DEVELOPMENT OF A DEVICE FOR MEASURING AND ANALYZING VIBRATIONS

It is known that vibration is generated to one degree or another by all moving parts of machines. Vibration processes arising in the process of functioning of machines and equipment are highly informative, reflecting the technical condition of many parts and assemblies quite fully. Therefore, the use of vibration diagnostics systems makes it possible to determine a defect even at the stage of inception, thereby excluding emergency stops of machinery. An urgent task is to create a vibration analysis device, which consists of a sensor for measuring vibration, the principle of operation of which is based on the use of a direct piezoelectric effect. The output signal of the sensor will go to a personal computer or any other device with the Windows operating system, where a spectral analysis of the measured vibration signal is carried out using a Matlab-based diagnostic program.

Optical actuation of a micromechanical photodiode via the photovoltaic-piezoelectric effect

Radiation pressure and photothermal forces have been previously used to optically actuate micro/nanomechanical structures fabricated from semiconductor piezoelectric materials such as gallium arsenide (GaAs). In these materials, coupling of the photovoltaic and piezoelectric properties has not been fully explored and leads to a new type of optical actuation that we call the photovoltaic-piezoelectric effect (PVPZ). We demonstrate this effect by electrically measuring, via the direct piezoelectric effect, the optically induced strain in a novel torsional resonator. The micron-scale torsional resonator is fabricated from a lattice-matched single-crystal molecular beam epitaxy (MBE)-grown GaAs photodiode heterostructure. We find that the strain depends on the product of the electro-optic responsivity and piezoelectric constant of GaAs. The photovoltaic-piezoelectric effect has important potential applications, such as in the development of configurable optical circuits, which can be used in neuromorphic photonic chips, processing of big data with deep learning and the development of quantum circuits.

Static Force Measurement Using Piezoelectric Sensors

In force measurement applications, a piezoelectric force sensor is one of the most popular sensors due to its advantages of low cost, linear response, and high sensitivity. Piezoelectric sensors effectively convert dynamic forces to electrical signals by the direct piezoelectric effect, but their use has been limited in measuring static forces due to the easily neutralized surface charge. To overcome this shortcoming, several static (either pure static or quasistatic) force sensing techniques using piezoelectric materials have been developed utilizing several unique parameters rather than just the surface charge produced by an applied force. The parameters for static force measurement include the resonance frequency, electrical impedance, decay time constant, and capacitance. In this review, we discuss the detailed mechanism of these piezoelectric-type, static force sensing methods that use more than the direct piezoelectric effect. We also highlight the challenges and potentials of each method for static force sensing applications.

A Block Diagram of Electromagnetoelastic Actuator for Control Systems in Nanoscience and Nanotechnology

The block diagram and the transfer functions of the electromagnetoelastic actuator are received for control systems in nanoscience and nanotechnology. The block diagram of the electromagnetoelastic actuator is reflected the transformation of electrical energy into mechanical energy, in contrast to Cady’s and Mason’s electrical equivalent circuits of piezotransducer. The electromagnetoelasticity equation and the second order linear ordinary differential equation with boundary conditions are solved for calculations the block diagram of the electromagnetoelastic actuator. The block diagram of the piezoactuator is obtained with using the reverse and direct piezoelectric effects. The back electromotive force is determined from the direct piezoelectric effect equation. The transfer functions of the piezoactuators are obtained for control systems in nanoscience and nanotechnology.

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.

Piezoelectric Polymer and Paper Substrates: A Review

Polymers and papers, which exhibit piezoelectricity, find a wide range of applications in the industry. Ever since the discovery of PVDF, piezo polymers and papers have been widely used for sensor and actuator design. The direct piezoelectric effect has been used for sensor design, whereas the inverse piezoelectric effect has been applied for actuator design. Piezo polymers and papers have the advantages of mechanical flexibility, lower fabrication cost and faster processing over commonly used piezoelectric materials, such as PZT, BaTiO3. In addition, many polymer and paper materials are considered biocompatible and can be used in bio applications. In the last 20 years, heterostructural materials, such as polymer composites and hybrid paper, have received a lot of attention since they combine the flexibility of polymer or paper, and excellent pyroelectric and piezoelectric properties of ceramics. This paper gives an overview of piezoelectric polymers and papers based on their operating principle. Main categories of piezoelectric polymers and papers are discussed with a focus on their materials and fabrication techniques. Applications of piezoelectric polymers and papers in different areas are also presented.