Design and mechanical characterization of lattice sandwich cylindrical shells

Lattice sandwich cylindrical shell has superior mechanical performances and relatively light structural weight, and is thus widely used in aerospace and aviation engineering. In this paper, deformation mechanisms are systematically investigated and failure analyses are conducted for the lattice cylindrical shells with various core topologies. Analytical models are proposed to predict the axial stiffness, critical elastic buckling load or effective yield strength of these shells. Finite element (FE) simulations are carried out to identify the validity of the models. Based on the homogenization theory of lattice materials, the overall buckling behavior of lattice sandwich cylindrical shells is analyzed through energy method and first-order shear deformation shell theory (FSDT). The buckling loads are calculated for different shell thicknesses and also compared with FE simulations, which yields good agreements. Furthermore, filament winding and twice co-curing processes are proposed to make a carbon fiber reinforced composite (CFRC) lattice sandwich cylinder with Kagome cores. Axial compression experiments are carried out to reveal the stiffness, load capacity of the fabricated sandwich cylinder.