High-Fidelity Reduced-Order Method for Postbuckling Analysis of Aeronautical Structures

Accurate yet efficient predictions of buckling and postbuckling phenomena are essential for the design of lightweight aeronautical structures. This work introduces a novel computational framework that addresses this challenge by combining the high-fidelity capabilities of the ps-finite element method and the robustness of the asymptotic numerical method as a nonlinear solver. In addition, an automatic Ritz-based strategy is introduced to reduce the problem size by several orders of magnitude starting from the initial finite element model. This approach enables accurate simulation for both global and local buckling behaviors without requiring mesh adaptivity or multiscale coupling, thus significantly reducing the model complexity and total analysis time. These features render the method particularly attractive for the early- and intermediate-stage designs, where repeated analyses are of concern for design optimization and sensitivity studies. Representative aerospace components are investigated by considering single- and multiple-stringer specimens and a wing box. The results demonstrate the method's accuracy and superior performance when compared to full-order simulations, highlighting its potential as a practical tool for nonlinear stability assessment of advanced composite structures.