Interaction Of Ultrasonic Waves Research Articles

Ultrasonic wave visualization as a teaching aid in non-destructive testing

Visualization of ultrasound by the technique of stroboscopic photoelasticity has been applied to the teaching of ultrasonic testing. This paper describes the principles involved in the visualization of compressional, shear and Rayleigh waves. Conventional ‘A-scope’ displays are explained in terms of the visualized ultrasonic wave interactions within notched glass testpieces. Ultrasonic wave mode conversions, by reflection at boundaries within testpieces, and ultrasonic wave interactions with defects in glass models, are visualized.

Interaction of ultrasonic waves incident at the Rayleigh angle onto a liquid-solid interface

The behavior of a Gaussian ultrasonic beam incident on a liquid-solid interface at the Rayleigh angle, the angle at which surface waves are excited on the interface, has been studied in some detail. The reflected beam is displaced in the manner predicted by Schoch; however, the ’’Schoch displacement’’ in general is too large. Good agreement is obtained between experimental results and the theory of Bertoni and Tamir, which assumes that the incident beam couples resonantly into a leaky surface wave at the Rayleigh angle and that the energy reradiated from this leaky surface wave interferes with specularly reflected energy. The propagation distance of the ultrasonic beam is explicitly included in describing the ultrasonic wave reflection at the Rayleigh angle.

Ultrasonic waves: their interferometric measurement and display

A system for the measurement and visualization of small displacements has been developed that features high sensitivity and acoustic-wavelength-limited resolution over apertures as large as 15 cm at frequencies up to 10 MH(z). Acoustic-wave displacement amplitudes as small as 0.07 A are measured by interferometrically detecting the motion of a thin, acoustically transparent, metallized pellicle as the ultrasonic wave passes through it. The system can also be adapted to measure and display any small vibratory motion. The basic arrangement is that of the Michelson interferometer with the addition of an open-loop method to stabilize the response and a deflection system in one leg of the interferometer to scan the pellicle. Presently, the system is used in the study of the interactions of ultrasonic waves with biologic tissue and the observation and measurement of radiation patterns of acoustic transducers.

Crack depth measurement in rail steel by Rayleigh waves aided by photoelastic visualization

Stroboscopic methods of visualization of ultrasonic waves by schlieren and photoelastic methods have been introduced in recent years. The author describes work which demonstrates the application of the photoelastic technique to a problem of crack-depth sizing in steel rails by Rayleigh waves. The visualization of the interactions of ultrasonic waves in notched glass testpieces provides explanations of multiple A-scan received signals, the origins of which were not previously understood.

Crack depth measurement in rail steel by Rayleigh waves aided by photoelastic visualization

Stroboscopic methods of visualization of ultrasonic waves by schlieren and photoelastic methods have been introduced in recent years. The author describes work which demonstrates the application of the photoelastic technique to a problem of crack-depth sizing in steel rails by Rayleigh waves. The visualization of the interactions of ultrasonic waves in notched glass testpieces provides explanations of multiple A-scan received signals, the origins of which were not previously understood.

Modeling Concepts for Studying Ultrasonic Wave Interaction with Adhesive Bonds

Abstract Recent research has shown that such adhesive bondline defects as chemical segregation, variation in cure, gas entrapment or inadequate surface preparation are responsible for many adhesively bonded structural failures. Analytical models have been developed in this work that can be used to relate these “flaws” to the manner in which they affect the reflection of an ultrasonic pulse from such a bondline. The results of this study provide a substantial resource base for extended research through which ultrasonic inspection can become a reliable NDT technique for bond strength determination.

Interaction of ultrasonic surface waves with conduction electrons in thin metal films

Ultrasonic surface waves propagating on a piezoelectric substrate are accompanied by electric fields which can interact with charge carriers in an adjacent medium. This interaction and the resulting attenuation of the elastic surface wave have been measured for different metal films on a quartz single-crystal substrate. As the films are deposited on the substrate, the resistivity of the films decreases continuously, and it was found that the interaction between the ultrasonic wave and the charge carriers in the film reaches a maximum for a resistivity of the films on the order of 5 MΩ/sq, but the magnitude of the resulting attenuation of the surface wave was dependent on the film material. Values of the maximum attenuation varied between 0.27 dB/cm for bismuth and 2.8 dB/cm for copper at a frequency of 31.5 MHz. A theoretical model was developed which showed good agreement with the experimental results for the materials used.

