Flutter Analysis and Morphing Evaluation of Biomimetic Wing Structure

Advanced aircrafts have incorporated bio-inspired morphing structures to adapt to multienvironment and perform multimission. But it will cause serious issues with structural reliability and aeroelastic stability. This paper studies the critical flutter speed of a morphing wing structure and evaluates the deformation strategies. First, a biomimetic wing is considered as a variable cross-section cantilever beam, and the flutter model with Theodorsen unsteady aerodynamics is theoretically derived. The finite element theory is used to discretize the obtained PDEs with variable coefficients. Second, three typical wing models are examined to verify the model’s accuracy against finite element simulation findings for modal frequencies and critical flutter speeds. The results indicate good agreement, with errors of less than 3% for modal frequencies and fewer than 2.1% for critical flutter speeds. Thirdly, the flutter wind speeds are examined to assess the aeroelasticity properties for three different morphing strategies of biomimetic wing structures. The findings show that both forward bending of the elastic axis and greater density concentration near the wing root increase flutter speed. And the density distribution has a smaller effect on flutter speed than elastic axis bending. When it comes to static aeroelasticity, excessive folding ratios cause divergence problems.