Ultrasonic Waves In Solids Research Articles

Results of the COOMET 706/RU-A/16 Pilot Comparison of National Standards of the Unit of Propagation Velocity of Longitudinal Ultrasonic Waves in Solids

Results of the COOMET 706/RU-A/16 Pilot Comparison of National Standards of the Unit of Propagation Velocity of Longitudinal Ultrasonic Waves in Solids

Reference installation for measuring acoustic parameters of solids

The issues of providing working standards of the 1st category of metrological organizations of the country with regard to modern needs in the field of ultrasonic measurements in solids are considered. There is presented a modernized reference installation designed for precision measurements of propagation velocities of longitudinal and shear ultrasonic waves and damping coefficient of longitudinal ultrasonic waves in solids. Measurements of acoustic parameters of solid media are made by pulse-echo and resonance methods using contactless broadband capacitive methods of excitation and registration of ultrasonic waves. This installation is used as working standard of the 1st category in accordance with the state verification schedule for measuring instruments of the propagation velocities and damping coefficient of ultrasonic waves in solids. The technical means included in the installation (mechanical and electronic parts) have been improved, analog measuring means have been replaced with digital ones, methods for measuring acoustic parameters of solids based on the use of digital measuring means have been developed and the thickness range of installed ultrasonic measures has been expanded. The composition and main components of the reference installation, the used measurement methods and the principles of operation of the installation in various operating modes are described. The technical and metrological characteristics of the installation are given. Sources of measurement error (uncertainty) were analyzed. The field of application of the results is high-precision measurements of the acoustic characteristics of solid media, metrological ensuring of ultrasonic non-destructive testing and diagnostics.

Results of the COOMET 706/RU-а/16 pilot comparison of national standards of the unit of propagation velocity of longitudinal ultrasonic waves in solids

Results of the COOMET 706/RU-а/16 pilot comparison of national standards of the unit of propagation velocity of longitudinal ultrasonic waves in solids

Mechanical behavior and material property of low-carbon steel undergoing low-frequency vibration-assisted upsetting

The propagation of ultrasonic wave in solids can cause a softening effect during metal deformation, and this concept has been widely exploited in micro-forming. Low-frequency vibration with micro-amplitudes was recently found to have a similar effect on metal deformation. In this study, the effects of low-frequency vibration on the mechanical behavior and microstructure of low-carbon steel DC04 during upsetting deformation was investigated. Vibration-assisted compression test results showed low-frequency vibration had a softening effect, that was proportional to vibration amplitude. Residual softening occurred in all cases during re-yield period after vibration removal. A sectional view of the deformed sample showed that vibration with larger amplitude could exacerbate the deformation of the contact area between the sample and the mold. The internal misorientation of grains in the deformation zone of the compressed sample increased significantly after large vibration treatment, indicating that low-frequency vibration promoted the occurrence of plastic deformation. A softening model considering transfer efficiency was proposed to explain the different performances under the action of small amplitude and large amplitude vibration. The residual softening effect that occurred in this study was an illusion produced by the uneven sample deformation caused by low-frequency vibration.

Elastic Phased Diffraction Gratings for Manipulation of Ultrasonic Guided Waves in Solids

Lamb waves and surface acoustic waves (SAWs) are of great interest for frontier technologies, including structural health monitoring, energy harvesting, sensors, and acoustic tweezers. This work presents elastic phased diffraction gratings, passive structures for controlling guided ultrasonic waves in solids. Such a grating adopts an array of interchangeable superstrates to modulate wave dispersion, and thus the diffraction wave field. Experiments demonstrate the ability to modulate antisymmetric and symmetric Lamb waves at 100 kHz, and Rayleigh SAWs at 100 MHz. These gratings are comparatively easy to fabricate, interchangeable, and theoretically feasible for all Rayleigh-Lamb modes.

