Issue 49

Y. Saadallah et alii, Frattura ed Integrità Strutturale, 49 (2019) 666-675; DOI: 10.3221/IGF-ESIS.49.60

As for the viscoplastic parameters, the coefficient of work hardening is constant whatever the strain-rate, or the other viscoplastic parameters are a function of the strain-rate. The higher the strain-rate, the greater the elastic limit e  and the modulus H, and the lower the viscoplasticity coefficient vp  .

Strain-rate 

 1 min  .

  E GPa .

  K GPa





. ve GPa min 

0.0000646

2.9765 2.9765 2.9765 2.9765

7.3122

23.8816 5.0066 0.7380 0.0640

000625 0.00612

12.2063 18.6363 32.3085

0.0556

Table 1 : Viscoelastic parameters

Strain-rate 

 1 min 

  . vp MPa min 

 e MPa 



  H MPa

n .

.

.

0.0000646 0.000625

22.0151

69.8468 94.9441 122.883 155.818

0.3072 0.3072 0.3072 0.3072

6962.33 3044.22 210.346 23.11376

20202

0.00612

24.8992

0.0556

26

Table 2 : Viscoplastic parameters

Figure 3 : Comparison test-model of the stress–strain curves of Polyamide 6 at various strain-rates

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