Active doublet method for measuring small changes in physical properties
Small changes in material properties of a work piece are detected by measuring small changes in elastic wave velocity and attenuation within a work piece. Active, repeatable source generate coda wave responses from a work piece, where the coda wave responses are temporally displaced. By analyzing progressive relative phase and amplitude changes between the coda wave responses as a function of elapsed time, accurate determinations of velocity and attenuation changes are made. Thus, a small change in velocity occurring within a sample region during the time periods between excitation origin times (herein called ''doublets'') will produce a relative delay that changes with elapsed time over some portion of the scattered waves. This trend of changing delay is easier to detect than an isolated delay based on a single arrival and provides a direct measure of elastic wave velocity changes arising from changed material properties of the work piece. 8 figures.
- Assignee:
- Dept. of Energy, Washington, DC (United States)
- Patent Number(s):
- US 5369997; A
- Application Number:
- PPN: US 8-000310
- OSTI ID:
- 6647711
- Resource Relation:
- Patent File Date: 4 Jan 1993
- Country of Publication:
- United States
- Language:
- English
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