Ultrasonic Energy Transmission Research Articles

A Universal Model for Ultrasonic Energy Transmission in Various Media.

This study presents a comprehensive model for ultrasonic energy transfer (UET) using a 33-mode piezoelectric transducer to advance wireless sensor powering in challenging environments. One of the advantages of UET is that it is not stoppable by electromagnetic shielding and can penetrate metal. Existing models focus on feasibility and numerical analysis but lack an effective link between input and output power in different media applications. The proposed model fills this gap by incorporating key factors of link loss, including resonant frequency, impedance matching, acoustic coupling, and boundary conditions, to predict energy transfer efficiency more accurately. The model is validated through numerical simulations and experimental tests in air, metal, and underwater environments. An error analysis has shown that the maximum error between theoretical and experimental responses is 3.11% (air), 27.37% (water), and 1.76% (aluminum). This research provides valuable insights into UET dynamics and offers practical guidelines for developing efficient wireless powering solutions for sensors in difficult-to-access or electromagnetically shielded conditions.

Evaluation Method for Underwater Ultrasonic Energy Radiation Performance Based on the Spatial Distribution Characteristics of Acoustic Power.

In recent years, underwater wireless ultrasonic energy transmission technology (UWUET) has attracted much attention because it utilizes the propagation characteristics of ultrasound in water. Effectively evaluating the performance of underwater ultrasonic wireless energy transmission is a key issue in engineering design. The current approach to performance evaluation is usually based on the system energy transfer efficiency as the main criterion, but this criterion mainly considers the overall energy conversion efficiency between the transmitting end and the receiving end, without an in-depth analysis of the characteristics of the distribution of the underwater acoustic field and the energy loss that occurs during the propagation of acoustic waves. In addition, existing methods focusing on acoustic field analysis tend to concentrate on a single parameter, ignoring the dynamic distribution of acoustic energy in complex aquatic environments, as well as the effects of changes in the underwater environment on acoustic propagation, such as spatial variability in temperature and salinity. These limitations reduce the usefulness and accuracy of models in complex marine environments, which in turn reduces the efficiency of acoustic energy management and optimization. To solve these problems, this study proposes a method to evaluate the performance of underwater ultrasonic energy radiation based on the spatial distribution characteristics of acoustic power. By establishing an acoustic power distribution model in a complex impedance-density aqueous medium and combining numerical simulation and experimental validation, this paper explores the spatial variation of acoustic power and its impact on the energy transfer efficiency in depth. Using high-resolution spatial distribution data and actual environmental parameters, the method significantly improves the accuracy of the assessment and the adaptability of the model in complex underwater environments. The results show that, compared with the traditional method, this method performs better in terms of the accuracy of the acoustic energy radiation calculation results, and is able to reflect the energy distribution and spatial heterogeneity of the acoustic source more comprehensively, which provides an important theoretical basis and practical guidance for the optimal design and performance enhancement of the underwater ultrasonic wireless energy transmission system.

Influence of contact characteristics of joint surface on vibration performance of the giant magnetostrictive transducer

The giant magnetostrictive transducer is a transducer device that realizes magneto-mechanical energy conversion. Each mechanical component is connected by the joint surface to realize the transmission of ultrasonic vibration energy. To ensure the efficient transmission of energy, the influence of the contact characteristics of the joint surface on the output stability of the transducer is studied. According to the contact conditions between the mechanical joint surfaces of the giant magnetostrictive ultrasonic transducer (GMUT), the key factors affecting the mechanical vibration performance of the ultrasonic system are obtained by analyzing the vibration transmission characteristics of the joint surfaces. The influence of different joint surface contact characteristics (JSCT) on the amplitude–frequency curve of the transducer is analyzed by the ANSYS software. Simulations and experiments have been conducted to verify the predicted results. As the preload force increases, the natural frequency of the transducer increases, but the growth rate decreases. The natural frequency of the double-rod GMUT with a small joint surface area is slightly higher in the optimal output mode shape, while its amplitude is significantly larger. The optimal prestress for the GMUT with different-sized joint surfaces is 3–5 MPa. This paper acquires the JSCT under a high-frequency vibration condition, reveals the influence of the joint surface on the mechanical output performance of the GMUT, and can provide a theoretical basis for the design and analysis of the rotary ultrasonic vibration processing system.

