Page 212 - IJB-9-4

International Journal of Bioprinting b-Ti21S TPMS FGPs produced by laser powder bed fusion

Figure 18. Finite element simulation of the complete TPMS-FGPS 2.5. (a) The contour mesh of the as-manufactured samples. (b) Loading condition
resembling the experimental condition, i.e., a fixed constraint on the bottom surface of the specimen and a fixed displacement equal to 0.1 mm in the
vertical direction on the top surface. (c) Results of the simulation analysis.

with unit cell sizes of 2.5 and 4.0 mm, and relative density
gradients of 0.17, 0.34, 0.50, 0.66, and 0.83. Quasi-static
and cyclic compression tests were carried out to evaluate
E quasi-elastic , yield stress and E cyclic . Homogenization analysis
and simple lumped model were conducted, and the
obtained results were compared with the experimental
values. FEA further explained the discrepancy observed
between experimental simulated values in the case
of TPMS-FGPS 4.0. The main results of the study are
summarized as follows.

(i) 2D metrological characterization by SEM highlights
an undersizing of both ligament and pore size with a
maximum variation of 16% (TPMS-FGPS 2.5) and 9%
(TPMS-FGPS 4.0) and of 66% (TPMS-FGPS 2.5) and
64% (TPMS-FGPS 4.0), respectively. The undersizing
of the pore and ligament with respect to the CAD can
Figure 19. Gibson–Ashby fitting equation for TPMS with 2.5 mm of unit be attributed to an excess of material, a higher amount
cell size. of unmelted powder in the upper part of the pores,
and variations in the diameter of the ligament.
obtain C equal to 0.94 and n equal to 2.13, as found by
1
1
other authors [36,73] . The exponential constants are very close (ii) 3D metrological characterization by X-ray and
to the pure bending-dominated behavior, as shown by the m-CT imaging shows an undersizing of both the pore
comparison with the red curve in Figure 19. size and ligament thickness, which is lower than 5%
in TPMS-FGPS 2.5 and TPMS-FGPS 4.0, confirming
4. Conclusion the excellent printability of these structures.

2D and 3D metrological characterizations were (iii) The 3D metrological characterization by means
performed on two different 3D-printed TPMS-FGPSs of m-CT imaging permits a more holistic evaluation

Volume 9 Issue 4 (2023) 204 https://doi.org/10.18063/ijb.729