PSI - Issue 68

Josef Arthur Schönherr et al. / Procedia Structural Integrity 68 (2025) 425–431 J. A. Scho¨nherr et al. / Structural Integrity Procedia 00 (2024) 000–000

430

6

a

b

c

1 . 2

1 . 2

1 . 2

1 . 1

1 . 1

1 . 1

1 . 0

1 . 0

1 . 0

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

Abaqus Contour 4

Abaqus Contour 8

Abaqus Contour 4

Abaqus Contour 8

Abaqus Contour 4

Abaqus Contour 8

Creep Stress Power

Creep Stress Power

Creep Stress Power

Abaqus Contour 12

Abaqus Contour 12

Abaqus Contour 12

Fig. 6. C ∗ results for a crack in the center line of ICHAZ B, normalized with the creep stress power solution given for the three material parameter sets (a) to (c) referring to Fig. 3 (a) to (c).

a

b

c

1 . 2

1 . 2

1 . 2

1 . 1

1 . 1

1 . 1

1 . 0

1 . 0

1 . 0

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

Abaqus Contour 4

Abaqus Contour 8

Abaqus Contour 4

Abaqus Contour 8

Abaqus Contour 4

Abaqus Contour 8

Creep Stress Power

Creep Stress Power

Creep Stress Power

Abaqus Contour 12

Abaqus Contour 12

Abaqus Contour 12

Fig. 7. C ∗ results for a crack in the interface FGHAZ B and ICHAZ B, normalized with the creep stress power solution given for the three material parameter sets (a) to (c) referring to Fig. 3 (a) to (c).

a

b

c

1 . 2

1 . 2

1 . 2

1 . 1

1 . 1

1 . 1

1 . 0

1 . 0

1 . 0

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

ASTME1457 Abaqus ( r → 0 ) C ∗ / C ∗ Creep Stress Power 0 . 8 0 . 9

Abaqus Contour 4

Abaqus Contour 8

Abaqus Contour 4

Abaqus Contour 8

Abaqus Contour 4

Abaqus Contour 8

Creep Stress Power

Creep Stress Power

Creep Stress Power

Abaqus Contour 12

Abaqus Contour 12

Abaqus Contour 12

Fig. 8. C ∗ results for a crack in the center line of FGHAZ B, normalized with the creep stress power solution given for the three material parameter sets (a) to (c) referring to Fig. 3 (a) to (c).

exponent. If n is not equal for all regions inside the specimen, the direct application of the Abaqus integral method does lead to erroneous results. The ASTM E1457 method performs well, if the crack is located su ffi ciently far away from material zones with momentously di ff ering n values, Fig. 7 and Fig. 8. If the crack is located at the interface or next to an interface where the material regions are described by di ff ering Norton exponents, Fig. 5 and Fig. 6, the di ff erences to the creep stress power evaluation are more pronounced.

5. Conclusions

In this preliminary study on the e ff ect of considering the heat a ff ected zone with its sub-zones when calculating C ∗ for a compact tension specimen, three approaches to calculate C ∗ are compared. For reference, the C ∗ is evaluated via