Nonlinear aeroelastic characteristics analysis of composite wing with high aspect ratio based on co-rotational method

Abstract

A flexible high aspect ratio wing (HARW) generate large structural deformations. The nonlinear static aeroelastic and flutter characteristics analysis for the wing were performed using a nonlinear approach based on the computational fluid dynamic and computational structure dynamics (CFD/CSD) coupled method. The structural analysis was performed using a high efficiency nonlinear 4-node thin shell element based on the co-rotational (CR) method and the developed 4-node linear element to analyse large structural deformations. The load was calculated by the CFD solver. The result showed that the change of aerodynamic load led to a decrease of pressure difference between the upper and lower airfoils, especially the locations between the front and rear beams. At the attack angle of 6°and flight speed of 0.75 Ma, the maximum deflection and torsion angle of linear wing structure were approximately 13.27% and 32.38% greater than that of nonlinear wing structure, respectively. Because of the influence of nonlinear characteristic, the vertical and spanwise displacements and torsion angle of wing cross-sections were less than the linear result under the same flight attitude. The experimental results of the AGARD 445.6 wing verified the accuracy of the established flutter analysis method. The influence of the geometrical nonlinear characteristics of the structure caused by large deformation must be considered during the flutter characteristic analysis of the high aspect ratio composite wing, and the limit cycle oscillation (LCO) phenomenon cannot be obtained by the linear structure in the flutter analysis.