PSI - Issue 38

Tuomas Skriko et al. / Procedia Structural Integrity 38 (2022) 393–400 Skriko et al. / Structural Integrity Procedia 00 (2021) 000 – 000

399

7

(a)

(b)

Nominal stress method

Structural stress method

1000

1000

R = 0.1 R = 0.5

R = 0.1 R = 0.5

Δ σ [MPa]

Δ σ [MPa]

FATmean, R = 0.1 FATchar, R = 0.1 FATmean, R = 0.5 FATchar, R = 0.5

FATmean, R = 0.1 FATchar, R = 0.1 FATmean, R = 0.5 FATchar, R = 0.5

100

100

10 000

100 000

1 000 000

10 000

100 000

1 000 000

N [cycles]

N [cycles]

(c)

(d)

Effective notch stress method

4R method

1000

1000

R = 0.1 R = 0.5

Δ σ [MPa]

Δ σ [MPa]

R = 0.1

FATmean, R = 0.1 FATchar, R = 0.1 FATmean, R = 0.5 FATchar, R = 0.5

σ res = 550 MPa Ahola et al. (2020) for S960: H = 1456 MPa n = 0.053

R = 0.5

FATmean

FATchar

100

100

10 000

100 000

1 000 000

10 000

100 000

1 000 000

N [cycles]

N [cycles]

Fig. 5. Fatigue test results of laser-dressed non-load-carrying fillet weld joints based on (a) nominal stress, (b) structural hot-spot stress, (c) ENS and (d) 4R method.

Table 4. FAT values from experimental fatigue tests of laser-dressed non-load-carrying cruciform joints. Method Stress ratio Slope parameter Mean fatigue strength Characteristic fatigue strength R [-] m [-] FAT mean [MPa] FAT char [MPa] Nominal stress 0.1 2.79 156 115 0.5 3.21 166 122 Structural hot-spot stress 0.1 3.37 188 151 0.5 3.73 185 136 ENS 0.1 2.58 231 160 0.5 3.25 282 213 4R both 5.48 524 453