PARAMETERISATION OF NONLINEAR AEROELASTIC REDUCED ORDER MODELS WITH AERODYNAMIC AND STRUCTURAL NONLINEARITY
Optimally sparse Taylor partial derivatives opens up exciting avenues for efficiently reducing the complexity of aeroelastic systems through nonlinear modelling. However, within this category of reduced order models (ROMs), the robustness observed in the linear regime often diminishes rapidly when faced with nonlinear dynamics, particularly variations in critical parameters such as dynamic pressure, control hinge linear stiffness, or freeplay. This paper addresses nonlinear sensitivity by employing an innovative approach: the interpolation of a library of nonlinear unsteady aerodynamic ROMs within a condensed parameter space defined by dynamic pressure and freeplay magnitude. The resulting ROM, based on Lagrange interpolation of sparse higher-order Taylor partial derivatives, demonstrates exceptional precision in simulating high-amplitude transonic limit cycle oscillations in an all-movable wing system with freeplay. It accurately captures the nonlinear instability region, encompassing up to 96% of the linear flutter boundary, across a range of freeplay values.
