piezoelectric ceramic/polymer transducers

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Enhancing the bandwidth of piezoelectric composite transducers for air-coupled non-destructive evaluation

Enhancing the bandwidth of piezoelectric composite transducers for air-coupled non-destructive evaluation

However, one area of investigation appears to offer more scope for improvement than was first thought. Although the ceramic itself cannot be machined as a solid block, it is feasible that when the ceramic is embedded with the passive polymer phase as a piezocomposite device, it may be possible to alter the transducer structure. As discussed, the inherent difficulty in ceramic machining is the cutting of the rigid ceramic due to the brittleness of the ceramic and the build up of heat within the structure. However, if the ceramic is embedded within the polymer phase, then the overall volume of ceramic is decreased significantly, meaning less ceramic to be machined. Also, utilising this machining method, the ceramic pillars are decoupled via the passive material that acts as an insulator, so that heat convection between pillars is minimised. Coupled to this, if properly cooled during the machining phase, the grinding/cutting tool will dissipate the heat generated in the machining of the ceramic structure during the machining of the polymer phase. With this method of manufacture, the tool is only cutting ceramic for a shorter period of time, depending upon the volume fraction, in comparison to attempting to machine solid ceramic.
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Harmonic analysis of lossy piezoelectric composite transducers using the plane wave expansion method

Harmonic analysis of lossy piezoelectric composite transducers using the plane wave expansion method

Periodic composite transducers are generally accepted as the design of choice in many biomedical [1], sonar [2] and nondestructive testing applications [3]. This is due to the constituent materials combining to realise better operational characteristics, coupled with the availability of new materials [4, 5]. The most frequently used designs are manufac- tured by dicing the ceramic into a series of pillars and then filling the void with a passive polymer phase [6]. The 1-3 design has connectivity in only one direction for the ceramic phase but in all three directions for the polymer phase. For the 2-2 design, the ceramic is cut longitudinally in one direction so that there is connectivity in two directions for both the ceramic and polymer phases. However, one of the problems with this architecture is the presence of parasitic waves, which are generated between adjacent pillars (inter- pillar modes) or within the pillars (intra-pillar modes), interfering with the piston like behaviour of the fundamental thickness mode [7]. Extensive experimental observations have highlighted the intricate dependency between the geometry of the design, the mate- rial properties and the key operational characteristics of the device. It has been suggested that a passive material with a low transverse coupling would enhance the transducer’s efficiency [7, 8].
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Theoretical modelling of frequency dependent elastic loss in composite piezoelectric transducers

Theoretical modelling of frequency dependent elastic loss in composite piezoelectric transducers

The large number of degrees of freedom in the design of piezoelectric transducers requires a theoretical model that is computationally efficient so that a large number of iterations can be performed in the design op- timisation. The materials used are often lossy, and indeed loss can be used to enhance the operational characteristics of these designs. Mo- tivated by these needs, this paper extends the one-dimensional Linear Systems Model to incorporate frequency dependent elastic loss. The re- ception sensitivity, electrical impedance and electromechanical coupling coefficient of a 1-3 composite transducer, with frequency dependent loss in the polymer filler, is investigated. By plotting these operating charac- teristics as a function of the volume fraction of piezoelectric ceramic an optimum design is obtained. A device with a non-standard, high shear attenuation polymer is also simulated and this leads to an increase in the electromechanical coupling coefficient. A comparison with finite element simulations is then performed. This shows that the two methods are in reasonable agreement in their electrical impedance profiles in all the cases considered. The plots are almost identical away from the main resonant peak where the frequency location of the peaks are comparable but there is in some cases a 20 percent discrepancy in the magnitude of the peak value and in its bandwidth. The finite element model also shows that the use of a high shear attenuation polymer filler damps out the unwanted, low frequency modes whilst maintaining a reasonable impedance magni- tude.
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Characterisation of the polarisation state of embedded piezoelectric transducers by thermal waves and thermal pulses

Characterisation of the polarisation state of embedded piezoelectric transducers by thermal waves and thermal pulses

Piezoelectric smart structures are created by embedding piezoelectric transducers into structural components to make them controllable or responsive to their environment. These structures find applications, for instance, for health- monitoring of safety components, for reducing noise emis- sion in automobile engineering, or for damping vibrations. Their mass-production requires control of the polarisation state due to mechanical and thermal loads appearing during device fabrication.

