PSI - Issue 2_A

P. Yasniy et al. / Procedia Structural Integrity 2 (2016) 3280–3287 Author name / Structural Integrity Procedia 00 (2016) 000–000

3285

6

a

3x10 5 4x10 5 5x10 5

N 0,25 N 0,5

2x10 5

10 5

-0,5 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 3x10 4 4x10 4 5x10 4 6x10 4 7x10 4 8x10 4 9x10 4

N , cycles

i

b

N 0,25 /N f N 0,5 /N f

0,9

0,8

N 1 /N f N 3 /N f

0,7

0,6

N/N f

0,5

0,4

0,3

-0,5 0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5

i

147    MPa): (a) fatigue crack initiation of a length of 0.25 mm, 0.5 mm;

Fig. 3. Durability of aluminum plates (

(b) relative period of fatigue crack initiation of a length of 0.25 mm, 0.5 mm, 1 mm and 3 mm

It was analyzed that local stresses

min yy  and

max yy  are already stabilized at the second half cycle of load.

Therefore stress state was analyzed being limited only by the second half cycle of load. In Fig. 4 the distribution of local stress range near the holes with diameter of 8 mm (Fig. 4а) and 10 mm (Fig. 4b) for the cold expansion 1%, 2%, 3% and without cold expansion for the second half cycle was shown. The