Degree Type

Thesis

Date of Award

1988

Degree Name

Master of Science

Department

Electrical and Computer Engineering

First Advisor

Steve H. Russell

Abstract

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.

DOI

https://doi.org/10.31274/rtd-180813-5230

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu

Copyright Owner

James A. Crowder

Language

en

Date Available

2013-12-10

File Format

application/pdf

File Size

92 pages

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