Buckling of Composite Sandwich Rectangular Panels (Grid Core

Abstract

Laminated composite sandwich panels are extensively used in many engineering indus tries. Stability studies are needed to achieve good structural performance with minimum weight. The work presented in this paper deals with the prediction of elastic buckling loads for composite sandwich rectangular panels with a grid core subjected to axial com pression. Kirchhoff-Love assumptions are used and each of the edges is considered to be clamped (C) or simply supported(S). The given panel is idealised as a homogeneous orthotropic plate whose equivalent properties are determined based on the given param eters of the panel. The boundary conditions considered are SCSC, CSCS, SCSS, CSSS, CCCC, CCCS, CCSC and CCSS. Critical buckling loads are obtained using conventional orthotropic plate theory. A large class of 0°/90°/45°/-45° lamination schemes leading to quadridirectional, tridirectional and bidirectional T300/N5208 sandwich Panals is ex amined and merit listed from buckling point of view. Results indicate that by proper choice of lamination scheme, very significant increases in buckling loads compared to quasi isotropic case can be obtained when a/b < 1 (the lower the value of a/b, the higher the gain) and for a/b > 2, the corresponding gains are smaller. For a/b > 3, having more 45° layers is found to be more advantageous from buckling point of view, whereas for a/b < 0.75 having more 0° layers is more advantageous.