Kh. B. Tolipov

Stagnant waves in an elastic wedge-shaped plate

Stagnant antisymmetric waves in an elastic wedge-shaped plate were studied theoretically and experimentally. The solution to the nonuniform problem was obtained in the approximation of a small and smooth field nonuniformity. The vibration amplitudes in a standing wave were calculated and measured for a small wedge angle. Experimental measurements were performed on an original setup.

Possibilities for Increasing the Efficiency of Contactless Emitters of Acoustic Waves

An electromagnetic-acoustic emitter has been designed that is capable of exciting widespectrum acoustic waves on a narrow section of the surface of metalware with a low voltage across the inductor. An engineering solution has been proposed that allows one to place emitter’s inductor directly on the surface of an article.

Surface acoustic waves in an elastic wedge media

We consider surface acoustic waves in an elastic wedge media. It is established that the investigated waves substantially differ from known ones. For example, the movement of surface Rayleigh wave in the direction to the edge leads to a change of its structure, accompanied by the splitting of the initial wave to two separate modes and radiation of shift and longitudinal waves. Along the edge of the wedge the surface wave is strongly localized in the transverse direction. Are discussed the properties of the wedge antisymmetric normal waves, propagating parallel to the edge of the wedge.

Diffraction of Surface Waves by the Edge of a Wedge

Conditions of propagation of Rayleigh waves over an elastic wedge are considered. Refraction factors are determined for conversion of the initial wave into secondary volume and surface waves. Calculation results for the modules of the refraction coefficient agree well with published experimental data.

An experimental setup for contactless measurement of the velocity of Rayleigh waves and the surface displacement amplitude

An experimental setup is described on which acoustic pulses were recorded from a small surface area. The setup consists of a contactless electromagnetic-acoustic receiver in which the inductor is two thin straight parallel conductors that are positioned a small distance from each other. The velocity of a Rayleigh wave was determined in the 2–10 MHz frequency range. At these frequencies, the length of a surface acoustic wave was varied from 600 to 240 μm and the minimal spacing for measuring the velocity of the Rayleigh wave at a frequency of 10 MHz was 500 μm. A new method for measurement of the time interval between two acoustic pulses is proposed.

The use of lamb waves for measuring the thicknesses of thin metal films

An experimental device that allows the determination of the thicknesses of thin metal films in the micron range is described. The method is based on the use of the dependence of the phase velocity of harmonic antisymmetric Lamb waves that propagate along a film on its thickness. The measurement accuracy was 8% and was virtually independent of the film thickness.

A facility for measuring the thickness of thin metal films

A facility is described for measuring the thickness of a thin metal film. A measurement method is proposed that is based on the dependence of the phase velocity of harmonic antisymmetric Lamb waves that propagate along the film on the film thickness. A continuous method for excitation of acoustic waves has been applied to velocity measurements. It makes it possible to eliminate the effect of dispersion of the Lamb-wave velocity on the measurement accuracy.

Theoretical and experimental study of waves propagating along the edge of a wedge

The properties of a surface acoustic wave moving along the edge of an elastic wedge are studied. The equations defining the character of the wave motion under consideration are obtained. A method is proposed to determine field parameters that adequately describe the experimentally confirmed acoustic phenomena taking into account the characteristics of wave propagation in the wedge-shaped region. The results of the theoretical study are compared with experimental data obtained on an original device used to determine displacements in small surface areas.

Propagation of Rayleigh Waves in an Elastic Wedge

Propagation of Rayleigh waves in an elastic wedge has been studied theoretically. The resulting curves for the refractive index are in good agreement with previously known experimental data.