PSI - Issue 39

Mario Álvarez-Blanco et al. / Procedia Structural Integrity 39 (2022) 379–386 Author name / Structural Integrity Procedia 00 (2021) 000–000

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3. Results 3.1. Mechanical characterization of PLA

The results obtained in the uniaxial tensile tests (see Fig. 3) were analysed for the mechanical characterization of the PLA. Fig. 5 represents the force-displacement curves of two tests at different strain rates (1 mm/min and 50 mm/min) to study the influence of this variable on the mechanical behaviour of the material.

Fig. 5. Force-displacement curves of tensile tests at different strain rates.

For the curve at 1 mm/min, note that there is a region with large deformations at a lower constant force (neck stabilization region). This phase is caused by the softening of the material at the plasticity neck, a very localised plastic strain zone with a reduced cross-section. On the other hand, the curve at 50 mm/min exhibits a brittle fracture (without neck formation) when the maximum force is reached, which is higher than for the test at 1 mm/min.

Fig. 6. Extensometer positioning and DIC’s region of interest in uniaxial tensile test before (a) and after (b) neck formation.