Issue 46

M. El Habiri et alii, Frattura ed Integrità Strutturale, 46 (2018) 34-44; DOI: 10.3221/IGF-ESIS.46.04

(a)

(b)

(c)

Figure 6: Distribution of Von-Mises equivalent stress around the hole.

0

-100

-200

-300

-400

Tangential residuals stresses (MPa)

-500

0

1

2

3

4

5

6

7

Distance from hole (mm)

Figure 7: Tangential residual stress throughout thickness of plate

I NFLUENCE O F C OMPRESSIVE R ESIDUAL S TRESS ON F ATIGUE C RACK I NITIATION

I

n order to evaluate the fatigue crack initiation life, local strain approach was applied by several researchers cited above. In fatigue case and at the notch tip, local strains are obtained by using the Neuber’s rule or Glinka [43] expressed in following form:

) 2

(





K

.

.   



f

a

(2)

=

4

E

2

where “  a ” is the applied stress and “  ” and “  ” are the resulting local stress and strain values corrected for the notch effect. The fatigue notch factor, (K f ), is essentially the K t value corrected to account for the notch sensitivity for the given material [44]. It is determined as follows:

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