Buckling Response of Porous Orthotropic Laminated Doubly-Curved Shallow Shells Subjected to Non-Uniform Edge Compressions Using Trigonometric Shear Deformation Theory

Abstract

Some of the existing analyzing models primarily focus on homogeneous or isotropic materials and uniform loading conditions, neglecting the combined effects of porosity, orthotropic material behavior, lamination sequences, and complex loading patterns. However, it is necessary to develop new analysis models that take these effects into account to perform more realistic stability analyses. The novelty of this study is a higher-order shear deformation theory-based formulation that incorporates non-uniform porosity distributions, lamination sequences, and various non-uniform edge loading conditions. This study investigates the buckling of porous orthotropic laminated doubly-curved shallow shells (D-CSSs) with different porosity distribution patterns under non-uniformly distributed edge compressions. Porous material properties are modeled along the thickness using special cosine and sine functions. The governing equations are conducted using the virtual work principle based on the trigonometric shear deformation theory and solved by Galerkin's method to obtain critical buckling load formulation. After confirmation of the formulation, a parametric study is performed to examine the influence of porosity, orthotropy, lamination sequences and orientations, shallow shell types, non-uniform lading patterns, and geometrical characteristics on the buckling of porous orthotropic laminated doubly-curved shallow shells. The results reveal that the NGD3 pattern enhances buckling performance and edge compression patterns significantly affect the buckling response. The buckling resistance difference between spherical shells (SSs) and hyperbolic paraboloidal shells (HPSs) tends to converge with increases in other material and geometrical parameters except for the arc length-to-thickness ratio (a/h). The outer orientation angles influence the buckling performance of shallow shells as first increasing and then decreasing. By capturing the more realistic influence of the above parameters on buckling behavior, the study offers valuable insights for optimizing the design and performance of advanced composite shell structures.