Micromachines

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15 pages, 4966 KiB

Open AccessArticle

Design and Experimental Evaluation of a Dual-Cantilever Piezoelectric Film Sensor with a Broadband Response and High Sensitivity

by Wei Xin, Zhaoyang He and Chaocheng Zhao

Micromachines 2023, 14(11), 2108; https://doi.org/10.3390/mi14112108 - 17 Nov 2023

Viewed by 1034

Abstract

Cantilever-beam-type PVDF (Polyvinylidene Fluoride) piezoelectric film sensors are commonly utilized for vibration signal detection due to their simple structures and ease of processing. Traditional cantilevered PVDF piezoelectric film sensors are susceptible to the influence of the second-order vibration mode and have a low [...] Read more.

Cantilever-beam-type PVDF (Polyvinylidene Fluoride) piezoelectric film sensors are commonly utilized for vibration signal detection due to their simple structures and ease of processing. Traditional cantilevered PVDF piezoelectric film sensors are susceptible to the influence of the second-order vibration mode and have a low lateral stress distribution at the free end, which limit their measurement bandwidth and sensitivity. This study is on the design of a dual-cantilever PVDF piezoelectric film sensor based on the principle of cantilevered piezoelectric film sensors. The results of the experiments indicate that, compared to a typical single-arm piezoelectric cantilever beam vibration sensor, the developed sensor has a longer second-order natural frequency that ranges from 112 Hz to 453 Hz, while the first-order natural frequency is maintained at around 12 Hz. This leads to a better ratio of the second-order natural frequency to the first-order natural frequency and a wider frequency response range. At the same time, the sensitivity is increased by a factor of 3.48. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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27 pages, 5555 KiB

Open AccessArticle

A Frequency-Dependent Dynamic Electric–Mechanical Network for Thin-Wafer Piezoelectric Transducers Polarized in the Thickness Direction: Physical Model and Experimental Confirmation

by Lin Fa, Dongning Liu, Hong Gong, Wenhui Chen, Yandong Zhang, Yimei Wang, Rui Liang, Baoni Wang, Guiquan Shi, Xiangrong Fang, Yuxia Li and Meishan Zhao

Micromachines 2023, 14(8), 1641; https://doi.org/10.3390/mi14081641 - 20 Aug 2023

Viewed by 924

Abstract

This paper is concerned with electric–acoustic/acoustic–electric conversions of thin-wafer piezoelectric transducers polarized in the thickness direction. By introducing two mechanical components with frequency-dependent values, i.e., radiation resistance and radiation mass, into the equivalent circuit of the thin-wafer piezoelectric transducer, we established a frequency-dependent [...] Read more.

This paper is concerned with electric–acoustic/acoustic–electric conversions of thin-wafer piezoelectric transducers polarized in the thickness direction. By introducing two mechanical components with frequency-dependent values, i.e., radiation resistance and radiation mass, into the equivalent circuit of the thin-wafer piezoelectric transducer, we established a frequency-dependent dynamic mechanic-electric equivalent network with four terminals for an arbitrary given frequency, an enhancement from the conventional circuit networks. We derived the analytic expressions of its electric–acoustic and acoustic–electric conversion impulse responses using the four-terminal equivalent circuit to replace the traditional six-terminal equivalent circuit for a thin-wafer transducer with harmonic vibrational motion. For multifrequency electrical/acoustic signals acting on the transducer, we established parallel electric–acoustic/acoustic–electric conversion transmission networks. These two transmission network models have simple structures and clear physical and mathematical descriptions of thin-wafer transducers for electric–acoustic/acoustic–electric conversion when excited by a multifrequency electric/acoustic signal wavelet. The calculated results showed that the transducer’s center frequency shift relates to its mechanical load and vibration state. The method reported in this paper can be applied to conventional-sized and small-sized piezoelectric transducers with universal applicability. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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15 pages, 5110 KiB

Open AccessArticle

Design and Experimental Study of Shape Memory Alloy and Piezoelectric Composite Power Generation Device

by Fengshuang Yang, Yingyu Shi, Jinlong Liu, Zhicong Wang and Xiaochao Tian

Micromachines 2023, 14(7), 1434; https://doi.org/10.3390/mi14071434 - 17 Jul 2023

Cited by 1 | Viewed by 1412

Abstract

In order to solve the problem of ineffective utilization of waste heat generated by energy consumption in industrial production and life, a low-frequency thermal energy conversion type piezoelectric energy trap is proposed, and relevant theoretical analysis and experimental research are conducted. The device [...] Read more.

