Renato Rebouças de Medeiros

With increasing requirements for lower emissions and costs, next-generation transport aircraft are poised to deal with high aspect ratio wings. Long lightweight structures are very flexible, and this fact brings new challenges to the aeroelastic analysis. Time-domain simulation of these nonlinear systems is desirable to analyze their aeroelastic behavior over the flight envelope.

In the structural end, while simplified methods exist to model long wings with equivalent beams, essential details can only be captured with built-up finite element models. Unfortunately, these models are expensive and non-robust for extensive dynamic simulations. This dissertation builds upon previous efforts to develop nonlinear modal reduced-order models (ROMs). Training these models requires the fitting of nonlinear stiffness and displacements from static solutions. The newly introduced Enhanced Implicit Condensation and Expansion (EnICE) method accounts for the contribution of nonlinear motion to inertia forces during dynamic simulations.

The EnICE approach was integrated into the computational fluid dynamics code CFL3D for high-fidelity aeroelastic analyses. An aerodynamic ROM was developed based on convolution corrected by a nonlinear factor obtained from steady solutions. For additional speedup, the Method of Segments provides these correction factors. The aeroelastic tool arising from the two reduced-order models simulates large displacements, taking into account structural and aerodynamic nonlinearities.

Doctoral Comittee
Chair: Prof. Carlos E.S. Cesnik
Cognate Member: Prof. Bogdan I. Epureanu
Members: Peretz P. Friedmann, Prof Krzysztof Fidkowski