Novel Design and Optimization of Aircraft Stiffened Panels for Improved Critical Buckling Load Resistance

This study proposes two novel stiffened panel configurations, designated X and X-30, manufactured from the conventional aerospace alloy Al 2024-T3 to enhance the critical buckling resistance under in-plane compression. Their performance was evaluated against traditional T-, I-, L-, and Omega-type stiffeners, as well as a newly introduced Y-panel found in the literature. Initial results show that both proposed designs achieve 80–200% higher buckling capacity than conventional panels, with only a 4.54% difference between the X and X-30 configurations. A weight-constrained optimization was then conducted using a Box–Behnken design of experiments combined with a multi-objective genetic algorithm in Ansys DesignXplorer. After correcting inconsistencies in the initial optimization ranges, the prediction error in the optimized buckling values was reduced to 4%. The optimized X panel attained the highest critical buckling load of 2920 kN, followed by the X-30 panel with 2744.3 kN, corresponding to a 114–258% improvement over traditional stiffener geometries. A Pearson correlation matrix further suggested that, for all the stiffened panels except Omega, the base plate showed a strong correlation with the critical buckling load, typically ranging from 0.83 to 0.99. In contrast, for the X-30 panel, the lower base part also showed a strong correlation of 0.93.