ASA 126th Meeting Denver 1993 October 4-8

4aSA7. Acoustic reflections from acoustically tailored nonhomogeneous viscoelastic coatings.

Courtney B. Burroughs Kimberly L. Beach

Engineering Sci. and Mech. Dept., Penn State Univ., State College, PA 16804

An analytic model for acoustic reflections from nonhomogeneous viscoelastic coatings is developed. The model includes variations in the viscoelastic properties of the coating in directions parallel to the surface of the coating. By converting acoustic pressure wave incident on the coating to high wave-number pressure and shear waves in the coating, the nonhomogeneities in the coating convert potentially reflected waves into nonreflecting waves, thereby trapping the energy in the coating where the energy is dissipated by the internal damping in the coating. Examples are presented to show the sensitivity of acoustic reflections from coatings to the nonhomogeneous properties and damping of the coating material.