Micro air vehicles, especially those that use flapping wings for propulsion and control, are characterized by complex, time-dependent, nonlinear interactions amongst a variety of physical disciplines. These interactions must be carefully controlled to attain desired levels of performance, but the number and range of parameters that describe possible micro aircraft is extremely large, poorly explored, and inadequately understood. Aerodynamic, structural, kinematic, and mechanical parameters are relevant and may be strongly ...
We are developing computational methods that will enable the computational design of air vehicles accounting for inherently nonlinear dynamic behaviors. These behaviors fall into two categories: behaviors that are beneficial for vehicle operation, such as could be observed for micro air vehicles propelled by wing flapping (e.g., a productive energy transfer between the unsteady vortical flow produced by a flapping wing and the associated nonlinear deformation of the wing), and ...
This work details a comparative analysis of six methods for computing the transient system response and adjoint design derivatives of a nonlinear structure under a periodic external actuation. Time marching via implicit integration, a time-periodic spectral element method, and a time-periodic cyclic-implicit method are all considered, each with or without POD-based model reduction of the system of equations. Details of each method, and the concomitant adjoint sensitivities, are provided in ...
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