently. A greater understanding of piezoelectricity is necessary regarding the future development and industry challenges.

Electro-mechanical performance of smart piezoelectric nanocomposite plates reinforced by zinc oxide and gallium nitride nanowires

The use of piezoelectric nano-fillers in a non-piezoelectric matrix is a very attractive proposition for developing smart nanocomposite materials with desired electro-mechanical properties. The eco-friendly nanowires (NWs) of zinc oxide (ZnO) and gallium nitride (GaN) are the two candidates used to introduce smart piezoelectric nanocomposite materials. Specifically, in this first effort, we examined the electro-mechanical performance of newly developed composite plates reinforced by piezoelectric ZnO NW and GaN NW of varied volume fractions. The static deflections and natural frequencies of the newly developed bimorph piezoelectric nanocomposite plates subject to electro-mechanical loads are analyzed using a mesh-free method in conjunction with the shape functions of MLS. Using third order shear deformation theory (TDST), the coupled electro-mechanical governing equations for the considered smart plates are obtained and numerically integrated. The effects of the electro-mechanical loading and plate thickness on static deflection and natural frequencies of piezoelectric plates are investigated and discussed. Our predictions reveal that the application of electrical input to the plates can induce greater deflection than the ones introduced by mechanical loads and that ZnO NWs offer greater deflection than GaN NW. However, dynamic analysis indicates that GaN NW-reinforced plates have higher natural frequencies than those reinforced by ZnO NW.

Active vibration control of truncated conical shell under harmonic excitation using piezoelectric actuator

Abstract In this study, active vibration control of an FGM truncated conical shell, subjected to the harmonic excitation, is investigated via a semi-analytical method. The governing equations of truncated conical shells in conjunction with piezoelectric layers are derived using Donnell shell theory and von Karman's non-linearity. Then, the dynamic equation of the system is discretized using Galerkin method to obtain the ordinary differential equation of system. Using the semi-analytical method by means of perturbation theory, the frequency response of superharmonic and sub-harmonic analysis of the system is performed. Then, using the piezoelectric smart materials, the active vibration control for the truncated conical shell is investigated and frequency-amplitude functions are analyzed for the superharmonic and subharmonic resonances. The results presents the influence of excitation amplitude and cone vertex angle on the frequency-amplitude response and in specific the effect of different control gain coefficients on the system's vibration behavior. Finally, the performance of active control strategy is investigated by means of the time response of system equipped with piezoelectric layers for different types of the FG distribution in thickness direction.

Analysis of size dependency on Love-type wave propagation in a functionally graded piezoelectric smart material

This study investigates Love-type wave propagation in a layered structure consisting of a functionally graded piezoelectric material (FGPEM) stratum followed by a semi-infinite couple-stress substrate exhibiting microstructural properties. Dispersion relations are obtained for electrically open and short conditions. Possible particular cases are discussed. The dispersion relation is reduced to the classical Love wave equation to validate the results. The influence of microstructural parameters, electromechanical coupling factor, thickness, functional gradedness and material parameters of the FGPEM stratum on the phase velocity of the Love-type wave has been scrutinized and illustrated graphically for electrically open and short conditions. The findings have meaningful practical application in the enhancement of efficiency and performance of sensors and transducers.

Investigation of Crack Repair in Orthotropic Composite by Piezoelectric Patching

Abstract This paper presents the investigation of a crack repair in a composite plate using piezoelectric smart material, which is also called as active repair. Composite plate with crack is modeled by a finite element method. An 8-node structural shell element is used to discretize composite material, and the 8-node coupled-field element is used for the modeling of the piezoelectric patch. The repair in the cracked composite plate is modeled and analyzed under both static and dynamic loading conditions. The unimorph and bimorph patching are used for active repair. Effectiveness of the patch repair is measured in terms of stress field near the crack tip. The usefulness of unimorph and bimorph patching is compared in three different cases, namely (i) passive, (ii) active and (iii) without patching. A significant reduction in the equivalent stress at the crack tip of the composite plate is observed because of repair by unimorph and bimorph active patching. Bimorph patching presents a greater reduction in the stress level near to discontinuity

Application of Adaptive Wave Cancellation Underwater to a Piezoelectric-Material-Based Multilayer Sensor.

