The Advanced Air Transport Technology project at NASA's Armstrong Flight Research Center is leading the effort. Using a 10-foot aluminum model called the Mock Truss-Braced Wing, engineers are testing the structural behavior of the TTBW design. Mounted upside down on a rigid vertical test frame, the model replicates in-flight lift forces by leveraging gravity, augmented by weights for stress simulation.
"A strut reduces the structure needed on the main wing, and the result is less structural weight, and a thinner wing," explained Frank Pena, NASA mock wing test director. "In this case, the test measured the reaction forces at the base of the main wing and at the base of the strut. There is a certain amount of load sharing between the wing and the strut, and we are trying to measure how much of the load stays in the main wing and how much is transferred to the strut."
The testing process includes adding incremental weights to both the wing and strut while monitoring strain data. Engineers also employed a dynamic technique by striking the wing with an instrumented hammer to analyze its vibration responses.
"The structure has natural frequencies it wants to vibrate at depending on its stiffness and mass," said Ben Park, NASA mock wing ground vibration test director. "Understanding the wing's frequencies, where they are and how they respond, are key to being able to predict how the wing will respond in flight."
These unconventional methods add complexity to the testing process but yield valuable insights. NASA Armstrong's team, which designed and constructed the model and testing apparatus, is completing the loads calibration and vibration tests.
Looking ahead, researchers are preparing a larger, 15-foot wing model constructed from advanced graphite-epoxy composite materials. This model, known as the Structural Wing Experiment Evaluating Truss-bracing, is being developed by NASA's Langley Research Center in Virginia. Its design will closely mimic what could be implemented in future commercial aircraft, enabling further validation of the TTBW concept.
The ultimate goal is to bridge predictive models with real-world data and refine testing methodologies for revolutionary aircraft structures. The Advanced Air Transport Technology project, part of NASA's Advanced Air Vehicles Program, continues to push boundaries in developing technologies for next-generation air travel systems.
Related Links
NASA's Advanced Air Transport Technology project
Aerospace News at SpaceMart.com
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