Actuation of Piezoelectric Layered Beams With and Coupling

Negative Poisson's ratio polyethylene matrix and 0.5Ba(Zr0.2 Ti0.8) O3-0.5(Ba0.7 Ca0.3)TiO3 based piezocomposite for sensing and energy harvesting applications

Finite element studies were conducted on 0.5Ba(Zr_0.2 Ti_0.8) O₃-0.5(Ba_0.7 Ca_0.3)TiO₃ (BCZT) piezoelectric particles embedded in polyethylene matrix to create a piezocomposite having a positive and negative Poisson's ratio of -0.32 and 0.2. Polyethylene with a positive Poisson's ratio is referred to as non-auxetic while those with negative Poisson's ratio are referred to as auxetic or inherently auxetic. The effective elastic and piezoelectric properties were calculated at volume fractions of (4%, 8% to 24%) to study their sensing and harvesting performance. This study compared lead-free auxetic 0-3 piezocomposite for sensing and energy harvesting with non-auxetic one. Inherently auxetic piezocomposites have been studied for their elastic and piezoelectric properties and improved mechanical coupling, but their sensing and energy harvesting capabilities and behavior patterns have not been explored in previous literatures. The effect of Poisson's ratio ranging between -0.9 to 0.4 on the sensing and energy harvesting performance of an inherently auxetic lead free piezocomposite composite with BCZT inclusions has also not been studied before, motivating the author to conduct the present study. Auxetic piezocomposite demonstrated an overall improvement in performance in terms of higher sensing voltage and harvested power. The study was repeated at a constant volume fraction of 24% for a range of Poisson's ratio varied between -0.9 to 0.4. Enhanced performance was observed at the extreme negative end of the Poisson's ratio spectrum. This paper demonstrates the potential improvements by exploiting auxetic matrices in future piezocomposite sensors and energy harvesters.

Power-Generation Optimization Based on Piezoelectric Ceramic Deformation for Energy Harvesting Application with Renewable Energy

Along with the increase in renewable energy, research on energy harvesting combined with piezoelectric energy is being conducted. However, it is difficult to predict the power generation of combined harvesting because there is no data on the power generation by a single piezoelectric material. Before predicting the corresponding power generation and efficiency, it is necessary to quantify the power generation by a single piezoelectric material alone. In this study, the generated power is measured based on three parameters (size of the piezoelectric ceramic, depth of compression, and speed of compression) that contribute to the deformation of a single PZT (Lead zirconate titanate)-based piezoelectric element. The generated power was analyzed by comparing with the corresponding parameters. The analysis results are as follows: (i) considering the difference between the size of the piezoelectric ceramic and the generated power, 20 mm was the most efficient piezoelectric ceramic size, (ii) considering the case of piezoelectric ceramics sized 14 mm, the generated power continued to increase with the increase in the compression depth of the piezoelectric ceramic, and (iii) For piezoelectric ceramics of all diameters, the longer the depth of deformation, the shorter the frequency, and depending on the depth of deformation, there is a specific frequency at which the charging power is maximum. Based on the findings of this study, PZT-based elements can be applied to cases that receive indirect force, including vibration energy and wave energy. In addition, the power generation of a PZT-based element can be predicted, and efficient conditions can be set for maximum power generation.

Modeling the Piezoelectric Cantilever Resonator with Different Width Layers

The piezoelectric cantilever resonator is used widely in many fields because of its perfect design, easy-to-control process, easy integration with the integrated circuit. The tip displacement and resonance frequency are two important characters of the piezoelectric cantilever resonator and many models are used to characterize them. However, these models are only suitable for the piezoelectric cantilever with the same width layers. To accurately characterize the piezoelectric cantilever resonators with different width layers, a novel model is proposed for predicting the tip displacement and resonance frequency. The results show that the model is in good agreement with the finite element method (FEM) simulation and experiment measurements, the tip displacement error is no more than 6%, the errors of the first, second, and third-order resonance frequency between theoretical values and measured results are 1.63%, 1.18%, and 0.51%, respectively. Finally, a discussion of the tip displacement of the piezoelectric cantilever resonator when the second layer is null, electrode, or silicon oxide (SiO₂) is presented, and the utility of the model as a design tool for specifying the tip displacement and resonance frequency is demonstrated. Furthermore, this model can also be extended to characterize the piezoelectric cantilever with n-layer film or piezoelectric doubly clamped beam.

