*********************************
There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
*********************************
Title: A Comprehensive Approach for Wavefield-based Characterization of Ultrasonic Shear Wave Scattering in Plates
Committee:
Dr. Jennifer Michaels, ECE, Chair , Advisor
Dr. Aaron Lanterman, ECE
Dr. Ying Zhang, ECE
Dr. Massimo Ruzzene, AE
Dr. Karim Sabra, ME
Abstract:
The objective of this research is to present a comprehensive approach for characterizing and quantifying the scattering of angle-beam ultrasonic shear waves from a variety of scatterers in plates. The motivation behind analyzing angle-beam shear wave propagation and scattering is to obtain a better understanding of shear wave interactions with defects and improve the reliability and accuracy of inspection techniques for NDE applications. The scatterers investigated here include through-holes, part-through holes, and notches emanating from through-holes. Scattering from both through-holes and notches, aimed to mimic actual ultrasonic defects in practice, is of particular interest to the aerospace industry because crack-like defects usually grow from fastener holes, which presents a potential hazard to aircraft components if undetected. There are two main contributions of this research. One is the acquisition of a comprehensive set of wavefield data for a variety of scattering scenarios via wavefield imaging. The other is the development of a systematic methodology for ultrasonic shear wave scattering estimation using a complete set of signal processing techniques. All methodologies presented in this thesis are demonstrated to be effective and reliable for showing useful scattering information.
