PSI - Issue 2_B

R.Citarella et al. / Procedia Structural Integrity 2 (2016) 2706–2717 Author name / Structural Integrity Procedia 00 (2016) 000–000

2714

9

a)

b)

Fig. 13. Numerical initial and final crack shapes vs. beach marks highlighting the experimental crack fronts: (a) circular notch; (b) semielliptical notch.

K I values along crack front for different propagation steps are plotted in Fig. 14: Fig. 14a shows K I values calculated for the configuration related to the circular notch, whereas, Fig. 14b shows K I values related to the semielliptical notch (the crack propagates under pure mode I conditions so that K II and K III values are negligibles). In final, crack sizes calculated with DBEM analyses are plotted in Fig. 15 and compared with those obtained by the experimental tests.

300 350 400 450 500 550 600 650 700

200 220 240 260 280 300 320 340 360 380 400

KI [MPa*mm^0.5]

KI [MPa*mm^0.5]

Step 0 Step 8

Step 4 Step 12

Step 0

Step 3

Step 7

0

0.5

1

1.5

2

0

0.5

1

a)

b)

Crack front [‐]

Position

Figure 14. K I values along crack front at several steps during propagation for tensile load: (a) circular notch; (b) semielliptical notch.