Acoustic Wave Parameters Research Articles

Application of the Finite Element Method for Calculating Parameters of Surface Acoustic Waves and Devices Based on Them

Application of the Finite Element Method for Calculating Parameters of Surface Acoustic Waves and Devices Based on Them

Magneto-acoustic coupling: Physics, materials, and devices

Acoustic wave in solid has two modes of propagation: the bulk acoustic wave (BAW), which propagates inside solid in the form of longitudinal or transverse wave, and the surface acoustic wave (SAW), which is generated on the surface of solid and propagates along the surface. In acoustic radio frequency (RF) technologies acoustic waves are used to intercept and process RF signals, which are typified by the rapidly developing RF filter technology. Acoustic filter has the advantages of small size, low cost, steady performance and simple fabrication, and is widely used in mobile communication and other fields. Due to the mature fabrication process and well-defined resonance frequency of acoustic device, acoustic wave has become an extremely intriguing way to manipulate magnetism and spin current, with the goal of pursuing miniaturized, ultra-fast, and energy-efficient spintronic device applications. The integration of magnetic materials into acoustic RF device also provides a new way of thinking about the methods of acoustic device modulation and performance enhancement. This review first summarizes various physical mechanisms of magneto-acoustic coupling, and then based on these mechanisms, a variety of magnetic and spin phenomena such as acoustically controlled magnetization dynamics, magnetization switching, magnetic domain wall and magnetic skyrmions generation and motion, and spin current generation are systematically introduced. In addition, the research progress of magnetic control of acoustic wave, the inverse process of acoustic control of magnetism, is discussed, including the magnetic modulation of acoustic wave parameters and nonreciprocal propagation of acoustic waves, as well as new magneto-acoustic devices developed based on this, such as SAW-based magnetic field sensors, magneto-electric antennas, and tunable filters. Finally, the possible research objectives and applications of magneto-acoustic coupling in the future are prospected. In summary, the field of magneto-acoustic coupling is still in a stage of rapid development, and a series of groundbreaking breakthroughs has been made in the last decades, and the major advances are summarized in this field. The field of magneto-acoustic coupling is expected to make further significant breakthroughs, and we hope that this review will further promote the researches of physical phenomena of the coupling between magnetism and acoustic wave, spin and lattice, and potential device applications as well.

Surface Acoustic Wave Interaction with a Mixture of Oxygen and Nitrogen

Parameters of surface acoustic waves (SAW) are very sensible to change of physical conditions of a propagation medium. In the classical theory formulation, the waves are guided along the boundary of semi-infinity solid state and free space. A real situation is more complex and a medium commonly consists of two physical components: a solid substrate and a gaseous or liquid environment. In the case of stress-free substrate, the strongest impact on SAW properties have surface electrical and mechanical conditions determined by solids or liquids adhering to the boundary. This impact is utilised for constructing sensors for different gases and vapours e.g. (Jakubik et al., 2007; Hejczyk et al., 2011; Jasek et al., 2012). The influence of gaseous environment on the SAW properties is usually very weak and ignored. However, in certain condition it can be significant enough to be applied to sensor construction. In general, it concerns Rayleigh wave devices where energy leakage phenomenon is perceptible, especially when the gas being detected considerably changes the density of environment. The paper presents the results of experiments with oxygen-nitrogen mixture. Their primary aim was focused on finding the dependence of resonant frequency and attenuation in SAW resonator on parameters and concentrations of the gas in the environment.

