The role of node fillet, unit-cell size and strut orientation on the fatigue strength of Ti-6Al-4V lattice materials additively manufactured via laser powder bed fusion

On the effect of the node and building orientation on the fatigue behavior of L‐PBF Ti6Al4V lattice structure sub‐unital elements

“…In fact, these specimens exhibit a more evident cross-sectional size variation (see Table 1). This peculiar trend has also been observed in the work of Dallago et al, 11 concerning cubic lattice structures, where it was noticed that if the main load bearing struts of the lattice were printed vertically (90 ), fracture occurred at the node, alternatively, if the main load bearing struts were printed parallel to the build plane (0 ), failure occurred along the strut gauge length. In Figure 4, the SEM fracture surfaces of one specimen for each batch are reported.…”

“…6 Until now, most of the work has been addressed to the understanding of the fatigue response of different types of lattices but little work has been focused on the sub-unital elements of the cell units, namely, struts and junctions. [7][8][9] In a previous work of the authors, 10 the fatigue behavior of thin struts and their dependency on the building orientation has been examined, while in the work of Dallago et al 11 and of Latture et al, 12 the role of strut junctions and of the fillet radius have been investigated in cubic and octet lattice structures, respectively. From these works, it has been revealed that junctions are a weak point of architected materials, due to the stress concentration and that improving the junction geometry by filleting can be beneficial in terms of fatigue resistance.…”

“…From these works, it has been revealed that junctions are a weak point of architected materials, due to the stress concentration and that improving the junction geometry by filleting can be beneficial in terms of fatigue resistance. 11 The aim of this work is to investigate the effect of the building orientation and the role of the fillet radius on the fatigue properties of the sub-unital elements of a cubic lattice cell. S-N fatigue curves have been obtained by performing an experimental campaign on L-PBF Ti6Al4V single strut specimens with a junction placed in the gauge length section.…”

Hybrid Ti6Al4V/Silk Fibroin Composite for Load-Bearing Implants: A Hierarchical Multifunctional Cellular Scaffold

“…The above-mentioned topology-related advantages are also reflected in the mechanical properties of prosthetic devices at a macro-scale level [ 13 , 14 ]. In fact, AM lattice structures exhibit a tunable bone-mimicking mechanical behavior in terms of Young’s modulus and fatigue strength as well as a bone-like mass transport behavior [ 15 , 16 , 17 , 18 ]. In particular, the possibility of tailoring its stiffness, reducing the mismatch between the implant and bone tissue, together with the compatibility with new titanium alloys (i.e., β-Ti alloys), guarantee a lower risk of stress shielding, implant loosening, and adjacent bone degeneration [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

Numerical and Experimental Investigation of Cumulative Fatigue Damage under Random Dynamic Cyclic Loads of Lattice Structures Manufactured by Laser Powder Bed Fusion

“…Despite the continuous technological improvement of L-PBF, the manufacturing of lattice structure still remains quite challenging due to the small feature size and complex shape. In this regard, Dallago et al [25] observed that node geometry and printing directions have a relevant impact on the fatigue behavior of lattice structures and can be tailored to improve fatigue life. In addition, the dependence from defects and strut irregularities has been addressed numerically by Boniotti et al [26] by way of a finite element model based on the as-manufactured geometry, which has been reconstructed by CT-scan.…”