Anisotropic Elasticity of Ceramic Micro-Scaffolds Fabricated by Robocasting

Anisotropic elastic and acoustic properties of robocast ceramic scaffolds are calculated by finite element method, utilizing real geometries and material parameters obtained from robocast silicon carbide samples. Six types of robocast geometries are studied, showing different material symmetries given by the arrangement of the ceramic rods in the scaffold structures. Due to the macroscopic periodicity of the structures composed of fully sintered ceramic rods, the robocast scaffolds exhibit metamaterial-like elastic and acoustic properties, never observed for natural materials. The effect of the micro-architecture is shown to be crucial: while for tetragonal and orthorhombic structures, strong acoustic focusing along the directions of the rods appears even in the low-frequency limit, hexagonal structures exhibit no energy focusing up to some frequency limit given by the geometry.