Özet:

We present results of research into the influence of characteristics of a heterogeneous medium on the Lamb wave propagation process parameters along a plate in contact with a given medium. A mathematical description of the Lamb wave propagation process in a metallic plate was formed. Analytical expressions are derived for determining the displacement potentials that describe, respectively, the longitudinal and transverse waves in a plate with a thickness of 2d at frequency ω. The possibility is shown of the existence under given conditions of a certain finite number of symmetric and antisymmetric Lamb waves. The mentioned waves are different one from another in phase and group velocities, as well as the distribution of displacements and stresses along the plate's thickness. We have investigated dependence of the Lamb wave attenuation on the characteristics of fluid in contact with the propagation medium. In the case when the Lamb wave propagation medium borders the fluid and the speed of sound in liquid Cl is less than speed C of the wave in a plate, the Lamb wave will attenuate radiating energy into liquid. It was established that the attenuation is due to the density of the studied medium. Viscosity and motion speed of a gas-containing suspension, for example iron ore pulp, have almost no effect on the magnitude of attenuation of the Lamb waves. The significance of the obtained results is emphasized by the fact that they could be used to develop improved methods and tools to control parameters of gas-containing suspensions. The use of Lamb waves makes it possible to avoid measurement errors associated with the presence of microdefects at the surface of propagation and gas bubbles in the examined liquid. From a practical point of view, the results obtained could be used for the calculation of parameters for the sources of ultrasonic waves in the systems of ultrasonic testing. Thus, there is an opportunity to improve efficiency of technological processes in the mining and metallurgical industry, specifically, the enrichment of ore. Author Biographies Vladimir Morkun, Kryvyi Rih National University Vitaliy Matusevych str., 11, Kryvyi Rih, Ukraine, 50027 Doctor of Technical Sciences, Professor, Vice-Rector for Research

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