Buckling of functionally graded cylindrical shells under non-uniform external pressure

An analytical investigation is proposed in this paper for cylindrical shell structures made of functionally graded material(FGM) subjected to non-uniform external pressure for the first time. Elastic properties of shell material change exponentially with respect to radial coordinate, and non-uniform lateral pressure is assumed to be arbitrary. The relation between buckling pressure and non-uniform external pressure is directly established based on the perturbation method. Utilizing the presented formula, uniform, axial linear, circumferentially varying and general non-uniform external pressure loads are analyzed in detail. The obtained buckling pressure results are all new. The comparative studies indicate that buckling pressure for uniform pressure coincides with those in literatures, and buckling pressure ratios of axial linear and circumferentially varying external pressure for pure ceramic or metal material are in good agreement with those for isotropic shells. Furthermore, buckling pressure for general non-uniform pressure is also validated by the Galerkin method. Numerical calculation and discussion on the effects of shell dimensions, load parameters and material properties on buckling pressure are also conducted.