Analysis of Higher-Order Shear Deformable Porous Orthotropic Laminated Doubly-Curved Shallow Shells Subjected to Non-Uniformly Distributed Edge Loadings: Nonlinear Post-Buckling Response

Abstract

This study presents a comprehensive nonlinear post-buckling analysis of porous orthotropic laminated doubly-curved shallow shells with varying porosity distributions under different non-uniform loading configurations. Both spherical (SS) and hyperbolic paraboloidal shells (HPS) are examined based on HSDT and von K & aacute;rm & aacute;ntype geometric nonlinearity. The governing equations are derived using the virtual work principle and solved via the Galerkin method, accounting for the effects of lamination sequence, loading pattern, orientation angle, orthotropy, geometrical parameter, porosity coefficient, and porosity distribution pattern. The numerical results reveal that three-layered shells generally outperform four-layered ones concerning post-buckling resistance, although this advantage diminishes with increasing porosity. SSs demonstrate superior load-carrying capacity compared to HPSs up to moderate non-dimensional deflection levels. At the same time, shell geometry plays a less prominent role at higher porosity or non-dimensional deflection. The loading pattern also significantly affects the post-buckling response; the triangular pattern (TGL) offering the highest strength. For angle-ply laminates, the alpha/90 degrees/alpha stacking sequence is more effective than 90 degrees/alpha/90 degrees, particularly under TGL loading and at lower non-dimensional deflection levels. Additionally, increasing the orthotropy ratio enhances load capacity, especially in SSs, while rising porosity coefficients consistently weaken the structural response. These findings contribute to the optimal design and structural performance evaluation of advanced porous laminated shell systems subjected to complex mechanical and material conditions.