Shear buckling of corrugated composite panels

Corrugated composite panels are used in aerospace vehicles primarily because of their ability to withstand higher loads before buckling compared to plain sheets. Shear buckling is one of the important modes of failure. In this paper are presented details of prediction of the shear buckling loads of composite panels having sinusoidal or hat type corrugation. The given panel is idealised as an homogeneous orthotropic plate whose equivalent properties are determined based on the given parameters of the panel. In the analysis Kirchhoff-Love assumptions are used. Two opposite edges of the panel in one direction are assumed to be simply supported and the panel is assumed to be very long in the other direction. 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 corrugated panels is examined and ranked based on buckling loads. Results indicate that by proper choice of lamination scheme, very significant increases in buckling load compared to the quasi-isotropic case can be obtained. Having the corrugation plane normal to the shorter side is significantly better than having the corrugation plane normal to the longer side. Optimum layup schemes are found for 8, 6, 4 and 2 ply cases.