The Southwest Research Institute (SwRI) (San Antonio, Texas, USA) recently received a $1 million contract from the U.S. Air Force, with Sabreliner Aviation. The contract calls for the provision of structural analysis and other maintenance work on a fleet of military aircraft, the Fairchild Republic A-10 Thunderbolt II.
“For the past roughly 20 years, SwRI has been involved with maintaining and monitoring the structural integrity of the A-10,” says Luciano Smith, principal engineer. “Work like this is vital to extending the lifetime of these aircraft.”
The A-10 came into service in the late 1970s, and the fleet is currently set to continue service until at least 2040. SwRI’s structural engineers perform damage tolerance analysis for military and commercial aircraft and provide the information necessary to safely and effectively manage the structural health of their fleets.
In 2002, SwRI developed a flight data recording system that is still utilized on the aircraft to help engineers understand the structural stresses associated with various flight maneuvers. “It’s important to understand the stresses on the aircraft because that will tell us where cracks will grow and how fast,” Smith says. “That also feeds into deciding how often inspections are needed.”
Smith and his colleagues also characterize materials to better understand crack growth, with controlled testing of aircraft materials helping to reveal how cracks originate and how quickly they can potentially grow. Using NASGRO software, which SwRI first developed with NASA in the 1980s, engineers analyze fracture and fatigue crack growth in structures and mechanical components.
“As these aircraft age and are updated, we’re updating and modernizing our analysis methods,” Smith says. “Without the work we do, big safety issues could arise fairly quickly. It’s important to think a few steps ahead.”