Piezo Plates Research Articles

Comparative analysis of flag based energy harvester undergoing extraneous induced excitation

This study presents a detailed comparative analysis of the piezoelectric flexible plate under the influence of oscillating wakes of different bluff bodies. The piezoelectric plate is tested to determine the optimal configuration for energy harvesting from the wake flow of bluff bodies with different cross-sections in a low-speed closed-circuit wind tunnel. The Reynolds number is varied from 10000 to 75000 and the distance between the bluff body and plate is changed from 1D to 7D (where D is the diameter of the bluff body). The flutter of the plate without a bluff body is considered as a benchmark case and then subsequently the bluff bodies are introduced to see energy generation behavior. The results show that the bluff body caused a significant reduction of 50% in the flow speed as compared to the flutter case along with an improvement of 847% in energy harvesting output. Furthermore, selecting an appropriate bluff body ensures higher peak-to-peak flapping amplitude, which in turn produces a higher amount of electrical energy due to higher bending curvature and resultant strain produced in the piezoelectric plate. An increase of 125% in flapping amplitude is obtained using a bluff body compared to the flutter case. Furthermore, comparison within the various bluff bodies shows that change in cross-section has an enormous impact on output, and an increase of 515% in output power is obtained compared to the typical circular bluff body, which is more often quoted in the literature. Additionally, bending modes are identified and the variation in output power is linked with the flapping behavior of the piezoelectric plate, which is helpful in understanding the energy generation behavior of the piezo plate.

Coronary artery lipid accumulation prevention through vibrating piezo electric nano plates embedded in smart stent.

Considering the lipid concentration and side effects regarding the stents used by surgeons, a new heart stent model is proposed. In the new stent, a few piezo plates are designed and attached to the stents by which release of the lipids can take place due to the applied alternative voltages. Due to the vibrations of small-scale piezoelectric plates, the deposition of low-density-lipoproteins (LDL) floating in the blood flow in the coronary arteries is prevented. Small-scale effects are considered using nonlocal elasticity theory, and the interaction between fluid and solid is modeled using the Navier-Stokes equation. The effect of fluid parameters as well as applied voltage and geometry structure is reported. Developing of smart stents maybe the key for prevention of short time conventional stents failure.

IoT Based Smart Street Lights Empowered by Piezoelectric Sensors

The power generated from piezo plates is connected to the lead acid battery which is rechargeable battery and supply the energy to the street light under two conditions first is the LDR should be detect a dark condition and the ultrasonic sensor should detect any human being or vehicle passes on the roadways under these conditions with a small delay and automatic turn on the street light with full brightness and as human being or vehicles go away from that location the street lights come back to low brightness mode. During daylight the LDR detects a full bright light due to this this circuit is in the disable state and no question of turning any of the straight light during day time the microcontroller is programmed for the ultrasonic sensor which sense the object or human being and triggers the output relay to enable or disable the time based operation of the street lights.

ABOUT INFLUENCE OF PARAMETERS OF A WEAR PLATE OF THE NORMAL PROBE ON CHARACTERISTICS FREQUENCY A SPECTRUM AND A PULSE OF A BOTTOM SIGNAL

Computer modelling of an acoustic channel of the normal probe for a reflector as a bottom surface has shown, that increase of amplitude of a pulse echo signal, registered by the probe with a wear plate from epoxy resin with fine – dispersed filler due to increase of its contents, causes reduction of speed of longitudinal waves in a wear plate with the appropriate downturn of the first resonant frequency owing to what the spectrum of a signal may vary essentially. Reception of short pulses, on amplitude of same duration considerably surpassing pulses for protectors from epoxy resin with filler, is provided with application of a protector from mineral ceramics, having own lowest resonant frequency is much higher than the basic own frequency piezo plate. Comparison of experimental and theoretical pulses and spectra of ground signals for direct converters with qualitatively distinguished protectors has confirmed an opportunity of presence of the several expressed maxima of a spectrum of a pulse with oscillating modulation of amplitude for a wear plate from epoxy resin with filler with low speed of distribution of longitudinal waves.

