PSI - Issue 68

4

B. Eyri et al. / Structural Integrity Procedia 00 (2025) 000–000

Büşra Eyri et al. / Procedia Structural Integrity 68 (2025) 332 – 338

335

3. Results And Discussion The three-point bending graphs of the samples produced from ABS and PLA materials are presented in Figure 2. As can be seen in Figure 2.a, the highest flexural strength among the various cell structures in ABS material is exhibited by the diamond cell, which has a value of approximately 6.5 MPa. It can be stated that the overexpanded cell structure exhibits a strength that is comparable to this. In contrast, the re-entrant structure exhibited a distinct auxetic behavior, displaying damage at a high strain value of 25%. The bending moduli presented in Table 2 indicate that the diamond cell configuration exhibits the highest modulus, which aligns with the observed strength outcomes. Upon examination of the PLA cell structures depicted in Figure 2.b, it can be ascertained that they exhibit a greater degree of strength in comparison to the ABS structures. While the highest flexural strength is observed in the diamond cell structure, the sample with the overexpanded cell exhibited a strength that was nearly equivalent. While these two cell structures of PLA samples exhibited comparable strain values with the ABS material, the sample comprising a re-entrant cell demonstrated inferior performance, exhibiting a difference of approximately 30%. Nevertheless, even if the PLA material exhibited an increase in strength values for all cell structures, showed a strain-limiting effect on the re-entrant cell. This effect is clearly evidenced by the values presented in Table 2. The re-entrant cell structure demonstrated lower performance than ABS, despite exhibiting a high strain value. The material displayed low strength and modulus values in compatible with its strain performance. The higher strength of the diamond and overexpanded cells can be attributed to the fact that the test was performed in-plane, as opposed to out-of-plane, which would have yielded different results. This phenomenon can be attributed to the fact that the cell walls are more rigid in this plane than in the re-entrant structure. Due to this fact, the two cell structures (OX and D) exhibited high strength (Günaydın et al. 2022).

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Figure 2. The curves obtained from the three-point bending test.