Shear buckling of flat orthotropic stiffened panels with application to glare material

This paper investigates the shear buckling of flat, stiffened panels of specially orthotropic skin material, for which the stiffeners are assumed to possess both flexural and torsional rigidity. It is shown that the shear buckling behavior can be captured by four generic, nondimensional panel parameters, two of which relate to the skin orthotropy, the other ones representing the flexural and torsional stiffness of the stiffeners. Several design curves, showing the nondimensional shear buckling load as a function of these four panel parameters, are generated using the STAGS FEM code. The validity of the FEM method is demonstrated through comparison with an analytical procedure based on the Rayleigh-Ritz and Lagrangian multiplier methods. Furthermore, to assess the accuracy of the design curves a number of Glare panels containing stiffeners of different shapes and attachment methods typically applied in aerospace structures are analyzed as well. These particular FEM analyses are more realistic than the ones used to generate the design curves in the sense that the exact shape of the stiffeners is modeled and the attachment method is explicitly accounted for. It is shown that the predictions from the design curves are in reasonable agreement with the detailed FEM results.