Miniaturized acoustic concentrators for ultrafast 3D ultrasound imaging

Ultrafast 3D ultrasound imaging is a rapidly growing research field that enables real-time imaging at a high frame rate and in a non-invasive manner. Currently, to achieve ultrafast 3D ultrasound, plane or diverging waves from virtual sources are used. These virtual sources can be considered as focal points during emission, allowing for improved transmission of ultrasonic energy. However, they have limitations in terms of transmitted energy, complex electronics, and timing issues, which impact the quality of the resulting images. To address this, a study was conducted to design and experiment with new miniaturized ultrasound transmitters based on cylindrical waveguides with tapered sections. These transmitters, with a diameter of approximately 100 μm, can replace the virtual sources. A numerical study based on 2D axisymmetric Finite Element Modeling (FEM) is first performed to model the transmission and reflection of longitudinal ultrasonic waves through various cylindrical rods. The results demonstrated that the transmission depends on the diameter ratio, frequency and longitudinal mode order (L0, L1, L2, etc.). An experimental study is then conducted on a stainless steel waveguide instrumented with 6mm piezo discs. The mechanical energy, estimated using Laser Doppler Vibrometer is transmitted through a 150 μm diameter rod, allowing mechananical focusing in the frequency range between 0.5 and 5 MHz. The application of this method to separate emission/reception transducers is then demonstrated for 3D ultrafast imaging.

Optimal design of ultrasonic transducer based on multi-layer backing with adjustable impedance

Ultrasonic transducers, especially used in medical imaging, strike a balance between sensitivity and bandwidth to yield high-quality images. This challenge centers on the optimal transmission of acoustic energy across the layers of transducer. The backing layer stands as a critical component of transducers, orchestrating the conversion of acoustic impedance to enhance bandwidth. While traditional designs often utilize metal particle-polymer composites, issues arise from material limitations, complex fabrications, and deviations in sample properties. This study introduces an optimized multilayer backing (MLB) design using a metal-polymer structure. Implementing an equivalent circuit model, an MLB of epoxy-aluminum composite is designed. The ultrasonic transducer has an operating frequency of about 6 MHz, in which the backing layer is a stacking composite of 19.3 μm epoxy resin and 30 μm aluminum foil. Notably, this optimized design increased the -6dB bandwidth from 27.72 % to 33.44 % and verified its superior electro-acoustic performance based on ultrasonic imaging. Furthermore, this innovative design approach provides a wider range of acoustic impedance, improves the efficiency of ultrasonic energy transmission, and provides a streamlined approach to miniaturized transducer design.

Highly morphing and reconfigurable fluid–solid interactive metamaterials for tunable ultrasonic guided wave control

Fluid–structural interactions enable the alternation of local resonance behaviors of elastic metamaterial unit cells. Magnetically active ferrofluids facilitate reconfiguration couplings for breaking and tunneling ultrasonic wave energy transmission. This Letter presents a magnetic fluid–solid interactive metamaterial to achieve the tunable manipulation of multimodal, dispersive ultrasonic guided waves. It is revealed that the phenomenon of the fluid–structure interaction plays an indispensable role in the achievement of bandgap formation and translation. The tunable mechanism stems from the variation of the fluid–solid coupling reconfiguration arising from liquid morphing via electromagnetic stimuli. The tunable wave control performance was explicitly validated through both numerical simulations and experimental verifications. Such an active metamaterial system may possess application potential for future highly flexible and tunable wave control, e.g., selective-tunnel waveguiding and adaptive mechanical frequency filtering.