Visualization of Three-Dimensional Acoustic Streaming Flow Patterns around an Inclined Triangular Obstruction using Digital In-Line Holographic Micro-Particle Tracking Velocimetry

Acoustic Streaming is a flow phenomenon with many applications in the field of microfluidics, such as micro mixing[1, 2] and particle manipulation[3]. With the manufacturing techniques evolves, more complicated geometries can be designed for microfluidic device and 3-D acoustic streaming patterns may occurs. In this study, 3-D trajectories of particle induced by acoustic streaming around an inclined triangular obstruction in a microchannel were visualized by a volumetric tracking method using Digital Inline Holographic Microscopy (DIHM)[4-6]. The triangular obstruction has a tip angle of 20° and an inclined angle of 30°. The acoustic streaming is created under 12 kHz oscillation of a piezo plate driven by 20V voltage. Illuminated by a 450nm continuous laser, the magnified hologram of the motion of 1.79μm tracer particles was recorded by a low-cost 10X industrial microscope with a machine vision camera of 10 fps (frames per second). Using RayleighSommerfeld back-propagation method[7], particle locations was reconstructed frame by frame and 3-D tracking of individual particles was performed afterwards. The trajectories of each particle were reconstructed to reveal the vortical structure of the acoustic streaming flow. For the current system setup, the measurable range was estimated to be 550×685×840 μm3. The 3-D location reconstruction accuracy was verified with a calibration target and the location sensitivity was found to be linear throughout the measurable range. Reconstruction at different depth locations show that the dick-shaped calibration dots and the spherical polystyrene particles have different intensity profiles. The calibration dots show local minimum of intensity at the correct depth location, while polystyrene particles show local maximum of intensity instead. Resolved particle trajectories show that the acoustic streaming flows cause particles to move with 3-D spiral shaped motions near the side of the triangular obstruction, while particles away from the obstruction shows planar motions.

К вопросу об интерпретации эхограмм ультразвукового импульсного дефектоскопа

The echogram of an ultrasonic pulse flaw detector is considered as an auto-convolution of an acoustic signal radiated into the load and received by a damped piezo plate. The reconstruction of the acoustic signal makes it possible to determine the drift of the reflection coefficients of ultrasonic vibrations at the boundaries of the piezo plate-load and piezo plate-damper, for example, when checking transducer during manufacture, under operating conditions. A method for evaluating the sensitivity of the transducer is proposed.

Comparison of Acoustic Streaming Flow Patterns Induced by Solid, Liquid and Gas Obstructions.

In this study, acoustic streaming flows inside micro-channels induced by three different types of obstruction—gaseous bubble, liquid droplet and solid bulge—are compared and investigated experimentally by particle tracking velocimetry (PTV) and numerically using the finite element method (FEM). The micro-channels are made by poly(dimethylsiloxane) (PDMS) using soft lithography with low-cost micro-machined mold. The characteristic dimensions of the media are 0.2 mm in diameter, and the oscillation generated by piezoelectric actuators has frequency of 12 kHz and input voltages of 40 V. The experimental results show that in all three obstruction types, a pair of counter-rotating vortical patterns were observed around the semi-circular obstructions. The gaseous bubble creates the strongest vortical streaming flow, which can reach a maximum of 21 mm/s, and the largest u component happens at Y/D = 0. The solid case is the weakest of the three, which can only reach 2 mm/s. The liquid droplet has the largest v components and speed at Y/D = 0.5 and Y/D = 0.6. Because of the higher density and incompressibility of liquid droplet compared to the gaseous bubble, the liquid droplet obstruction transfers the oscillation of the piezo plate most efficiently, and the induced streaming flow region and average speed are both the largest of the three. An investigation using numerical simulation shows that the differing interfacial conditions between the varying types of obstruction boundaries to the fluid may be the key factor to these differences. These results suggest that it might be more energy-efficient to design an acoustofluidic device using a liquid droplet obstruction to induce the stronger streaming flow.

