Piezoelectric Transmitter Research Articles

ISO 24543 for AE sensor sensitivity verification - support packages help to implement software scripts

This paper presents an overview over ISO 24543, the new ISO Standard for acoustic emission (AE) sensor sensitivity verification, published in Sept. 2022. ISO 24543 is based on the face-to-face setup, where a piezoelectric transmitter generates a known particle motion pulse, stimulating a directly coupled AE sensor. ISO 24543 gives two procedures, one for the determination of a transmitter’s transmitting sensitivity spectrum, referring to absolute units of nm/V, and one for the determination of the AE sensor’s receiving sensitivity spectrum, referring to absolute units of V/nm. ISO 24543 has been developed to replace the face-to-face method that delivers sensitivity spectra referring to units of V/µbar, whereby the units of µbar used for the stimulation of the SUT are neither proven nor reproducible. This paper introduces two support packages, containing descriptions and examples of software scripts that shall help experts getting their sensor verification setup quickly running. This presentation also discusses the influence of the sensor’s load on the particle motion at the ransmitter’s output.

High-resolution 3D ultrasonic imaging using high-frequency piezoelectric transmitter and ultra-multiple laser 2D scanning

In this paper, we extend a piezoelectric and laser ultrasonic system (PLUS) to a high-frequency version for high-sensitivity three-dimensional (3D) ultrasonic imaging by utilizing a unique characteristic of PLUS. PLUS combines a piezoelectric transmitter and a two-dimensional (2D) scan of a laser Doppler vibrometer (LDV). A high frequency can be used simply by adopting a high-frequency piezoelectric transmitter with a center frequency, such as 15 MHz, since the LDV has a broad bandwidth reception of 0–25 MHz. Furthermore, a 2D array receiver with a small interelement pitch can be achieved by precisely scanning a small laser irradiation spot. We experimentally demonstrate its 3D imaging capability for flat-bottom-hole and fatigue-crack specimens.

MODELING OF VIBRATIONS OF A STACKED PIEZO ELEMENT MADE OF POROUS PIEZOCERAMICS

The work is devoted to a numerical study of the effectiveness of using porous piezoceramics in a stacked piezoelectric element, which can be used as a power drive element, a piezoelectric generator, or an ultrasonic emitter. The use of porous piezoceramics in stacked piezoelements has not received enough attention in the literature. The use of porous piezoceramics in stacked piezo elements has not received enough attention in the literature. The paper considers a stacked piezo element consisting of eight solid cylinders counter-polarized in the axial direction. The material of the cylinders is PZT-4 piezoceramic, the porosity of which varies from 0% to 80%. The problem of axial steady-state oscillations in the vicinity of the first resonance frequency and below it is solved. The lower end of the cylinder is fixed along the normal, excitation of oscillations is carried out by mechanical action under uniformly distributed pressure at the upper face or by the action of electric potential difference at the electrodes. The problems are solved in the framework of linear axisymmetric theory of electroelasticity. With mechanical action, the output characteristic of the device is the electrical potential of the free electrodes; with electrical action, it is the amplitude of the axial vibrations of the upper end or the reaction force if it is fixed. The finite element method implemented in the ACELAN package is used as the solution method. As a result of the numerical solution, the dependence of the percentage of porosity on the output characteristics of the piezo element is investigated: the frequencies of resonance and antiresonance, the electromechanical coupling coefficient, the output potential under mechanical loading, the amplitude of oscillations of the free upper end and the coupling reaction at its fixing when the oscillations are excited by the potential difference and the energy of the elastic element attached to this end. The analysis of the dependence of these characteristics allows us to conclude that it is reasonable to use such an element with porous ceramics as a piezoelectric generator and transmitter. It is noted that the choice of the percentage of porosity depends directly on the intensity of loads and the strength of porous piezoceramics.

Evaluation of Repellency and Lethal Effects of Ultrasonic Waves on the Blattella germanica (Blattodea: Blattellidae).

