Mechanical properties of an extruded pyramidal lattice truss sandwich structure

Metallic sandwich structures with lattice topology cellular cores are being developed for weight-sensitive applications. A combination of extrusion and electrodischarge machining has been used to fabricate pyramidal lattice sandwich structures from 6061 aluminum, where the nodes have identical properties to those of the trusses/facesheets. Inelastic buckling dictated the compressive behavior, whereas tensile fracture of the extensionally strained trusses governed the shear response. No nodal failure modes were observed and the compression and shear properties agree well with predictions of micromechanical models.