Issue 49

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

10000 15000 20000 25000 30000 35000

10000 15000 20000 25000 30000 35000

K (MPa)

µ_ve (MPa.min)

0 5000

0 5000

0

0,02

0,04

0,06

0

0,02

0,04

0,06

Strain-rate (1/min)

Strain-rate (1/min)

Figure 6: Dependence of viscoelastic parameters at the strain-rate

12000

100 120 140 160 180

10000

8000

6000

0 20 40 60 80

4000

H (MPa)

µ_vp (MPa.min)

2000

0

0

0,02

0,04

0,06

0

0,02

0,04

0,06

Strain-rate (1/min)

Strain-rate (1/min)

Figure 7: Dependence of viscoplastic parameters at the strain-rate To define the functions that represent the mathematical relationship of the strain rate with the viscoelastic and viscoplastic parameters, a nonlinear regression technique is considered. As a result, a power law connects both the viscoelastic parameters and the viscoplastic parameters to the strain-rate. The curves that represent the sensitivity of the viscoelastic parameters to the strain-rate are illustrated in Fig. 6. The sensitivity of the viscoplastic parameters is illustrated in Fig. 7. With the exception of the elastic modulus E and the coefficient of hardening n which are independent of it, the functions obtained are shown in Tab. 3.

H .

K



e  .



vp

ve

0,87 6, 6166   

0,88 2, 3512   

0,02 28, 059  

0,12 222, 27  

0,21 58881  

Table 3 : Relationship of the parameters with the strain-rate

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