PSI - Issue 33

Vitor E.L. Paiva et al. / Procedia Structural Integrity 33 (2021) 159–170 Author name / Structural Integrity Procedia 00 (2019) 000–000

169 11

Table 1. Experimental Results.

Measured circumferential strain amplitude at hot spot location, ε a (10 3 µε), using DIC or FBSG

Number of cycles to failure using Eq. (1), N c , S u = 500 MPa, E = 200 GPa

Number of cycles to failure using Eq. (1), N c , S ue = 420 MPa, E = 182 GPa

Number of applied test cycles until failure, N

Specimen* ID and test conditions

DIC in-air

FBSG, in-air FBSG, after burying

1-air 2-air 4-air 5-air 6-air 7-air 8-air 9-air

1.9 2.5 5.0 1.6 3.5 2.2 1.5 2.0 2.4 2.2 1.0 0.9 2.0 3.3 3.3

Nm** Nm** Nm**

- - - - - - - -

25980 10340 1632 50562 3957 15580 66510 21610 11750 15580 527500 1011000 21610

21000 9000 1530 40000 3600 13400 51000 18000 10200 13400 351000 643000 18000

38300 7990 2100 220000 4270 34400 53300 38900 26800 21700 905500 130200 21900

1.3

Nm**

2.0 1.3 2.0 1.8 1.8 0.9 1.0 1.7 3.3 3.2

1.9 1.7

11-buried 12-buried 13-buried 15-buried 17-buried 20-buried 21-buried

N*** N***

2.0 3.2 2.9

4632 4632

4200 4200

4610

5970 * Results of specimens 3 (see Paiva (2020)) and 18 not presented due to tests carried out under different conditions ** Nm = Not measured at the same site area where DIC showed the maximum strain

***N = Not monitored when buried - specimen tested in air (not buried)

Fig. 13. Comparison between buried tests results and in-lab specimens tested by Freire et al. (2020).