High Power Ultrasonic Transducer Research Articles

High thermal stability of piezoelectric properties in tetragonal Pb(In1/3Nb2/3)O3-PbTiO3 single crystal

The representatives of relaxor ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZNT) and (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMNT) have been extensively studied due to their excellent dielectric and piezoelectric properties near the morphotropic phase boundary (MPB). However, low rhombohedral to tetragonal phase transition temperature and Curie temperature directly affect the performance and stability of devices, particularly for high-power ultrasonic transducers. In this paper, the large size tetragonal 0.62Pb(In1/2Nb1/2)O3-0.38PbTiO3 (PINT) crystal was grown by the modified Bridgman technique. The crystals were oriented along the ⟨100⟩ direction to make bars with electrodes on (001) faces. The variation of the dielectric constant with temperature showed that the Curie temperature of PINT was 250 °C, and the maximum dielectric constant was 7.29 × 104 ɛ0. Fitting with Curie-Weiss’s law, we obtained that the relaxation degree was 1.44, which could mean that the dielectric properties of PINT are between relaxor ferroelectric and ordinary ferroelectric. At room temperature, electromechanical coupling coefficient k31 and piezoelectric strain constant d31 were 0.56 and 551 pC/N, respectively. Piezoelectric properties were relatively stable between room temperature and 175 °C. The material has good temperature stability in terms of piezoelectricity and dielectric properties. These results proved that the working temperature of the PINT crystal could reach about 175 °C, much higher than PZNT and PMNT single crystal, indicating their application in ultrasonic transducers at high temperatures.

Vibration characteristics of polymer-based Langevin transducers

Our previous studies demonstrated that some functional polymers could exhibit satisfactorily low mechanical loss in high-amplitude bending vibration in the ultrasonic frequency range. In this study, to explore further applications of these functional polymers in high-power ultrasonic transducers, we focus on Langevin transducers as they are most widely employed in industrial applications. The developed transducer has a sandwich structure: piezoelectric ceramic elements are clamped between two polymer cylindrical bodies with a metal screw. The vibration characteristics of the polymer-based Langevin transducers differ from the metal-based ones owing to the difference in the material constants. When working in the 1st-order longitudinal modes, the polymer-based transducers exhibit dumbbell-shaped deformations because of the higher stiffness of the metal screws. Their mechanical losses reach the maximal values on the vibrating bodies instead of the piezoelectric ceramic elements. Besides, when the strains on polymer vibrating bodies exceed certain values, there exist sharp reductions in mechanical quality factors (Q factors), which restrict the maximal vibration velocities of polymer-based transducers. The poly phenylene sulfide (PPS)-based transducer yields Q factors of 350 and its vibration velocity linearly increases to 1060 mm s−1, comparable to the maximal values achievable on metal-based ones. These properties indicate the potential of PPS-based transducers for ultrasonic applications.

Effects of high power ultrasonic vibration on temperature distribution of workpiece in dry creep feed up grinding

Temperature history and distribution of steel workpiece (X20Cr13) was measured by a high tech infrared camera under ultrasonic assisted dry creep feed up grinding. For this purpose, a special experimental setup was designed and fabricated to vibrate only workpiece along two directions by a high power ultrasonic transducer. In this study, ultrasonic effects with respect to grinding parameters including depth of cut (ae), feed speed (vw), and cutting speed (vs) has been investigated. The results indicate that the ultrasonic vibration has considerable effect on reduction of temperature, depth of thermal damage of workpiece and width of temperature contours. Maximum temperature reduction of 25.91% was reported at condition of vs=15m/s, vw=500mm/min, ae=0.4mm in the presence of ultrasonic vibration.

The development of recent high-power ultrasonic transducers for Near-well ultrasonic processing technology

With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology.With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology

Nonlinear dynamics of thin plates excited by a high-power ultrasonic transducer

Strong superharmonic and high-order subharmonic vibrations of thin metal plates are observed in the experiments when a high-power ultrasonic transducer is used to excite plate vibrations. A finite element model and a lumped-mass discrete parameter model are established, respectively, and numerical simulations are carried out to study the mechanism of nonlinear vibrations. The plate vibrations are characterized by time series, power spectra, phase portraits, Poincare maps and bifurcation diagram. It can be seen that the contact force waveform distortion is the reason for generating superharmonic vibration, while the intermittent contact between the thin plates and the ultrasonic transducer is the cause of subharmonic vibrations in the plates. The FEM simulation results are in agreement with the numerical results obtained from the discrete model, which have implications for the predication and control of nonlinear vibrations in ultrasonic assisted manufacturing and testing.

