Diffuse Field Analysis (DFA) applies the concepts of statistical room acoustics to the study of diffuse, short wavelength, reverberant ultrasound in solids. Multiply reflected and/or scattered ultrasound has lost all phase information (the coherent part can be said to have fully attenuated) but retains some information in its spectral energy density. DFA studies this spectral energy as it evolves in time and space and deduces information on the source which emitted the ultrasound and on the medium in which it reverberates. There are three major applications which have so far shown promise. These are acoustic emission source characterization, material characterization by internal friction, and microstructure characterization by incoherent transport.
This paper reviews the promise and limitations of Diffuse Field Analysis for the NDE of materials, and in particular, discusses possible applications towards the better understanding of acousto-ultrasonics.
KeywordsLamb Wave Shear Wave Speed Diffuse Wave Spectral Energy Density Statistical Energy Analysis
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