PSI - Issue 47

Andrea Iadarola et al. / Procedia Structural Integrity 47 (2023) 383–397 A. Iadarola / Structural Integrity Procedia 00 (2019) 000 – 000

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Overall, it is possible to notice an increasing trend of the strain at failure by increasing the total bio-content (especially for dynamic testing conditions at 10 mm/s, Fig. 6b), even if this effect is not always visible probably due to the relevant presence of residual defects in the material that leads to a premature failure of the specimens. Fig. 6 also shows a reduction of the softening behavior by increasing both the bio-content and the strain rate. In this case, only the blend with 51% total bio-content shows a relevant increment of the strain at failure. Fig. 7 shows the same stress-strain curves reported in Fig. 6, but in this case with the aim to highlight the effect of the strain rate for each tested blend.

ε

a)

b)

c)

d)

Fig. 7 . Stress-Strain curves of tensile tested materials at different bio-contents to highlight the effect of the strain rate: a) 27% total bio-content; b) 31% total bio-content; c) 41% total bio-content; d) 51% total bio-content.

An increase in modulus and a reduction in maximum elongation are observed in Fig. 7 by increasing the strain rate. On the other hand, reduced strength and elastic modulus are observed in Fig. 7 by increasing the total bio content. These results are in agreement with those found in the literature [12, 14]. Moreover, the curves obtained by testing the same material at different strain rates present a good repeatability, following a similar trend by increasing the total bio-content. The mean values of the elastic modulus and the Ultimate Tensile Strength (UTS) obtained from the tensile tests are reported in Table 6 and Table 7, respectively.

Table 6. Elastic modulus mean values in quasi-static and dynamic tensile test conditions Total Bio-Content Elastic modulus at 0.1 mm/s (Std. Deviation) Elastic modulus at 10 mm/s (Std. Deviation)

Elastic modulus at 10 mm/s (Std. Deviation)

2831.5 MPa (110.00)

3014.2 MPa (130.70)

3249.6 MPa (243.00)

27%