Mechanical properties of carbon fiber composite octet-truss lattice structures

Octet-truss lattice structures have been made from balanced [0/90] carbon fiber reinforced polymer (CFRP) laminates using a simple snap-fit method. The lattice structures moduli and strengths have been measured during [001] and [100] directions free compressions as a function of the lattice relative density. Core failure occurred by either (i) Euler buckling (ρ¯<5%) or (ii) delamination dominated failure (ρ¯>5%) of the struts. The measurements are shown to be well predicted by micromechanics models of these composite strut failure modes. Snap-fit CFRP octet-truss lattice structures are found to exhibit mechanical properties competitive with other cellular materials and topologies. Their isotropic response may provide new opportunities for ultra-lightweight multiaxial loaded structures.