Project focuses on structural weakness in airplanes

Michael Weinbeck

Recent airline disasters have brought new relevance to a Navy research project that aims to improve aircraft safety.
The $5 million project, funded by the Office of Naval Research, seeks to develop a silicone microchip that would detect structural weaknesses in aircraft.
The project involves researchers from three University departments working with researchers from Georgia Technical Institute and Northwestern University.
Because of cuts in both commercial airline and military budgets, aging aircraft are kept in service longer than their manufacturers originally intended.
“The problem with the Department of Defense aircraft,” said the project’s principal investigator Dennis Polla, “is that these aircraft were designed for 25 or 30 years and intended to be replaced after that time period. With budgets being cut … the only choice that the Department of Defense has is to extend their existing aircraft beyond their usable life.”
Just as the tab on a can of soda comes off after being bent back and forth a few times, Polla said, so will the rotors on a helicopter or the wings on an airplane after being subjected to frequent takeoffs and landings.
“Fatigue issues are real,” said Mostafa Kaveh, a member of the team of nine faculty members and several graduate students involved with the project. “Anything that vibrates or moves will eventually wear out,” said Kaveh, head of the electrical engineering department.
In order for technology to be successful at preventing catastrophes it must integrate innovations from several areas, Polla said.
“It’s a very multidisciplinary project,” said Polla, an electrical engineering professor. “It involves materials science, the microtechnology laboratory, the Department of Electrical Engineering and the Department of Mechanical Engineering.”
One of the goals of the project is to develop a silicon microchip, which will be about the size of a single letter on this page. The chip will detect the temperature, vibration and acoustics of the aircraft part to which it is attached.
As an aircraft ages, tiny “microcracks” develop in the metal. Just as a windshield on a car makes a cracking noise as a crack grows larger, the microcracks emit a high-pitched tone. The chips will be able to detect this and alert the pilot and the ground crew to worn-out areas of the aircraft’s body.
University researchers are also developing ways to process data collected by microchips to insure that the chips remain attached to the aircraft under the harshest conditions. The complexity of the technology requires the expertise of professionals in several disciplines.
“This (project) is very unique,” said Susan Mantell, assistant professor of mechanical engineering and a member of the project’s team. It’s hard to coordinate a team to create this technology, Mantell said, but different departments at the University have been successful at integrating their talents for this project.
Once the technology is in place and the silicone chips have been embedded in the aircraft, maintenance crews will be able to take periodic readings of the chips’ data. Using this data, problem areas on the aircraft can be identified and repaired. Equally important will be the chips’ ability to warn pilots of imminent catastrophe. An on-board computer will constantly monitor the output of the microchips and inform the pilot of problems.
This technology will also have widespread application beyond aviation. For instance, it can be used to monitor the structural reliability of bridges and buildings.
The University’s team is 15 months into the project. But before this technology can be used in commercial aircraft, the military must test and approve it, which will take several years.