Evaluation of Structural Metal Materials Damage by Acoustic Methods

The purpose of this research is to study the damage of structural metal materials by acoustic method under various external fatigue and thermal influences. A structural model describing the process of accumulation of scattered micro-damages in the material is proposed, the parameters of which can be measured by acoustic method. It is shown that irreversible processes occur in the structure of structural metal materials during cyclic loading, leading to changes in physical and mechanical characteristics. The assessment of changes in a large number of informative parameters of acoustic control in the process of damage accumulation was carried out. It is established that the parameters of elastic waves depend on the characteristics of the medium under study. It is shown that the state of the surface layer can be used in the tasks of earlier assessment of the developed resource of the structural material. A model that takes into account the influence of degradation processes of the surface layer on the parameters of surface waves is proposed. The results of experimental studies confirming the proposed model are presented. Methods for determining material mechanical characteristics are proposed: elastic modulus, yield strength, fracture toughness, internal stresses, grain size, etc. on structural elements, without violating their strength characteristics. The results of studies of medium influence on parameters of elastic waves serve as the basis for constructing a complex acoustic method for determining physical and mechanical characteristics of structural materials. Examples of practical use of the obtained results in the tasks of ensuring the safe operation of critical structural elements are considered. The data obtained during the study make it possible to assess the damaged state and properties of metal materials under cyclic loading quickly using the parameters of acoustic waves.

Propagation and imaging analysis of vortex acoustic waves in ocean turbulence

AbstractVortex acoustic waves (VAW) with helical phase wavefronts could provide a new dimension for the detection and imaging of targets in the ocean. To explore the propagation characteristics of VAW under the effect of ocean turbulence (OT) and the impact on imaging, the phase screen method is used to simulate the propagation of VAW generated by a phase‐modulated uniform circular array under the effect of OT and the imaging of the target. The phase change and detection probability under the influence of the acoustic wave parameters and OT parameters during the propagation process are studied. Second, the azimuth resolution performance and focussing performance of the target imaging are studied. Under the effect of OT, the VAW of different frequencies and topological modes become scattered, and the degree of scattering is different when the parameters are different; and the resolution performance and focussing performance have also deteriorated. However, the VAW still has a reliable resolution under the effect of medium and low‐intensity OT, which provides theoretical support for the practice of the VAW in underwater target imaging.

Comment on Mahariq et al. Investigation and Analysis of Acoustojets by Spectral Element Method. Mathematics 2022, 10, 3145

The paper under discussion has some shortcomings in regard to mathematical formulation of the problem related to acoustics, its justification, some references analyses and the text, and we feel that this study has not been finished to its full extent. From the point of view of acoustic jet formation, the mathematical model used by the authors has a number of significant limitations which are not taken into account. Moreover, the formal analogy between the parameters of electromagnetic waves and acoustic waves should be used with caution in the conditions of localized beams (acoustic jet), and the limits of their application should be justified.

Fast Extraction of Coupling of Modes Parameters for Surface Acoustic Wave Devices Using Finite Element Method Based Simulation

The finite element method (FEM) has been applied to extract the coupling-of-modes (COM) parameters of surface acoustic wave (SAW) devices for a long time. It always involves calculating the dispersive curves or harmonic admittance, which makes the extraction process and results sophisticated, time-consuming and inaccurate. Therefore, a simple method is proposed to extract all COM parameters of the SAW devices rapidly and accurately in this paper. It is based on the FEM and combines the stationary analysis with modal analysis. We have described in detail the basic principles and procedures of the proposed method, and made a comprehensive comparison between the proposed method and the other two existing methods. We have also examined the proposed method by extracting COM parameters of some common SAW substrate, and compared our extracted results with those reported in the other literatures. Results show that our proposed method holds higher accuracy and more efficiency (~s order) than the others (~h order). Moreover, our extracted COM parameters are in an excellent agreement with those reported in the other literatures.

Monitoring of Properties Subjected to Innovative Technological Treatments of Subsurface Layers of Materials by AMD-Methods

In this paper, it is proposed to use modern research AMD-methods to monitor the properties of the subsurface layers of materials subjected to innovative technological treatments. They are based on the analysis of the parameters of acoustic waves reflected from the subsurface layers of the studied materials. The technological processing leads to a change in the acoustic characteristics, the value of which is calculated by the values of the parameters of the material of the samples. The effectiveness of the application of methods of acoustic-microscopic flaw detection for the analysis of the state of materials after thermal, chemical, deformation, and diffusion effects is demonstrated.

