Issue 38

F. Berto et alii, Frattura ed Integrità Strutturale, 38 (2016) 215-223; DOI: 10.3221/IGF-ESIS.38.29

2.0

R 0,III

= 0.438 mm

(a)

= 0.280 MJ/m 3

ΔW A,50%

N A = 2 ∙10 6 cycles Scatter Index (10%-90%): T W = 0.346/0.227 = 1.52 Slope k = 5.27

SUS 316L

1,0

SED range, ΔW [MJ/m 3 ]

NA NB NC NA NB NC

0.346 0.280 0.227

Torsion fatigue loading, R = -1

Torsion fatigue loading, R = -1 with superimposed static tension σ m

= τ a

N A

0,1

1,E+03

1,E+04

1,E+05

1,E+06

1,E+07

Number of cycles to crack initiation

2.00

R 0,III

= 0.716 mm

(b)

= 0.145 MJ/m 3

ΔW A,50%

1,00

N A = 2 ∙10 6 cycles Scatter Index (10%-90%): T W = 0.220/0.096 = 2.29 Slope k = 5.01

SGV 410

0,10 SED range, ΔW [MJ/m 3 ]

0.220 0.145 0.096

NA NB NC NA NB NC

Torsion fatigue loading, R = -1

Torsion fatigue loading, R = -1 with superimposed static tension σ m

= τ a

N A

0,01

1,E+03

1,E+04

1,E+05

1,E+06

1,E+07

Number of cycles to crack initiation

Figure 5 : Averaged SED-based scatter-band calibrated on the crack initiation experimental fatigue results for (a) SUS 316L and (b) SGV 410 steels. The smaller symbols indicate the total fatigue life for comparison purposes: the black ones are for pure torsion loading, while the gray ones are for torsion loading with superimposed static tension.

R EFERENCES [1] Tanaka, K., Hashimoto, A., Narita, J., Egami, N., Fatigue life of circumferentially notched bars of austenitic stainless

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