Influence of Concentric Cutouts on Axially Compressed Laminated Shell Panel Buckling Behavior

This study presents a numerical assessment of the critical buckling behavior of various geometrical configurations of laminated composite flat/curved panels featuring concentric cutouts of different shapes and dimensions. A finite element formulation, incorporating higher-order kinematic assumptions, is employed to model the multi-layered structure with accuracy. An isoparametric element framework is used to simulate the panel geometry, with the cutout represented through a quarter-plate modeling technique and extended to form the complete configuration. The approach is verified by benchmarking its results against those available in the published literature. The predicted normalized critical buckling loads show excellent agreement with three-dimensional elasticity with deviations generally within ±2%. In contrast, classical laminate plate theory (CLPT) exhibits significantly larger deviations reaching up to about 38%, highlighting the importance of higher-order shear deformation effects. Also, the present HSDT predictions differ by only 0.86-6.99% from experimental results. The model is further tested for its adaptability across various geometrical forms, such as flat plates, cylindrical, spherical, hyperbolic, and elliptical surfaces, under different material systems and boundary settings. The findings highlight the significance of using a higher-order numerical strategy in predicting accurate modal characteristics of perforated laminated composites. A series of case studies is conducted to examine the influence of critical design parameters such as aspect ratio, thickness, curvature, and boundary conditions. The study underscores the necessity of advanced modeling techniques for effective structural analysis of composite components with geometric discontinuities.