Ultrasonic-Assisted Rock-Breaking Technology and Oil and Gas Drilling Applications: A Review

High-efficiency rock-breaking is a problem that has long been studied in the oil- and gas-drilling industry. The successful use of ultrasonic technology in related fields has prompted us to study how to introduce ultrasonic technology into rock-breaking in oil and gas drilling. This paper introduces and discusses the successful cases of ultrasonic breaking technology in related fields, summarizes the three basic forms of ultrasonic action on rocks, namely, resonance, impact and cavitation, expounds the factors and laws that affect ultrasonic-assisted rock-breaking, and summarizes the research results reported in recent years. It is believed that, at present, the application of ultrasonic-assisted rock-breaking technology in the oil- and gas-drilling industry still faces some problems and challenges: first, the downhole high-temperature and high-pressure conditions will affect the effect of ultrasonic-assisted rock-breaking, and the related mechanisms and research are not clear; second, the impact of circulating media on ultrasonic-assisted rock-breaking is not clear; third, the problem of ultrasonic propagation and utilization in the downhole has not been well-solved; fourth, the stability of drilling tools and circulating media caused by high-frequency characteristics has not been well-solved. Therefore, it is suggested to increase research on the mechanism of ultrasonic-assisted rock-breaking with oil- and gas-drilling characteristics and the transmission and utilization of downhole ultrasonic energy in the future, and increase the development of supporting products to support the application of this technology in the oil and gas industry.

Planar acoustic transducer and underwater ultrasonic wireless energy transmission

Planar acoustic transducer and underwater ultrasonic wireless energy transmission

Rock Triaxial Tests: Global Deformation vs Local Strain Measurements\u2014Implications

Accurate stress–strain measurements in triaxial tests are critical to compute reliable mechanical parameters. We focus on compliance at the interfaces between the specimen and endcaps, and test specimens under various triaxial conditions using different instrumentation protocols. The tested materials include aluminum, Eagle Ford shale, Berea sandstone, and Jubaila carbonate. Results obtained following common practice reveal that surface roughness at the specimen-endcap interfaces leads to marked seating effects, affects all cap-to-cap based measurements and hinders ultrasonic energy transmission. In particular, cap-to-cap deformation measurements accentuate hysteretic behavior, magnify biases caused by bending and tilting (triggered by uneven surfaces and misalignment), and affect the estimation of all rock parameters, from stiffness to Biot’s α-parameter. Higher confining pressure diminishes seating effects. Local measurements using specimen-bonded strain gauges are preferred (Note: mounting strain gauges on sleeves is ill-advised). We confirm that elastic moduli derived from wave propagation measurements are higher than quasi-static moduli determined from local strain measurements using specimen-bonded strain gauges, probably due to the lower strain level in wave propagation and preferential high-velocity travel path for first arrivals.

A Physics-Based Signal Processing Approach for Noninvasive Ultrasonic Characterization of Multiphase Oil-Water-Gas Flows in a Pipe.

A signal processing technique is presented for determining the composition of multiphase oil-water-gas flow in a pipe using noninvasive ultrasonic speed of sound measurements from a transmitter-receiver pair bonded to diametrically opposite sides of a pipe. A linear chirp excitation is used to send broadband ultrasonic energy that propagates in two paths from transmitter to receiver such as: 1) a wave through the pipe wall and then the multiphase mixture and 2) ultrasonic guided waves along the pipe wall in the circumferential direction. As the ultrasonic attenuation of the multiphase mixture increases, the amplitude of the signal through the fluid mixture decreases relative to that of circumferential guided waves, making it difficult to determine the time of arrival of the fluid-path signal and, hence, the speed of sound in the mixture. The proposed signal processing technique overcomes this challenge by using: 1) a guided wave subtraction approach to suppress the strength of guided wave signals relative to the fluid-path signal and 2) a Gaussian reconstruction approach for synthetic enhancement of the fluid-path signal by output signal reconstruction at frequencies corresponding to peak transmission of ultrasonic energy. The efficacy of the technique is demonstrated using experiments carried out in a field-scale flow loop with varying compositions of oil-water-gas mixtures. It is shown that the proposed approach can enhance the signal detectability by approximately 20 dB in comparison with the traditional approach that does not utilize guided wave subtraction and also improves the gas tolerance of composition measurements up to 20% in gas volume fraction.