Review on application of the recent new high-power ultrasonic transducers in enhanced oil recovery field in China

Ultrasonic oil production technique is characterized by high adaptability, simple operation, low cost and zero pollution. In this paper, the recent new high-power ultrasonic transducers for Enhanced Oil Recovery field in China are summarized. The application of high-power ultrasonic transducers for Enhanced Oil Recovery are also introduced in the view of preventing paraffin precipitation by ultrasonic wave, ultrasonic crude oil viscosity reduction, ultrasonic demulsification/dehydration, removing plug using ultrasonic wave and ultrasonic descaling/anti-scaling. Finally, installation speculations and operable speculations for ultrasonic oil production in offshore oil fields are given. the purposed of this paper is to provide important process parameters and technical support for future large-scale application of ultrasonic oil production technique.

Lithium niobate ultrasonic transducer design for Enhanced Oil Recovery

Due to the strong piezoelectric effect possessed by lithium niobate, a new idea that uses lithium niobate to design high-power ultrasonic transducer for Enhanced Oil Recovery technology is proposed. The purpose of this paper is to lay the foundation for the further research and development of high-power ultrasonic oil production technique. The main contents of this paper are as follows: firstly, structure design technique and application of a new high-power ultrasonic transducer are introduced; secondly, the experiment for reducing the viscosity of super heavy oil by this transducer is done, the optimum ultrasonic parameters for reducing the viscosity of super heavy oil are given. Experimental results show that heavy large molecules in super heavy oil can be cracked into light hydrocarbon substances under strong cavitation effect caused by high-intensity ultrasonic wave. Experiment proves that it is indeed feasible to design high-power ultrasonic transducer for ultrasonic oil production technology using lithium niobate.

Piezoceramic Transducers Selection Method for High Power Ultrasonic Devices

(Received May 12, 2014) A universal method for selecting piezoceramic transducers used in high power ultrasonic devices such as ultrasonic welding and cutting systems has been presented. The key element of such systems is a high power ultrasonic sandwich transducer consisting of a stack of piezoceramic transducers mounted between two masses. Because of relatively large dispersion of piezoceramic transducer parameters between production lots, they must be selected in order to obtain a high quality and long-life sandwich transducer. Presented selection method consists of three stages. First, the parametric identi cation of the Butterworth Van Dyke equivalent circuit model is performed based on piezoceramic transducer electrical impedance measurements. Next, the electrical impedance frequency samples are estimated using the identi ed Butterworth Van Dyke model. Finally, the k-means clustering algorithm is used to select the best tted piezoceramic transducer sets.

Modelling and Designing of Ultrasonic Welding Systems

Abstract This article presents the main stages and challenges in modelling and designing of modern ultrasonic welding and cutting systems. First, the key components of such a system, such as an ultrasonic stack (con- sisting of a high power ultrasonic transducer and a sonotrode) and a digitally controlled ultrasonic power supply with precise control of the output power, have been considered. Next, a concept of measurement system for verification and validation of mathematical models of ultrasonic stacks and its components has been presented. Finally, a method of ultrasonic stack e-diagnosis based on ultrasonic transducer electrical impedance measurement during welding and cutting process has been described

Achieving Both High d 33 and High Q m for the Pb(Zr0.26Sn0.26Ti0.48)1−x Fe x O3−x/2 Ternary System for Use in High-Power Ultrasonic Transducers

For applications in high power ultrasonic transducers, both high piezoelectric coefficients d 33 and high mechanical quality factor Q m are essential. In this work, acceptor-doped Pb(Zr0.26Sn0.26Ti0.48)1−x Fe x O3−x/2 ferroelectric ceramics with compositions near the morphotropic phase boundary were prepared by routine solid-state reaction. By introducing Fe3+ ion into the perovskite crystal lattices, defect dipoles resulting from Fe3+ ions and oxygen vacancies are formed, pinning extrinsic domain wall motion, and hence increasing Q m but reducing d 33. It was found that substitution with 0.5 mol% Fe3+ resulted in high d 33 (390 pC/N) and high Q m (540). The nonlinear dielectric responses of these ceramics were evaluated on the basis of the Rayleigh law. Both Rayleigh coefficients, $$\alpha$$ and $$\kappa_{\rm{init}},$$ are reduced by doping with the acceptor ion Fe3+, indicating that the intrinsic contribution and reversible domain wall mobility are both reduced.

