PSI - Issue 38

Antti Ahola et al. / Procedia Structural Integrity 38 (2022) 457–465 Ahola et al. / Structural Integrity Procedia 00 (2021) 000 – 000

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2.1. Fatigue strength of single-sided and double-sided fillet weld joints

(a)

(b)

400 500

400 500

SSFW

DSFW

200 Nominal stress range Δ σ nom (MPa) 300

200 Nominal stress range Δ σ nom (MPa) 300

SSFW, UHSSs (Ahola et al., 2021) DSFW, UHSSs (Ahola et al., 2020)

SSFW, S355 (Ahola et al., 2021) DSFW, S355 (this study)

100

100

10 4

10 5

10 4

10 6

10 5

10 6

Cycles to failure N f

Cycles to failure N f

Fig. 3. CA fatigue test results of NLC SSFW and DSFW joints made of (a) S355 mild steel grade ( t = 6 mm) and (b) UHSS (S960 and S1100) grades ( t = 8 mm), tested at the R = 0.1 ratio. The upper and lower limits of scatter bands correspond to the survival probabilities of P s = 10% and P s = 90%, respectively. The results of statistical analyses are summarized in Table 1. 2.2. Fatigue strength of intermittent and continuous fillet weld joints Fig. 4 presents the experimental fatigue test results for the intermittent SSFW joints made of the S355 steel grade in comparison with the scatter bands for the continuous SSFW joints. In the intermittent welds, the fatigue cracks initiated at the weld root, similarly as in the continuous welds. Furthermore, the results shows that the intermittent SSFW joints had a similar fatigue performance to the continuous SSFW joints.

200 400 500 Nominal stress range Δ σ nom (MPa) 300

Continuous SSFW (S1100, Fig. 3b)

Continuous SSFW (S355, Fig. 3a)

Intermittent Continuous

Intermittent SSFW (this study)

100

10 4

10 5

10 6

Cycles to failure N f

Fig. 4. CA fatigue test results of NLC intermittent SSFW joints made of S355 in comparison with the NLC continuous SSFW joints made of S355 and S1100 steel grades.