A Novel Heat Shrinkable Ultrasonic Transducer for Rotary Ultrasonic Micro-Nano Precision Manufacturing

Rotary ultrasonic machining (RUM) has been proven to be a suitable technology for micro-nano precision manufacturing for hard and brittle ceramics/composite materials. However, the working frequency of the ultrasonic transducer in current RUM is in range from 20 kHz to 30 kHz. Moreover, the tool is tightened by an elastic chuck, which is in low clamping precision, high radial run-out, and unstable ultrasonic energy transmission. In this paper, we developed a novel heat shrinkable RUM ultrasonic transducer with 60 kHz frequency by equivalent circuit and finite element method (FEM). An analytical electromechanical equivalent circuit model was deduced to obtain the initial structure dimensions of the ultrasonic transducer. Three flange mounting structures were proposed to optimize and improve the energy transmission at the working resonant frequency. The influence of the proposed flanges on the resonant frequency of three transducers was analyzed and presented. The designed transducers were manufactured and tested in experiment. It shows that resonant frequencies of these three transducers with step, circular, and plate flange are 62.2 kHz, 61.46 kHz, and 61.4 kHz, and vibration amplitudes in 90 V driving voltage are $1.33\mu \text{m}$ , $4.74\mu \text{m}$ , $5.33\mu \text{m}$ , respectively. The working resonant frequencies by experimental measurement are consistent with the calculation result of the equivalent circuit and FEM. Moreover, the plate flange transducer shows the optimal amplitude capability with enough ultrasonic energy in micro-nano precision manufacturing.

The Modeling Framework for Through-Metal-Wall Ultrasonic Power Transmission Channels Based on Piezoelectric Transducers

The investigation of the wireless ultrasonic energy and signal transmission through metal barrier into hermitical metallic structures has become an interesting field of research. The most often constructed acoustic-electric ultrasonic power transmission channels are based on piezoelectric transducers. Effective modeling methods with accuracy are essential to the performance prediction and optimal design of such channels. Up to now, there exists a variety of modeling methods including theoretical analytical method, equivalent circuit method, two-port network method, and finite element modeling method. However there is a little chaos about how to choose an appropriate modeling method among them. There is also a lack of a systematic modeling framework presented involving principles, advantages, disadvantages, and constraint conditions of these methods. In this review, a common modeling framework for through-metal-wall acoustic-electric channels based on piezoelectric transducers is presented. The principles of the major modeling methods are introduced and the adoptability and constraints of each method are discussed. For each modeling method, simulation and or experimental results are also presented to validate the accuracy of the corresponding modeling method.

Factors Related to Successful Energy Transmission of Focused Ultrasound through a Skull : A Study in Human Cadavers and Its Comparison with Clinical Experiences.

ObjectiveAlthough magnetic resonance guided focused ultrasound (MRgFUS) has been used as minimally invasive and effective neurosurgical treatment, it exhibits some limitations, mainly related to acoustic properties of the skull barrier. This study was undertaken to identify skull characteristics that contribute to optimal ultrasonic energy transmission for MRgFUS procedures. MethodsFor ex vivo skull experiments, various acoustic fields were measured under different conditions, using five non-embalmed cadaver skulls. For clinical skull analyses, brain computed tomography data of 46 patients who underwent MRgFUS ablations (18 unilateral thalamotomy, nine unilateral pallidotomy, and 19 bilateral capsulotomy) were retrospectively reviewed. Patients' skull factors and sonication parameters were comparatively analyzed with respect to the cadaveric skulls. ResultsSkull experiments identified three important factors related skull penetration of ultrasound, including skull density ratio (SDR), skull volume, and incidence angle of the acoustic rays against the skull surface. In clinical results, SDR and skull volume correlated with maximal temperature (Tmax) and energy requirement to achieve Tmax (p<0.05). In addition, considering the incidence angle determined by brain target location, less energy was required to reach Tmax in the central, rather than lateral targets particularly when compared between thalamotomy and capsulotomy (p<0.05). ConclusionThis study reconfirmed previously identified skull factors, including SDR and skull volume, for successful MRgFUS; it identified an additional factor, incidence angle of acoustic rays against the skull surface. To guarantee successful transcranial MRgFUS treatment without suffering these various skull issues, further technical improvements are required.

