Accession Number:

ADA067664

Title:

Acoustical Speckle Interferometry.

Descriptive Note:

Technical rept.,

Corporate Author:

ARMY MISSILE RESEARCH AND DEVELOPMENT COMMAND REDSTONE ARSENAL AL TECHNOLOGY LAB

Personal Author(s):

• Schaeffel,John Arnold , Jr

Report Date:

1979-03-22

Pagination or Media Count:

103.0

Abstract:

When a continuous wave or pulsed beam of ultrasound is scanned over an object an echo from the object may be detected. If the echo has a random variation in amplitude versus position of the beam, the resulting variation is referred to as acoustical speckle. An analysis is presented for using acoustical speckle to determine displacements on the surface or interior to an object. Two experimental configurations, pulse-echo scanning and continuous wave scanning, are treated in the verification of the analysis. Six experiments are conducted using numerical cross-correlation analysis to verify the hypothesis that acoustical speckle interferometry may be used to determine displacements. The experiments indicate that displacements as small as the discrete sampling interval of the ultrasonic beam can be predicted. Pulse-echo scanning is found to be sensitive to motion in three-dimensions while continuous wave CW scanning is sensitive to motion primarily in two-dimensions. Both methods of beam scanning produce excellent results for interferometric displacement analysis. Author

Descriptors:

• *INTERFEROMETRY
• *ACOUSTIC REFLECTION
• *SPECULAR REFLECTION
• SCANNING
• STRESS STRAIN RELATIONS
• DEFORMATION
• DISPLACEMENT
• CONTINUOUS WAVES
• NUMERICAL ANALYSIS
• WAVE PROPAGATION
• ULTRASONIC TESTS
• CROSS CORRELATION
• INTERNAL PRESSURE

Subject Categories:

• Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE