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1773442 
Journal Article 
Development of nondestructive non-contact acousto-thermal evaluation technique for damage detection in materials 
Sathish, S; Welter, JT; Jata, KV; Schehl, N; Boehnlein, T 
2012 
1 
Review of Scientific Instruments
ISSN: 0034-6748
EISSN: 1089-7623 
83 
9 
23020415 
WOS:000309426700062 
This paper presents the development of a new non-contact
acousto-thermal signature (NCATS) non-destructive evaluation technique. The physical basis of the
method is the measurement of the efficiency of the material to convert acoustic energy into heat,
and a theoretical model has been used to evaluate this. The increase in temperature due to
conversion of acoustic energy injected into the material without direct contact was found to
depend on the thermal and elastic properties of the material. In addition, it depends on the
experimental parameters of the acoustic source power, the distance between sample and acoustic
source, and the period of acoustic excitation. Systematic experimental approaches to optimize
each of the experimental variables to maximize the observed temperature changes are described.
The potential of the NCATS technique to detect microstructural-level changes in materials is
demonstrated by evaluating accumulated damage due to plasticity in Ti-6Al-4V and low level
thermal damage in polymer matrix composites. The ability of the technique for macroscopic
applications in nondestructive evaluation is demonstrated by imaging a crack in an aluminum test
sample. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4749245]