National Primary Standard for the Units of the Propagation Velocities and Damping Coefficient of Ultrasonic Waves in Solids Get 189-2014

Improvements in the National Primary Standard for the Units of the Propagation Velocities of Longitudinal, Shear, and Surface Ultrasonic Waves in Solids are discussed. A new standard apparatus for reproduction of the unit of the damping coefficient for longitudinal ultrasonic waves is described. It is based on contactless capacitive methods for generating ultrasonic waves and pulse-echo and resonance measurement techniques for receiving them. The metrological characteristics of the National Primary Standard for the Units of the Propagation Velocities and Damping Coefficient of Ultrasonic Waves in Solids, GET 189-2014, are given.

Three-dimensional numerical modeling of ultrasonic wave propagation in concrete and its experimental validation

To understand the characteristics of ultrasonic wave propagation in concrete more completely, we propose a time domain simulation tool based on the finite integration technique (FIT) and an image-based modeling approach. When modeling ultrasonic wave propagation in concrete, it is important to introduce three-dimensional mesoscopic and microscopic structures because ultrasonic waves in solids are transmitted by mechanical interaction between adjacent media. In this paper, wave velocity, center frequency, and attenuation of ultrasonic waves in concrete are evaluated quantitatively by comparing the waveforms obtained by FIT simulation with those obtained by experimental measurement. It was observed that these factors were in good agreement between the simulation and measurements. It was also observed that amplitude of the transmitted signal was sensitive to the allocation pattern of the aggregates. Thus, attenuation due to multiple scattering by aggregates is more dominant than the attenuation by intrinsic absorption and geometrical spreading in concrete.

Nonlinear ultrasonic waves for monitoring thermal stresses in solids

It is known that nonlinear ultrasonic waves in solids are sensitive to quasi-static stresses. The stress sensitivity of elastic waves is typically associated to finite strains (e.g., theory of acoustoelasticity). In the case of waveguides, classical nonlinear theories for guided waves are still based on the assumption of finite strains. In the case of constrained solids subjected to thermal excursions, however, there are theoretically no finite strains (for perfectly constrained solids) associated with thermal stresses. A new model is therefore needed to justify the existence of wave nonlinearities in this case of stress without strain. This problem is solved on the basis of the interatomic potential of the solid that indicates a “residual” strain energy, due to the prevented thermal expansion, which is at least cubic as a function of strain. Consequently, a nonlinear wave equation can be derived. The solution to this equation leads to a new nonlinear parameter for double harmonic generation that is directly related to the thermal stresses in the structure. This study finds applications in the monitoring of thermal stresses in buckling-prone structures, such as continuously welded railroad tracks and pipelines. Experimental tests conducted on railroad tracks with realistic support will be also presented.

National Primary Standard for the Units of the Propagation Velocities of Longitudinal, Shear, and Surface Ultrasonic Waves in Solids

Improvements in the national standard for the unit of the propagation velocity of longitudinal ultrasonic waves in solids are examined. The measurement techniques and standard measures for velocity are described. The composition and metrological characteristics of the new standard are discussed. In accordance with the scientific and technical program "Standards of Russia" and the steps planned for the intro- duction of the national primary standard for the unit of the propagation velocity of longitudinal ultrasonic waves in solids, GET 189-2010 (1), work has been under way at the Far Eastern Branch of the All-Russia Research Institute of Physicotech- nical and Radio Measurements (VNIIFTRI) during 2010-2012 to improve the standard, including the development and intro- duction of two new standards facilities as part of the standard for measuring the propagation velocities of shear and surface ultrasonic waves in solids. Thus, the new national primary standard GET 189-2012 ensures the uniformity of measurements of the propagation velocities of the main types of acoustic waves in solids. This standard is at the top of the national verifi- cation scheme for means of measuring the propagation velocity of ultrasonic waves in solids, which establishes the order of transfer of reproduced units to working standards and means of measurement. The need for measurements of the propagation parameters of ultrasonic waves in solids arises from fundamental, as well as applied research. The propagation parameters of ultrasonic waves are used in fundamental research for calculating the elastic constants and moduli of elasticity - the most important characteristics of solids (2). These parameters are also need- ed for determining the physical and mechanical characteristics, as well as the endurance properties of solids, and are of the greatest importance for creating new materials, and in developing techniques for producing and using these in technology and industry. However, the demand for measurements of the propagation velocity of ultrasonic waves is primarily related to the need to ensure the uniformity of measurements in the area of nondestructive testing of the quality of materials and work pieces using acoustic methods and means of measurement. An analysis of Russian and foreign literature in this area shows that the most promising approach for the develop- ment of original standard means of measurement in solid-state acoustics is the use of contactless methods for generating and receiving ultrasonic waves: optical and capacitive (3-8). Optical methods form the basis of the standard GET 189-2012. The standard laser-interference system for measuring the propagation velocity of longitudinal ultrasonic waves in the standard GET 189-2010 (1) serves as the basis for creating the unified standard facility for reproduction of the units of the prop-

