Location

La Jolla, CA

Start Date

1-1-1983 12:00 AM

Description

We study the recently derived reflection coefficient for plane waves in a liquid that are incident on the liquid-solid interface of a solid half space which consists of a single layer of one elastic material bonded to a substrate of a different material. Plots of the magnitude of the reflection coefficient versus the incident angle are presented for several sets of material parameters and values of frequency f and layer thickness d. The use of the results presented for the study of nonspecular reflection of bounded acoustic beams is of primary interest. We therefore seek to identify all the critical incidence angles for nonspecular reflection.

We also investigate, in particular, the surface wave propagation for the case of a stiff layer on a soft half space, and we find that the purely propagating mode cuts off with increasing fd (f is the frequency and d the layer thickness) when its speed reaches approximately the shear wave speed of the substrate, as reported in the literature. However, as fd increases further, a leaky mode appears that approaches the Rayleigh wave for the layer. This leaky mode is also associated with nonspecular reflection for large enough fd.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

2B

Chapter

Section 15: New Approaches to Ultrasonic Inverse Scattering

Pages

923-936

DOI

10.1007/978-1-4613-3706-5_59

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

On Nonspecular Reflection of Bounded Beams for Layered Half Spaces Under Water

La Jolla, CA

We study the recently derived reflection coefficient for plane waves in a liquid that are incident on the liquid-solid interface of a solid half space which consists of a single layer of one elastic material bonded to a substrate of a different material. Plots of the magnitude of the reflection coefficient versus the incident angle are presented for several sets of material parameters and values of frequency f and layer thickness d. The use of the results presented for the study of nonspecular reflection of bounded acoustic beams is of primary interest. We therefore seek to identify all the critical incidence angles for nonspecular reflection.

We also investigate, in particular, the surface wave propagation for the case of a stiff layer on a soft half space, and we find that the purely propagating mode cuts off with increasing fd (f is the frequency and d the layer thickness) when its speed reaches approximately the shear wave speed of the substrate, as reported in the literature. However, as fd increases further, a leaky mode appears that approaches the Rayleigh wave for the layer. This leaky mode is also associated with nonspecular reflection for large enough fd.