Torsional Buckling Analysis of Composite Anisogrid Conical Shells: Theoretical Approach and Numerical Validation

Abstract

Torsional buckling analysis of composite anisogrid conical shells, with equiangular helical ribs, was investigated based on an equivalent variable stiffness continuum model. The buckling analysis is complicated by the variable geometry and stiffness of the lattice conical shell along the meridian. The smearing approach and the gradual function of the lattice cells were used to build the corresponding continuum model with varying stiffnesses. Recurrence relations were constructed from linearized buckling equations of the equivalent conical shell using the power series method and Fourier decomposition. The excellent precision and tremendous efficiency of the analytical solution was validated compared with numerical results through many design parameters of the lattice conical shell, such as the thickness of the ribs, the radius at the small end, and the height of the cone. Finally, a parametric analysis was used to discuss the influence of parameters on the critical buckling torsional moment. It is found that increasing rib thickness, end radius, the height of the cone, and strengthening boundary constraints can improve the critical buckling torsional moment.