Piezoelectric Composite System Research Articles

Enhancing the Performance of 1–3 Lead-Free Piezoelectric Composites Using a CNT-Doped Matrix

This work presents a computational study on the impact of carbon nanotube (CNT) enriched matrix on the performance of 1–3 lead-free piezoelectric periodic composites. Specifically, we investigate a piezoelectric composite system consisting of [Formula: see text] parallel aligned fibers of polycrystalline barium titanate (BaTiO3) embedded in a polydimethylsiloxane (PDMS) matrix doped with multiwalled CNT. The effective properties and several figures of merit have been obtained to evaluate the performance of this composite system as is typically done for these materials used for sensing, actuating, or harvesting applications. The results reveal that, in lead-free BaTiO3/PDMS piezocomposites, the addition of CNTs in the PDMS matrix should be [Formula: see text] “being [Formula: see text] the percolation threshold”, but not higher. In another case, we will only improve the performance of the lead-free piezocomposite for sensing or actuating, but not for energy harvesting applications. This study provides insights into the use of multiwalled CNTs in lead-free piezocomposites and suggests the optimal concentration of CNTs to enhance their performance. The findings have potential implications for the development of new piezoelectric materials and devices for sensing and harvesting applications.

Rational design of piezoelectric metamaterials with tailored electro-momentum coupling

Piezoelectric materials have wide sensing and energy transduction applications due to their inherent coupling of mechanical deformation and electric field. Recent discoveries have revealed that asymmetric or heterogeneous microstructures of piezoelectric composites can create an additional coupling of macroscopic momentum to an electric field termed electro-momentum coupling, introducing a new degree of design freedom. In this work, by employing the homogenization scheme, the physical origin of electro-momentum coupling is explored by a high throughput sweep over the microstructure design space of a piezoelectric composite system. This study shows how material constituent properties and geometrical arrangements can affect electro-momentum coupling and be smartly tailored for applications of interest.

Structure-preserving low-order modeling approach of laminated composite plates integrated with macro-fiber composite transducers for dynamic applications

An Equivalent Substructure Modeling (ESM) approach of laminated composite plates with integrated macro-fiber composite (MFC) transducers is described. The proposed approach generates structure-preserving low-order system models for dynamic applications such as vibration suppression and energy harvesting. The direct piezoelectric effect of MFC transducers is derived from the electrical boundary conditions and it has the same coupling patterns as equivalent forces which describe the inverse piezoelectric effect. Hence, the reversibility of the piezoelectric effect is ensured and the electrical dynamics of the system can be simulated. The dual electromechanical couplings are assigned to a low-order structural model generated by an equivalent substructure concept. A laminated composite plate with integrated MFC transducers is used for validations and the simulated results agree well with experimental data. Two given study cases demonstrated that the ESM approach not only can generate accurate low-order system models but also provides a flexible fashion to design piezoelectric composite systems.

Numerical Investigation of Ultrasonic Guided Wave Dynamics in Piezoelectric Composite Plates for Establishing Structural Self-Sensing

This article presents a numerical investigation of guided wave generation, propagation, interaction with damage, and reception in piezoelectric composite plates for the purpose of establishing structural self-awareness. This approach employs piezoelectric composite materials as both load bearing structure and sensing elements. Finite element modal analysis of a plate cell with Bloch-Floquet boundary condition (BFBC) is performed to understand the wave propagation characteristics in piezoelectric composite plates. A comparative study is carried out between a standard composite plate and a piezoelectric composite plate to highlight the influence of piezoelectricity on guided wave dispersion relations. Subsequently, a transient dynamic coupled-field finite element model is constructed to simulate the procedure of guided wave generation, propagation, interaction with damage, and reception in a piezoelectric composite plate. Active sensing array is designed to capture the structural response containing the damage information. Three engineering scenarios, including a pristine case, a one-damagelocation case and a two-damage-location case, are considered to demonstrate the ultrasonic sensing capability of the piezoelectric composite system. Finally, time-reversal method is utilized to locate and image the damage zones. This research shows that piezoelectric composite material possesses great potential to establish structural self-awareness, if it serves both as the load bearing and structural sensing components.

