A signal processing approach to exploit chirp excitation in Lamb wave defect detection and localization procedures

Luca De Marchi, Alessandro Perelli, Alessandro Marzani

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)

Abstract

A non-linear Lamb wave signal processing strategy aimed at extending the capability of active–passive networks of PZT transducers for defect detection is proposed. In particular, the proposed signal processing allows to use chirp shaped pulses in actuation, instead of classically applied spiky pulses, requiring thus lower input voltages. To such aim, the acquired Lamb waves are processed by means of a two-step procedure: a warped frequency transform (WFT) to compensate for the dispersion due to the traveled distance, followed by a compression procedure to remove from the signals the induced chirp frequency modulation. Next, the resulting signals are exploited to feed an imaging algorithm aimed at providing the position of the defect on the plate. The potential of the procedure is demonstrated and validated by analyzing experimental Lamb waves propagating in an aluminum plate where defects were emulated by posing an added mass on the plate. The proposed automatic procedure is suitable to locate defect-induced reflections and can be easily implemented in real applications for structural health monitoring.
Original languageEnglish
Pages (from-to)20-31
Number of pages12
JournalMechanical Systems and Signal Processing
Volume39
Issue number1-2
DOIs
Publication statusPublished - Aug 2013

Keywords

  • Chirped pulses
  • Warped frequency transform
  • Time–frequency analysis
  • Dispersion compensation
  • Defect localization

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