음향화학 반응용 강력초음파 개발

High-power ultrasonic promotes a chemical reaction by its own energy, thus it has been used for sonochemistry applications. For example, it has been mostly used for mixing, reaction catalyst, dispersion and disintegration. High-power ultrasonic transducer is made with structure based on a Bolt-clamped Langevin type Transducer (BLT), But it has difficulty in the development because degradation of piezoelectric ceramic by the heat generation of BLT. In this study, for a development of the transducer of 25 kHz and 1000 W used in sonochemistry and industrial cleaning, BLT with a hole in its center and tubular type waveguide of the transducer were designed based on finite element method (FEM). The transducer was fabricated based on the design parameter, and the impedance characteristics are measured experimentally and compared with the numerical results.

Simulation and Experiment Researches on Acoustic Field of Spherical Shell Focused Ultrasonic Transducer

Aiming at the deficiency of existing focused ultrasonic technology, a new high-power Spherical Shell Focused Ultrasonic Transducer (SSFUT) was designed. The SSFUT is composed of a sandwich piezoelectric ultrasonic transducer and a bending vibration spherical shell. Simulation on acoustic field of SSFUT was carried out. the acoustic field pressure distribution nephogram and the axial acoustic pressure curve of the SSFUT were obtained. The consistency of finite element simulation results and experimental results was verified by testing. The research provides a theoretical basis for implementation and application of the new focused ultrasonic technology.

Measurement System for Parameter Estimation and Diagnostic of Ultrasonic Transducers

The paper presents an architecture and design of measurement system and methods for parameter estimation and diagnostic of ultrasonic transducers used in ultrasonic welding and cutting systems manufactured by Tele and Radio Research Institute. The key element of the ultrasonic welding and cutting system is a high power ultrasonic transducer implemented as a sandwich transducer consisting of a stack of piezoelectric ceramic rings mounted between two masses. High quality welding and cutting demand predetermined frequency characteristic of transducer impedance. Also important are: high energy e ciency, high coupling coe cient, low dielectric loss, and the optimal radiation pattern. In order to manufacture high quality and long-life transducers the piezoelectric rings must be selected and the sandwich transducers diagnosed on the basis of their measured parameters. Presented measurement system takes advantage of the virtual instrument technique in the NI LabVIEW environment. It uses Agilent U2761A Function Generator, U2531A Data Acquisition Unit, and the linear ampli er to measure impedance frequency characteristic in the frequency range of 10 kHz to 100 kHz. Moreover, the system can measure the vibration amplitude in the range of 1 μm up to 100 μm, using an optical sensor, and the temperature of the transducer using a pyrometer sensor.

Resonance tracking and vibration stablilization for high power ultrasonic transducers

Resonant frequency shift and electrical impedance variation are common phenomena in the application of high power ultrasonic transducers, e.g. in focused ultrasound surgery and in cutting. They result in low power efficiency and unstable vibration amplitude. To solve this problem, a driving and measurement system has been developed to track the resonance of high power transducers and to stabilise their vibration velocity. This has the ability to monitor the operating and performance parameters of the ultrasonic transducers in real time. The configuration of the system, with its control algorithm implemented in LabVIEW (National Instruments, Newbury, UK), ensures flexibility to suit different transducers and load conditions. In addition, with different programs, it can be utilised as a high power impedance analyser or an instantaneous electrical power measurement system for frequencies in the MHz range. The effectiveness of this system has been demonstrated in detailed studies. With it, high transducer performance at high power can be achieved and monitored in real time.

Electroacoustic response of 1-3 piezocomposite transducers for high power applications

The electroacoustic performance of 1-3 piezoelectric composite transducers with low loss polymer filler was studied and compared to monolithic Pb(Zr,Ti)O(3) (PZT) piezoelectric transducers. The 1-3 composite transducers exhibited significantly high electromechanical coupling factor (k(t) ∼ 0.64) when compared to monolithic counterparts (k(t) ∼ 0.5), leading to the improved bandwidth and loop sensitivity, being on the order of 67% and -24.0 dB versus 44% and -24.8 dB, respectively. In addition, the acoustic output power and transmit efficiency (∼50%) were found to be comparable to the monolithic PZT transducers, demonstrating potential for broad bandwidth, high power ultrasonic transducer applications.