Fiber-optic vector acoustic receiver based on adaptive holographic interferometer

A mobile scalar–vector acoustic receiver is proposed, experimentally implemented and investigated. The key components of the receiver are (a) the six-channel fiber-optic coil-type sensor configured as to detect three projections of acoustic intensity vector, (b) the six-channel optical phase demodulator based on six-channel adaptive holographic interferometer configured with use of dynamic holograms multiplexed in a photorefractive crystal of cadmium telluride and (c) the signals recording ADC-based system combined with software package for data processing. Field tests of the developed receiver applied for obtaining scalar and vector parameters of acoustic waves generated by a stationary and moving acoustic source in open air and water area are carried out. Experimental results show perceptiveness of use of the fiber-optical adaptive interferometry system for bearing of weak acoustic sources in real conditions.

Influence of Propagation Distance on Characteristic Parameters of Acoustic Emission Signals in Concrete Materials Based on Low‐Frequency Sensor

Acoustic emission is a nondestructive testing technology based on the propagation of transient elastic waves captured by acoustic emission sensors. The acoustic emission signal depends not only on the distance and quality of the propagation path of the transient elastic wave but also on the sensitivity and frequency bandwidth of the receiving sensor that converts the transient elastic wave into a voltage signal. The frequency range of damage signals in concrete materials is generally in the low‐frequency band. If high‐frequency sensors are used, the low sensitivity to low‐frequency signals will cause measurement errors, while the bandwidth of general commercial acoustic emission sensors is relatively narrow. Therefore, a high‐sensitivity, low‐frequency acoustic emission sensor is proposed, whose bandwidth is almost four times that of commercial sensors. Based on the customized sensor, we quantitatively analyzed the influence of propagation distance on the characteristic parameters of acoustic waves propagating in concrete. The results show that the different propagation modes of acoustic waves in concrete have different attenuation with the propagation distance, related to the position relationship between the acoustic source and the sensor and the propagation path and path quality. This result gives us a better understanding of the propagation mechanism of acoustic emission signals in concrete materials.

Application of electric explosion technologies for protection of mobile marine objects from means of detection and destruction by naval weapons

The article discusses the possibilities of using electric discharge technologies to create sources of acoustic waves in sonar countermeasure systems. Presented are the results of preliminary research works aimed at determining the parameters of acoustic waves generated by electric discharge technologies. The possibility of using electric discharge as a source of acoustic interference for undersea weapon guidance systems is shown.The current situation in the world, the armed conflicts and terrorist threats require ensuring the safety of maritime mobile objects (vessels, ships) from being hit by naval weapons. Today, one of the means of surface or submarine ship destruction is a torpedo weapon. The main means of protection against destruction by torpedo weapons are the ship maneuvering and its sonar countermeasures to the weapon guidance facilities [1]. The methods of sonar countermeasure are divided into passive and active ones [1 – 4]. Active methods are aimed at interfering with guidance systems, interrupting the wake, placing target simulators, etc.

DETERMINATION OF ACOUSTIC FEATURES OF CATALYTIC CONVERTERS OF ESHAUST SYSTEMS

The object of the presented work are ceramic blocks and diesel particulate filters manufactured by CORNING and applied in the development and serial production of the exhaust gas aftertreatment systems for cars and trucks, providing the required emission standards and noise regulations. The purpose of the work is the definition of acoustic parameters of the blocks for the further use of these data in the design of the system components applying finite-element modeling. A set of the blocks with different model parameters (diameter, length, and the cell density) was tested on acoustic stand using previously developed methods. Acoustic wave parameters have been identified for each block (namely, the comprehensive speed of sound and comprehensive density). The technique of the test preparation on acoustic test bench, the methodology and results of testing, the methodology and the processing of the results are presented. The estimation of measurement and calculation of errors are presented.

