The detection of flaws in austenitic welds using the decomposition of the time reversal operator

Laura J. Cunningham, Anthony Mulholland, Katherine Margaret Mary Tant, Anthony Gachagan, Gerry Harvey, Colin Bird

Research output: Contribution to journalArticle (Academic Journal)peer-review

22 Citations (Scopus)


The non-destructive testing of austenitic welds using ultrasound plays an important role in the assessment of the structural integrity of safety critical structures. The internal microstructure of these welds is highly scattering and can lead to the obscuration of defects when investigated by traditional imaging algorithms. This paper proposes an alternative objective method for the detection of flaws embedded in austenitic welds based on the singular value decomposition of the time-frequency domain response matrices. The distribution of the singular values is examined in the cases where a flaw exists and where there is no flaw present. A lower threshold on the singular values, specific to austenitic welds, is derived which, when exceeded, indicates the presence of a flaw. The detection criterion is successfully implemented on both synthetic and experimental data. The datasets arising from welds containing a flaw, are further interrogated using the decomposition of the time reversal operator (DORT) method and the total focussing method (TFM) and it is shown that images constructed via the DORT algorithm typically exhibit a higher signal to noise ratio than those constructed by the TFM algorithm.
Original languageEnglish
Article number20150500
JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Early online date1 Apr 2016
Publication statusPublished - 30 Apr 2016


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