PSI - Issue 42

Takumi Ozawa et al. / Procedia Structural Integrity 42 (2022) 730–737 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

735

6

Based on the result, we determined the LC condition for experiment as shown in the Fig. 8. In this LC condition, a 20 mm×30 mm jig is used to compress the position with 5 mm distance from the future crack tip until the LC strain reaches 3 %. The required load was estimated to be 950 kN and pressure to be 1600 MPa. They are satisfy the constraint condition.

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

Computing point Objective funciton=0

Critical CTOD [mm]

ĞƚƚĞƌ > ĐŽŶĚŝƚŝŽŶƐ

-1000

-500

0

500

1000

Minimum residual stress at notch tip [MPa]

 ISO ŝƐ ůŽǁ ǁŚĞŶ d = 0

 ŝƐ ůŽǁ ;ĐƌĂĐŬ ǁŝůů ďĞ ďŽǁŝŶŐͿ ǁŚĞŶ ⚫ S ŝƐ ƐŝŐŶŝĨŝĐĂŶƚůLJ ŚŝŐŚ Žƌ ůŽǁ͖ Žƌ ⚫ d ŝƐ ƐŝŐŶŝĨŝĐĂŶƚůLJ ŚŝŐŚ͘

Fig. 6. Calculation history and characteristics of each group.

a

b

10

10

1

1

0.1

0.1

d

0.01

S

0.01

Objective function

Objective function

0.001

0.001

0 1 2 3 4 5 6 7 8 9 10

Fig. 7. Relationship between objective function and each parameter: (a) Compression area; (b) Distance from the future crack tip. 0 100 200 300 400 500 600 700 800 Compression area, S [mm2] Distance from notch tip and platen edge, d [mm]

hŶŝƚ͗ ŵŵ

>ŽĂĚ ϵϱϬ ŬE ;фϭϬϬϬͿ WƌĞƐƐƵƌĞ ϭϲϬϬ DWĂ ;фϮϬϬϬͿ  ISO Ϭ͘ϭϬϭ ŵŵ ; ≒ Ϭ͘ϭͿ  min ϲϴϬDWĂ ;х  Y Ϳ

> ƐƚƌĂŝŶ с ϯй

ϱ

ϮϬ

ϯϬ

hŶŝƚ͗ ŵŵ

Fig. 8. LC condition for experiment