Piezoelectric Sensing Element-Assisted Ceramic Art Process Optimization and Visual Quantitative Characterization

In this paper, piezoelectric sensing elements are used to assist in the study and analysis of ceramic art process optimization and visual quantization characteristics. A series piezoelectric element impedance sensor is designed based on the resonant frequency characteristics of the series piezoelectric element. Combining the resonant frequency characteristics of the series piezoelectric element and the basic principle of the impedance method, a multisensing impedance method based on the series piezoelectric element impedance sensor is proposed. The feasibility of the multisensing impedance method for monitoring the grout compactness was verified experimentally, and the basic principle of the method was further investigated by finite element simulation. The vase-type porcelain vessels were classified according to symmetry elements to find the characteristic points, the abdominal morphology was used as the basis for classification, and the screened samples were extracted from the contours to exclude the influence of other factors on the vessel shape. By the symmetrical elements of each type of ware, the classification principle of the ware type was designed and divided into six types, and each type was further subdivided into various types to establish a typological map of Qing dynasty bottle porcelain. The information entropy redundancy that describes the uniformity of the code appearance probability and the visual redundancy that describes the human eye’s sensitivity to image content or details are all entry points that can be considered for image coding. The experimental results show that the LBP-HOG fusion features can digitally express the information of ancient ceramic ornamentation and dig and verify the evolution of ceramic ornamentation with the times from the digital quantity. The GRNN model has an excellent performance in processing small samples of ancient ceramic data.

A hybrid linear actuator based on screw clamp operation principle: Design and experimental verification

This paper presents a hybrid linear actuator using screw clamp operation principle. The actuator mainly consists of a hollow electromagnetic torque motor located between two clamping nuts, two hollow cylindrical shaped piezoelectric stacks symmetrically configured at two ends of the actuator and a feed-screw (also considered as the mover of the actuator) assembled throughout all the parts. The torque motor is symmetrically connected to two clamping nuts via two torsion coupling springs located at either end of the motor spindle. Two piezoelectric stacks can work independently to propel the opposing loads, which effectively take advantage of the anti-compression and non-tensile characteristics of piezoelectric element. The special feature of the actuator is the screw clamp mechanism, the operation of which involves intermittent rotation of two nuts (driven by the torque motor) on a feed-screw to achieve the bi-direction piezoelectric motion accumulation. Furthermore, the application of feed-screw could decrease the actuator’s sensitivity to wear, in order to realize a rigid self-locking and thus ensure the actuator’s holding capacity. A prototype was fabricated and the experimental results show that the no-load speed, maximum thrust, and peak power of the actuator were 20 mm/s, 280 N, and 1.54 W, respectively.

Electrical Efficiency of SECE-based Interfaces for Piezoelectric Vibration Energy Harvesting

Piezoelectric energy harvesting (PEH) interfaces have been widely investigated during the last decades in order to maximize the harvested power. Among the energy extraction circuits proposed in the literature, some of the most effective ones consist of extracting the electric charges from the piezoelectric elements in a synchronous way with the vibrations and within a very short portion of the vibration period (SECE, SECPE, FTSECE, etc.). For these strategies, most previous studies take the electrical efficiency (i.e., the electrical losses between the energy extracted from the piezoelectric element and the energy which is finally transferred in a storage element) into account in an ad-hoc and case-by-case manner. In this brief, we propose a unified analysis that applies to model the electrical efficiency of these SECE-based strategies taking into account losses introduced by the electrical interface. We identify the main loss mechanisms by demonstrating that the electrical efficiency mainly varies with two parameters: the quality factor of the electrical interface and the voltage inversion ratio of the considered strategy. Measurements on the FTSECE strategy show that our model predicts the stored power with a good accuracy and allows a better optimization of the harvesting interface (up to 5.4 times more stored power at off-resonance frequencies, and 30% larger harvesting bandwidth).

Piezoelectric Ceramics with High d33 Constants and Their Application to Film Speakers

A multilayer piezoelectric material was fabricated using piezoelectric materials with low-temperature sintering capabilities and high piezoelectric coefficients to develop a functionally superior piezoelectric speaker with a large-displacement deformation. A soft relaxor was utilized to prepare the component materials, with the optimized composition of the investigated piezoelectric ceramics represented by 0.2Pb((Zn0.8Ni0.2)13Nb23)O3−0.8Pb(Zr0.5Ti0.5)O3. Li2CO3 was added to assist the low-temperature sintering conducted at 875 °C, which yielded a multilayer piezoelectric material with superior properties (d33 = 500 pC N−1, kp = 0.63, g33 = 44 mV N−1). A multilayer piezoelectric actuator with a single-layer thickness of ~40 µm and dimensions of 12 × 16 mm2 was fabricated by tape casting the prepared green sheets. Finite element analysis revealed that the use of a PEEK film and a smaller silicone–rubber film as a composite in the diaphragm realized optimal frequency-response characteristics; the vibrations generated by the piezoelectric element were amplified. The optimal structure obtained via simulations was applied to fabricate an actual piezoelectric speaker with dimensions of 20 × 24 × 1 mm3. The actual measurements exhibited a sound pressure level of ~75 dB and a total harmonic distortion ≤15% in the audible frequency range (250–20,000 Hz) at an applied voltage of 5 Vp.

Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation

Instrumented implants can improve the clinical outcome of total hip replacements (THRs). To overcome the drawbacks of external energy supply and batteries, energy harvesting is a promising approach to power energy-autonomous implants. Therefore, we recently presented a new piezoelectric-based energy harvesting concept for THRs. In this study, the performance of the proposed energy harvesting system was numerically and experimentally investigated. First, we numerically reproduced our previous results for the physiologically based loading situation in a simplified setup. Thereafter, this configuration was experimentally realised by the implantation of a functional model of the energy harvesting concept into an artificial bone segment. Additionally, the piezoelectric element alone was investigated to analyse the predictive power of the numerical model. We measured the generated voltage for a load profile for walking and calculated the power output. The maximum power for the directly loaded piezoelectric element and the functional model were 28.6 and 10.2 µW, respectively. Numerically, 72.7 µW was calculated. The curve progressions were qualitatively in good accordance with the numerical data. The deviations were explained by sensitivity analysis and model simplifications, e.g., material data or lower acting force levels by malalignment and differences between virtual and experimental implantation. The findings verify the feasibility of the proposed energy harvesting concept and form the basis for design optimisations with increased power output.

Recent acoustic energy harvesting methods and mechanisms: A review

This review article summarises the mechanism of the acoustic energy harvester or converter which includes the compact structure of the piezoelectric element, electromagnetic transducer and Helmholtz resonator; different shapes of Helmholtz resonators, piezoelectric cantilever, acoustic metamaterial-based approach, electrostatic transduction method, auxetic structure of material and other techniques. The recently established methods of acoustic energy harvesting and converting mechanisms; devices are carefully reviewed, and their results are compared and listed in the table. The technique of energy conversion by using acoustic metamaterial will tend to be more efficacious due to its complexity and the structure. Even in the few noise attenuation applications, more metamaterial is used, where, with the help of the conversion mechanism, the noise or sound energy can be converted into electrical energy for small electronic applications. It is demonstrated that the acoustic energy-conversion technique will become an essential part of the environmental energy harvesting research field.

Embedded Metamaterial Subframe Patch for Increased Power Output of Piezoelectric Energy Harvesters

These days, piezoelectric energy harvesting (PEH) is introduced as one of the clean and renewable energy sources for powering the self-powered sensors utilized for wireless condition monitoring of structures. However, low efficiency is the biggest drawback of the PEHs. This paper introduces an innovative embedded metamaterial subframe (MetaSub) patch as a practical solution to address the low throughput limitation of conventional PEHs whose host structure has already been constructed or installed. To evaluate the performance of the embedded MetaSub patch (EMSP), a cantilever beam is considered as the host structure in this study. The EMSP transfers the auxetic behavior to the piezoelectric element (PZT) wherever substituting a regular beam with an auxetic beam is either impracticable or suboptimal. The concept of the EMSP is numerically validated, and the COMSOL Multiphysics software was employed to investigate its performance when a cantilever beam is subjected to different amplitude and frequency. The FEM results demonstrate that the harvesting power in cases that use the EMSP can be amplified up to 5.5 times compared to a piezoelectric cantilever energy harvester without patch. This paper opens up a great potential of using EMSP for different types of energy harvesting systems in biomedical, acoustics, civil, electrical, aerospace, and mechanical engineering applications.

Design Study on Customised Piezoelectric Elements for Energy Harvesting in Total Hip Replacements

Energy harvesting is a promising approach to power novel instrumented implants that have passive sensory functions or actuators for therapeutic measures. We recently proposed a new piezoelectric concept for energy harvesting in total hip replacements. The mechanical implant safety and the feasibility of power generation were numerically demonstrated. However, the power output for the chosen piezoelectric element was low. Therefore, we investigated in the present study different geometry variants for an increased power output for in vivo applications. Using the same finite element model, we focused on new, customised piezoelectric element geometries to optimally exploit the available space for integration of the energy harvesting system, while maintaining the mechanical safety of the implant. The result of our iterative design study was an increased power output from 29.8 to 729.9 µW. This amount is sufficient for low-power electronics.

A 1.02 μW Autarkic Threshold-Based Sensing and Energy Harvesting Interface Using a Single Piezoelectric Element

A self-powered piezoelectric sensor interface employing part of the signal that is not intended for measurement to sustain its autonomous operation was designed using XH018 (180 nm) technology. The aim of the proposed circuit, besides the energy self-sufficiency of the sensor, is to provide an interface that eliminates the effect of the harvesting process on the piezoelectric output signal which contains context data. This is achieved by isolating part of the signal that is desirable for sensing from the harvesting process so that the former is not affected or distorted by the latter. Moreover, the circuit manages to self-start its operation, so no additional battery or pre-charged capacitor is needed. The circuit achieves a very low power consumption of 1.02 μW. As a proof of concept, the proposed interfacing circuit is implemented in order to be potentially used for weigh-in-motion applications.