Ultrasonic stress wave interaction with domain walls in KD2PO4

The experimental results on ultrasonic stress wave interaction with domain walls in KD2PO4 crystals are presented. It is shown that the interaction takes place only if stress waves are piezoelectrically coupled to ferroelectric polarization. The temperature dependence of domain wall mobility is found.

Acoustooptic interactions and devices

A review of recent advances in the understanding of the interaction of light and ultrasonic waves in solids and liquids is presented, emphasizing the Bragg diffraction regime wherein the diffracted optical energy is confined near one angular direction. The usefulness of optical beam probing techniques, using laser light sources, for investigating such subjects as ultrasonic attenuation and diffraction, acoustic nonlinear phenomena, magnetoelastic interactions, and photoelastic properties of materials is described. The application of the acoustooptic interaction for the design of devices intended to perform optical information processing functions is also mentioned. Present applications include optical modulators, switches, sequential scanners (such as are useful for television display), random access optical deflectors, and optical correlators. An attempt is made to describe the assets and liabilities of acoustooptic devices and to speculate concerning their future in the practical world.

Analysis of frequency modulation of junction lasers by ultrasonic waves

An analysis of the interaction of ultrasonic waves with the junction-laser modes is performed, using first-order perturbation theory. It demonstrates that in the presence of sound waves, each laser mode is frequency-modulated with negligible harmonic distortion or mode mixing. It is also shown that bandwidths of several GHz, with high-modulation index are possible.

Interaction of light and ultrasonic surface waves: Mayer, W.G., Lamers, G.B. and Auth, D.C. Journal of the Acoustical Society of America, Vol 42, No 6 (December 1967) p1255

Pentasilicon dodecachloride, Si5Cl12, and hexasilicon tetradecachloride, Si6Cl14, produced in the amine induced disproportionation of disilicon hexachloride, form stoicheiometric 1:1 adducts with silicon tetrachloride, methyltrichlorosilane, and dimethyldichlorosilane. These adducts dissociate reversibly and plots of the logarithm of the dissociation pressure vs. 1T yielded straight lines from which the ΔH of dissociation was calculated. A discussion of the probable bonding in these adducts is presented. The infra-red spectra of pentasilicon dodecachloride and hexasilicon tetradecachloride in the vapour phase and in solutions of methylene chloride and silicon tetrachloride are presented along with a discussion of these spectra elucidating the molecular structure of pentasilicon dodecachloride and hexasilicon tetradecachloride.

Interaction of Light and Ultrasonic Surface Waves

The intensity distribution in the orders of a light-diffraction pattern produced by the interaction of a progressive ultrasonic surface wave and a monochromatic light beam is calculated. The amplitude of the surface wave is determined from the light-intensity distribution in the diffraction pattern. The spacing of the diffraction orders is related to the surface wave velocity and the angle of light incidence.

Interaction of Ultrasonic Waves with Thin Magnetic Films

We discuss the interaction of an externally generated ultrasonic wave with a thin magnetic film, and the generation of phonons by driving such a film with a microwave field. Several geometries are considered. If the frequency of the driving wave is close to one of the spin-wave resonance frequencies of the film, we exhibit an exact solution to the phonon equation of motion in the presence of one-magnon-one-phonon terms in the magneto-elastic coupling. Some difficulties present in an earlier theory are eliminated.We find a contribution to the spin wave resonance linewidths from the one-magnon-one-phonon terms. For the $n=0$ term of a Ni film, we estimate the magneto-elastic coupling may make a contribution to the linewidth of roughly ten percent of the total linewidth. If we denote this contribution to the linewidth by ${{\ensuremath{\Gamma}}_{n}}^{(\mathrm{pn})}$ and the total linewidth by ${\ensuremath{\Gamma}}_{n}$, then we show that study of the interaction of an externally generated ultrasonic wave with the film provides a direct measure of the ratio $\frac{{{\ensuremath{\Gamma}}_{n}}^{(\mathrm{pn})}}{{\ensuremath{\Gamma}}_{n}}$. The presence of a poor acoustical impedance match at a film surface is shown to introduce a factor in the expression for ${{\ensuremath{\Gamma}}_{n}}^{(\mathrm{pn})}$ periodic in the external magnetic field, for a film of fixed thickness.

