Date of Award
Master of Science
Electrical and Computer Engineering
Steve H. Russell
In manufacturing, the ability to detect and characterize failure-initiating flaws is important in the assurance of the structural integrity of materials and components. One major technique in the detection and characterization of such flaws is ultrasonics. In recent years, significant advances have been made in inverse ultrasonic scattering in the region where the ultrasonic wavelength is of the same order as the "radius" of the flaw. Such work is based on physical models that describe the interaction between an elastic wave and the flaw for both long and intermediate wavelength inverse scattering.
To exploit these theoretical advances in elastic wave inverse scattering, an automated multiviewing ultrasonic transducer system and associated software has been designed and built in order to perform characterization and analysis of volumetric flaws. The flaw is characterized by its size, shape, and orientation within a material. Utilizing inverse ultrasonic scattering theories, signal processing algorithms perform three-dimensional reconstruction by finding an ellipsoid that best fits the inverse scattering data taken from many independent perspectives within a specified aperture.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu
James A. Crowder
Crowder, James A., "Automated angular scans to determine flaw orientation for use in model-based flaw reconstruction" (1988). Retrospective Theses and Dissertations. 228.