Seminar: On the use of guided ultrasonic waves for the inspection of immersed structures

Monday, April 8, 2013 - 12:00pm - 1:00pm EDT

  • Location:LC433
    US

Mechanical and Aerospace Engineering Department Seminar Series

Spring 2013

4/8 (Monday) Noon-1:00 pm
LC433
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On the use of guided ultrasonic waves for the inspection of immersed
structures

Piervincenzo Rizzo, Ph.D.
Associate Professor
Laboratory for Nondestructive Evaluation and Structural Health Monitoring Studies
Department of Civil and Environmental Engineering
University of Pittsburgh, Pittsburgh, PA, US

Structures containing or surrounded by water are ubiquitous in the modern
world. They can be arbitrarily clustered into the following groups: oil or
natural gas offshore structures, communication cables, pipelines, naval
vessels, waterfront facilities, water mains and pipes, and sea wind farms.
The economic and strategic impact of these structures is enormous but,
owing to the operational conditions, they are vulnerable to corrosion, ship
anchors, and seismic movements of the sea bed. As such, the periodic
inspection or the permanent monitoring of structures surrounded or
containing water is necessary.

This seminar presents the results of experimental and numerical studies
where guided ultrasonic waves are used for the structural health monitoring
/ non-destructive evaluation of immersed waveguides. Leaky Lamb waves were
generated by means of a pulsed laser and detected by an array of immersion
transducers. The signals are processed using continuous wavelet transform
to extract few damage-sensitive features that are fed to an unsupervised
learning algorithm based on outlier analysis. Moreover the features are
used to create an image of the structure. The experimental setup is
simulated numerically using commercial finite element software to predict
the time of arrival of the propagating modes. In this presentation we show
the capability of the monitoring system to detect four defects artificially
devised on an aluminium plate prior to the immersion in water. We find that
the non-contact probing system and the signal processing enable the
detection of cracks and simulated corrosion.

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*Biosketch*

Dr. Piervincenzo Rizzo earned his Laurea (M.S. equivalent) in Aeronautical Engineering at the University of Palermo, Italy in 1998. After serving in the Italian Army Corps of Engineering, Dr. Rizzo moved to the U.S.A. where he earned a Master (2002) and a Ph.D. (2004) in Structural Engineering at the University of California, San Diego. In September 2006 he became an assistant professor at the Department of Civil and Environmental Engineering at the University of Pittsburgh and promoted
to Associate Professor with tenure in 2012. Dr. Rizzo?s research interests are in nondestructive evaluation and structural health monitoring using techniques such as ultrasound, acoustic emission, thermography, solitary waves, and electromechanical impedance. His current and past researches have been supported by the Pennsylvania Department of Transportation, the National Science Foundation, the American Society for Nondestructive Testing, and various Pitt?s seed funding mechanism. He is the recipient of the 2002 Fellowship Research Award and the 2007 Faculty Grant Award from the American Society for Nondestructive Testing, and the 2012 Achenbach Medal, which has been created to recognize a young individual who has made an outstanding contribution to the advancement of the field of Structural Health Monitoring. Dr. Rizzo is the author of 7 book chapters, 51 peer-reviewed journal papers, and 120+ conference papers and presentations. For more information, visit Dr. Rizzo's home page http://www.pitt.edu/~pir3/.