PSI - Issue 42

Marouene Zouaoui et al. / Procedia Structural Integrity 42 (2022) 680–686 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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3. Results and discussions 3.1. Load-displacement curves The tested specimens are shown in Fig. 5. It shows that the crack path is not straight forward, but instead it follows the deposit pattern.

Fig. 5. SENB specimens after testing.

The load-displacement curves of all tested specimens are compared in Fig. 6. All curves exhibit a quasi linear regime till the drop of load. This indicates that the sample behavior is almost elastic. The drop of load observed in all samples corresponds to sample failure by (i) the crack growth from the notch tip and (ii) the debonding between cells. The results show that the solid specimen is the stiffest one. The maximum load reaches at almost 8880 N. This specimen exhibits a brittle-like behavior with a small maximum deflection (fracture is triggered at 0.89 mm) compared to the specimens with cell patterns. Applying the cell pattern increases the maximum deflection δ* and decreases the stiffness. For the conventional honeycomb structure, δ* is lower than that of the auxetic cell. For only a loss of 22% of the ultimate applied load, the auxetic pattern at 0° improves the displacement at fracture by around 64% compared to the honeycomb cells.