Theoretical Properties of Acoustical Speckle Interferometry.
Abstract
Acoustical speckle interferometry is based locally on the elastodynamic response of solids subjected to ultrasonic waves. The presence of a subsurface layer or discontinuity generally produces a change in the wave propagating in a medium. Acoustical speckle interferometry utilizes the reflection, refraction, and mode conversion of incident elastic waves at the interface of two elastic media as a basic description of the transmission and reflection of elastic waves. Basic equations for the reflection and refraction of a layered elastic half space are derived. Numerical examples of liquid-solid interfaces are presented. A two-layer solid medium immersed in water is solved to illustrate the effect of an incident p-wave on the refraction and reflection properties. Theoretical properties of acoustical speckle interferometry are discussed which includes the effect of deformation. A data analysis procedure is described which utilizes a two-dimensional correlation of acoustical signals as a direct measure of object motion. Numerical examples are presented to illustrate the correlation of reference and deformed ultrasonic signals. Uniform translations without geometric distortion are presented. Geometric distortions for both infinitesimal and finite deformations are illustrated to show this effect on the deformed acoustical surface. All results are presented in graphical form. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1980
- Accession Number
- ADA126672
Entities
People
- W. F. Ranson
Organizations
- United States Army Aviation and Missile Command