PSI - Issue 52

A.D. Cummings et al. / Procedia Structural Integrity 52 (2024) 762–784 A. Cummings / Structural Integrity Procedia 00 (2023) 000–000

778

17

(a)

(b)

(c)

(d)

Fig. 11. Cracked body model and contour integral results for a 5x25mm (2a x 2c) embedded (p = 1.5mm), elliptical flaw in the base centre. K I and T-stress calculated with FEA - where φ = 90 ◦ is at the point closest to the material surface, φ = 0 ◦ is at the ends of the crack and φ = -90 ◦ is at the deepest point within the body (a) 1 / 4 symmetry cracked body model (b) Mesh at crack tip (c) K I about crack front (d) T-stress about crack front

Table 6. Base internal radius surface flaw assessment P m P b W B Flawsize

c mat

K mat

T-stress

K

K I

K r

L r

[MPa.m 0 . 5 ]

[MPa.m 0 . 5 ]

[MPa.m 0 . 5 ]

[MPa]

[MPa]

[mm]

[mm]

(a x 2c) [mm]

[MPa]

101

277

1000

118 118 118

1x5 1x 5 1x5

33.6 33.6 33.6

N / A N / A

N / A N / A 57.4

20.0 42.8 42.8

0.6

0.67

-9665 -9665

10851 1000 10851 1000

1.27 N / A 0.74 N / A

-532.4

6.5mm. This might be slightly non-conservative for the 2x7mm flaw but provides a good indication on the benefits of requesting a tighter re-inspection criteria. Again, the K r values are calculated with and without constraint e ff ects. Fig. 12 shows a Failure Assessment Diagram (FAD) of the results for the base internal radius. The Option 1 Failure Assessment Lines (FALs) plotted are from BS7910 (2019) - the two FALs represent a material with and without a yield discontinuity. It is likely that this material does not exhibit a yield discontinuity in its stress-strain curve due