PSI - Issue 24

Bruno Atzori et al. / Procedia Structural Integrity 24 (2019) 66–79 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

73

8

10.00

ΔW A,50% = 0.105 MJ/m 3 N A = 2 ∙10 6 cycles Scatter Index (2.3%-97.7%): T W = 0.192/0.058 = 3.31 T σ = √T W = 1.82 Slope k = 1.5

SED-based design scatter-band for steel welded joints

0.10 Averaged strain energy density [MJ/m 3 ] As-welded, toe failure 1.00

0.192 0.105 0.058

Steel welded joints R 0 ≈ 0.3 mm at both weld root and toe side 600 fatigue test data, load ratio R = 0-0.3

As-welded, root failure

N A

(a)

0.01

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

Number of cycles to failure, N

10.00

ΔW A,50% = 0.103 MJ/m 3 N A = 2 ∙10 6 cycles Scatter Index (2.3%-97.7%): T W = 0.184/0.058 = 3.17 T σ = √T W = 1.78 Slope k = 2.0

SED-based design scatter-band for aluminium welded joints

0.10 Averaged strain energy density [MJ/m 3 ] As-welded, toe failure 1.00

0.184 0.103 0.058

Aluminium welded joints (R 0 = 0.12 mm) 120 fatigue test data, load ratio R = 0

As-welded, root failure

N A

(b)

0.01

1.E+03

1.E+04

1.E+05

1.E+06

1.E+07

Number of cycles to failure, N

Figure 1: Fatigue test results expressed in terms of averaged SED and relevant to welded joints tested in the as welded conditions under axial or bending loading and made by (a) structural steels and (b) aluminium alloys.