Inter-relations of domain orientations and piezoelectric properties in composites based on relaxor-ferroelectric single crystals

ABSTRACTThis paper presents results on a detailed comparative study of 2–2 relaxor-ferroelectric single crystal / polymer composites. Examples of the hydrostatic piezoelectric performance are discussed for 2–2 composites based on [011]-poled Mn-modified 0.26Pb(In1/2Nb1/2)·O3−0.42Pb(Mg1/3Nb2/3)O3−0.32PbTiO3 single crystals at a molar Mn concentration in the range of 1–5 mol. %. The high piezoelectric activity of these single crystals and rotations of the main crystallographic axes in the single-crystal layers of the composite lead to large values of hydrostatic piezoelectric coefficients , and , squared figure of merit , and electromechanical coupling factor . A rotation mode that leads to a weakening the piezoelectric activity related to the piezoelectric coefficient d32 < 0 is important to achieve composites with a range of large hydrostatic parameters, e.g., ≈ (300–350) pC / N, ∼ 100 mV·m / N, ≈ (21–23) C / m2, ∼ (24–30)·10−12 Pa−1, and ≈ 0.30. In contrast to , higher values of ∼ 10−10 Pa−1 are achieved due to the longitudinal piezoelectric effect. The results obtained in this piezoelectric composite system are interpreted by taking into account the orientation of 71° ferroelectric domains in the single-crystal layers and provide a route to form novel high-performance piezoelectric composites.

Reciprocity failure in piezoelectric polymer composite

Reciprocity principles, which entail equivalent outcome on exchange of cause and effect, are widely used and accepted. We present a piezoelectric composite system designed so that reciprocity does not hold; sensitivity is substantially enhanced. Reciprocity failure is observed in which the piezoelectric direct effect (stress causes polarization) sensitivity is unequal to the converse effect (electric field causes deformation) sensitivity . The piezoelectric polymer PVDF under isothermal conditions on a polymer substrate obeys reciprocity. Reciprocity failure occurs when a bumpy contact condition causes stress gradients. Reciprocity failure with strong frequency dependence occurs in the presence of thermal flux that is modulated by force: a non-equilibrium condition. Non-reciprocal effects give rise to a maximum enhancement of a factor of five in sensitivity.

A Study on PZT-Epoxy Piezoelectric Composites by Dynamic Mechanical Analyzer

In this study, a new type of piezoelectric damping composites was prepared by embedding thin plates of piezoelectric ceramic (Pb (ZrxT1−x) O3, PZT) with various sizes in epoxy resin matrix. An external electric resistor was connected to the piezoelectric plates of the composites to improve the damping behaviors of the composite structure. Dynamic Mechanical Analyzer (DMA8000 manufactured by Perkin Elmer) was used to study the PZT/epoxy piezoelectric composite system at different temperature and frequency range. The experimental results were discussed in terms of the damping and viscoelastic effect of the PZT-epoxy composite system.

Electromechanical response of 1–3 piezoelectric composites: An analytical model

An analytical model that captures the complete electromechanical response of a 1–3 piezoelectric composite system where both the matrix and fiber phases are, in general, elastically anisotropic and piezoelectrically active is developed. Upon identifying 36 classes of 1–3 composites based on the nature of the isotropy and the piezoelectric properties of the constituents, a detailed methodology for determining all the 45 independent material constants of a general 1–3 composite is presented. By comparing the predictions of the analytical model with that of a finite element model for a range of composite materials, it is demonstrated that the composite material properties in the longitudinal direction (i.e., C33, κ33 and ε33) are well predicted by the analytical model. However, as a consequence of the approximation introduced in the model formulation (where the fiber composite is modeled as a layered composite) the analytical model could significantly underpredict the composite material properties in the transverse direction (especially the dielectric properties, κ11 and κ22) for some (“matrix-dominant”) composite material systems.