CIVIL & ENVIRONMENTAL ENGINEERING
Piervincenzo Rizzo, PhD
729 Benedum Hall | 3700 O’Hara Street | Pittsburgh, PA 15261
Professor Director, Laboratory for Nondestructive Evaluation and Structural Health Monitoring Studies
P: 412-624-9575 C: 412-417-4846 pir3@pitt.edu http://www.pitt.edu/~pir3/
HNSWs for the Prevention of Rail Thermal Buckling
Prof. Rizzo has nearly 15 years’ experience in nondestructive evaluation (NDE), structural health monitoring (SHM), and signal processing. To date, Dr. Rizzo has published nearly 70 peerreviewed papers, over 120 conference proceedings, and he holds 2 patents. His research portfolio spans from the application of guided waves for the NDE of rails, pipes, and cable structures, to the use of infrared technology in NDE and sustainability. His research has been supported by the National Science Foundation, the Federal Railroad Administration, the American Society for Nondestructive Testing and the Pennsylvania Department of Transportation. Recently, he is applying some NDE techniques for biomedical applications.
One of the major structural problems in the railroads made of continuous welded rails is buckling in hot weather and breakage or pulling apart in cold weather. The prevention of buckling is related to the determination of the temperature, called rail neutral temperature, at which the net longitudinal force in the rail is zero. Our group is investigating the capability of a novel sensing system to indirectly measure applied stress in rails. This system consists of a simple and cost-effective transducer, recently developed at Pitt. The transducer enables the generation and detection of highly nonlinear solitary waves (HNSWs), which are compact non-dispersive stress waves that can form and travel in nonlinear systems such as granular materials.
Top: Example of buckling (http://www.powelectrics.co.uk/content/rail.jpg Bottom: proposed NDE inspection scheme.
EMI for the Assessment of Dental Implants Missing teeth is a problem that involves people of any country and race. Dental implants are increasingly used to replace missing teeth, but the proper success of the therapy is related to the ability to assess the occurrence of full osseointegration, when a stable implant-bone interface is reached. We propose a new biomedical device to assess such stability. The device exploits the electro-mechanical impedance (EMI)
of a piezo-transducer glued to the abutment screwed to an implant. We hypothesize that the electrical impedance of this disposable transducer glued to the abutment inserted, during periodic visits, to the implant, can diagnose the progress of the implant therapy.
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Left: Photo of an artificial tooth supported by an implant. Right top: PZT bonded to an implant. Right bottom: finite element model for EMI study
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Guided Ultrasonic Waves (GUWs) for SHM Applications
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The demand for robust and cost-effective SHM systems is on the rise. Among the several methods proposed to monitor waveguide-like structures, ultrasonic-based and impedance-based methods are gaining increasing attention in the research community. Dr. Rizzo’s group has positioned itself in the area of GUWs-based SHM. We developed a general paradigm that combines guided waves with discrete wavelet transform to extract a set of damage sensitive features that are fed to a supervised (artificial neural network) or an unsupervised learning (outlier analysis) algorithm. The paradigm aims at identifying and/or classifying damage.
Examples of of waveguides Examples waveguides
DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING
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