PSI - Issue 13

Author name / Structural Integrity Procedia 00 (2018) 000 – 000

5

P.N.B. Reis et al. / Procedia Structural Integrity 13 (2018) 1999–2004

2003

Fig. 4. Comparison between the experimental results against the theoretical KWW model.

Table 1. Parameters of the KWW model. Strain[%]  0 [MPa]

Error [%]





2.71 1.41 0.64

58 38 19

421438.1 398657.9 433685.8

0.2075 0.2247 0.2476

- 0.71 - 0.82 - 0.06

4. Conclusions

This study analysed the strain-rate sensitivity and stress relaxation of SRPP composites under bending loads. It is possible to conclude that the main flexural properties are strain-rate sensitive, and a linear model fits successfully the tendency observed. Both flexural strength and bending modulus increase with the increasing of the strain-rate, while the strain at maximum bending stress presents an opposite tendency. The stress relaxation tests evidence a decrease of the stress with time, and this tendency further persists with the increase of the strain values. Kohlrausch-Williams-Watts (KWW) model was used to fit the data obtained from the stress relaxation tests, and it fits the data with good accuracy.

Acknowledgements

The research leading to these results was funded by KU Leuven in the framework of the visiting fellowship for P.N.B. Reis.

References

Alcock, B., Cabrera, N.O., Barkoula, N.M., Loos, J., Peijs, T., 2006. The mechanical properties of unidirectional all-polypropylene composites, Compos Part A Appl Sci Manuf 37, 716-726. Alcock, B., Cabrera, N.O., Barkoula, N.M., Spoelstra, A.B., Loos, J., Peijs, T., 2007a, The mechanical properties of woven tape all polypropylene composites, Compos Part A Appl Sci Manuf 38, 147-161.