More than a dozen international companies in the fields of science and transportation rely on Iowa State’s Center for Nondestructive Evaluation.

CNDE’s mission is to advance research and education in the evaluation of the structural materials that make up airplanes, space shuttles and engines.

“Nondestructive evaluation is basically evaluating material used in machinery and transport vehicles without disassembling them,” said Lisa Brasche, associate director at CNDE. “We are currently researching and testing many different methods of testing materials and are able to select appropriate ones to use for a variety of projects.”

Brasche said the center provides many unique opportunities to ISU students.

“We send our investigators and graduates to both companies nationally and internationally,” she said.

History of CNDE

The center was created in 1980, when the U.S. Air Force needed to develop ways to inspect its aircraft. Iowa State was chosen because of its strong engineering programs and the presence of the U.S. Department of Energy’s Ames Laboratory.

In 1985, the National Science Foundation funded the development of the CNDE and its Industry/University Cooperative Research Center to focus on industrial research to test the integrity of materials used in aviation and machinery.

The methods developed by CNDE examine and measure the discontinuities, defects, imperfections and composition of materials.

This type of inspection is essential to ensure the serviceability of materials used in aviation and space exploration. Some of the techniques used for measuring involve ultrasonics, electromagnetics, X-rays, thermal testing and acoustic emission measurement.

The center also educates students from kindergarten to graduate level to help increase expertise in nondestructive evaluation and engineering.

Brasche said Iowa State is the only university to offer a minor in nondestructive evaluation.

“Most students who want to work in this field of investigation choose aerospace engineering, electrical engineering, material sciences or mechanical engineering,” she said. “They often complement it with the NDE minor and are able to come to the CNDE to complete their senior projects and get involved with research.”

CNDE investigators and U.S. company participation

CNDE currently works with 15 to 20 companies that utilize nondestructive evaluation techniques on their materials and products. Companies such as Boeing, NASA, Eaton Corporation, Rolls-Royce Corporation and Honeywell Engines and Systems pay an annual fee of $35,000 to fund research at the CNDE.

“They commit to belong for three years at a time, and we have investigators that work to use our methods in testing the durability of materials like airlines and spacecraft,” Brasche said. “We also receive funding from industrial and federal sources, along with private companies and those with specific product needs.”

Researchers and graduate students at the CNDE

Frank Margeton, research scientist at CNDE, is currently working with ultrasonics to test for subsurface damage in metal parts. Set up in a laboratory with an ultrasonic machine submerged in water, he watches a computer screen for color disparities.

“We are trying to detect damage beneath the surface, and the ultrasonic waves project images that help assess possible areas of damage or weakness in the metal,” he said. “Metal is basically composed of tiny crystals, and changes in their structure and arrangement can be detected using computer images generated from the ultrasonic technology.”

Cory Foreman, graduate student in aerospace engineering, will complete his research project, then move to Maryland to work for Lockheed-Martin in May. His project focuses on using low-frequency waves to detect damage to honeycomb composite materials.

“Honeycomb material is new to the aeronautic industry and is used in airline paneling and as control surface material,” he said. “I am researching methods to evaluate the material for flaws and damage.”

Sara Blatz, senior in aerospace engineering, will be taking a job at NASA upon graduation this spring. Her senior project involves radome material, which makes up the noses of aircraft, and a tap-testing method to detect damage.

“When lightning strikes the noses of airplanes in flight, small holes are created; they allow water to get in. This can cause corrosion and damage,” she said.

Normal testing of the airplane is done by people tapping along the aircraft and listening for changes in sound to detect material weakness. Tap-testing, as she described, uses a machine instead of the human ear to detect damage in the aircraft’s material. Sara’s project uses a small, mouse-like device that taps along an aircraft automatically and can make a square image from the nose of the aircraft.

“My experience at the CNDE has been rewarding, and I have learned a great deal,” she said.