Stiffness tailoring for enhanced buckling performance of isotropic panels

This study investigates the buckling performance of isotropic panels with spatially varying stiffness distributions, achieved through three design strategies: thickness variation, modulus variation, and a combined approach. A semi-analytical formulation based on Classical Plate Theory and the Rayleigh–Ritz method was developed to compute critical buckling loads for arbitrary stiffness profiles. To explore the design space, multi-objective optimization was conducted using Fourier-based parameterization, producing Pareto fronts that capture the trade-off between buckling capacity and structural weight. Results show that tailored stiffness distributions can significantly improve buckling resistance—by up to 76%—compared to constant-stiffness designs of equal mass. Among the strategies, combined thickness–modulus variation outperformed individual approaches, and higher-order Fourier terms enabled finer control of stiffness gradients. The semi-analytical model was validated through finite element simulations, with discrepancies within 5%, confirming its accuracy. This work provides both a computational framework and mechanistic insights for designing lightweight, buckling-resistant structures via spatial stiffness tailoring.