Crack Paths 2006

reaching the value r = 0.5, in agreement with results reported for the low-cycle fatigue

region [22]. Figs. 6 and 7 show fractal dimensions DDand DB. There is no significant

0

0.23

0.23

1.5

1.5

0.5

0.5

0.73

0.73

1.4

1.4

1

1

1.3

1.3

1.2

1.2

1.1

1.1

1.0

1.0

0

100 200 300 400

0

100 200 300 400

y[Pm]

x[Pm]

0

Figure 3. The linear roughness RL of profiles parallel (x-axis) and perpendicular (y-axis)

to the local crack propagation direction.

0

0

1.0

1.0

0.23

0.23

0.9

0.5

0.5

0.89

0.73

0.73

0.8

1

1

0.7

0.7

0.6

0.6

0.5

0.5

0.4

0.4

0.3

0.3

0.2

0.2

320 400

0 80 160 240 y[Pm]

0 80 160 240 320 400 x[Pm]

Figure 4. The vertical roughness RV of profiles parallel (x-axis) and perpendicular (y

axis) to the local crack propagation direction.

relation between r and DDor DB . Values of both fractal dimensions strongly differ, DB

is changing in the range of 0.96-1.18 and DD in the range of 1.03-1.08. Therefore, the

method used for determination of the fractal dimension seems to be very important and

should be always presented.