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Ultrasonic Characterization-Sensors
- Professors: Yves Berthelot, Nico Declercq
- Post-doc: L. Satyanarayan
- Ph.D. Student: Sarah Herbison
- Masters Student: Peter McKeon
Ultrasound is not only a useful inspection tool for classical materials, but for new novel materials as well. However, innovative materials, such as those being developed by other research teams at the GT-CNRS UMI 2958, may be highly complex and require sophisticated inspection techniques and appropriate expertise. Within the framework of developing techniques and innovations that can be applied to the ultrasonic evaluation of new materials, the research of the Laboratory for Ultrasonic Non-destructive Evaluation follows three main themes. Within each theme, numerical and experimental research is conducted. For the theoretical work we have developed plane wave expansion tools and finite element code, etc. For experimental work, the lab is equipped with a custom-designed polar/C-scan apparatus, a Ritec Snapscan for nonlinear acoustics, and a Polytec laser vibrometer, in addition to other laboratory equipment.
Techniques for Ultrasonic NDE: Polar Scanning and Nonlinear Acoustics
First, the lab explores and develops innovative techniques and tools for ultrasonic non-destructive evaluation (NDE). Examples include polar scanning and nonlinear acoustic techniques, both of which can be used to help determine the level of damage sustained by a material. In particular, the lab has focused on the fatigue damage sustained by fiber reinforced composites.
The Interaction of Ultrasound with Periodic Structures
Second, the lab is investigating the interaction of ultrasound with periodic structures. Much research in the last decade has been dedicated to the study of phononic crystals, which are periodic structures that are considered the acoustic counterparts of photonic crystals in optics. The ultrasonics lab at the GT-CNRS UMI 2958 studies the diffraction that occurs on periodic structures with periodically corrugated surfaces and plates as an example. Applications exist in acoustic filtering and in furthering the understanding of the diffraction mechanisms that occur in devices such as phononic crystals. The developed techniques are also applied to larger constructions, such as the Hellenistic theater of Epidaurus in Greece and the El Castillo pyramid at Chichen Itza in Mexico, to name only a few.
Development of Innovative Air-Coupled Transducers using Piezoactive Polymer Foams
Finally, the lab is also focusing on the development of innovative air-coupled ultrasonic transducers. Currently, the air-coupled ultrasonic transducers that are commercially available are very expensive. However, a new porous polymer foam film that exhibits a piezoelectric-like effect has presented an inexpensive alternative material for the design of these transducers. Research activities include material characterization of the foam material and studies on the efficacy of ultrasonic propagation from the foam.
