Buckling analysis of a lattice anisogrid cylindrical shell under torsion: Application to design procedure

The present paper addresses the global buckling behaviour of a lattice anisogrid cylindrical shell subjected to torsion using the Galerkin method. The analysis employs a continuous model in which the lattice shell is represented as an orthotropic shell with averaged membrane and bending stiffnesses. Displacements and deflections are approximated using trigonometric series that accurately capture the characteristic buckling mode under torsion and fully satisfy the boundary conditions at simply supported shell edges. Application of the Galerkin method results in a homogeneous system of linear algebraic equations with unknown coefficients for the approximating functions. Transforming this system yields a generalised eigenvalue problem of small dimension. The solution provides a practical procedure for determining the critical shear load of a twisted shell. This procedure is applied to examine the effects of the helical rib orientation angle, the number of helical ribs, and shell length on the critical load. The analysis results are validated using the finite element method. The developed procedure is also demonstrated for selecting shell parameters under specified edge shear loads.