Manufacturing and testing of a CFRC sandwich cylinder with Kagome cores

Filament winding and twice co-curing processes were proposed to make a carbon fiber reinforced composite (CFRC) sandwich cylinder with Kagome cores. Axial compression was carried out to reveal the stiffness and load capacity of the fabricated sandwich cylinder. Compared with the stiffened cylinder with similar dimensions and mass, the sandwich cylinder is shown to be stiffer and stronger by several times. Restrained by the double skins, the buckling of lattice ribs is effectively suppressed, leading to the elimination of the dominant failure mode. Skin crippling and strength failure were observed in the testing to be the competing failure mechanisms of the lattice sandwich cylinder. The prediction based on the weakest link of these mechanisms only overestimates the testing load capacity by 30%. The novel sandwich structure shows the promise of lattice composites in upgrading the mechanical properties.