Researchers at Missouri University of Science and Technology recently worked with The Boeing Company to establish a new nondestructive evaluation laboratory that uses millimeter wave technology to improve the detection of potential flaws in coatings, surfaces and materials.
Researchers in Missouri S&T’s Applied Microwave Nondestructive Testing Laboratory (amntl) designed the new lab for Boeing, and it was recently assembled at the Boeing Research & Technology Center in Charleston, S.C. Boeing’s South Carolina center is focused on research and development efforts in areas of advanced manufacturing with a focus on composite fuselage and propulsion systems production.
“Today, nondestructive evaluation (NDE) encompasses a variety of techniques to achieve many critical objectives, including maintenance assurance, quality control, structural health monitoring and product safety, to name a few,” says Dr. Reza Zoughi, the Schlumberger Distinguished Professor of Electrical and Computer Engineering at Missouri S&T and director of the amntl. Microwave and millimeter-wave NDE techniques, spanning the range of approximately 300 megahertz to 300 gigahertz, have proven effective for addressing many of these needs over the past three decades, Zoughi adds. As a result, these techniques “have been steadily receiving greater attention as potential NDT methods.”
“Recent advances have made these techniques more attractive from a nondestructive evaluation perspective,” says Dr. Don Palmer Jr., Boeing Technical Fellow and NDE expert. Microwave and millimeter wave NDE can be used to detect flaws under attenuative materials, make precise thickness measurements of dielectric coatings and even detect small surface cracks in metallic structures. Boeing and amntl researchers are working together to investigate a millimeter wave crack-detection approach that could significantly improve ultrasonic and eddy-current approaches currently used for small-crack detection associated with widespread fatigue damage.
“The ability to detect smaller cracks simplifies required repairs and, in turn, extends the life of the structure,” Palmer says.
This increasing potential of microwave and millimeter-wave techniques to address complex inspection problems led to Boeing’s decision to work with Missouri S&T to establish the laboratory. It will be used to address a number of needs spanning materials characterization and high-resolution imaging.
In addition to Zoughi, the Missouri S&T research team that designed the lab included Dr. M.T. Ghasr, assistant research professor of electrical and computer engineering; Jeffrey Birt, a technical assistant in the ECE department; and several ECE students.
“This collaborative endeavor allows Boeing to be at the forefront of microwave and millimeter-wave NDT technology for years to come,” says Zoughi.