Fatigue Crack Paths 2003

a

P

E

A D

O

B

'E

1

r

1

T

1

C

b

Y

A

B

r

0

O

X

C

D

Figure2. Crack growth trajectory approximation, (a) single-edge crack geometry,

(b) central notched biaxially loaded crack geometry

along B C oriented at the angle

T . In this case 1

The next step plotting A C = ¦ ¦ 2 2 y x and

1r

tan

I

¦ ¦ x y 1 ,

(5)

1

1 1 1 1 1 1 sin ,cos J J r y r x

where

(6)

1 0 1 1 1 , x x x ¦ ' T E J , 1 0 y y y ¦

and so on. For the central crack geometry subjected to biaxial loads (Fig.2,b) the crack

path can be determined using the formulae Eq.1.