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A Semantic Approach of ITS: Perspective on Road Safety

A Semantic Approach of ITS: Perspective on Road Safety

The objective of the work is to estimate the underwater sea floor environment and also to measure the depth of the sea floor by installing the SODAR equipment in a ship. For the long range transmission and reception of echo back, a low frequency of 33 KHz is used. The ultrasonic waves are transformed into acoustic waves and are transmitted into the acoustic medium. As it travels towards the depth, after hitting the target the waves gets reflected back and reaches the transducer. The transducer is a bi-directional transducer that converts the electrical energy to acoustic energy during transmission and back converts acoustic energy to electrical energy during reception. From the received echo signal the depth of the sea floor and sea bed surface variations can be measured. The arrangement of multibeam transducers helps in the estimation of objects below the water surface.
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Design and analysis of two piezoelectric cymbal transducers with metal ring and add mass

Design and analysis of two piezoelectric cymbal transducers with metal ring and add mass

It is obvious that previous structure with bonding layer has a low strength and efficiency especially in deep water. In this paper, based on traditional structure two piezoelectric transducers names piezoelectric transducer A (PTA) and piezoelectric transducer B (PTB) as were reported. PTA adopted and integrated most of previous effective methods such as metal ring, add mass and none glue layer. PTB was designed with a multilayer cavity structure and compared with PTA. In these two transducers, optimizations of metal ring and add mass were adopted to protect the ceramic, avoid corrosion, and increase its strength. Every structural parameter of PTA was simulated and evaluated to investigate its influence. Section 2 illustrates the theoretical principle and physical mechanism in simulations. In Section 3, experimental arrangements and results are introduced and discussed. Then, the conclusions are summarized and displayed in Section 4.
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Novel Design of Buchholz Relay by Implementation of Ultrasonic Liquid Level Transducer

Novel Design of Buchholz Relay by Implementation of Ultrasonic Liquid Level Transducer

Ultrasonic transducers convert AC signal into ultrasound signal &vice versa. Ultrasonic, specifically refers to piezoelectric transducers or alternativelycapacitive transducers. Piezoelectric crystals change structure and shape when a voltage is connected ; AC voltage makes them vibrate at the same frequency and generate ultrasonic sound. Capacitive sensor or transducer use electrostatic fields between a conductive diaphragm and plate.The beam pattern of a transducer can be explained by the active transducer surface and shape& size, the ultrasound wavelength produce by sensor , and the sound velocity of the propagation medium. The diagram represent the sound fields of an unfocused and a focusing ultrasonic transducer in oil, plainly at differing energy band. Piezoelectric materials producing a voltage when force is indulge to them, they can also work as ultrasonic finder. Few systems use separate transmitters signals and receivers, while others combine both functions into a single piezoelectric transceiver. Ultrasound transmitters can also use non-piezoelectric principles to produce signal. such as magnetostriation. Materials with this property change size slightly when exposed to a magnetic field, and make practicalpurpose transducers.
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Experimental evaluation of three designs of electrodynamic flexural transducers

Experimental evaluation of three designs of electrodynamic flexural transducers

The receive signals, with 128 averages and a low pass filter applied to reduce noise, are shown in Figure 8a. The signal amplitude is small for all three transducers, with single shot signal-to-noise ratio (SNR) ' 2 dB. It is, however, measurable, which is an important proof of concept. The largest signal comes from transducer C, which was specifically designed so that the magnetic field is oriented to enhance reception. The frequency content of the received signals of the three transducers, as well as from the microphone, are shown in Figure 8b. By comparing the received signals, it was seen that the transducers represented an accurate number of cycles, without adding much ringing. This is again seen in the frequency spectra, where the width of the 50 kHz frequency peaks from the EDFTs is comparable to that of the microphone. Since the EDFTs (and flexural transducers in general) are narrowband (high Q) devices, this would not be true for a broadband source. Transducers B and C do not accurately capture the centre frequency of the Airmar transducer, which is overestimated by approximately 2 kHz. This is another consequence of using a resonant system, where the transducers will skew the received signal frequency towards their mode frequency. As seen in the transmission data (Figure 8b), both transducers B and C have a mode frequency above 50 kHz, which explains the shift in centre frequency of the receive signals. Transducer A has a slightly narrower bandwidth, as it exhibited a longer ring down time, as seen in Figure 8a.
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Fabrication and Characterization of Piezoelectric Ceramic Fiber/Aluminum Alloy Composites

Fabrication and Characterization of Piezoelectric Ceramic Fiber/Aluminum Alloy Composites

873 K is omitted because it is the same as Fig. 5 (b) ). From this, it can be seen that at T = 853 K, the amount of residual eutectic alloy is large. This may be attributed to the low temperature, which caused insufficient softening of the matrix material, resulting in less plastic deformation and more residual eutectic alloy. It can be seen that at T = 893 K, the amount of residual eutectic alloy is insignificant, but the piezoelectric fiber was damaged. As the temperature is high, softening of the matrix material might have proceeded, resulting in an increase in plastic deformation, which may have caused excess pressure on the piezoelectric fiber, leading to its rupture. In case of T = 873 K, the amount of residual eutectic alloy is less and damage to the piezoelectric fiber could not be seen, therefore, T = 873 K seems to be optimum temperature.
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Piezoelectric Ceramic Controlled with Platinum Implant as New Isolator in ECG

