PSI - Issue 39

Wei Song et al. / Procedia Structural Integrity 39 (2022) 214–221 Author name / Structural Integrity Procedia 00 (2020) 000–000

220

7

(b)

(a)

10 4

10 2

axial misliagnments specimens angle misliagnments specimens weld root failure

axial misliagnments specimens angular misliagnments specimens weld root failure

10 -1 Averaged SED Range ∆ W (Nmm/mm 3 ) 90% 50% 10% 10 0 10 1 R=0.1

10 2 Normal Stress Range ∆σ ( MPa ) 10% R=0.1 10 3 90% 50%

proposed by Lazzarin: 0.056; m=1.5

68 MPa 96 MPa

m=2.7

m=1.1

FAT Class(IIW): 63; m=3

0.07

T σ =1.41

0.03 T σ =2.3

10 1

10 -2

10 3

10 4

10 5

10 6

10 7

10 3

10 4

10 5

10 6

10 7

(c)

(d)

Number Of Cycles N

Number Of Cycles N

10 4

10 4

axial misliagnments specimens angle misliagnments specimens weld root failure

10% 50% 90%

axial misalignments specimens angle misalignments specimens

50% 10% 90%

10 2 Hot Spot Range ( MPa ) 10 3

10 3

FAT Class(IIW): 68; m=3

277 MPa

FAT Class(IIW): 100; m=3

147 MPa

127 MPa

m=2.1

m=2

10 2

64 MPa

T σ =2.2

T σ =2.3

Effective Notch Stress Range (MPa)

R=0.1

10 1

10 1

10 3

10 4

10 7

10 5

10 6

10 3

10 4

10 5

10 6

10 7

Number Of Cycles N

Number Of Cycles N

Fig. 5 S-N curves expressed by different methods. (a) nominal stress method; (b) SED methods; (c) hot spot method; (d), ENS method.

4. Conclusion In this study, the influence of different geometric parameters on SED and the failure modes were analyzed. The LCWJ experiments of 907L and D32 are developed to present the misalignment effect by different fatigue assessment methods. According to the survey, the following conclusions can be drawn: (1) The SED calculated by FEM were be analyzed, the results show that different weld penetrations have a great influence on the weld root, the effect of misalignments on weld toe is greater than weld root. (2) The effect of misalignment on the failure mode of fatigue is significant. With the increase of e/t and a, the failure mode is more inclined to failure at welding toe, otherwise, the weld root failure. When the axial misalignment(a/t) is greater than 0.8, or the angular misalignment(a) is greater than 5°, almost weld toe failure occurs. (3) The fatigue data considering the misalignment effect were presented by different assessment methods, and were compared with the corresponding reference lines. 5. References [1] Oliveira P.I., Antunes F.V., Loureiro A., Costa J.M., Effect of the angular misalignment of laser welded T-joints on fatigue curves %J International Journal of Fatigue, 128 (2019). [2] Andrews R.M., THE EFFECT OF MISALIGNMENT ON THE FATIGUE STRENGTH OF WELDED CRUCIFORM JOINTS, J Fatigue & Fracture of Engineering Materials & Structures, 19(6) (1996). [3] Ottersböck M.J., Leitner M., Stoschka M., Maurer W.J.W., Analysis of fatigue notch effect due to axial misalignment for ultra high-strength steel butt joints, (2019). [4] Xing S., Dong P.S., An analytical SCF solution method for joint misalignments and application in fatigue test data interpretation, 50 (2016) 143-161. [5] Hobbacher A.F., Recommendations for Fatigue Design of Welded Joints and Components, (2016).