Adaptive Aerostructures for Revolutionary Civil Supersonic Transportation

To enable commercially viable civil supersonic transport (SST) aircraft,
innovative solutions must be developed to meet noise and efficiency
requirements for overland flight. This research effort consists of a multidisciplinary
team of academic and industrial experts exploring for the first time
the potential of small real-time geometric outer mold line (OML)
reconfigurations to minimize sonic boom signatures and aircraft drag in
response to changing ambient conditions, thereby enabling noise-compliant
overland supersonic flight. The team utilizes recent advances in supersonic
computational fluid dynamic (CFD) methods, new noise prediction tools, and
new design approaches to consider embedded highly energy-dense shape
memory alloy (SMA) actuators for local shape modifications to an SST aircraft
leading to optimal low boom signature and low drag in different
environments. This university-led program will provide strategic leadership
toward technology convergence that advances NASA's Aerospace Research
Mission Directorate's (ARMD) research objectives with regard to Thrust 2:
“Innovation in Commercial Supersonic Aircraft” by exploring for the first time
enabling low-boom operation across a range of flight conditions via structural
adaptivity, and will promote education of the next generation of engineers.
The overall research strategy is to pursue three critical areas: the design of
configurations for reducing boom, SMA material development and modeling,
and technology feasibility demonstration in a relevant environment. Initially,
the team will identify potential applications where structure or geometry
adaptivity provides 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 sonic boom ground signature and drag
reduction using new design tools, trade studies, and atmospheric sensing
techniques. Designs will be developed and evaluated against requirements on
loading, stroke length, and operational temperature. New alloy formulations
will be developed tailored for both autonomous and controlled actuation
modes. As the SMA material development matures, integrated system-level
factors will be investigated. Optimized designs for small-scale distributed
adaptivity applications of maximum benefit will then be matured and tested,
moving toward demonstration of the innovative technology approaches at a
TRL 4-5 and showing that sonic booms can be reduced by reconfiguration on
demand.