Piezoelectric Ceramic Controlled with Platinum Implant as New Isolator in ECG

During this process, two Pt-wires of 0.25 mm diameter (Aldrich 349402) were implanted in the middle of the ceramic in a longitudinal way separated each from other 2 mm in a parallel form; thus Platinum electrodes to- tally immersed in the ceramic was created. This ceramic was sintered in air with a heater ramp rate of 5˚C/min from room temperature to 600˚C and a second heater ramp rate of 10˚C/min from 600˚C to 1200˚C; the latter process lasted for one hour in a Platinum crucible. After sinterization, silver electrodes were deposited on the lower and upper face and on the Pt-wires of the CCP2. Finally, the discs were electrically poled to 1.5 kV/mm of voltage for one hour at 60˚C in a silicone oil bath. The schematic symbol used for describing the CCP2 and the graphical symbol can be seen in Figure 1.
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Polymer composites for 3D printing of functional sensors and transducers

Polymer composites for 3D printing of functional sensors and transducers

To demonstrate the incorporation of functional sensors into AM manufactured devices, we formulated a simple conductive thermoplastic composite termed ‘carbomorph’ using carbon black (Fig. 5a and b) in a matrix of polycaprolactone. The carbon black particles were dispersed in the matrix via solution dispersion. The resultant composite was then formulated into a feedstock filament for a desktop FDM system with multi-material capability (Fig. 5c and d). The loading of carbon black within the polymer matrix was optimized so as to be easily printable by the desktop FDM without modification (Fig. 5e). Higher loadings of carbon black resulted in a composite with high melt viscosity that would not easily pass through the nozzle of the FDM system.
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Developing of Ultrasound Experimental Methods using Machine Learning Algorithms for Application of Temperature Monitoring of Nano-Bio-Composites Extrusion

Developing of Ultrasound Experimental Methods using Machine Learning Algorithms for Application of Temperature Monitoring of Nano-Bio-Composites Extrusion

Polypropylene (PP) is a commonly used thermoplastic polymer with excellent properties such as chemical inertness, lightweight, low cost, and easy processing. Despite these benefits, it has some disadvantages, such as small impact resistance and stiffness and low thermal stability [79, 80]. Thermal and mechanical properties of plastics can be significantly improved using fillers. Natural fibers are currently getting considerable attention as a new advanced material for application in automotive, building and packaging industries. The main advantage is biodegradability, sustainability, low cost, low density, high strength and lower abrasiveness. However, due to their hydrophilic nature, the natural fibers have poor compatibility with the polymer matrix, poor water resistance and produce low-performance materials. The University of Toronto has overcome several of these problems in interfacial adhesion for natural fiber composites, developing the composite that has excellent fiber dispersion on the PP matrix with excellent compatibility between the fibers and polymer [78]. Low thermal stability of the natural fibers can lead to the decomposition during material processing, which limits their applications significantly.
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Characteristics and applications of air coupled micromachined ultrasonic transducers

Characteristics and applications of air coupled micromachined ultrasonic transducers

By producing series of graphs as in Figure 7.13 for a particular green state ceramic, and having a system of high temperature air-coupled capacitance transducers to monitor the resonant [r]

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Electromechanical surface damping combining constrained layer and shunted piezoelectric matetrials with passive electrical networks of second order

Electromechanical surface damping combining constrained layer and shunted piezoelectric matetrials with passive electrical networks of second order

structure was arbitrary piezoelectric ceramic shunted with an electrical circuit of two resonant provides similar characteristics to viscoelastic materials with effective ranges at the e[r]

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Two Temperature Heat Flux of Semi Infinite Piezoelectric Ceramic Rod

Two Temperature Heat Flux of Semi Infinite Piezoelectric Ceramic Rod

[2] H. S. Tzou, “Multifield Transducers, Devices, Mecha- tronics Systems and Structronic Systems with Smart Ma- terials,” The Shock and Vibration Digest, Vol. 30, No. 4, 1998, pp. 282-294. doi:10.1177/058310249803000402 [3] S. S. Rao and M. Sunar, “Piezoelectricity and Its Use in

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Analysis of Possible Nonlocal Effects in Laser Beams Generated by Piezoelectric Ceramic

