PSI - Issue 2_A

Yusuke Seko et al. / Procedia Structural Integrity 2 (2016) 1708–1715 Author name / Structural Integrity Procedia 00 (2016) 000–000

1714

7

2000

2000

(a) 2a=6mm, 2c=40mm

m = 20

m = 20

1800

1800

(b) 2a=9mm, 2c=40mm ( ) : Calculation point for CTOD RS : Residual stress

( ) : Calculation point for CTOD RS : Residual stress

1000 Weibull stress ,  w (MPa) 1200 1400 1600

1000 Weibull stress ,  w (MPa) 1200 1400 1600

h=2mm (TOP) h=2mm (BOT) h=9.5mm (TOP) h=9.5mm (BOT)

h=2mm (TOP) h=2mm (BOT) h=8mm (TOP) h=8mm (BOT)

h=2mm with RS (TOP) h=2mm with RS (BOT) h=8mm with RS (TOP) h=8mm with RS (BOT)

h=2mm with RS (TOP) h=2mm with RS (BOT) h=9.5mm with RS (TOP) h=9.5mm with RS (BOT)

0

0.1 0.2 0.3 0.4

0

0.1 0.2 0.3 0.4

CTOD,  (mm)

CTOD,  (mm)

Figure 8 Effect of welding residual stress on relationship between Weibull stress and CTOD

2000

2000

(a) 2a=6mm, 2c=40mm

(b) 2a=9mm, 2c=40mm

m = 20

m = 20

1800

1800

1000 Weibull stress ,  w (mm) 1200 1400 1600

1000 Weibull stress ,  w (mm) 1200 1400 1600

h=2mm h=9.5mm h=2mm with RS h=9.5mm with RS

h=2mm h=8mm

h=2mm with RS h=8mm with RS

RS : Residual stress

RS : Residual stress

0 0.1 0.2 0.3 0.4 0.5 0.6

0 0.1 0.2 0.3 0.4 0.5 0.6

Overall strain,  ∞ (%)

Overall strain,  ∞ (%)

Figure 9 Effect of welding residual stress on relationship between Weibull stress and overall strain

5. Conclusion In this study, the effect of crack depth and residual stress on the brittle fracture limit of embedded flaw based on the Weibull stress criterion using finite element analysis. The brittle fracture limit of embedded crack without welding residual stress decrease with decreasing crack depth in all strain region. The welding residual stress decrease the brittle fracture limit of embedded crack with welding residual stress before overall strain reaches yield strain. After yielding, the Weibull stresses were almost same between with and without residual stress

References

BS7910:2013. Guide to methods for assessing the acceptability of flaws in metallic structures, British Standard Institution, 2013. WES2805:2011. Method of Assessment for Flaws in Fusion Welded Joints with respect to Brittle Fracture and Fatigue Crack Growth, The Japan Welding Engineering Society, 2011. ISO27306:2009. Method of constraint loss correction of CTOD fracture toughness for fracture assessment of steel components, 2009. F. Minami, 1996, Fracture toughness requirement for fracture performance evaluation of welded joints based on the local approach, Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering, pp. 193-202. F. Minami, 1997, Prediction of specimen geometry effect on fracture resistance of HAZ-notched welds by local approach, Mis-Matching of Interfaces and Welds, pp. 319-330.