Crack Paths 2006

The following remarks can be made:

x Each curve related to point A (Fig. 3a) increases by increasing the parameter [ .

For a given value of the relative crack depth, the value of

*XM,I K increases by

decreasing the crack aspect ratio

D;

x The curves related to point C (Fig. 3b) either increase or decrease by increasing

the parameter [. For a given value of the relative crack depth, the value of

*XM,I K increases by increasing the crack aspect ratio D.

16.0 12.0

6.0 2.0 4.0

] ] /=1h.0

D-1.2 -0.086

] ] / h = 0 . 1

D

C

0.0

A

-0.2

-0.4

8.0

-0.6

-0.42

0.0

-0.8

4.0

0.0

-1.2 -1.0

(b)

(a)

0.0

-2.0

0.0 0.2 0.4 0.6 0.8 RELATIVEC R A C DKEPTH, [ a / D

0.0 0.2 0.4 0.6 0.8 RELATIVEC R A C DKEPTH,

[ a / D

*XM,I K against relative crack depth [ , for different values

Figure 3. Dimensionless SIF

D: (a) point A; (b) point C.

of the crack aspect ratio

In Figure 4, some numerical results (SIF

*XM,I K at point A) are compared with those

experimentally determined by Radebe [14]. The agreement is quite satisfactory, even if

the Radebe’s SIF values are slightly lower than the numerical results. The scatter could

be due to the following reasons:

D and [ experimentally measured by Radebe are

x The values of the parameters

related to crack fronts which are not exactly elliptical arcs;

x In some of the experimental cases, the crack shape is not exactly symmetric with

respect to the Y axis (Fig. 1b).

As can be observed in Fig. 4, both numerical and experimental SIFs are well fitted by

second order polynomials (dashed lines).