PSI - Issue 2_B

R.Citarella et al. / Procedia Structural Integrity 2 (2016) 2706–2717

2715

10

R. Citarella et al. / Structural Integrity Procedia 00 (2016) 000–000

12

10 12 14 16

10

8

6

0 2 4 6 8

4

Crack sizes [mm]

Crack sizes [mm]

EXP ‐ Size a EXP ‐ Size b EXP ‐ Size c

NUM ‐ Size a NUM ‐ Size b NUM ‐ Size c

2

EXP ‐ Size a EXP ‐ Size b EXP ‐ Size c

NUM ‐ Size a NUM ‐ Size b NUM ‐ Size c

0

360,000

385,000 Cycles [‐]

410,000

290,000 310,000 330,000 350,000

Cycles [‐]

a)

b)

Fig. 15. Crack sizes comparison between experimental tests and DBEM analyses: (a) circular notch; (b) semielliptical notch.

4.2. Specimen undergoing tension/torsion loading The DBEM model undergoing tensile and torsion loads, after the crack insertion, has been solved and crack propagation automatically performed; von Mises stresses are plotted for the initial and final crack configurations in Fig. 16, whereas a comparison between numerical and experimental crack shapes is shown in Fig. 17. Fig. 18 shows K I , K II , K III values along crack front at several steps during the growth, whereas, a cross comparison between experimental test and numerical results is shown in Fig. 19 with reference to crack size vs. cycles.

a)

b)

Fig. 16. Von Mises stress scenario (MPa) for the initial (a) and final (b) cracked configuration for model undergoing tension/torsion loads.