Guided Wave (GW) testing for Structural Health Monitoring (SHM) iscomplicated by dispersion in wave mode propagation. Compensation approachesavailable in literature are often limited to active monitoring technique as theyrequire the knowledge of the time instant in which the acoustic emissionstarts. In this work we present a novel procedure for passive sensors whichovercomes this limitation and precisely locates the acoustic source. Theproposed procedure is based on the Warped Frequency Transform (WFT). Suchtransformation causes a resampling of the time-frequency domain which matchesthe spectro-temporal behavior of guided waves. In the resampled domain a givenguided wave mode have an unique pattern which is independent from the distanceof propagation thus allowing a precise time of flight measurement. This workdemonstrates how this property can be effectively combined with an hyperbolicpositioning algorithm to accurately image the source location from the signalcaptured by passive sensors.
L. De Marchi, A. Marzani, N. Speciale, E. Viola (2010). Dispersion compensation of Lamb waves with the warped frequency transformin passive monitoring techniques. Institute of Electrical and Electronics Engineers (IEEE) [10.1109/ULTSYM.2010.5935873].
Dispersion compensation of Lamb waves with the warped frequency transformin passive monitoring techniques
DE MARCHI, LUCA;MARZANI, ALESSANDRO;SPECIALE, NICOLO'ATTILIO;VIOLA, ERASMO
2010
Abstract
Guided Wave (GW) testing for Structural Health Monitoring (SHM) iscomplicated by dispersion in wave mode propagation. Compensation approachesavailable in literature are often limited to active monitoring technique as theyrequire the knowledge of the time instant in which the acoustic emissionstarts. In this work we present a novel procedure for passive sensors whichovercomes this limitation and precisely locates the acoustic source. Theproposed procedure is based on the Warped Frequency Transform (WFT). Suchtransformation causes a resampling of the time-frequency domain which matchesthe spectro-temporal behavior of guided waves. In the resampled domain a givenguided wave mode have an unique pattern which is independent from the distanceof propagation thus allowing a precise time of flight measurement. This workdemonstrates how this property can be effectively combined with an hyperbolicpositioning algorithm to accurately image the source location from the signalcaptured by passive sensors.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