The German cockroach, Blattella germanica (Insecta: Blattodea, Blattellidae), which occurs widely in human buildings, is a small cockroach species. Cockroach control chemical pesticides are toxic to the environment, and it is sometimes impossible to prevent them. Controlling Blattella germanica through ultrasonic waves can be efficient and less dangerous for the environment. In this study, the repellency and lethal effect of ultrasonic waves on male and female German cockroaches was tested in a twin glass cubic chamber at laboratory condition. The wave frequencies tested ranged from 20 to 100kHz with 5kHz steps. A signal generator generated these frequencies, and the piezoelectric transmitter of these ultrasonic waves was positioned in the chamber's center on the upper side. Fisher's test showed that there was the greatest repellency effect in both male and female at frequencies of 35 and 40kHz. According to the results of the regression test, the most lethal effect is at the frequencies of 40 and 75kHz. The operating ultrasonic frequencies investigated in this study can be used to repel and kill German cockroaches as pests endangering human health and environment.

Acoustic Sensing Response in Human Tissues for Theranostics and Implants

This letter investigates the impacts of high- and low-frequency acoustic waves on various human tissues. It is observed that low-frequency (4.6 kHz) acoustic energy works as a better alternative for acoustic power distribution across the tissues. Using a 4.6 kHz piezoelectric diaphragm transmitter and receiver, finite-element simulation was performed, and then, an experimental examination was done to evaluate the energy distribution. The average electrical output voltage produced by the low-frequency transducers was 0.758 V in the male subject's palm, 0.187 V in the wrist, and 0.015 V close to the elbow region. In comparison, it was 1.27 V in the female subject's palm, 0.534 V in the wrist, and 0.146 V close to the elbow region. The low-frequency response of the sensors was found to be equal to or a maximum of 39.7% better than that of the high-frequency alternative. The obtained output voltage can be used to power medical implants and extract medical data at great depths with minimal attenuation.

Multi-mode 3D ultrasonic phased array imaging method using piezoelectric and laser ultrasonic system (PLUS)

As a high-resolution 3D phased-array imaging method, a piezoelectric and laser ultrasonic system (PLUS) was proposed, which is a combination of a piezoelectric transmitter and an ultra-multiple scan of a laser Doppler vibrometer. Thus far, PLUS has used an identical mode for incident and scattered waves. On the other hand, the ultrasonic scattering phenomena can accompany the mode conversion, which may provide further information on defects. In this paper, we propose multi-mode PLUS to enhance its imaging capability and attain more robustness. After describing the principle of multi-mode PLUS, we validated the imaging algorithm and demonstrated the improvement in the image resolution using a dataset of simulated received waves for the longitudinal-wave incidence to scatterers. Furthermore, we experimentally demonstrated the efficacy of multi-mode PLUS in a specimen with branched stress corrosion cracking.

A high-efficient piezoelectric wireless energy transmission system based on magnetic force coupling.

This research reports an acoustic wireless energy transmission system featuring high efficiency and robustness. The proposed energy transmission system is composed of a piezoelectric cantilever-based transmitter and receiver that are coupled using the forces of permanent magnets. Taking advantage of the strong coupling effect of magnet force, we can transfer mechanical energy wirelessly through mediums of the air and metal plate. The experimental studies show that the voltage transmission efficiencies reach 55.59% and 51.58% in cases of energy transfer through mediums of the air and the air-metal-air, respectively. In addition, the maximum power transmission reaches 42.73 mW at an operational frequency of 104.2Hz. This wireless energy transmission system can be used for powering devices in enclosed, electrically shielded, and biomedical areas.

Flood Detection in Steel Tubes Using Guided Wave Energy Leakage.

A study that evaluated the use of ultrasonic-guided waves to detect water in hollow pipes is presented. In this work, a guided wave system employed a 40 kHz piezoelectric (PZT) transmitter and a PZT ultrasound transducer. The transmitter was based on a battery-operated microcontroller, and the receiver was composed of a digital signal processor (DSP) module connected to a PC via a USB for monitoring purposes. The transmitter and receiver were attached, non-intrusively without perfect alignment, to the external wall of a steel tube 1 m × 270 mm × 2 mm in size. Flood detection was performed based on guided wave attenuation due to energy leakage from the internal steel wall of the tube to water. Two approaches were carried out. The former was an off-line signal response based on the wavelet energy entropy analysis of a received pulse; the latter was a real-time hit-and-miss analysis centered on measuring the time-space in-between two transmitted pulses. Experiments performed in the laboratory successfully identified flooded tubes.

