Influence of Defects on the Effective Properties of Selectively Laser Melted Cellular Structures

Cellular structures have continued to gain increased interest over the years due to their excellent properties and advancements in manufacturing. This work investigates the influence of laser powder bed fusion (L-PBF) manufacturing-induced defects on the effective properties of the octet-truss (OT) lattice structure. Four configurations of the two different defect types, namely missing struts and reduced struts, were investigated numerically. Unit-cell models were developed in Abaqus CAE commercial software to predict the effective elastic modulus and the OT structure’s effective yield strength (0.2% offset). The developed models were validated using experimental results. The validated models were then extended to investigate the effects of defects on the effective elastic modulus and the effective yield strength of the OT structure. Results indicated that both defects (reduced strut and missing strut) negatively affected the relative density, effective elastic modulus, and the effective yield strength of the OT structure. The location of the defect influenced the degree to which the effective properties were reduced. OT structures with missing strut defects experienced a higher reduction in effective properties than OT structures with reduced strut defects. It was also observed that the investigated defects were more detrimental to the OT structure’s effective yield strength compared to the effective elastic modulus.