(Georgia Institute of Technology, 2017-06)
Rajaram, Dushhyanth; Cai, Yu; Chakraborty, Imon; Puranik, Tejas G.; Mavris, Dimitri N.
The aerospace industry's current trend towards novel or More Electric architectures results in some unique challenges for designers due to both a scarcity or absence of historical data and a potentially large combinatorial space of possible architectures. These add to the already existing challenges of attempting to optimize an aircraft design in the presence of multiple possible objective functions while avoiding an overly compartmentalized approach. This paper uses the Integrated Subsystem Sizing and Architecture Assessment Capability to pursue a multi-objective optimization for a Large Twin-aisle Aircraft and a Small Single-aisle Aircraft using the Non-dominated Sorting Genetic Algorithm II with parallel function evaluations. One novelty of the optimization setup is that it explicitly considers the impacts of subsystem architectures in addition to those of traditional aircraft-level design variables.
The optimization yielded generations of non-dominated designs in which substantially electrified subsystem architectures were found to predominate. As a first assessment of the impact of epistemic uncertainty on the results obtained, the optimization was re-run with altered sensitivities for the thrust-specific fuel consumption penalties due to shaft-power and bleed air extraction. This analysis demonstrated that the composition of architectures on the Pareto frontier is sensitive to the secondary power extraction penalties, but more so for the Small Single-aisle Aircraft than the Large Twin-aisle Aircraft.
(Georgia Institute of Technology, 2017-06)
Goron, Gael; Duca, Ruxandra; Sarojini, Darshan; Shah, Somil R.; Chakraborty, Imon; Briceno, Simon; Mavris, Dimitri N.
Federal Aviation Regulations pertaining to structural integrity are key drivers in aircraft design and certification, and often involve critical loads occurring during dynamic maneuvers. In the context of increasing costs of testing and the general trend towards
parametric design, there is a need for a more thorough consideration of such dynamic load cases earlier in the design process. In this work, a simulation framework is introduced to assess structural requirements stemming from such dynamic load conditions. Relevant aspects of the dynamics of the aircraft, the control system, and the pilot are modeled in
order to simulate the maneuver and thereafter obtain inertial and aerodynamic loads on
the empennage during the simulated maneuver. The loads are then translated into structural shear forces and bending moments through structural post-processing routines. This approach is demonstrated for the case of a representative business jet during the checked pitch maneuver. The analyses are repeated for three weight conditions and over the flight
envelope for the aircraft from which the load cases resulting in the most constraining loads
are determined.