ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

5aPA10. Leaky Rayleigh wave scattering from elastic media with microstructure.

Yuan Zhang

Richard L. Weaver

Dept. of Theor. and Appl. Mech., Univ. of Illinois, 216 Talbot Lab., 104 S. Wright St., Urbana, IL 61801

Scattering of leaky Rayleigh wave from a flat fluid--solid interface is studied. The fluid half-space is taken to be ideal and homogeneous while the solid half-space has randomly inhomogeneous anisotropic elastic constants due to the microstructure of the material. For plane waves incident from the fluid onto the interface at the critical Rayleigh angle, the singly scattered incoherent field is obtained by utilizing a first Born approximation. When the solid is a crystal aggregate and when the correlation function is of exponential form, the mean-square scattered signal level is found to be inversely proportional to the dimensionless frequency in the high-frequency limit but proportional to the third power of frequency in the low-frequency limit. Numerical results are given for water--aluminum interface scattering. [Work supported by NSF.]