Issue 43

B. Saadouki et alii, Frattura ed Integrità Strutturale, 43 (2018) 133-145; DOI: 10.3221/IGF-ESIS.43.10

(predominance of ∆ε p

-N relation), and the yield strength and ultimate tensile strength at high cycle (predominance of ∆ ε el -

N ).

(a) (b) Figure 12 : Resistance fatigue curves for SICLANIC ® predicted using (a) four correlation point method and (b) a universal slopes method.

ε f

σ f (MPa)

ε f ’

σ f ’ (MPa)

b

c

Manson’s four points

0.29

793.35

0.19

931.71

-0.09

-0.46

Manson’s universal slopes 0.29

793.35

0.36

1168.5

-0.12

-0.6

Table 4 : Low cycle fatigue characteristics for the SICLANIC ® .

Moreover, many researchers have linked coefficients b and c to the cyclic hardening coefficient n ’ , Tab. 5 shows some formulas results. Morrow has proposed the following relation:

 ' 1 5 ' n n 1 1 5 ' n 

 

b

(12)

 

c

(13)

Tomkins [28] proposes on his side:

 ' 1 2 ' n n

 

b

(14)

 1 1 2 ' n

 

c

(15)

142