Crack Paths 2006

Horizontal stress-strain

4.5

4

3.5

3

p)a

2.500

4.000

4.500

012.50120.000

0.500

1.000

1.500

2.000

3.000

3.500

(M

F R A C T U RPEOINT

s t r e s s

strain gauge

DIC

strain %

a) Horizontal stress-strain response in the fracture zone above the hole-notch

Horizontal stress-strain

4.5

4

3.5

3

Pa )

2.5

e s s ( M

F R A C T U RPEOINT

s t r

2

strain gauge

1.5

1

0.50.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500 DIC

4.000

strain (%)

b) Horizontal stress-strain response in the fracture zone below the hole-notch

Figure 2: Comparison between strain gauge and DICmeasurements

Figure 3 shows the measured horizontal strain mapfrom crack initiation to major

crack opening. Comparing the DIC strain map at microcrak initiation with the

correspondent image (Fig. 3a), it’s evident that fracture point always occurs before the