PSI - Issue 77

Boyu Li et al. / Procedia Structural Integrity 77 (2026) 316–322

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Boyu Li et al. / Structural Integrity Procedia 00 (2026) 000 – 000

(a)

(b)

(c)

Z

Y

X

0.900% 0.825% 0.750% 0.675% 0.600% 0.525% 0.450% 0.375% 0.300% 0.225% 0.150% 0.075%

0

Fig. 3. Water diffusion in homogeneous (a), horizontal (b), and vertical (c) models after 1200 s.

Fig. 4. Evolution of water concentration in three models.

4. Conclusions and future work The experimental and simulation results of this study confirmed that 3D-printed PLA specimens exhibited heterogeneous diffusivity caused by their printing patterns. In the experimental study, the internal architecture of the printed material contributed to this anisotropy. Consequently, the diffusivity values derived by fitting mass variation data to Fick’s diffusion equation were influenced by the presence of wall structures, thicker top or bottom layers, complex infill patterns, and boundary effects. For 3D printed specimens, it is therefore essential to simulate the diffusion process using FE models reconstructed directly from the G-code to capture the influence of these