Fatigue Crack Paths 2003

4

4

x 10

x 10

7

2.2

2

c e V

6.5

A x i a l f o r c e P

1.8

S h e a r f o r

6

1.6

5.5

1.4

5

1.2

0

0.2

0.4

0.6

0

0.2

0.4

0.6

Dimensionless crack depth

Dimensionless crack depth

x 104

-2

Bgendin m o m e n t M

t

-1.5

Cracked Section

q( t )

-1

H

-0.5

B

q(t)

0

a

0

0.2

0.4

0.6

Dimensionless crack depth

Cracked frame

Figure 2. Variation of axial force, bending momentand shear force, at the cracked

section, as a function of the dimensionless crack depth.

40

230

K

= K

2 = K I M K

10

66

IP

eff

eff

10

0 0.4 0.6 01234 Dimensionless crack depth 0.2

0

0.2 Dimensionless crack depth 0.4

0.6

34

1.52

0

0.2

0.4

0.6

I M I P K + K e f f = K

2 + K ( K I P ) I M + 3 K I I V e q = K

6

2

1

01

0

0.2

0.4

0.6

0.5

0

Dimensionless crack depth

Dimensionless crack depth

Figure 3. Fatigue cycles calculation according to various criteria of loading

combinations.