National primary standard for the unit of the propagation velocity of ultrasonic waves in solids

The results of creating a national standard for the unit of the propagation velocity of ultrasonic waves in solids are discussed. The structure of the standard and its metrological characteristics are described.

Nonlinear interaction of ultrasonic waves: A tribute to Mack Breazeale.

While at Brown University (∼1977), this graduate student was fortunate enough to learn about Mack Breazeale’s important early work in nonlinear ultrasonic waves in solids [J. Appl. Phys. 36, 3486 (1965)] through his thesis advisor (R. T. Beyer), who had friendly and most collegial interactions with Mack, through the ASA. When I met Mack Breazeale at ASA Meetings, he would discuss how he made some of his measurements and helped me understand some complexities involving the scattering of sound by sound. While Mack Breazeale was Associate Editor of nonlinear acoustics he gave a wealth of good advice (over a period of several years) on how to improve a manuscript on crossed beam scattering in turbulence and divide the material into at least two parts—which was done. When the paper was out, one agreed with Mack that it was much better and worth the effort. Years later, doing summer research at NCPA, Mack helped improve a manuscript on nonlinear acoustic landmine detection. As a tribute to Mack Breazeale, his work on “Quantum mechanical theory on nonlinear interaction of ultrasonic waves” (with I. L. Bajak) [J. Acoust. Soc. Am. 68, 1245 (1980)] will be discussed in some detail.

An NDT technique for composite structures using visualized Lamb-wave propagation

This study proposes a non-destructive testing (NDT) technique that visualizes the propagation of ultrasonic waves in solids, including composite laminates. This technique provides a moving diagram of traveling waves through the use of a pulsed laser that scans a test piece. A non-contact scan by the pulsed laser for ultrasound generation with reception at a fixed point enables us to inspect an arbitrarily shaped object and also facilitates easy operation of the measurement system. We applied the proposed technique to the inspection of CFRP laminates and successfully visualized the wave scattering due to impact-induced delamination as well as the propagation of the S 0 and A 0 Lamb modes. We also addressed disbonding detection in a composite skin-stringer structure and concluded that the reliable detection of damage and the advantages of the proposed technique are applicable to inspections of composite structures.

Diffuse fields in ultrasonics and seismology

We review the history of diffuse ultrasonic waves in solids with emphasis on recent developments in field-field correlations and their identification with Green’s function. The basic principles appear to be well understood now, and the identity between these two waveforms has been proven under a variety of assumed conditions that guarantee a diffuse field. Promise for practical passive imaging is good; nevertheless, measurements sometimes fail to fully agree with theory. We ascribe this in some cases to incomplete convergence — insufficient amounts of data have been processed. In other cases, it is probably because of a lack of perfect diffuseness; ambient nonmultiply scattered fields are often not equipartitioned and imperfectly diffuse.

A device for the measurement of ultrasonic velocity and attenuation in solid materials under different thermal conditions

We present the design and fabrication of an indigenous low cost experimental set up for the measurement of velocities and attenuation for the propagation of ultrasonic waves in solids using through transmission technique at different temperatures. The measured parameters such as ultrasonic velocities, attenuation and elastic constants as a function of temperature reveal the possibility of utilizing the proposed technique for complete characterization of materials over wide range of temperatures.

