Structural optimization of lattice cellular structures: incorporating the fatigue strength dependency on the building orientation of sub-unit struts

Additive manufacturing (AM) techniques are widely involved in the production of lattice-based prosthetic devices. Nevertheless, the development of implants with improved fatigue resistance is still an open debate. In lattice structures, the fatigue life of a component is a crucial issue, since it is not only strongly affected by the wide variety of manufacturing-induced defects but also by the specimen building direction. To gain a better comprehension of fatigue in AM, an investigation of sub-unit lattice elements according to their building orientation should be addressed. Additionally, this knowledge can be exploited to design a fatigue-optimized component. In this work, the authors propose a combined approach of fatigue experimental tests on sub-unit lattice elements along with optimization strategies for a wise design and fabrication of a Ti6Al4V laser powder bed fusion (L-PBF) octet truss lattice component. The specimen orientation with respect to the printing plane is chosen as the optimization variable.