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Proceedings Paper

Developing an optimal acoustic reflector for air-coupled impact-echo sensor
Author(s): Seong-Hoon Kee; Nenad Gucunski; Farhad A. Fetrat
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Paper Abstract

The objectives of this study were to investigate interaction of a parabolic acoustic reflector with leaky stress waves in air-coupled IE testing, and to develop an optimal geometry of the acoustic reflector. The resulting acoustic reflector will be used as a part of an air-coupled impact-echo device for delamination detection in concrete bridge decks. The study was conducted on a series of 2D finite element (FE) models. The models included both solid concrete plate and air domains. The models were developed to investigate interaction of leaky stress waves (in particular, S1 resonance mode in Lamb waves) with a parabolic reflector. A series of parametric studies was conducted to determine the optimal geometry of parabolic reflectors (cylinders). The main variables were the rim angle and the width of the reflectors, and location of air-coupled sensors. Furthermore, numerical simulations using 2D FE models, including delamination defects in concrete decks, were conducted to verify the optimal parabolic reflector is effective in enhancing the amplitude of S1 resonance modes in Lamb waves corresponding to the various depths of delamination defects. Finally, the results clearly demonstrate that the optimal parabolic domes can significantly improve signal-to-noise ratio in the air-coupled IE measurements. This will increase the feasibility of air-coupled sensing in actual impact echo testing on concrete bridge decks.

Paper Details

Date Published: 5 April 2012
PDF: 9 pages
Proc. SPIE 8347, Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2012, 834706 (5 April 2012); doi: 10.1117/12.914718
Show Author Affiliations
Seong-Hoon Kee, Rutgers, The State Univ. of New Jersey (United States)
Nenad Gucunski, Rutgers, The State Univ. of New Jersey (United States)
Farhad A. Fetrat, Rutgers, The State Univ. of New Jersey (United States)


Published in SPIE Proceedings Vol. 8347:
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2012
Andrew L. Gyekenyesi, Editor(s)

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