Development of methods and devices for air-coupled ultrasonic through transmission testing of large-sized objects made of polymer composite materials

It is shown that in order to increase the sensitivity of air-coupled ultrasonic through transmission testing of products made of polymer composite materials, it is necessary to develop highly sensitive low-frequency wideband air-coupled piezoelectric transducers. The methods of providing both high sensitivity and a wideband of air-coupled ultrasonic piezoelectric transducer are considered. Air-coupled ultrasonic highly sensitive broadband piezoelectric transducer based on the use of mosaic contact piezoelectric transducer technology, the choice of optimal matching layers and the use of various options for excitation of piezoelectric transmitter have been proposed and developed. It is shown that by use of mosaic air-coupled low-frequency broadband piezoelectric transducers, it is possible to ensure high sensitivity of testing and ensure the accuracy of measurement of acoustic characteristics (ultrasound velocity, density, etc.) with air-coupled ultrasonic low-frequency through transmission testing of large-sized objects made of polymer composite materials.

Exploring 3D elastic-wave scattering at interfaces using high-resolution phased-array system

The elastic-wave scattering at interfaces, such as cracks, is essential for nondestructive inspections, and hence, understanding the phenomenon is crucial. However, the elastic-wave scattering at cracks is very complex in three dimensions since microscopic asperities of crack faces can be multiple scattering sources. We propose a method for exploring 3D elastic-wave scattering based on our previously developed high-resolution 3D phased-array system, the piezoelectric and laser ultrasonic system (PLUS). We describe the principle of PLUS, which combines a piezoelectric transmitter and a 2D mechanical scan of a laser Doppler vibrometer, enabling us to resolve a crack into a collection of scattring sources. Subsequently, we show how the 3D elastic-wave scattering in the vicinity of each response can be extracted. Here, we experimentally applied PLUS to a fatigue-crack specimen. We found that diverse 3D elastic-wave scattering occurred in a manner depending on the responses within the fatigue crack. This is significant because access to such information will be useful for optimizing inspection conditions, designing ultrasonic measurement systems, and characterizing cracks. More importantly, the described methodology is very general and can be applied to not only metals but also other materials such as composites, concrete, and rocks, leading to progress in many fields.

High-resolution 3D phased-array imaging of fatigue cracks using piezoelectric and laser ultrasonic system (PLUS)

This paper reports the effectiveness of a novel imaging system, piezoelectric and laser ultrasonic system (PLUS), for the three-dimensional (3D) imaging of fatigue cracks with a high-resolution. The PLUS combines a piezoelectric transmitter and the two-dimensional (2D) mechanical scanning of a laser Doppler vibrometer, enabling the 2D matrix array with an ultra-multiple number of receiving points for 3D phased array imaging. After describing the principle and 3D imaging algorithm of PLUS, we show the fundamental 3D imaging capability of the PLUS in a flat-bottom-hole specimen with varying the number of receiving points under a fixed large receiving aperture. We then demonstrate that the PLUS with 4275 receiving points (i.e. 75 × 57) achieves high-resolution 3D imaging of a fatigue crack with a high signal-to-noise ratio, providing the outline of the fatigue crack geometry. We also discuss the effectiveness of the ultra-multiple receiving points for suppressing grating lobes and random noise.

Nonlinear acoustic-structure interaction in high intensity focused ultrasound power transfer systems

Ultrasound power transfer (UPT) has emerged as one of the most promising technique to wirelessly transfer power. The mechanism of UPT involves vibration-induced generation of acoustic waves from a piezoelectric transmitter which propagate in a medium to interact with a piezoelectric receiver, and generate vibrations-induced electrical response in the receiver. In this work, a novel technique of using a high intensity focused ultrasound (HIFU) is proposed to enhance the power transfer efficiency as compared to current UPT systems. HIFU concentrates the entire transmitted energy at a focal spot where the piezoelectric receiver is placed, thus dramatically reducing the input energy required, as compared to unfocused UPT systems. The physics of the HIFU-UPT system consists of a nonlinear acoustic wave propagating in a medium to induce a nonlinear structural response in the receiver. Implementing the HIFU-UPT phenomena in an experimentally validated finite-element based model shows that the nonlinear acoustic field can induce disproportionately high responses in a receiver if the harmonics in the acoustic wave coincide with the structural resonant frequencies of the receiver. This research aims to provide a comprehensive framework for designing UPT systems operating in nonlinear acoustic fields with a finite size receiver.

