Equivalent Beam Modeling Method for Geometric Nonlinear Static Aeroelastic Analysis

Unit load method is a commonly used way to simplify complex high-aspect-ratio wing models to beam models, which can greatly reduce the time cost of linear/nonlinear aeroelastic analysis. An improved scheme of applying loads and extracting structural stiffness in unit load method is proposed in this paper. Unit loads and fixed-end boundary condition are applied on the ends of whole wing rather than the ends of each segment of wing, then stiffness characteristics are calculated using the relative displacements and equivalent loads of two equivalent beam nodes of each wing segment. By this scheme, the number of static analyses can be decreased, and the influence of cross-section warping can be minimized. Furthermore, polynomial fitting can be used to correct the results of both ends with the results of segments far away from ends. Linear and nonlinear static aeroelastic analysis are carried out for validation. The small relative error between the results obtained by the equivalent model and the original model indicates that this method can meet the requirements of linear and nonlinear static aeroelastic analysis.