Research Seminar: Resonant Characteristics of Surface Bonded Piezoelectric Wafer Transducers

Abstract

Ultrasound inspection using surface bonded piezoelectric wafer transducers has become one of the most prevalent technologies for structural health monitoring. Past researches have been focused on understanding the interactions between the ultrasound waves and various structural damage. The resonant characteristics of the surface bonded transducers and their influences on damage detection, on the other hand, had received very little attention. This presentation will discuss our recent work on the resonant characteristics of surface bonded transducers. First, by incorporating the adhesive layer into an efficient simulation model, we discovered that the adhesive layer strongly influences the transducer resonances. Parametric studies predicted that there is an optimum adhesive thickness for maximum ultrasound generation, which was confirmed by experiments. Secondly, we introduced the scattering-parameters, a network characterization tool commonly used in microwave engineering, to study the resonance characteristics of surface bounded piezoelectric transducers. We discovered that the electro-mechanical impedance signature of the transducer, which is widely used for damage detection, is essentially the frequency representation of the time-domain pulse-echo signal. Separating the time-domain pulse-echo signal into the resonant and echo phases further revealed that the resonance signal is more sensitive to the bonding conditions while the time-of-flight of the echo signal can be correlated to the damage location. These understandings led to significant improvements on detection sensitivity and damage differentiation. Evaluating the resonant characteristics of the transducer also enabled us to select the correct resonance mode that produces monotonously changes with the damage severity.

Biography

Dr. Haiying Huang is a professor of Mechanical and Aerospace Engineering at the University of Texas Arlington. She received a PhD degree in Aerospace Engineering and a master degree in Electrical Engineering; both from the Georgia Institute of Technology. Her research is focused on structural and human condition monitoring using ultrasound, microwave, and optical fiber technologies. Prof. Huang has published more than 100 journal and conference papers and has nine granted patents. She is a recipient of the 2009 NSF CAREER award and the 2007 Air Force Summer Faculty Fellowship. Prof. Huang is a member of the ASME, IEEE, and a lifetime member of AIAA and SPIE.

Additional Information:

For additional details call Diane K. Bierly 863-6491.

 

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