Toward an ultra-high resolution phased-array system for 3D ultrasonic imaging of solids

Ultrasonic phased-array (PA) systems have been widely adopted in the field of nondestructive evaluation for material characterization and imaging of internal defects. Whereas many defects exhibit complex three-dimensional structures, most PA systems provide only two-dimensional images. In this Letter, we demonstrate the ability to create high-resolution 3D images of internal defects using a PA system based on a piezoelectric and laser ultrasonic system (PLUS). The PLUS combines a piezoelectric transmitter to insonify the structure to be inspected with a laser Doppler vibrometer to create a matrix array of receiver points without contact. The small size of the laser beam results in an ultra-multiple number of elements on the order of thousands, which is impossible to achieve with a conventional piezoelectric matrix array transducer. An emission from a piezoelectric transmitter compensates for the intrinsically low sensitivity of a laser Doppler vibrometer. After formulating the 3D imaging algorithm of the PLUS, we demonstrate that the PLUS with 4096 receiving points (i.e., 64 × 64 points) achieves high-resolution 3D imaging in a specimen with a flat bottom hole. We also visualize the complex structure of stress corrosion cracking. We believe that the 3D imaging capability of the PLUS may open up new avenues to the accurate evaluation of material strength, the identification of the types of defects, and the elucidation of the mechanisms of defect initiation.

A Block Diagram of Electromagnetoelastic Actuator Nanodisplacement for Communications Systems

The parametric block diagram of the electromagnetoelastic actuator nanodisplacement or the piezoactuator is determined in contrast the electrical equivalent circuit types Cady or Mason for the calculation of the piezoelectric transmitter and receiver, the vibration piezomotor with the mechanical parameters in form the velosity and the pressure. The method of mathematical physics is used. The parametric block diagram of electromagnetoelastic actuator is obtained with the mechanical parameters the displacement and the force. The transfer functions of the electroelastic actuator are determined. The the generalized parametric block diagram, the generalized matrix equation for the electromagnetoelastic actuator nanodisplacement are obtained. The deformations of the electroelastic actuator for the nanotechnology are described by the matrix equation. Block diagram and structural-parametric model of electromagnetoelastic actuator nanodisplacement for nanodisplacement of the communications systems are obtained, its transfer functions are bult. Effects of geometric and physical parameters of electromagnetoelastic actuators and external load on its dynamic characteristics are determined. For calculations the communications systems with the piezoactuator for nanodisplacement the parametric block diagram and the transfer functions of the piezoactuator are obtained.

Electroelastic Actuator Nano- and Microdisplacement for Precision Mechanics

In the present work the structural-parametric model of the piezoactuator is determined in contrast electrical equivalent circuit types Cady or Mason for the calculation of the piezoelectric transmitter and receiver, the vibration piezoactuator and the vibration piezomotor with the mechanical parameters in form the velosity and the pressure. The aim of this work is to obtain the structural-parametric model of the electroelastic actuator with the mechanical parameters the displacement and the force. The method of mathematical physics is used. Structural scheme of electroelastic actuator for nanotechnology is obtained. The transfer functions of the actuators are determined. For calculations control systems for nanotechnology with piezoactuator the structural scheme and the transfer functions of piezoactuator are obtained. The generalized structural-parametric model, the generalized structural scheme, the generalized matrix equation for the electroelastic actuator nano- and microdisplacement are obtained in the matrix form. The deformations of the electroelastic actuator for the precision mechanics are described by the matrix equation.

Parametric structural schematic diagram of electroelastic actuator in nanotechnology.

In this work the parametric structural schematic diagram of the electroelastic actuator or the piezoactuator is determined in contrast the electrical equivalent circuit types Cady or Mason for the calculation of the piezoelectric transmitter and receiver, the vibration piezomotor with the mechanical parameters in form the velocity and the pressure. The method of mathematical physics is used. The parametric structural schematic diagram of electroelastic actuator is obtained with the mechanical parameters the displacement and the force. The transfer functions of the electroelastic actuator are determined. The generalized parametric structural schematic diagram, the generalized matrix equation for the electroelastic actuator nano displacement are obtained. The deformations of the electroelastic actuator for the nanotechnology are described by the matrix equation.