Light Diffraction by Ultrasonic Surface Waves

The diffraction pattern produced by monochromatic light reflected from a solid on which an ultrasonic surface wave is propagated is shown to be useful in the determination of velocity and amplitude of the surface wave. The formalism describing the interaction of light and ultrasonic surface wave is compared to the theory applicable to light diffraction by ultrasonic waves through transparent media. [Work supported by the U. S. Office of Naval Research.]

Use of the interaction of thermal and ultrasonic waves to study radiation induced defects in quartz crystal: Journal of applied physics, 35, No. 5, 1639 (1964)

Use of the interaction of thermal and ultrasonic waves to study radiation induced defects in quartz crystal: Journal of applied physics, 35, No. 5, 1639 (1964)

Ultrasonic effects in piezoelectric semiconductors

Several interesting phenomena involving the interaction of ultrasonic waves and electrons have been observed in piezo-electric semiconductors. These include the processes of ultrasonic amplification and nonlinear harmonic generation, which are manifestations of the action of electrons on ultrasonic waves. The reaction upon the electrons as a result of their strong coupling to ultrasonic waves is manifested by the phenomena of current saturation and current oscillations in amplifying semiconductor crystals. We discuss the principle of acoustoelectric amplification and the role it plays in these effects. The difference between the amplification process and the Cerenkov emission of sound waves is emphasized. The generation of harmonics of the sound wave due to the nonlinear transport properties of the electrons is reviewed. Various models of current saturation are considered, including an elementary treatment of the role of acoustoelectric fields. A discussion is given of the possibility of propagating collective sound waves under amplifying conditions and the role that this may play in the current oscillations in cadmium sulphide.

Use of the Interaction of Thermal and Ultrasonic Waves to Study Radiation-Induced Defects in Quartz

Evidence is presented showing that the interaction of high-frequency stress waves with lattice vibration waves provides a means of studying crystal perfection. This discussion is concerned specifically with quartz single crystals, but the method has been found to apply to other materials as well.

Interaction of Ultrasonic Waves with Electron Spins

We discuss the interaction between paramagnetic atoms and elastic waves at microwave frequencies by means of a total Hamiltonian comprising sound field, interaction, and spins. From this Hamiltonian and the Heisenberg commutation rules we obtain a set of coupled equations of motion. The condition of compatability leads in the usual way to a secular determinant, the solution of which is a dispersion relation exhibiting the familiar anomalous change in velocity and absorption of waves near resonance.

Interaction of Spin Waves and Ultrasonic Waves in Ferromagnetic Crystals

A field-theoretical treatment is given of the magnetoelastic coupling of magnons and phonons in a ferromagnetic crystal. The effects of the coupling are large when the wavelengths and frequencies of the two fields are equal. If the two transverse phonon states of a given wave vector are degenerate, then the rotatory dispersion of the phonons will be large. The possibility exists of creating nonreciprocal acoustic elements, such as acoustic gyrators. At simultaneous resonance the phonon attenuation is expected to be large. The possibility of magnetostrictive transducers at microwave frequencies is discussed. A calculation is given of the damping by eddy currents of spin waves in a metal.

The Interaction of Acoustical Waves with Concentration Gradients

The interaction of ultrasonic waves with concentration gradients in solutions has been studied quantitatively with schlieren techniques having a resolution of the order of 10−4 cm. Although the gradients have been produced electrochemically at anodes and cathodes in copper sulfate solutions, the conclusions have been extended to concentration gradients in solutions in general. Moderately intense ultrasonic waves (e.g., 1 watt/cm2) are more effective than conventional agitation in disrupting these concentration gradients primarily because of the micro agitation associated with cavitation at or near the interface. Streaming effects in the ultrasonic field augment cavitation. The effective dimensions of the concentration gradients are reduced to a value approaching 10−4 cm as compared with 10−3 cm for ordinary directional flow. This accounts in good part for the increments produced by ultrasonic waves in the rates of various physical and chemical processes involving two or more phases. In a standing wave of low intensity with the wave front perpendicular to the phase boundary, the concentration gradients become localized at the displacement nodes or loops depending on whether there is a deficit or excess of solute at the interface.