This paper concerns the use of adaptive wave cancellation in a new multilayer smart skin sensor to attenuate the primary low-frequency noise underwater. The proposed multilayered system is designed with a piezoelectric actuator (Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 composite) and two layers of polyvinylidene fluoride to accelerate wave absorption. Furthermore, the use of a combination of an adaptive control scheme and a time-delay signal separation method has the potential to provide the proposed absorber system with a wave cancellation capability and thereby enable the absorber system to respond to environmental changes underwater. The use of smart piezoelectric materials and an adaptive control approach enables the absorber system to achieve the high attenuation level of the reflected waves, unlike typical absorber systems based on active noise control. Echo reduction experiments showed that the proposed piezoelectric-based multilayer sensor with an adaptive controller could attenuate reflected wave signals effectively.

Research on actuation performance of macro fiber composites based on third order shear deformation theory

Macro fiber composite (MFC) is a new type of high-performance smart piezoelectric material with an ultrathin section, which is used to decrease vibration and the noise of plate and shell structures due to high output and good flexibility. At present, the classical plate theory (CPT) has been adopted to study actuation performance of MFC. It does not consider shear deformation of an MFC integrated plate structure and cannot obtain the actuation force distribution of MFC, so that the accurate exerting position of the actuation force cannot be obtained. To solve this problem, this paper proposes that the third order shear deformation theory (TSDT) should be used to deduce the MFC actuation force formula which considers shear deformation of the MFC integrated plate structure and introduces a local displacement distribution function to ensure that the adhered interface between the MFC and the plate satisfy deformation compatibility and stress balance. Consider the end displacement calculation of an MFC integrated beam structure, for example. The comparison among the MFC actuation force formula based on TSDT, the MFC actuation force formula based on CPT, and the MFC integrated beam experiment indicates that the first can obtain higher calculation accuracy. On the basis of studying the MFC actuation force formula, the actuation simulation calculation of the plate by MFC is performed through making MFC equivalent to the actuation force and bending moment acting on plate structure to carry out the actuation experiment of an MFC integrated plate structure under the actuation of harmonic voltage of different amplitude values. The result shows that the experiment well matches the acceleration time history of simulation.

Recent Trends in Piezoelectric Smart Materials and Its Actuators for Morphing Aircraft Development

The need to develop aerodynamically and structurally efficient aircraft for a variety of purposes or missions has motivated aircraft designers to seek inspiration from nature and mimic the features of avian flight. The goal is to develop a promising morphing structure based on piezoelectric smart material technology to ensure structural integrity, reduced weight penalty, and enhanced performance. The embedding of smart piezoelectric actuators within an adaptive structure provides a great opportunity to affiliate the efficiency of avian flight with a smart adaptive wing. Piezoelectric actuators for these adaptive structures are constrained to have a high-energy density, an ease of restraint, a variable stiffness, and a high proficiency for carrying substantial strains. Our study enumerates recent trends in the development of piezoelectric smart materials and actuators and their applications to morphing aircraft. These advancements will motivate the development of new morphing techniques and aid in maximizing the potential of shape shifting.

Corrosion Investigation of Reinforced Concrete Based on Piezoelectric Smart Materials.

An embedded piezoelectric transducer was developed for monitoring the corrosion process of reinforcement bars in concrete based on the piezoelectric impedance technique. The electrochemical method was employed to accelerate the corrosion process of the reinforcement bar with relative mass loss of 0.5–10%, and the resistance spectra of the piezoelectric transducers were investigated to assess the corrosion process. The results show that the corrosion process of the reinforcement bar has significant influence on the resistance spectra of the piezoelectric transducers. Statistical parameters were used to intuitively evaluate the corrosion evolution based on variations of the resistance spectra. The corrosion process of reinforcement bar in concrete can be classified into three periods; that is, the initial period when the relative mass loss is less than 2%, the developing period at a relative mass loss of 2–4%, and the rapid corrosion period when the relative mass loss is higher than 4%.