Crack Paths 2006

Figure 6 and 7 show the experimental and prediction crack initiation angle and critical

load.

80

70

60

(de g )

50

aengl

40

I n i t i a t i o n

30

0.5 CrackInitiation angle-experiments )Predicted crack initiation angle. ( 1 1.5 2

120 0

2.5

3

3.5

4

4.5

A 2 / A1

0

Figure 6: Crack initiation angle for the M A C O Rspecimens experimental and prediction

7000

6000

123000 4000 5 0

0.5

2.5

3.5

1

1.5

2

3

4

4.5

[N]

Load-Experiment

L o a d

Predictedload

A2/A1

Figure 7: Critical load experimental and prediction for the M A C O sRpecimens

S U M M A AR NYDC O N C L U S I O N S

The failure criterion of Leguillon at reentrant corners in brittle elastic materials was

extended herein to mixed mode loading. The validity of the proposed failure criterion is

examined by comparing predicted failure loads and crack initiation angles for a range of

mode mixity ratios to these measured in experiments. Two sources of experimental

results were considered for validating the failure criterion: a) Experiments performed on

P M M Aspecimens with different V-notch opening angles and 4PB V-notched Macor

specimens.