Modeling and analysis of material anisotropy-topology effects of 3D cellular structures fabricated by powder bed fusion additive manufacturing

For lightweight cellular structures fabricated via powder bed fusion additive manufacturing (PBF-AM), both the material anisotropy and the cellular topology design are both important design factors. In this work, a direct stiffness matrix-based analytical modeling approach was employed for the evaluation of material anisotropy topology effects on three representative 3D cellular structures (auxetic, BCC and octahedral). The established models were verified via experimentation with samples fabricated by EB-PBF using Ti6Al4V as material, using the material anisotropy information established experimentally using single struts with different build orientations (0?, 15?, 30?, 45?, 60?, 75? and 90?). The predicted mechanical properties of the Ti6Al4V cellular structures showed good agreement with experimental results. It was shown that both the strength and elastic modulus anisotropy of the materials affect the strength of the cellular structures, which must be determined based on the topology design. In addition, the material anisotropy-topology effects on cellular structures of varying cellular pattern sizes were also investigated in order to quantify the pattern size effects. It was found that the pattern size effects and the material anisotropy effects can be decoupled during the design of the mechanical properties of these cellular structures.