Hu Rui, Xie Changchuan, Liu Yi
DOI Number: N/A
Conference Number: IFASD-2015-064
Due to the light weight and small stiffness of highly flexible aircrafts, the coupling between structural statics and flight dynamics will happen. Furthermore, such flexibility of aircrafts will lead to large elastic deformation of the wing when they are bearing with aerodynamic loads and then present the notable geometrical nonlinearity. Large deformation causes distinct changes such as nonlinear structural stiffness and curved distributed aerodynamic load, thus the geometrically nonlinear aeroelastic analysis for a complete aircraft considering coupling of the rigid-body motion and the large elastic deformation becomes inevitable. Considering the geometric nonlinearity of the structure and the nonplanar effects of aerodynamics, nonplanar vortex lattice method combined with the nonlinear finite element method is iteratively computed to search for the nonlinear trim equilibrium state, on which the trim and stability analysis are conducted. For instance, the longitudinal trim analysis of a flexible aircraft with large-aspect-ratio wings is carried out by both the nonlinear method and the linear method. Results obtained by these two methods are compared, and it is indicated that the nonlinear method is much more reliable to the facts and very suitable for rapid and efficient analysis in the preliminary stage of very flexible aircraft design.