In order to solve the problem of ineffective utilization of waste heat generated by energy consumption in industrial production and life, a low-frequency thermal energy conversion type piezoelectric energy trap is proposed, and relevant theoretical analysis and experimental research are conducted. The device utilizes a piezoelectric film (polyvinylidene fluoride) combined with a shape memory alloy and features a simple green structure that can supply energy to microelectronic devices. First, the structural design and working principle of the device are analyzed and the dynamics model is built. Second, COMSOL Multiphysics simulation software (Version 5.6) is used to analyze and calculate the output voltage of shape memory alloy shrinkage, piezoelectric film shape and parameters. Finally, the experimental prototype is machined and fabricated by the fine engraving machine, and the experimental platform is built for relevant performance tests. The experimental results show that when the temperature is 100 °C, the maximum strain of shape memory alloy with 1 mm diameter is 0.148 mm. When the shape of the piezoelectric film is triangular, the length of the bottom edge is equal to the height of the triangle and the thickness ratio is 0.5, the maximum output voltage is 2.12 V. The experimental results verify the feasibility of the designed device and provide new ideas for subsequent research on piezoelectric energy capture. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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9 pages, 3022 KiB

Open AccessArticle

Two-Dimensional Omnidirectional Wind Energy Harvester with a Cylindrical Piezoelectric Composite Cantilever

by Mingyong Xin, Xueling Jiang, Changbao Xu, Jing Yang and Caijiang Lu

Micromachines 2023, 14(1), 127; https://doi.org/10.3390/mi14010127 - 3 Jan 2023

Cited by 6 | Viewed by 1820

Abstract

To improve the response-ability of the energy harvester to multidirectional wind, this paper proposes a wind energy harvester to scavenge wind-induced vibration energy. The harvester comprises a cylindrical beam instead of conventional thin rectangular cantilevers, a bluff body (square prism or circle cylinder), [...] Read more.

To improve the response-ability of the energy harvester to multidirectional wind, this paper proposes a wind energy harvester to scavenge wind-induced vibration energy. The harvester comprises a cylindrical beam instead of conventional thin rectangular cantilevers, a bluff body (square prism or circle cylinder), and a piezoelectric tube bonded to the bottom side of the beam for energy conversion. Benefiting from the symmetry of the cylindrical structure, this harvester can respond to airflow from every direction of the two-dimensional plane. The performance of the harvester under a wind speed range of 1.5–8 m/s has been tested. The results demonstrate that the proposed harvester can respond to the wind from all directions of the two-dimensional plane. It provides a direction for the future in-depth study of multidirectional wind energy harvesting. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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14 pages, 3059 KiB

Open AccessArticle

A Piezoelectrically Excited ZnO Nanowire Mass Sensor with Closed-Loop Detection at Room Temperature

by Xianfa Cai and Lizhong Xu

Micromachines 2022, 13(12), 2242; https://doi.org/10.3390/mi13122242 - 16 Dec 2022

Cited by 3 | Viewed by 1573

Abstract

One-dimensional nanobeam mass sensors offer an unprecedented ability to measure tiny masses or even the mass of individual molecules or atoms, enabling many interesting applications in the fields of mass spectrometry and atomic physics. However, current nano-beam mass sensors suffer from poor real-time [...] Read more.

One-dimensional nanobeam mass sensors offer an unprecedented ability to measure tiny masses or even the mass of individual molecules or atoms, enabling many interesting applications in the fields of mass spectrometry and atomic physics. However, current nano-beam mass sensors suffer from poor real-time test performance and high environment requirements. This paper proposes a piezoelectrically excited ZnO nanowire (NW) mass sensor with closed-loop detection at room temperature to break this limitation. It is detected that the designed piezo-excited ZnO NW could operate at room temperature with a resonant frequency of 417.35 MHz, a quality factor of 3010, a mass sensitivity of −8.1 Hz/zg, and a resolution of 192 zg. The multi-field coupling dynamic model of ZnO NW mass sensor under piezoelectric excitation was established and solved. The nonlinear amplitude-frequency characteristic formula, frequency formula, modal function, sensitivity curve, and linear operating interval were obtained. The ZnO NW mass sensor was fabricated by a top-down method and its response to ethanol gas molecules was tested at room temperature. Experiments show that the sensor has high sensitivity, good closed-loop tracking performance, and high linearity, which provides great potential for the detection of biochemical reaction process of biological particles based on mechanics. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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16 pages, 5385 KiB

Open AccessArticle

A Linear Ultrasonic Motor Based on Coupling Vibration Mode

by Danhong Lu, Hong Liu, Jianqiao Xu, Ting Yang and Hanwen Hu

Micromachines 2022, 13(11), 1852; https://doi.org/10.3390/mi13111852 - 28 Oct 2022

Cited by 2 | Viewed by 1413

Abstract

A coupled linear ultrasonic motor (LUSM) based on an eccentric constraint was proposed. Two pieces of oblique piezoelectric ceramics were arranged at each end of the elastomer, and the polarization direction of the ceramics was vertically upward. Using the tilting characteristics of the [...] Read more.