Evaluation of Cumulative Damage of Sandstone under Cyclic Wetting and Drying through Acoustic Wave Parameters and Resistivity Testing

This paper carries out cyclic wetting and drying experiments on the sandstones from the bank slope of an inland port, and explores the deterioration features and acoustic wave parameters and resistivity (AWPR) of the sandstone. The variations in P-wave velocity, attenuation coefficient, nonlinear coefficient, resistivity, and other indices with the cycle number were discussed in details. Then, the correlations between P-wave velocity, resistivity, and physical-mechanical indices were analyzed based on the experimental results. Through the analysis on instantaneous damage analysis, a cumulative damage model was proposed, in the light of the AWPR. The results show that: the evolution of sandstone resistivity can accurately reflect the deterioration features of the sandstone under cyclic wetting and drying, providing a desirable tool to characterize rock strength deterioration and internal damage changes. Taking cycle number into account, the proposed theoretical model for cumulative damage can derive the damage and deterioration of sandstone excellently. By this model, the AWPR at any moment can be acquired in real time on site, which is convenient for engineering application.

Temperature extraction from spacecraft density profiles in the presence of wave activity

In the absence of direct atmospheric temperature measurements, density data along spacecraft trajectories are often used to extract temperature profiles, a process that can fail in the presence of wave activity (Leclercq et al., 2020). Because spacecraft data are often not sufficient to uniquely characterize wave-like perturbations, we examine the difference between predicted and extracted temperature profiles based on linearized solutions to the wave equations and briefly discuss the relevance to wave activity in the upper atmospheres of Mars and Titan. We find that the extracted temperatures are significantly overestimated for the full range of acoustic gravity wave parameters but are somewhat underestimated for a range of internal gravity wave parameters, and the density amplitudes can serve as a proxy for the extracted temperature amplitudes when estimating the heating rates.

Dynamics of the Explosion of Microparticles Containing Unbound Water during Laser Shockwave Destruction of Biological Tissues

We present here the results of studies of laser-induced shockwave destruction of biological tissues obtained experimentally and by computation. In the experiments, microexplosion dynamics were studied by analysis of acoustic pulses induced by explosion of activated charcoal during laser heating of unbound water. The computational method was based on automodel solution of the Stefan problem using a quasilinear approximation. Good agreement was obtained between computation and experimental data for assessment of the main parameters of acoustic waves arising as a result of thermal explosion of microparticles. Morphological studies and clinical testing of the method provided the evidential aspect of the proposed description of the mechanism of shockwave actions.

К ВОПРОСУ ВЫБОРА ПАРАМЕТРОВ АКУСТИЧЕСКОГО СИГНАЛА ДЛЯВИЗУАЛИЗАЦИИСТРУКТУРЫБИОЛОГИЧЕСКИХ ТКАНЕЙНА ОСНОВЕ НЕЛИНЕЙНОГО ВЗАИМОДЕЙСТВИЯ АКУСТИЧЕСКИХ ВОЛН

The paper considers the choice of optimal acoustic wave parameters for ultrasonic im-aging based on nonlinear effects of its interaction with biological tissues. The changes of the second harmonic pressure at different values of the frequency and pressure of the first har-monic are calculated. As a model, the medium consisting of the following biological tissues was considered: adipose tissue, muscle tissue, whole liver, blood, pathological tissue (fi-broids). For adipose and muscle tissues, the calculation of the change in the acoustic wave rupture distance at different parameters of the probing pulse of the main frequency was car-ried out. The calculation of the distance of the gap was conducted in order to determine the most optimal ratio of the initial characteristics of the ultrasonic wave and a second harmonic of an acoustic signal, allowing you to visualize the distribution of the acoustic nonlinearity parameter.

