WAVE PROCESSES IN A LAYERED MICROINHOMOGENEOUS MEDIUM WITH INHOMOGENEOUS BOUNDARY CONDITIONS
The question of how to determine the characteristics of an heterogeneous medium using the measured parameters of a surface wave is considered. The paper studies the propagation of surface waves in a microheterogeneous layered medium of the “steel-graphite” type with inhomogeneous boundary conditions at the boundaries of the layers. Dispersion equations for vertically and horizontally polarized longitudinal and transverse waves are derived and solved for the wave number. Dispersion equation is derived for a surface wave propagating in an elastic inhomogeneous half-space with given effective elastic moduluses. Expressions of longitudinal and transverse waves obtained for a medium with inhomogeneities are substituted into the dispersion equation, then the equation is solved for the wavenumber of the surface wave. Graphic dependences of the obtained velocities on the relative layer thickness are constructed. The obtained dependences are used in relation to the tasks of determining the physicomechanical characteristics of an inhomogeneous medium when the object is monitored by a surface wave. The calculations were performed for a total thickness of the steel-graphite layer equal to 1 mm at an ultrasound frequency of 1 MHz.
Authors: K. E. Abbakumov, A. V. Vagin
Keywords: Dispersion equation, longitudinal wave, transverse wave, surface wave, heterogeneous environment, propagation velocity
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