Global buckling analysis of laminated sandwich conical shells with reinforced lattice cores based on the first-order shear deformation theory

Abstract

In this paper, a new effective smeared stiffener method is presented for investigating the global buckling behavior of the laminated sandwich conical shells with lattice cores. Superimposing the stiffness contributions of the skins with those of the stiffeners, the total stiffness of the whole sandwich structure is obtained. Theoretical formulation is derived based on the first-order shear deformation theory. Using Galerkin method, the buckling load of sandwich conical shell is calculated. A 3-D model of the structure has been numerically analyzed by the finite element method in order to validate the accuracy of the analytical solutions. Finally, the effects of several important design parameters such as stiffener orientation angle, lamination angle, lattice core dimensions, number of the stiffeners, semi-vertex cone angle and skin thickness, have been examined on both buckling and specific buckling loads. The results indicated that at higher semi-vertex angles, an increment in the stiffener paramters such as the number, orientation angle and dimension, although increases the buckling load but decreases specific one. Moreover, the analytical approach led to high-accuracy results for higher skin thicknesses. It was found that variations of the lamination, inner and outer skin thicknesses, significantly affect the buckling load of sandwich conical shells. Results can be considered as a benchmark for the design of these structures which are extensively used in the aerospace structures.