Experimental Analysis of 1-3 Piezocomposites for High-Intensity Focused Ultrasound Transducer Applications

Piezocomposites with 1-3 connectivity have been extensively used in medical imaging transducers and high-intensity focused ultrasound transducers, but most studies of 1-3 piezocomposites address medical imaging applications. The purpose of this study was to completely investigate 1-3 composites specifically for high-power ultrasonic transducer applications via a series of experimental analyses. PZT4-epoxy composite focused transducers with various aspect ratios and volume fractions were constructed in-house for the evaluation of the coupling factor, dielectric loss tangent, quality factor, bandwidth, acoustic impedance, and electroacoustic efficiency. The experimental analyses demonstrated that although the coupling factor of composite transducers was higher than that of the ceramic transducer, the composite transducers had a lower efficiency due to the high dielectric loss and high mechanical energy loss of the composites. In addition, the bandwidth and acoustic impedance of composite transducers were superior to the ceramic transducer. For the composite transducers, the efficiency and acoustic impedance were inversely proportional to the aspect ratio and linearly proportional to the volume fraction. The coupling of inter pillars that are too close to each other could cause a significant decrease in the efficiency of the composite transducer. With an appropriate design in terms of the aspect ratio, volume fraction, and PZT-pillar spacing, a high-efficiency composite high-intensity focused ultrasound transducer can be achieved.

FEM Modeling of Vibro-Impact Response of Metal Plates Excited by a High-Power Ultrasonic Transducer

When thin metal plates are excited by a high-power ultrasonic transducer, superharmonic and high-order subharmonic vibration phenomena of the plates are observed in our experiments. However, the nonlinear mechanism in the system is still not fully understood. In this paper, a finite element model is established based on the experimental conditions and numerical simulations are performed to explore the generation mechanism of the nonlinear vibration. By comparing the waveforms and frequency spectra of the vibration velocity of the plate to these of the contact force between the ultrasonic horn tip and the plates, it can be found that waveform distortion of the contact force is the main reason for generating the superharmonic vibration, while the intermittent contact-impact between the horn tip and the plate is the reason for subharmonic vibration in the plate. The FEM simulation results can explain reasonably the observed experimental phenomena, which are useful to help to improve the effects of the nonlinear phenomena occurred in ultrasonic processing.

Effect of Inter-Rod Coupling on 1-3 Piezocomposite High-Power Ultrasonic Transducers

Efficiency is a critical performance for a high-power ultrasonic transducer composed of 1-3 piezocomposites and geometric parameters of the composites can influence the efficiency of the transducer. The effect of inter-rod responses in the composite matrix on the efficiency was experimentally investigated in this study. For analyses, four PZT4-epoxy composite ultrasonic transducers with various volume fractions and inter-rod spacing were fabricated in-house. The experimental results demonstrated that the inter-rod coupling of the 0.1-mm spacing could significantly degrade the efficiency of the composite probe at about 1.0 MHz resonance since the 0.1-mm spacing between PZT4 rods was so small as to cause a high interference. At the same volume fraction, the transducer engineer should take the inter-rod coupling into account for the design of the high-power ultrasonic transducer.

An improved phase-locked loop method for automatic resonance frequency tracing based on static capacitance broadband compensation for a high-power ultrasonic transducer

The phase-locked loop (PLL) method is widely used for automatic resonance frequency tracing (ARFT) of high-power ultrasonic transducers, which are usually vibrating systems with high mechanical quality factor (Qm). However, a heavily-loaded transducer usually has a low Qm because the load has a large mechanical loss. In this paper, a series of theoretical analyses is carried out to detail why the traditional PLL method could cause serious frequency tracing problems, including loss of lock, antiresonance frequency tracing, and large tracing errors. The authors propose an improved ARFT method based on static capacitance broadband compensation (SCBC), which is able to address these problems. Experiments using a generator based on the novel method were carried out using crude oil as the transducer load. The results obtained have demonstrated the effectiveness of the novel method, compared with the conventional PLL method, in terms of improved tracing accuracy (±9 Hz) and immunity to antiresonance frequency tracing and loss of lock.

Nonlinear Behaviors of Giant Magnetostrictive High Power Ultrasonic Transducer

GMHPUT has a wide range of potential application in industrial. However, nonlinearity between exciting current and output displacement spoils GMHPUT’s performance. To explore the nonlinearity behaviors of GMHPUT, a nonlinear dynamic model was established. The bifurcation diagrams, phase portrait, Poincaré mapping diagrams, amplitude spectrum, Lyapunov exponent, etc. which demonstrate dynamical characteristics of the system were obtained by numerical integration. Analysis indicates: Nonlinearity of response could be improved by increasing of damping coefficient. Chaos would appear when stiffness of the system is low. At last experiments were done to verify the model. Calculation results and experimental results show a good agreement.