Aeroelastic Stability Analysis of Damaged High-Aspect-Ratio Composite Wings

In this paper, linear and nonlinear divergence and flutter analyses for damaged high-aspect-ratio wings undergoing large deformations are presented. To exploit the computational efficiency of reduced dimensional beam models along with the accuracy of three-dimensional continuum models, a joined multidimensional finite element approach is proposed. To this end, the computational model of a high-aspect-ratio wing is divided into two parts: a one-dimensional geometrically exact beam model, which constitutes most of the wing structure, and a small three-dimensional region encompassing structural damages. The two parts are rigorously joined together at their intersection through a transformation derived using the variational asymptotic method. Aerodynamic forces and moments, acting upon the wing, are accounted for using a two-dimensional finite-state unsteady aerodynamic theory. The wing structure is made of layered composite materials with various layup arrangements. The preexisting structural damages are assumed to be in the form of crack and delamination. The intensity and locations of the structural damages are varying along the wing. Accordingly, linear and nonlinear aeroelastic stability analyses are carried out in order to study the effects of various structural damages on the divergence and flutter boundaries of the wing.