*3.2.3 Mechanical property comparison for PPSGFC*

The data obtained by the SHPB system (**Table 7**) evidence an increase of 27% on the peak stress when the average values for the quasi-static and dynamic regimes are compared (358.295 and 491.554 MPa). Similarly, the deformation on the ultimate stress is increased by 36% when the average values for the quasi-static and dynamic regimes are compared (1.676 and 2.647%). It was not evidenced a significant change in the Young's modulus for the material tested in the dynamic regime with respect to that of the semi-static regime (2% increase).

According to the data obtained when strain is measured by DIC (**Table 8**), the tendency of strength increase is kept at 38% when the averages of the quasi-static

#### **Figure 19.**

*Stress-strain curve obtained for PPSGFC with strain measured by DIC and SHPB strain gages under (a) 558.5 s<sup>−</sup><sup>1</sup> and (b) 891.1 s<sup>−</sup><sup>1</sup> .*

**45**

**Figure 22.**

*SEM images for PPSGFC tested at 891.1 s<sup>−</sup><sup>1</sup>*

*(b) "un-melted" surface at 100× with 500× zoom of the marked zone.*

**Figure 21.**

*High Strain Rate Characterization of Thermoplastic Fiber-Reinforced Composites…*

given that the determination of the peak stress is made with the same data. However, the increase in the strain at peak stress is just 21% based on the average values for each regime (1.676% quasi-static and 2.034% dynamic). The aforementioned affects the behavior of the Young's modulus, which presents an increase of 23% according to the average values for quasi-static and dynamic regimes (21.999 and 27.168 GPa). The behavior previously described is graphically evidenced in **Figure 23** where the properties' tendency with respect to the strain rate is shown.

and dynamic regimes are compared (358.295 and 496.758 MPa), which is expected

*.*

*. (a) "Melted" surface at 100× with 500× zoom of the marked zone,* 

*DOI: http://dx.doi.org/10.5772/intechopen.82215*

*Images sequence taken by HSIS for PPSGFC tested at 891.1 s<sup>−</sup><sup>1</sup>*