Ultrasonic wave transport in resonant emulsions made of slow or fast droplets

The key transport parameters of acoustic waves travelling in disordered media are studied through ultrasonic experiments on monodisperse resonant emulsions. Through accurate measurements of both ballistic and diffusive transport over a wide range of frequencies, we show that the group velocity of the ballistic component may differ significantly from the energy velocity of the diffusive waves, in particular in the vicinity of scattering resonances. Moreover, we demonstrate the crucial role played by the refractive acoustic index of the droplets relative to the surrounding media by studying emulsions made of “slow” fluorinated oil droplets or “fast” liquid metallic droplets dispersed in a water-based gel. Our observations are successfully explained by theories based on independent scattering approximations relevant for these diluted media. Effects of droplet resonances in the diffusive regime are also discussed giving a complete study of the energy velocity of scalar waves in strongly scattering media. B. Tallon, T. Brunet, and J.H. Page, Phys. Rev. Lett. 119, 164301 (2017).The key transport parameters of acoustic waves travelling in disordered media are studied through ultrasonic experiments on monodisperse resonant emulsions. Through accurate measurements of both ballistic and diffusive transport over a wide range of frequencies, we show that the group velocity of the ballistic component may differ significantly from the energy velocity of the diffusive waves, in particular in the vicinity of scattering resonances. Moreover, we demonstrate the crucial role played by the refractive acoustic index of the droplets relative to the surrounding media by studying emulsions made of “slow” fluorinated oil droplets or “fast” liquid metallic droplets dispersed in a water-based gel. Our observations are successfully explained by theories based on independent scattering approximations relevant for these diluted media. Effects of droplet resonances in the diffusive regime are also discussed giving a complete study of the energy velocity of scalar waves in strongly scattering media. B. T...

Holographic measurement of surface acoustic wave parameters in crystals

The theoretical basis of a specialized technique for applying digital holographic interferometry to measure the parameters of surface acoustic waves is presented, a measuring system for visualization and quantitative analysis of the parameters of ultralow-amplitude high-frequency oscillations arising in electronic devices using surface acoustic waves is developed, and experimental results of the study of surface acoustic waves in crystals of lithium niobate are obtained. In this case, to ensure the possibility of recording precision double-exposure interferograms of high-frequency surface acoustic waves, a picosecond pulsed laser with two-stage frequency multiplication was used as a radiation source, and to increase the spatial resolution of the system with the possibility of observing a wide field of view, an adjustable optical zoom of the incoming image was applied to the matrix input (based on charge-coupled devices) of the recording camera and digital zoom was used for obtained interferogram. We achieved the measuring sensitivity of the surface acoustic waves amplitude and spatial-temporal resolution allowing visualization and measurement of surface acoustic waves with amplitudes of the order of 1 nm and frequencies of the order of 10 MHz, which is far beyond the capabilities of standard methods of holographic interferometry.

Influence of duct parameters on the acoustic wave generation

PurposeThis paper aims to determine the influence of geometrical features of the channel on the acoustic wave generation in a ducted cavity. The analysis is focussed on the effects of the change in the entrance length upstream the cavity and the height. The study is supposed to investigate boundary layer and acoustic wave parameters, and an attempt will be made to determine the correlation between the geometrical dimension and those parameters.Design/methodology/approachAnalysis is conducted with the aim of a computational fluid dynamics (CFD) tool and selected results are validated with experimental investigations. The influence of grid resolution and time discretization is analysed. Four different entrance lengths and height are investigated. Qualitative and quantitative comparison between cases is presented.FindingsThe investigations prove the small influence of the entrance length on acoustic wave generation, but channel height due to wave reflection and interference inside of the cavity has a significant impact on wave frequency and sound pressure level. Channel height has also impact on generation and shape of the vortex created in the cavity inlet.Originality/valueThe paper extends the knowledge of phenomena taking place in the ducted cavities. Results obtained from these investigations will be useful in designing new cooling techniques and in noise reduction. The CFD analysis makes it possible to determine the correlations between channel dimensions and SPL function and frequency of sound waves.

THERMAL MODEL FRO SAW CALCULATIONS IN THE LAYERED SYSTEMS

The calculation of surface acoustic wave (SAW) parameters in the layered systems consists of half infinite substrate and one or several layers when the temperature is variable have been considered. SAW phase velocity calculation with temperature dependent material constants have been discussed. Expressions for the temperature coefficients of delay (TCD) and the temperature coefficients of frequency (TCF) of the first and the second order with taking into account SAW dispersion have been evaluated. Numerical procedures for TCD and TCF calculation have been proposed.