Analysis of Possible Nonlocal Effects in Laser Beams Generated by Piezoelectric Ceramic

isting condition of generalized quantum entanglement (GQE) between all exist- ing particles in a physical system, usually extremely weak because of the huge en- tropy, rises when a myriad of group of particles are conditioned to have the same quantum state (local entropy reduction) via a strong local field such as electric or magnetic one, for example. In the present work we report that the anomalous forces verified can be microscopically originated from the state of generalized quan- tum entanglement of their particles, in a manner similar to the anomalous effects analyzed in other physical systems mainly based on dipoles, dielectric materials and superconductors. The difference between the anomalous effect raised from piezoelectric materials and each previous physical system analyzed is in the type of the source device and the nature of the effect. For instance, in case of capaci- tors under high voltage, it appears on them an upward anomalous force decreas- ing their apparent weight and in case of superconductors and diode laser beams it is produced a field of forces at distance in the surroundings.
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Investigation the Dimensional Ratio Effect on the Resonant Properties of Piezoelectric Ceramic Disk

Investigation the Dimensional Ratio Effect on the Resonant Properties of Piezoelectric Ceramic Disk

have been reported to compete with PZT family [6]. In practical applications, the piezoelectric ceramics are usually circular, so the vibration characteristics of piezo- electric ceramic disks are important in design and appli- cation of devices. Knowledge of the vibration modal shapes and the influence of the material property and geometry are of interest for the further development of novel devices and selection of the appropriate disk ge- ometry for specific applications [7-9]. Moreover, the vibration characteristics of piezoelectric ceramic disks had been studied intensively by many of the researchers [7,10-13]. These characteristics are identified by the resonant response and the resulting modal shapes of the
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Online Full Text

Online Full Text

Bilgi et al. [2] studied on the electrochemical deep hole drilling and concluded that the material removal rate varies with supply voltage and bare tip length. Hyun Ahn et al. [3] performed a study on electro-chemical micro drilling using ultra short pulses and concluded that localization distance can be controlled by controlling the voltage and pulse duration. Kazak et al. [4] investigated the micro-holes and grooves features during micro-electrochemical machining. Authors conclude that the side gap and the frontal gap decrease with increase in feed rate. Bhattacharya and Munda [5] studied on the ECDM during machining of non-conductive ceramic materials and conclude that the MRR is very low at low applied voltage, and over-cut on hole radius is greater at higher electrolyte concentration. Sarkar et al [6] investigated on the electrochemical discharge micro-drilling during machining of advanced ceramics. They concluded that the quality of the hole during micro-drilling greatly depends on the applied voltage and electrolyte concentration. Basak and Ghosh [7] studied on the mechanism of material removal in electrochemical discharge machining and concluded that the substantial increase in the material removal rate can be achieved by introducing an additional inductance in the control circuit. Ming-Chang et al. [8] studied the effect of carbon content and microstructure on the metal removal rate in electrochemical machining. They concluded that the material removal rate and current efficiency increase with carbon content and the roughness of the machined surface for annealed microstructure is greater than those of the quenched and tempered steels. Singh et al. [9] studied on the electrochemical spark machining (ECSM) process during machining of piezoelectric ceramic and concluded that material removal rate increased with increase in supply voltage and electrolyte concentration. Manna and Bhattacharyya [10] studied on dual response approach for parametric optimization of CNC wire cut EDM of particulate reinforced aluminium silicon carbide metal matrix composite. The significant factors were determined for each machining performance criteria from experimental results, through
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Electrical Output Characteristics of Piezoelectric Ceramics Cymbal Transducer with Drop Weight Impact Techniques

Electrical Output Characteristics of Piezoelectric Ceramics Cymbal Transducer with Drop Weight Impact Techniques

Compared with the results determined in a previous study [10], the results of the present study suggested that the generated voltage of the Cymbal transducer was much higher than that of an uncapped piezoelectric ceramic disk. The results of the previous study [10] indicated that when the applied mechanical energy was 45mJ, the generated voltage of an uncapped piezoelectric ceramic disk with a diameter of 15mm and thickness of 0.9mm was approximately 10V; however, when the same piezoelectric ceramic disk was used as the piezoelectric element in a Cymbal transducer, the generated voltage increased to between approximately 160V to 220V, depending on the end-cap geometry. The amplification factor of the Cymbal transducer used in this study ranged from 16 to 22.
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Design And Development Of Battery-Less Electronic Floor Based On Human Foot Step Impact Force

Design And Development Of Battery-Less Electronic Floor Based On Human Foot Step Impact Force

In doing this project, there are some problem that were faced during the completion of this project. One of them is to test the piezoelectric itself. The machine which is the actuator can only press one piezo at a time. So, the problem is when doing an experiment to test a combination of connection of piezoelectric. It cannot be done with the help of the machine thus it need to be done manually with real human impact foot step. There are a few questions that need to be answered which one of them is how many piezoelectric should be used in this project, what is the best rectifier diode that has less power requirement and low voltage drop. Furthermore, this project involved a wireless transmission of data. One of the intention of this project is where a power generated from the piezo will be go through the rectifier and the power will power up a transmitter to transmit the bit to be received by receiver. With this, come another problem which is to find a suitable transmitter and receiver circuit that has low power consumption and can be power up by the energy harvester.
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