Fatigue Crack Paths 2003

Figure 1. Damageinitiation and failure curves in (on, 1'”) plane: elliptic condition for

6” 2 lt'nltangod and the Coulombcondition for 6,, < lt'nltangod.

The non-local failure function can nowbe expressed as follows [16]

d0 d0

- 1 Rf‘, = maxR6 = max 2J-J-Radéd’g’2

(16)

(.H’XO)

(n’xfl) d o

0 0

and the failure condition is

Rf‘, —1 = 0.

(17)

For the case of cyclic fatigue condition, the threshold surface of damage initiation

was assumed in a similar form to Eq. (14), namely

maxRc,0 G",Tl — 1 = 0

(18)

(nlxo)

G O To

and the non-local condition of damageinitiation is

d o d o

l G T R — 1 = i R " , l d — 1 = 0

l9

fo'o

6,02

O ' o [ 6 o1 : 0 } ég12

( )

0 0