Experimental validation of time-reversal technique for defect detection in air-filled pipes using high frequency acoustic waves

2019 ◽  
Vol 146 (4) ◽  
pp. 2867-2867
Author(s):  
Mehmet M. Gozum ◽  
Moez Louati ◽  
Saber Nasraoui ◽  
George Grigoropoulos ◽  
Mohamed S Ghidaoui
Keyword(s):  
Defect Detection ◽  
Time Reversal ◽  
Acoustic Waves ◽  
High Frequency ◽  
Experimental Validation

Time-reversal techniques for defect detection in pipe system using high frequency acoustic waves

2019 ◽  
Vol 146 (4) ◽  
pp. 2867-2867
Author(s):  
Saber Nasraoui ◽  
Moez Louati ◽  
Mehmet Murat Gozum ◽  
George Grigoropoulos ◽  
Mohamed S Ghidaoui
Keyword(s):  
Defect Detection ◽  
Time Reversal ◽  
Acoustic Waves ◽  
High Frequency ◽  
Pipe System

scholarly journals Crack-Length Estimation for Structural Health Monitoring Using the High-Frequency Resonances Excited by the Energy Release during Fatigue-Crack Growth

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4221
Author(s):  
Roshan Joseph ◽  
Hanfei Mei ◽  
Asaad Migot ◽  
Victor Giurgiutiu
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Health Monitoring ◽  
Acoustic Waves ◽  
High Frequency ◽  
Fem Analysis ◽  
Signal Frequency ◽  
Propagation Pattern

Acoustic waves are widely used in structural health monitoring (SHM) for detecting fatigue cracking. The strain energy released when a fatigue crack advances has the effect of exciting acoustic waves, which travel through the structures and are picked up by the sensors. Piezoelectric wafer active sensors (PWAS) can effectively sense acoustic waves due to fatigue-crack growth. Conventional acoustic-wave passive SHM, which relies on counting the number of acoustic events, cannot precisely estimate the crack length. In the present research, a novel method for estimating the crack length was proposed based on the high-frequency resonances excited in the crack by the energy released when a crack advances. In this method, a PWAS sensor was used to sense the acoustic wave signal and predict the length of the crack that generated the acoustic event. First, FEM analysis was undertaken of acoustic waves generated due to a fatigue-crack growth event on an aluminum-2024 plate. The FEM analysis was used to predict the wave propagation pattern and the acoustic signal received by the PWAS mounted at a distance of 25 mm from the crack. The analysis was carried out for crack lengths of 4 and 8 mm. The presence of the crack produced scattering of the waves generated at the crack tip; this phenomenon was observable in the wave propagation pattern and in the acoustic signals recorded at the PWAS. A study of the signal frequency spectrum revealed peaks and valleys in the spectrum that changed in frequency and amplitude as the crack length was changed from 4 to 8 mm. The number of peaks and valleys was observed to increase as the crack length increased. We suggest this peak–valley pattern in the signal frequency spectrum can be used to determine the crack length from the acoustic signal alone. An experimental investigation was performed to record the acoustic signals in crack lengths of 4 and 8 mm, and the results were found to match well with the FEM predictions.

Demonstration of a high-frequency acoustic barrier with a time-reversal mirror

2003 ◽  
Vol 28 (2) ◽  
pp. 246-249 ◽  
Author(s):  
H. Song ◽  
W.A. Kuperman ◽  
W.S. Hodgkiss ◽  
T. Akal ◽  
P. Guerrini
Keyword(s):  
Time Reversal ◽  
High Frequency ◽  
Time Reversal Mirror

Source point discovery through high frequency asymptotic time reversal

2012 ◽  
Vol 231 (14) ◽  
pp. 4643-4661 ◽  
Author(s):  
Jean-David Benamou ◽  
Francis Collino ◽  
Simon Marmorat
Keyword(s):  
Time Reversal ◽  
High Frequency ◽  
Source Point ◽  
Asymptotic Time

High-frequency acoustic waves are not sufficient to heat the solar chromosphere

Nature ◽  
2005 ◽  
Vol 435 (7044) ◽  
pp. 919-921 ◽  
Author(s):  
Astrid Fossum ◽  
Mats Carlsson
Keyword(s):  
Acoustic Waves ◽  
High Frequency ◽  
Solar Chromosphere
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