Fatigue Crack Paths 2003

+n5(a:'_) fr P,,,,3(e'—,o)w3(o)dr(e)

: tiger) fr WM, e'—,o)p,(o)dr(o)

(3)

one’) + are”) i. Petite’: awitndrta

were”) 74, Peert'nnwtradrra

~ new) /F Wetter. epitome) +

(4)

are”) f, were’: optimum) +

are”) [9 Wrso3(93'_i95)q3($)dQ($)

and

tart’) + new) inert’: mantra -

"180-"'0]€Ua6~7(93/_»$)tw($)dm$)

(5)

where pa 2 Maflnb’, pg 2 Tgflnb’ and to, I Nafgnfi. The kernels Pafl,(a:’,a:) ,

W.,/3dr’, as) are obtained from the linear combination of the derivatives of Pij(1:,,1:)

and Wig-(ofa) respectively; Ua5.,(a:’,a:),

Ta5.,(a:’,a:)

are linear combination of the

derivatives of U00,(a:’, as) and T0O,(a:’,a:).

To satisfy the additional continuity requirements for the traction boundaryin

tegral equations onto 1“ discontinuous elements have been used

Stress Intensity Factor

In plate theory five stress intensity factors have to be computed accordingly to

the five crack modes (see Fig.3). The extrapolation of crack surface displacements

technique (see

is used to evaluate the SIF. The relationship between the crack

opening displacements and the SIF can be expressed as:

A m [ 5f? 0

0

0

0

]

KI.

Au,

0

if? 0

0

0

K51

4101 I 0

0

4%? 0

0

Ki’

(6)

4% 0

0

0

“T? 0

Ki;

A w e 0

0

0

0

24(1+o)\/Z

K 3

5 E h