NNX17AJ96A

To enable commercially viable civil supersonic transport (SST) aircraft, innovative solutions must be developed to meet noise and efficiency requirements for overland flight. This effort employs a multidisciplinary team of academic and industrial experts to explore, for the first time, the potential of small real-time geometric outer mold line (OML) reconfigurations to minimize boom signatures and drag in response to changing ambient conditions. This will enable noise-compliant SST flight from takeoff to landing.

Our team exploits advances in low-volume energy-dense solid-state shape memory alloy (SMA) actuators, the modeling thereof, proven supersonic computational fluid dynamic methods, and sonic boom propagation tools to consider embedded solutions for in situ adjustment of an SST aircraft for an optimal low boom signature and low drag in different environments. Previous research efforts have shown that small distributed changes in SST OML can substantially reduce perceived sonic boom noise without negatively affecting aerodynamic performance. However, signatures optimized through OML shaping at a single flight condition degrade rapidly with slight changes in flight condition. Angle of attack, altitude, air density, and speed are known to significantly impact boom signature and SST flight performance, endangering true commercial viability of overland supersonic flight.

To be commercially viable, an SST must robustly meet boom signature limits for a range of flight conditions and thus requires real-time adaptability. The novel multidisciplinary and structurally integrated effort explores new engineering tools and materials, demonstrating that distributed structural adaptivity can enable robust low boom SST performance in varying conditions and thus develops technologies to enable community-accepted SST aircraft.

Our team was carefully chosen to address this unique aeronautics problem, is strong in each important technical area, and is synergistic across multiple disciplines and identified challenges. The Texas A&M leadership is natural for this effort, given its many previous interdisciplinary research successes and long history of smart materials and structures developments and supersonics/hypersonics exploration. Partner institutions (Florida International University, Princeton University, University of Houston, University of North Texas, Utah State) were chosen on the basis of their technical capabilities and provide new opportunities for supporting NASA's mission of extending inclusion to a wider range of researchers. Industrial partners (ATA Engineering, Boeing, Fort Wayne Metals) were selected for their background in supersonic platform and application development and understanding of shape memory alloys.

The overall research strategy is composed of three major focus areas or technical challenges that must be met for program success: I) distributed adaptivity design tools development and trade studies, II) materials development and integrated solid-state actuation design, and III) detailed design and demonstration. Initially, the team is identifying potential applications where small-scale distributed adaptivity can provide a benefit in noise or drag across the entire flight envelope. For selected applications/structural locations, required OML geometry changes will be determined based on analysis of boom ground signature and drag reduction using new design tools and trade studies. Adaptive structure designs will be developed and evaluated against the requirements (e.g. loading stroke length, operational temperature), including the development of novel alloy formulations tailored for both autonomous and controlled actuation. As the SMA material development matures, integrated system-level factors will be considered. Optimized designs for selected adaptive structural applications will then be matured and tested, moving toward system-level wind tunnel demonstration of the innovative technology approaches at a TRL 4-5.

Texas A&M Engineering Experiment Station

43.002 - Aeronautics

Shared Services Center (NSSC) [NASA]

College Station, Texas 77840-4030 United States

Single Zip Code

None

Amendment Since initial award the End Date has been extended from 06/14/22 to 05/31/23 and the total obligations have increased 399% from $1,992,140 to $9,944,792.