Influence of Ultrasound on the Anticorrosion Properties of Carbonate Scale in its Thermal Formation

We study the processes of thermal formation of carbonate scale on steel surface and the influence of ultrasound on the scale structure with the help of two different approaches to the introduction of ultrasonic energy into the zone of scale formation: through water and through the metal. It is shown that the transmission of ultrasonic energy through the metal makes it possible to form protective scale layers with better barrier properties. The scale layer on the steel surface formed in the mode of steam boiler with simultaneous ultrasonic treatment for 50 h is continuous, microcrystalline, and very dense. The sizes of crystals do not exceed 2–3 μm and the density of the layer reaches 2.55 g/cm3, which is close to the density of calcite mineral (2.71 g/cm3). At the same time, in the absence of ultrasound, it is equal to 1.7 g/cm3 with crystal sizes of 30–40 μm. It is shown that, for this layer, the rate of steel corrosion does not exceed the normative rate equal to 0.05 mm/yr and heat transfer from the metal to water is almost not disturbed by the high density and small thickness of the scale layer.

Modeling and Characteristic Analysis of Wireless Ultrasonic Vibration Energy Transmission Channels through Planar and Curved Metal Barriers

Wireless ultrasonic vibration energy transmission systems through metal barriers based on piezoelectric transducers have drawn a lot of focus due to the advantage of nonpenetration of the barriers, thus maintaining the integrity of sealed structures. It is meaningful to investigate appropriate modeling methods and to characterize such wireless ultrasonic energy transmission channels with different geometric shapes. In this paper, equivalent circuit modeling and finite element modeling methods are applied to the planar metal barrier channel, and a 3‐dimensional finite element modeling method is applied to the cylindrical metallic barrier channel. Meanwhile, the experimental setup is established and measurements are carried out to validate the effectiveness of the corresponding modeling methods. The results show that Leach’s equivalent circuit modeling method and finite element modeling method are nearly similarly effective in characterizing the planar metal barrier channel. But for a cylindrical metal barrier, only the three‐dimensional finite element modeling method is effective. Furthermore, we found that, for the planar barrier, the effect of standing waves on the efficiency of wireless energy transmission is dominated. But for the curved barrier, only the resonant phenomenon of the piezoelectric transducer exists.

Study on energy transmission through metal wall based on piezoelectric material

The efficiency of electric energy transmission through metal wall by ultrasonic wave mainly depends on the relevant parameter of the sandwich structure system, which is consist of a transit piezoelectric transducer, a receive piezoelectric transducer and a metal wall. This paper discussed the characteristics measurement of piezoelectric energy transmission channel through metal wall based on a kind of piezoelectric transducer. First, the intrinsic impedance characteristic of piezoelectric transducer is measured using a high precision impedance analyzer. Then ultrasonic energy transmission channel through a metal wall testing system is analyzed. The voltage ratio under different frequencies of the channel is measured and the maximum energy transmission frequency is obtained. Mason model is verified and compared with the experimental results, which provides a beneficial reference for further researches on ultrasonic through metal wall energy transmission.

Note: Decoupling design for high frequency piezoelectric ultrasonic transducers with their clamping connections.