Piezoelectric Energy Harvesting Design Principles for Materials and Structures: Material Figure-of-Merit and Self-Resonance Tuning

Piezoelectric energy harvesters (PEHs) aim to generate sufficient power to operate targeting device from the limited ambient energy. PEH includes mechanical-to-mechanical, mechanical-to-electrical, and electrical-to-electrical energy conversions, which are related to PEH structures, materials, and circuits, respectively; these should be efficient for increasing the total power. This critical review focuses on PEH structures and materials associated with the two major energy conversions to improve PEH performance. First, the resonance tuning mechanisms for PEH structures maintaining continuous resonance, regardless of a change in the vibration frequency, are presented. Based on the manual tuning technique, the electrically- and mechanically-driven self-resonance tuning (SRT) techniques are introduced in detail. The representative SRT harvesters are summarized in terms of tunability, power consumption, and net power. Second, the figure-of-merits of the piezoelectric materials for output power are summarized based on the operating conditions, and optimal piezoelectric materials are suggested. Piezoelectric materials with large k_ij , d_ij , and g_ij values are suitable for most PEHs, whereas those with large k_ij and Q_m values should be used for on-resonance conditions, wherein the mechanical energy is directly supplied to the piezoelectric material. This comprehensive review provides insights for designing efficient structures and selection of proper piezoelectric materials for PEHs.

Piezoelectric Energy Harvesting Solutions: A Review

The goal of this paper is to review current methods of energy harvesting, while focusing on piezoelectric energy harvesting. The piezoelectric energy harvesting technique is based on the materials' property of generating an electric field when a mechanical force is applied. This phenomenon is known as the direct piezoelectric effect. Piezoelectric transducers can be of different shapes and materials, making them suitable for a multitude of applications. To optimize the use of piezoelectric devices in applications, a model is needed to observe the behavior in the time and frequency domain. In addition to different aspects of piezoelectric modeling, this paper also presents several circuits used to maximize the energy harvested.

Design, Modeling, and Experimental Evaluation of a Compact Piezoelectric XY Platform for Large Travel Range

A novel piezoelectric XY platform driven by a single actuator was presented for a large travel range and compact structure. The actuator operated at the inertial mechanism and moved the output platform step-by-step. A dynamic model of the piezoelectric actuator was established based on the Timoshenko beam theory and Galerkin procedure, which was used to aid the structure design. The dynamic model of the platform system was established based on the dynamic model of the actuator and the LuGre friction model. A prototype was fabricated and its experimental system was established; the total size was 100 × 100 × 93.5 mm³ and the travel range was 15 × 15 mm². The measured stepper motions agreed well with the simulation results, and the correctness of the dynamic model was confirmed. The proposed platform achieved maximum speeds of 2.13 and 3.11 mm/s along the axes X and Y , respectively, and a carrying capacity of 20 kg was achieved. Furthermore, the closed-loop control experiments, including the positioning resolution and the sinusoidal trajectory tracking, were carried out, and a positioning resolution better than [Formula: see text] and a tracking error rate of 4% were achieved, which revealed the potential of the proposed piezoelectric platform in field of manipulating heavy objects with submicrometer accuracy and large travel range, especially for some specific fields including microparticle manipulation, ultraprecision manufacturing, and optical device posture adjustment where large travel range, high accuracy, and multidimension are expected.

Constitutive Equations of Piezoelectric Layered Beams With Interdigitated Electrodes

This paper establishes the constitutive equations, or linear two-port models, of piezoelectric layered beams with interdigital electrodes (IDEs). The effect of the nontrivial field on the transduction is analyzed. Based on conformal mapping techniques, we derive new analytic expressions for the capacitance, the electric field, and the electromechanical coupling factor of an anisotropic dielectric with the IDE configuration on top. The IDE capacitance with an anisotropic permittivity can be treated as the one with an isotropic permittivity. The complex expression for the nonuniform field is simplified to a quadratic form. A correction is required for the transducer's coupling constant. All modifications are expressed analytically. The analytic models are verified against the finite element method. Finally, the two-port models help to compare the devices with other electrode configurations, such as beams with a top and bottom electrode.