PSI - Issue 38

5

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

461

Table 1. Summary of the statistical analyses of the fatigue test results of transverse NLC attachments with SSFW and DSFW details.

m = 3

m free

FAT 50% (MPa)

FAT 50% (MPa)

m (-)

T σ (-)

T σ (-)

Symbol

Fig.

Material Series

S355

SSFW DSFW

2a 2a

2.99 3.57 3.38 3.04 4.05

121 184 132 112 157

1.13 1.10 1.11 1.16 1.19

120 176 126 111 129

1.13 1.16 1.16 1.17 1.30

Intermittent SSFW

3

UHSS

SSFW DSFW

2b 2b

2.3. Effective notch stress analysis of single-sided and double-sided fillet weldsSe. From the engineering design viewpoints, screening critical locations and details in welded connection is an important step. The experimental results, see Section 2.1 and Section 2.2 indicated that there is slight difference in the fatigue strength capacity of SSFW joints failing from the weld root and DSFW joints failing from the weld toe in the nominal stress system. Effective notch stress (ENS) concept has been extensively applied for the fatigue assessment of components, and will be also included in the new revision of EC3 fatigue design standard. The aim of this section is to analyze the fatigue strength capacity of SSFW and DSFW joints employing the ENS concept, and to address the capability of the ENS concept to assess the critical location of these joints (weld toe and weld root). Fig. 5b presents the experimental results of SSFW and DSFW joints in the ENS system (Sonsino et al., 2012). The stress concentration factors (SCFs) using the reference radius of r ref = 1.0 mm (for plate thicknesses of t > 5 mm) were obtained using finite element (FE) analysis. 3D parabolic solid element models were created for each geometry, and 48 elements over the 360° circumference of the reference radius was applied (Baumgartner and Bruder, 2013). At the weld root, a fillet-type modeling was employed in both SSFW and DSFW joints. The FE models and obtained SCFs have been presented in Fig. 5a.