In the aftermath of the disastrous engine failure on Southwest Flight 1380, that caused debris to puncture the fuselage, killing one passenger and forcing an emergency landing, the airline and the National Transportation Safety Board have been taking a deeper look at the source of the problem in hopes of preventing similar occurrences in the future. Drexel College of Engineering faculty helped to explain this process and shed some light on the material monitoring technology that could help to detect problems well before they turn into catastrophic failures.
Christopher Peters, PhD, a teaching professor in the Electrical and Computer Engineering department, explained in an April 19 Philadelphia Inquirer story, how air traffic controllers can use radar to figure out where debris from the plane’s engine might have landed.
“These beams of electromagnetic energy are used to track thousands of airplanes every day, enabling air traffic controllers to pinpoint each aircraft’s location by measuring how long it takes to radar to be reflected off a plane’s metal surface back to an antenna.
But at the frequency used in standard air traffic radar — about 3 gigahertz — the system can pick up objects as small as one inch across, according to Peters.”
Gathering these pieces is an essential part of understanding what caused the engine malfunction and why safety measures failed to prevent debris from damaging the plane’s fuselage.
Another part of the NTSB investigation is looking at the fatigue of the engine blade that caused it to fracture. The FAA will be issuing a directive calling for all airlines to run ultrasonic inspections of their engine blades to search for structural fatigue that might not be detected in a routine inspection.
Antonios Kontsos, PhD, an associate professor in the College of Engineering and director of the Theoretical & Applied Mechanics Group in the Department of Mechanical Engineering and Mechanics, explained in an April 19 WIRED story how ultrasound technology can help predict material failure before it happens.
“Much like a doctor inspecting an expectant mother, technicians go back and forth over each blade with a hand-held sensor, pulsing ultrasonic waves through the metal, looking for defects. The results don’t come back as an image, but more like an EKG graph, says Antonios Kontsos, an expert in structural fatigue and failure detection at Drexel University. Cracks in the metal show up as an abnormal sign. It’s laborious, time-consuming, and the best way to see inside these all-important metals.”
Kontsos’ lab has been pushing material fatigue detection forward for a number of years. In addition to ultrasonic monitoring of materials, the group has been working with infrared thermography to spot flaws at the molecular level.
Following Superstorm Sandy, Kontsos was part of a team of researchers who affixed this technology to drones to monitor the structural health of buildings that survived the storm. His group is also working with local municipalities to deploy it for infrastructure monitoring, and it is working with the Army Research Lab to develop a system for monitoring vehicles and armor in the field.
Kontsos gave NBC-10 a look at the next-generation structural monitoring technology in his lab that could one day find its way into commercial airplanes.
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