PSI - Issue 41

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Fabio Distefano et al. / Procedia Structural Integrity 41 (2022) 470–485 Author name / Structural Integrity Procedia 00 (2019) 000–000

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(a) (b) Fig. 6 Gibson-Ashby model for the mechanical characterization of the G7 cell: (a) relative modulus against relative density; (b) relative strength against relative density 3.4. Failure modes All the tested specimens presented a macroscopic failure in the form of a shear plane inclined with an angle of about 45°, as shown in Fig. 7. This behaviour is in accordance with data reported in literature for similar microlattice structures (Choy et al., 2017).

G7_0.05

G7_0.1

G7_0.2

Fig. 7 Macroscopic failure mode of G7 specimens. SEM analysis results are reported in Fig. 8 and Fig. 9

. In Fig. 8 are reported the failure modes of the entire unit cells. For all cases the fractures were observed at the cross nodes of the structures, which are critical points due to stress intensification. In Fig. 9 are shown details of the fracture surfaces, in which different behaviour can be observed for the three configurations. The G7_0.05 structure presents a ductile fracture with the presence of notch effect, G7_0.1 structure presents both ductile and brittle fracture surface, while in the G7_0.2 specimen a brittle fracture can be observed.