NASA validates truss-braced wing design after structural limit tests
Researchers at NASA’s Armstrong Flight Research Centre have completed a deliberate test-to-failure of a 15-foot truss-braced wing, providing critical data for future fuel-efficient commercial aircraft.
NASA researchers have successfully conducted structural tests on the 15-foot SWEET-15 test article, a long, thin wing design featuring a lightweight truss-braced structure, at the Armstrong Flight Research Centre in California. The tests, which included a deliberate test-to-failure, confirmed that the wing withstood anticipated in-flight forces and failed at approximately 127% of its design limit load. The results validated computer models and manufacturing methods for advanced composite structures, supporting NASA’s efforts to develop more fuel-efficient commercial aircraft.
The SWEET-15 design is based on NASA’s earlier Transonic Truss-Braced Wing concept and incorporates five different advanced composite manufacturing and assembly technologies. The test article was fabricated at NASA’s Langley Research Centre in Hampton, Virginia, before being transported to Armstrong for testing. The manufacturing approach utilised the Integrated Structural Assembly of Advanced Composites robot, aiming to produce lighter and stronger composite structures for aerospace vehicles.
Over several months, NASA engineers intentionally bent the test wing in the Flight Loads Laboratory at NASA Armstrong. Numerous strain and load sensors, including fiber-optic strain sensors, were placed throughout the structure to track how the wing responded as forces increased. The data from the sensors confirmed the predictions made by NASA’s computer models, with the wing withstanding anticipated in-flight forces without issue.
The test concluded with a deliberate test-to-failure, where engineers increased loads beyond the wing’s design limits to determine how and where it would fail. The structure ultimately failed at roughly 127% of its design limit load, with visible damage appearing near the back edge of the wing and in the upper wing cover. This element of testing provided valuable insight into how the joints connecting the wing to its main strut and a secondary one, called a jury strut, behave under forces beyond the expected flight envelope.
This marks the first time a representative composite truss-braced wing configuration has undergone this type of structural evaluation. It was made possible through NASA collaboration across centres and projects, with researchers utilising agency resources such as the Fiber Optic Sensing System developed to gather data on both aircraft and spacecraft. The work is being conducted through NASA’s Subsonic Flight Demonstrator project in the agency’s Research Technology Mission Directorate.
Researchers will now analyse the data collected during testing to inform future airframe designs and support NASA’s ongoing efforts to develop more efficient aviation technologies. The successful testing of multiple innovative components marks a milestone in NASA’s aeronautics research, providing confidence in the new manufacturing approaches and methods for connecting wing parts used in SWEET-15.
