From three-dimensional tessellations to lightweight filling materials for additively manufactured structures: Concept, simulation, and testing

To improve the structural efficiency and reduce costs, most additively manufactured parts are printed as thin shells filled with a lightweight cellular material. The filling material reacts to secondary stresses and provides distributed support for the load-carrying outer shell. In a recent publication, the authors have proposed a two-step method to design lightweight filling metamaterials that are intrinsically strong and stiff. Conceptually, the space is first divided into repetitive volumes according to known three-dimensional tessellation schemes. The tessellation is then replaced by a kinematically rigid wireframe with beams along the edges and across the faces of the native volumes. Elaborating on that idea, the present paper pursues three objectives: (a) show the variety of material designs that derive from the tessellation-wireframe approach; (b) characterize the materials through finite element analyses on full-scale models and compare them with former predictions based on scaling and homogenization techniques; (c) validate the numerical results against experimental tests on a selection of prototype structures. Good correlation is revealed between theoretical predictions, computational models, and experimental data.