PSI - Issue 61

Lívia Mendonça Nogueira et al. / Procedia Structural Integrity 61 (2024) 122–129 L. M. Nogueira et al. / Structural Integrity Procedia 00 (2024) 000–000

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For the investigation of mechanical properties using the MT method, a sensitivity analysis was also performed to evaluate the influence of pore shape and orientation on Young’s modulus. Three distinct aspect ratios were taken into account for the representative ellipses, namely: R = 1 . 00, R = 0 . 75, and R = 0 . 50. These aspect ratios were selected for their alignment with the patterns previously depicted in Fig. 4. Initially, the dimensionless elastic moduli E 1 and E 2, aligned with the major and minor semi-axis directions, were examined concerning porosity ranging up to 40%. This threshold corresponds to the percolation limit employed in the MT scheme. Additionally, the modulus ratio ( E 1 / E 2) was considered for each aspect ratio. The results are presented in Fig. 5. It can be observed that under random conditions ( R = 1 . 00), the moduli E 1 and E 2 align, consistent with an isotropic scenario. Furthermore, one observes that the gradual alignment of the pore due to the reduction of the aspect ratio ( R ) leads to an increase in the longitudinal Young’s modulus ( E 1), as there is an increase in the matrix material portion associated with this cross-section. Conversely, the transverse modulus ( E 2) experiences the opposite e ff ect, with a smaller matrix material portion, i.e., a greater presence of void associated with this cross-section, resulting in a reduction in Young’s modulus compared to the isotropic scenario. This illustrates that considering the isotropy hypothesis in oriented microstructure scenarios could lead to inadequate sti ff ness predictions. In anisotropic cases, the orientation-dependent moduli became evident. The highest discrepancy is observed for the R = 0 . 50 condition, where the smaller aspect ratio leads to a larger di ff erence between the elastic moduli E 1 and E 2.

Fig. 5. Mechanical properties investigation for di ff erent void aspect ratios: (a) Young’s modulus E1 and E2; (b) Young’s modulus ratio.

4. Conclusions

The results demonstrated the critical impact of microstructure anisotropy on mechanical properties, where orien tation dependence is particularly pronounced in anisotropic cases. The study concluded that overlooking microstruc tural anisotropy, especially in cases involving oriented microstructures, could lead to inadequate sti ff ness predictions. In summary, this research sheds light on the intricate interplay between microstructural attributes and macroscopic characteristics within heterogeneous materials. Through the integration of micromechanical techniques like the MT homogenization model and microstructural analysis methods such as the MIL technique, this study is expected to contribute to an enriched understanding of anisotropic materials and their significance in the field of materials science and engineering. Furthermore, it is worth noting that the validation of our findings through Finite Element Method (FEM) simulations will be addressed in future work. By incorporating FEM simulations, we aim to strengthen the robustness of our results and enhance the applicability of our findings in real-world engineering scenarios.

References

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