On the Peculiarities of Reflection of Shear Waves With Linear Polarization From the Rough Surface of a Crack

The reflection coefficient of shear waves with SV- and SH-linear polarization from a statistically inhomogeneous surface consisting of scattering linear elements with a feature of their height distribution according to the normal law in a two-dimensional approximation is estimated. The estimation of the reflection coefficients in the reverse and forward directions is based on the calculation of the reflected wave energy flow propagating from an inhomogeneous surface averaged over the possible values of the height of the reflecting elements. It is theoretically shown and confirmed experimentally that the ratio of the coefficients of the reverse reflection of SH- and SV-polarization waves is significantly greater than 1, which provides better detection of cracks by SH-waves. The peculiarity of the behavior of the dependence of the coefficients of the reverse and direct reflected signal of the SV-polarization waves on the mean square deviation corresponds to the results of theoretical estimates. The coefficient of variation of the ratio of reflection coefficients shows the statistical stability of the direct reflected signal, which determines the feasibility of using such a signal to measure the equivalent area of the reflector.