Structural Health Monitoring (SHM) of 2D areas can be performed bycombining time waveforms acquired by an array of Guided Wave (GW) transducersthrough phased addition algorithms. However, spatial resolution in defectlocalization is often limited by both dispersion in wave mode propagation andimaging noise associated to conventional delay-and-sum (DAS) beamforming.Starting from a statistical interpretation of DAS, this paper combines arecently proposed time-frequency procedure based on the Warped FrequencyTransform (WFT) and convex optimization with an adaptive thresholding techniqueto process multi-mode and dispersive Lamb waves. The proposed signal processingis applied to time waveforms recorded at an array of scan points after waveguideexcitation. The results show high-resolution source and scatterer imaging, thusconsiderably improving localization accuracy by imaging noise removal.
An improved beamforming technique for increased imaging resolution in GW-based SHM / Emanuele Baravelli;Luca De Marchi;Massimo Ruzzene;Philipp Schatzer;Nicolo Speciale. - STAMPA. - (2010), pp. 120-123. (Intervento presentato al convegno IEEE International Ultrasonics Symposium, IUS 2010 tenutosi a San Diego, CA; United States nel 11 October 2010 - 14 October 2010) [10.1109/ULTSYM.2010.5935875].
An improved beamforming technique for increased imaging resolution in GW-based SHM
BARAVELLI, EMANUELE;DE MARCHI, LUCA;SPECIALE, NICOLO'ATTILIO
2010
Abstract
Structural Health Monitoring (SHM) of 2D areas can be performed bycombining time waveforms acquired by an array of Guided Wave (GW) transducersthrough phased addition algorithms. However, spatial resolution in defectlocalization is often limited by both dispersion in wave mode propagation andimaging noise associated to conventional delay-and-sum (DAS) beamforming.Starting from a statistical interpretation of DAS, this paper combines arecently proposed time-frequency procedure based on the Warped FrequencyTransform (WFT) and convex optimization with an adaptive thresholding techniqueto process multi-mode and dispersive Lamb waves. The proposed signal processingis applied to time waveforms recorded at an array of scan points after waveguideexcitation. The results show high-resolution source and scatterer imaging, thusconsiderably improving localization accuracy by imaging noise removal.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
