An efficient analytical framework for buckling and post-buckling analysis of composite stiffened panels

Purpose To address the challenges of limited design data and time-consuming optimization in the preliminary phase of aircraft development, this paper proposes an efficient analytical framework for the rapid iteration of structural schemes. Design/methodology/approach An integrated computational tool is developed in MATLAB using effective width and segmented methods to estimate buckling and ultimate loads. These analytical predictions are validated against high-fidelity ABAQUS finite element models incorporating the Riks method, the Hashin failure criterion, and the cohesive zone model. The study investigates I-, J- and T-shaped stiffened panels with varying stringer cross-sectional area ratios (30% and 40%). Findings Results demonstrate that I-shaped stiffened panels exhibit superior post-buckling load-carrying capacity compared to J- and T-shaped counterparts. Parametric analysis reveals that ultimate capacity is predominantly governed by the stringer cross-sectional area rather than skin thickness. Under the constraint of constant total cross-sectional area, results indicate that an optimal stringer-to-skin area ratio exists that maximizes structural stability; however, excessive reduction in skin thickness may trigger premature local instabilities. Originality/value The study provides a validated, efficient tool for early-stage structural assessment. It offers specific design guidelines regarding stringer shape selection and optimal area distribution, balancing the trade-off between stringer reinforcement and skin stability for composite panels.