Validation of a thermal bias control technique for Coda Wave Interferometry (CWI)

by Yuxiang Zhang, Odile Abraham, Vincent Tournat, Alain Le Duff, Bertrand Lascoup, Ahmed Loukili, Frédéric Grondin, Olivier Durand
Abstract:
The Coda Wave Interferometry (CWI) analysis serves to monitor the variation of propagation velocity in a heterogeneous medium with high precision (10(-3)% in relative terms). In combination with acoustoelastic theory, this type of analysis offers an NDT method for stress evaluation and/or damage detection. Since the CWI method is intended to evaluate extreme levels of accuracy, the presence of bias under certain circumstances can undermine evaluation results and/or test repeatability. In this paper, we offer a bias control technique involving the use of a second (reference) specimen for CWI analysis that is designed to compensate: (1) the thermally-induced velocity variation due to environmental temperature fluctuations; and (2) bias originating from experimental procedures. The presentation of this technique contains both a theoretical analysis and experimental protocol for the purpose of implementation. Furthermore, comparisons of experimental results have been included in order to demonstrate the utility of this bias control technique under laboratory conditions.
Reference:
Yuxiang Zhang, Odile Abraham, Vincent Tournat, Alain Le Duff, Bertrand Lascoup, Ahmed Loukili, Frédéric Grondin, Olivier Durand, « Validation of a thermal bias control technique for Coda Wave Interferometry (CWI) », In Ultrasonics, pp. : Disponible en ligne, 2012.
Bibtex Entry:
@ARTICLE{ZhangUltrasonics20122,
  author = {Yuxiang Zhang and Odile Abraham and Vincent Tournat and Le Duff,
	Alain and Bertrand Lascoup and Ahmed Loukili and Fr'ed'eric Grondin
	and Olivier Durand},
  title = {Validation of a thermal bias control technique for Coda Wave Interferometry
	({CWI})},
  journal = {Ultrasonics},
  year = {2012},
  pages = {: Disponible en ligne},
  abstract = {The Coda Wave Interferometry (CWI) analysis serves to monitor the
	variation of propagation velocity in a heterogeneous medium with
	high precision (10(-3)% in relative terms). In combination with acoustoelastic
	theory, this type of analysis offers an NDT method for stress evaluation
	and/or damage detection. Since the CWI method is intended to evaluate
	extreme levels of accuracy, the presence of bias under certain circumstances
	can undermine evaluation results and/or test repeatability. In this
	paper, we offer a bias control technique involving the use of a second
	(reference) specimen for CWI analysis that is designed to compensate:
	(1) the thermally-induced velocity variation due to environmental
	temperature fluctuations; and (2) bias originating from experimental
	procedures. The presentation of this technique contains both a theoretical
	analysis and experimental protocol for the purpose of implementation.
	Furthermore, comparisons of experimental results have been included
	in order to demonstrate the utility of this bias control technique
	under laboratory conditions.},
  owner = {gplantier},
  timestamp = {2012.11.24}
}