Measurement of diesel exhaust fluid concentration in urea-SCR after-treatment system

In an effort to meet the established emission standards Selective Catalytic Reduction (SCR) is used to reduce NOx emissions with diesel exhaust fluid (DEF) as additive in the exhaust of diesel engines. ISO 22241-1:2006 specifies the quality characteristics of DEF in order to maintain efficiency and hence, it is essential that the concentration of urea in DEF is accurately monitored. In this paper, a measurement system is designed, developed and tested for measuring the concentration of urea in DEF. The design involves piezoelectric ultrasound transmitter and receiver with associated electronics operating at a frequency of 4 MHz. The concentration of urea in DEF is measured (i) by measuring the time of flight of ultrasound waves between transmitter and receiver (ii) by measuring the amplitude of received signal in terms of frequency using voltage-to-frequency converter. The measurement system is modeled using two-port network model for piezoelectric transmitter/receiver and transmission line model for DEF medium. The prototype of measurement system is fabricated with all associated electronics and tested for variation in concentration of urea in DEF. The results from prototype are in close agreement with the results obtained from analytical model. The measurement system is tested for repeatability and sensitivity to temperature.

Characterization of Piezoelectric Accelerometers Beyond the Nominal Frequency Range

Abstract Ultrasonic testing is preferred widely for the evaluation of material properties. However, ultrasonic signals are highly affected by the characteristics of the piezoelectric transducers employed for the measurements. Since ultrasonic transducers are mostly used to measure the travel time of waves only, their non-flat frequency response does not affect the results. On the other hand, the analyses based on the full-waveform provide more reliable results, as thousands of additional data points in the measured signals are taken into account to determine the material properties (e.g., material damping). To perform such analyses, however, the transfer function of the transducer is required in order to normalize the recorded signals. In this paper, a new calibration approach was proposed to determine the transfer function of the piezo-electric accelerometers that are used beyond their nominal frequency range. A nano-laser vibrometer was utilized to measure the high frequency ultrasonic vibrations generated by the piezoelectric transmitter employed as the excitation source for the accelerometers. The transfer functions of two accelerometers with different nominal frequency ranges were determined for frequencies between 20 and 70 kHz, which were then used to capture the ultrasonic waves on a lightly cemented-sand medium. The original signals and the ones corrected by eliminating the effect of the transfer functions were processed to determine the material damping of the medium. Improvement in the accuracy of the material damping is achieved with the corrected signals compared to the uncorrected ones.

Peculiarities of quasi-longitudinal elastic wave propagation through the interface between isotropic and anisotropic media: Theoretical and experimental study

The peculiarities of elastic wave propagation in a bilayer medium are studied theoretically and experimentally. One (isotropic) layer was an acrylic glass plate, and the other (anisotropic) was a quartz single-crystal. In experiments, the elastic waves were generated by a piezoelectric transmitter and received by a piezoelectric transducer contacting the surface of the model medium. The propagation time of a quasi-longitudinal wave was determined using high-order statistics. In the general case, the incident elastic waves are split at the interface between the layers: beams undergo double reflection and triple refraction. The measured dependences of the propagation times of quasi-longitudinal split waves on the angles of refraction are in satisfactory agreement with the calculated ones. The calculation was performed by solving the Christoffel equation with allowance for the boundary conditions.

A Fibre Bragg Grating Sensor as a Receiver for Acoustic Communications Signals

A Fibre Bragg Grating (FBG) acoustic sensor is used as a receiver for acoustic communications signals. Acoustic transmissions were generated in aluminium and Carbon Fibre Composite (CFC) panels. The FBG receiver was coupled to the bottom surface opposite a piezoelectric transmitter. For the CFC, a second FBG was embedded within the layup for comparison. We show the transfer function, frequency response, and transient response of the acoustic communications channels. In addition, the FBG receiver was used to detect Phase Shift Keying (PSK) communications signals, which was shown to be the most robust method in a highly resonant communications channel.