This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges.

Factors associated with successful magnetic resonance-guided focused ultrasound treatment: efficiency of acoustic energy delivery through the skull.

Magnetic resonance-guided focused ultrasound surgery (MRgFUS) was recently introduced as treatment for movement disorders such as essential tremor and advanced Parkinson's disease (PD). Although deep brain target lesions are successfully generated in most patients, the target area temperature fails to increase in some cases. The skull is one of the greatest barriers to ultrasonic energy transmission. The authors analyzed the skull-related factors that may have prevented an increase in target area temperatures in patients who underwent MRgFUS. The authors retrospectively reviewed data from clinical trials that involved MRgFUS for essential tremor, idiopathic PD, and obsessive-compulsive disorder. Data from 25 patients were included. The relationships between the maximal temperature during treatment and other factors, including sex, age, skull area of the sonication field, number of elements used, skull volume of the sonication field, and skull density ratio (SDR), were determined. Among the various factors, skull volume and SDR exhibited relationships with the maximum temperature. Skull volume was negatively correlated with maximal temperature (p = 0.023, r(2) = 0.206, y = 64.156 - 0.028x, whereas SDR was positively correlated with maximal temperature (p = 0.009, r(2) = 0.263, y = 49.643 + 11.832x). The other factors correlate with the maximal temperature, although some factors showed a tendency to correlate. Some skull-related factors correlated with the maximal target area temperature. Although the number of patients in the present study was relatively small, the results offer information that could guide the selection of MRgFUS candidates.

High-intensity ultrasound production of Maillard reaction flavor compounds in a cysteine–xylose model system

Application of high intensity ultrasound has shown potential in the production of Maillard reaction odor-active flavor compounds in model systems. The impact of initial pH, sonication duration, and ultrasound intensity on the production of Maillard reaction products (MRPs) by ultrasound processing in a cysteine–xylose model system were evaluated using Response Surface Methodology (RSM) with a modified mathematical model. Generation of selected MRPs, 2-methylthiophene and tetramethyl pyrazine, was optimal at an initial pH of 6.00, accompanied with 78.1min of processing at an ultrasound intensity of 19.8Wcm−2. However, identification of volatiles using gas chromatography–mass spectrometry (GC/MS) revealed that ultrasound-assisted Maillard reactions generated fewer sulfur-containing volatile flavor compounds as compared to conventional heat treatment of the model system. Likely reasons for this difference in flavor profile include the expulsion of H2S due to ultrasonic degassing and inefficient transmission of ultrasonic energy.

Design of High Frequency Ultrasonic Transducers with Flexure Decoupling Flanges for Thermosonic Bonding

This paper presents the design of high-frequency ultrasonic transducers for micro/nano device thermosonic bonding. The transducers are actuated by piezoelectric ceramics and decoupled with their connecting parts through novel flexure decoupling flanges. First, the initial geometric dimensions of the transducers were calculated using electromechanical equivalent method, then dynamic optimization design was carried out based on three-dimensional (3-D) finite element method (FEM), and the geometric dimensions of the transducer were finally determined. Flexure decoupling flanges were presented, and the decoupling principle of the flanges was explained through compliance modeling using compliance matrix method and FEM. After that the dynamic characteristics of the transducers were analyzed through finite element analysis (FEA). The vibration frequencies and modes of the piezoelectric converter, concentrators, and transducers were obtained through modal analysis, and the displacement nodes were determined. The longitudinal ultrasonic energy transmission was presented, and the decoupling effects of the flexure flanges were compared. Finally, the transducers were manufactured and experimental tests were conducted to examine the transducer characteristics using an impedance analyzer. The experimental results match well with the FEA. The results show that the longitudinal vibration frequencies of the transducers with ring, prismatic beam, and circular notched hinge-based flanges are 126.6, 125.8, and 125.52 kHz, respectively. The decoupling flange with circular notched hinges shows the best decoupling effect among the three types of flanges.