Aeroelastic Optimization of Stick Models for Parametric Flutter Analysis in Blended-Wing-Body Aircraft

Abstract

Blended-wing-body aircraft offer significant promise in future aircraft design due to improvements in aerodynamic efficiency and reduction in structural weight. At the same time, this unconventional configuration gives rise to complex aeroelastic interactions. A reduced-order stick model was calibrated through an optimization-based workflow to reduce computational time, while preserving the model's physical interpretability. Three case studies were conducted to match the static deformation, modal response, and aeroelastic behavior of the full aircraft. Error metrics were introduced to quantify discrepancies in deformations, natural frequencies, and mode shapes. Two novel aeroe-lastic metrics are proposed: an eigenvalue error metric based on the Error Vector Magnitude (EVM) concept, and a aeroelastic mode shape metric tailored to complex eigenvectors. The optimized model predicts flutter speeds with less than 3% error and accurately reproduces the underlying flutter mechanisms. The reduced-order model is used in a parametric study. Across 600 configurations evaluated, the governing instability was bending-torsion flutter (BTF). The proposed methodology can identify modifications to the configuration capable of increasing flutter speed by up to 30%.