Issue34

V. Oborin et alii, Frattura ed Integrità Strutturale, 34 (2015) 422-426; DOI: 10.3221/IGF-ESIS.34.47

crack growth and can be used for the identification of phenomenological parameters (power index) providing self-similar law for the crack path.

L pz , mkm 20.6 10.9 21.4

Sample number

Elongation (mm)

Striker velocity (m/s)

number l sc

H

, mkm

 , MPa

  , cycles Zone

1

0.89

28.4

130

7.33·10 +6

2

1.4

0.57

0.5 0.8

0.63 0.62

2 3

2

1.77

40.3

120

7.82·10 +8

2

1.0

18.2

0.60

3

1.27

32.1

120

5.72·10 +7

2

1.0

14.2

0.46

4

2.21

40.3

105

5.83·10 +6

and l sc

Table 1 : The values of the Hurst exponent H and scales L pz

at various levels of fatigue longevity.

A CKNOWLEDGEMENT

T

his study was supported by the Russian Science Foundation, project № 14-19-01173.

R EFERENCES [1] Peters, J. O., Influence of foreign object damage on crack initiation and early crack growth during high-cycle fatigue of [2] Ti-6Al-4V, Eng. Fract. Mech., 67 (2000) 193-207. [3] Paris, P., Lados, D., Tad, H., Reflections on identifying the real  K effective in the threshold region and beyond, Eng. [4] Fract. Mech., 75 (2008) 299–3052. [5] Barenblatt, G.I., Scaling phenomena in fatigue and fracture, Int. J. of Fracture, 138 (2006) 19–35. [6] Ritchie, R.O., Incomplete self-similarity and fatigue-crack growth, Int. J. of Fracture, 132 (2005) 197–203. [7] Bouchaud, E., Scaling properties of cracks, J. Phys. Condens. Matter, 9 (1997) 4319– 4344. [8] Froustey, C., Naimark, O., Bannikov, M., Oborin, V., Microstructure scaling properties and fatigue resistance of [9] prestrained aluminium alloys (part 1: Al-Cu alloy), European Journal of Mechanics A/Solids, 29 (2010) 1008–1014 .

426