Ultrasonic time reversal, basic principles

For about 10 years now, time reversal methods have been widely developed in the laboratory and applied to various domains of acoustics like medical imaging/therapy and nondestructive evaluation. Many experiments and theoretical works have shown the robustness of this approach in multiple conditions (inhomogeneous and multiscattering media, solid layers, submarine acoustics,...). This paper will first present an overview of the basic theoretical principles which govern the time reversal approach. It will be shown how the concept of closed time reversal cavity yields theoretical predictions of the intrinsic limitations of the process. Starting from the closed time reversal cavity, the discussion will migrate in direction of (i) time reversal mirrors and (ii) time reversal arrays of final aperture. It will be shown how the general performances of the system are degraded. Then the presentation will focus on the time reversal methods applied to ultrasonic waves in solids. It will be shown how the time reversal technology takes advantage of longitudinal and transverse propagation modes in order to increase the focusing efficiency. These results will be illustrated by an experiment carried out with an aluminum plate partially immersed in water and excited by a laser impact.

Acoustic wavefronts and internal diffraction

We have developed new imaging methods for the study of ultrasonic waves in solids. The signal from a point source of ultrasound is detected as a function of space and time, revealing the acoustic wavefront (or group-velocity surface) striking a surface of the solid. By Fourier transforming the x-y-t “data cube” resulting from a short pulse on silicon, the internal diffraction of acoustic waves is observed.

Time reversal of ultrasonic waves in solids: Theory and experiments

In previous works, the capacity of time-reversal mirrors (TRM) has been presented to optimize ultrasonic focusing on a pointlike source. However, the evaluation of the focusing quality has so far been limited to fluid media. In this paper, the first theoretical approach is presented to determine the capacity of the TRM to focus on a point situated in a homogeneous isotropic solid. P and S waves emitted by a pointlike source in the solid yield the generation of transmitted pressure waves in a fluid that limits the solid via a plane boundary. A TRM placed in the fluid behind the interface measures both incoming wavefronts and is hence able to reverse them one by one. The reversed pressure fields backpropagate to the interface, resulting in P and S waves in the solid. It is shown that, in spite of the losses at the interface, both kinds of waves focus at the location of the initial source. Numerical simulations are carried out, showing that the time reversal is more favorable using the S waves than the P waves, in terms of the width of the focal spot as well as in terms of displacement amplitude. The results are compared with experiments carried out with a laser source working in the ablation regime.

Automated system for measuring the phase, velocity, and amplitude of ultrasonic waves in solids

An automated system for measuring the velocity, phase, and amplitude of ultrasonic waves in solids in the frequency range 1–20 MHz in CAMAC standard is described. The measurement errors fall within the limits 0.5% for the absolute velocity of acoustic waves, 0.2° for the phase, and 0.5% for the amplitude.

Comparison among Several Digital Methods of Measuring Time-of-Flight of Ultrasonic Waves in Solids.

A digital measurement system for the time-of-flight of ultrasonic longitudinal and transverse waves is constructed in terms of a conventional pulser/receiver, a transducer and a high-speed digital wave memory for material characterization and acoustoelastic stress measurement of solid materials with weak dispersion. Three methods, zero-crossing, cross-correlation and phase spectral methods, are compared from the viewpoint of precision for the time-of-flight measurement. The measurements of aluminum (10 mm in thickness) and acrylic (5 mm) plates have shown that the precision (2σ) of the time-of-flight is estimated to be less than 0.01 ns by the cross-correlation methods, which corresponds to the relative velocity variation of 2×10-6 for the longitudinal velocity of the aluminum plate. The cross-correlation method is found to have the highest stability.

Transient radiation of ultrasonic waves in solids by nonuniformly excited and focusing annular arrays

Analysis of the transient ultrasonic fields radiated in solids by nonuniformly excited and focusing annula has been performed. The influence of the number of annula in the array on the structure of the particle velocity fields radiated has been investigated. The different driving stress profiles on the radiating surface create substantially differing spatial-temporal distributions of axial and radial components of the particle velocity.