Buckling of biaxially compressed anisogrid stiffened composite cylindrical panel with clamped edges

Buckling of a biaxially compressed anisogrid stiffened composite cylindrical panel with clamped edges is considered in this paper. The panel is subjected to compressive load applied to its curved sides. This loading results in the biaxial compression of the panel due to Poisson's effect. The anisogrid lattice reinforcement of the panel is modelled as a layer with average effective stiffness characteristics. And the buckling of this two-layered shallow panel has been modelled using the engineering theory of laminated orthotropic cylindrical shells. The interface surface between the ribs and the skin layer is adopted as a reference surface of the panel. The corresponding governing system of equations is presented in terms of unknown displacements and deflection of the reference surface. The equations have been solved using the Galerkin method in which the displacements and deflection were approximated by the clamped-clamped beam functions and their first derivatives. Based on this solution, an analytical formula has been derived for the critical compressive buckling load. Using this formula, the critical loads are calculated for the cylindrical and flat panels having different geometric parameters. The results of calculations have been verified by the finite-element analyses. •Buckling problem for a biaxially compressed anisogrid stiffened composite cylindrical panel with clamped edges is solved.•The buckling of the two-layered shallow panel has been modelled using the engineering theory of laminated shells.•The displacements of the panel were approximated by the clamped-clamped beam functions and their first derivatives.•An analytical formula has been derived for the calculation of the critical compressive buckling load.•The results of calculations were successfully verified by the finite element analyses.