Study of two-spring piezoelectric harvesters

The paper considers two piezoelectric harvesters, consisting of two springs, attached to a piezoelectric transformer, and having a common concentrated mass. Modeling has been done by means of ANSYS, whereas the horizontal deviation of the mechanical system has been obtained, and the charge, accumulated on the electrodes of the piezo plate has been calculated. An equivalent circuit has been drawn and experimental studies have been conducted in order to validate the developed model.

Poled piezo plates kill bacteria resting on their surface

The surfaces of a positively poled ferroelectric material prove deadly to E. coli, depolarizing the cells after attracting the extra surface charge used by their membranes for selectivity and function.

A method to improve the resolution of the diffraction spectrophotometer

In a number of situations, the resolution of modern spectrometers may be not high enough. This communication describes the use of an auxiliary interferometer together with a diffraction spectrometer, thus enabling its resolution and sensitivity to be enhanced during spectroscopy of adsorbed molecular layers. In this way, the industrial device is turned into a combined diffraction-interference monochromator. Numerical calculations and experiments show that the resolution of the combined diffraction spectrometer can be enhanced by an order of magnitude. In addition, the described device is a tunable multi-beam interferometer, allowing scanning through the spectrum. Scanning is done by turning the multi-beam interferometer. The article provides experimental data on adjusting the interferometer by tilting it with respect to incident radiation. Provision is made for the adjustment of the device by using a piezo plate. The increased sensitivity of the combined device allows it to be used as a spectrum analyzer of adsorbed substances. The design of the attachment provides an easy-to-install fitting for the input of the substance under test.

Recycling Piezo-Crystal Based Sounders from Small (Electronic) Devices into Energy Harvesting Devices

Many small devices now incorporate a sound feedback device using piezo crystal plates of varying sizes (10mm-20mm diameter). After these devices are discarded, the piezo crystal plates are usually of no value other than a curious toy or component. This work presents a potential use of this device (18.8mm diameter unimorph PZT 5H piezo plate) for harvesting energy by mounting it on the wrist (at the base of meta carpal) of human subjects. The subjects were made to walk at an average steady pace of 0.7m/s. The device generated voltage in the range of 180.4mV to 1674.60mV. ANSYS 10 simulation shows that the optimum voltage will be generated at resonance frequency of approximately 204Hz.

Modal Analysis of 27 mm Piezo Electric Plate for Small-Scale Underwater Sonar-Based Navigation

This work presents progress towards the development of a small-scale, purely sonar-based navigation device for a robotic fish (~394 mm long). Aperture overloading of small (5 mm diameter) ultrasonic transmitters does not allow them to be used effectively inside water. A test on a 27 mm diameter buzzer piezo plate shows promising performance under water at frequencies from 4.5 kHz to 80 kHz. ANSYS-based simulation was therefore used to find modal frequencies at higher frequencies so as to optimize this encouraging result. The simulation process also discovered several antiresonant frequencies such as 38.5 kHz, 54 kHz, and 57.5 kHz. All frequencies above the 8th harmonic (10,589.02 Hz) are out of phase with the input load except a resonance frequency of 42.5 kHz and an antiresonance frequency of 56.5 kHz. Also, the first harmonic (1,648.73 Hz) is the only frequency that gave a nodal deformation.

Perceptional Characteristics of Vibration and Torque through Hand and Arm.

Perceptional characteristics of both hand and arm regarding the externally applied vibration and torque were investigated to design the information tool for physically handicapped people who lost their visual sensation or hearing. Perceptional characteristics of vibration were varied by the direction of vibration source, the frequency and the amount of weight. Perception of the torque that rotates the right arm anticlockwise seemed to become indistinct when the moment of inertia of rotating element was small. These results were thought to be caused by the area covered with the palm on the handle and the link mechanism of both ulna and radius bones. It was possible to recognize positions of the vibration through piezo plates on the skin of the palm. However, the perception was affected by the input frequency and voltage to the piezo plates.