A coupled linear ultrasonic motor (LUSM) based on an eccentric constraint was proposed. Two pieces of oblique piezoelectric ceramics were arranged at each end of the elastomer, and the polarization direction of the ceramics was vertically upward. Using the tilting characteristics of the piezoelectric ceramics, the two ends of the fixed piezoelectric ceramics formed an eccentric restraint on the motor, providing conditions for the motor to generate coupled modes. When the elastomer of the motor generated the coupling vibration, the motion trajectories of the driving feet ends were oblique straight lines, and the oblique straight-line motion trajectories of the upper and lower driving feet ends were in opposite directions, driving the upper and lower sliders to run simultaneously. The stator parameters were optimized by using ANSYS to obtain larger amplitudes for the ends of the driving feet in both X and Z directions. The structure and operation principle of the motor are explained in detail. A prototype was fabricated to study the arrangement scheme with fixed constraints at the ends of the motor. The frequency–velocity characteristics, voltage–velocity characteristics, and mechanical characteristics of the motor were tested. The no-load speed and maximum output power were measured to be 45.9 mm/s and 3.24 mW. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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14 pages, 3678 KiB

Open AccessArticle

An Experimental Investigation on Polarization Process of a PZT-52 Tube Actuator with Interdigitated Electrodes

by Yonggang Liu, Aoke Zeng, Shuliang Zhang, Ruixiang Ma and Zhe Du

Micromachines 2022, 13(10), 1760; https://doi.org/10.3390/mi13101760 - 18 Oct 2022

Cited by 5 | Viewed by 1583

Abstract

The manipulator is the key component of the micromanipulator. Using the axial expansion and contraction properties, the piezoelectric tube can drive the manipulator to achieve micro-motion positioning. It is widely used in scanning probe microscopy, fiber stretching and beam scanning. The piezoceramic tube [...] Read more.

The manipulator is the key component of the micromanipulator. Using the axial expansion and contraction properties, the piezoelectric tube can drive the manipulator to achieve micro-motion positioning. It is widely used in scanning probe microscopy, fiber stretching and beam scanning. The piezoceramic tube actuator used to have continuous electrodes inside and outside. It is polarized along the radial direction. There are relatively high polarization voltages, but poor axial mechanical properties. A new tubular actuator is presented in this paper by combining interdigitated electrodes and piezoceramic tubes. The preparation, polarization and mesoscopic mechanical properties were investigated. Using Lead Zirconate Titanate (PZT-52) as a substrate, the preparation process of interdigitated electrodes by screen printing was studied. For initial polarization voltage determination, the local characteristic model of the actuator was extracted and the electric field was analyzed by a finite element method. By measuring the actuator’s axial displacement, we measured the actuator’s polarization effect. Various voltages, times and temperatures were evaluated to determine how polarization affects the actuator’s displacement. Optimal polarization conditions are 800 V, 60 min and 150 °C, with a maximum displacement of 0.88 μm generated by a PZT-52 tube actuator with interdigitated electrodes. PZT-52 tube actuators with a continuous electrode cannot be polarized under these conditions. The maximum displacement is 0.47 μm after polarization at 4 kV. Based on the results, the new actuator has a more convenient polarization process and a greater axial displacement from an application standpoint. It provides technical guidance for the preparation and polarization of the piezoceramic tube actuator. There is potential for piezoelectric tubular actuators to be used in a broader range of applications. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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18 pages, 5439 KiB

Open AccessArticle

Dahl Friction Model for Driving Characteristics of V-Shape Linear Ultrasonic Motors

by Bo Zhang, Xianghui Yuan, Yuansong Zeng, Lihui Lang, Hailong Liang and Yanhu Zhang

Micromachines 2022, 13(9), 1407; https://doi.org/10.3390/mi13091407 - 27 Aug 2022

Cited by 5 | Viewed by 1550

Abstract

The contact process of stator and slider described by the Coulomb friction model is basically in a pure sliding friction state, and a mechanical model based on the Dahl friction theory was proposed to describe the contact process between stator and slider of [...] Read more.

The contact process of stator and slider described by the Coulomb friction model is basically in a pure sliding friction state, and a mechanical model based on the Dahl friction theory was proposed to describe the contact process between stator and slider of V-shape linear ultrasonic motor. With consideration for the tangential compliance of stator and slider, the dynamic contact and friction processes of stator and slider were addressed in stages. The simulation results show that the ratio of the friction positive work decreases with the increase of the preload, and the vibration amplitude of the stator increases the proportion of positive work of the friction force. Improving the contact stiffness of the stator and slider is conducive to improving the output performance of the ultrasonic motor. The asymmetry of the left and right performance of the V-shaped vibrator will cause a difference in the left and right running speeds of the ultrasonic motor. The improved Dahl friction-driving model makes up for the discontinuity of tangential contact force calculated by the Coulomb friction model. This study demonstrates that the friction-driving model based on the Dahl theory is reliable and reasonable for linear ultrasonic motors according to the experimental results. Full article

(This article belongs to the Special Issue Piezoelectric Actuators and Sensors: Materials, Devices and Applications)

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