Masters Theses

Keywords and Phrases

Corrosion; Crack; Imaging; Microwaves; Paint; SAR


"We live in the world of "aging infrastructures". In this environment, critical and heavily utilized infrastructure, i.e. ships, planes, bridges, etc., are operating at or beyond their designed age. Replacement is no longer an option and "retirement for cause" is the current approach to maintenance and replacement. Consequently, there is an ever-increasing demand for efficient and robust nondestructive evaluation (NDE) methods that can determine the physical health of these structures. Large structures, which are primarily made of metals, either steel or aluminum, are susceptible to high-stress cracking and corrosion. Stress-induced cracks in heavily corroded steel, used in bridges, railroads, storage tanks, etc., are extremely difficult to detect. Current methods have limitations that render inspection to take longer either than it should or risk not detecting an existing crack. Microwave signals readily penetrate through dielectric materials such as paint and corrosion byproducts (i.e., rust), while conducting materials (i.e., metals) strongly reflect microwave signals. Therefore, interrogating a metal surface for surface-breaking cracks is readily possible even in the presence of a relatively thick layer of corrosion or paint. Normally, surface-breaking cracks are very small and the perturbations they cause to an irradiating microwave signal are small in amplitude unless the detection is performed very close to the surface. In this thesis, the implementation of a microwave imaging system that utilizes a synthetic aperture radar (SAR) approach to detect surface-breaking cracks in metallic structures under heavy corrosion and corrosion preventive paints is investigated. The resulting SAR images were analyzed and compared to numerical simulations to identify real-world capabilities and theoretical limitations"--Abstract, page iii.


Zoughi, R.

Committee Member(s)

Ghasr, Mohammad Tayeb Ahmad, 1980-
Newkirk, Joseph William


Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering


Missouri University of Science and Technology

Publication Date

Spring 2019


xi, 77 pages

Note about bibliography

Includes bibliographical references (pages 74-76).


© 2019 John Robert Gallion, All rights reserved.

Document Type

Thesis - Open Access

File Type




Thesis Number

T 11527

Electronic OCLC #