PSI - Issue 2_A

Shaowei Hu et al. / Procedia Structural Integrity 2 (2016) 2818–2832 S. Hu et al./ Structural Integrity Procedia 00 (2016) 000–000

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The subcritical crack propagation length

c a  represents the length of crack propagation from initial crack to

unstable failure, the greater the c a  , it means the greater the distance of crack propagation, and the better tenacity of specimen. As can be seen from Fig.10, in addition to the specimen which initial seam height ratio is 0.2, the subcritical crack propagation length c a  of other groups are all have a downswing with the initial seam height ratio increase. This suggest that except the specimen with a relatively small initial seam height ratio, the smaller the initial seam height ratio of non-standard wedge splitting tensile specimen, the greater the subcritical crack propagation length, the crack propagation more fully and the better tenacity of specimen. Moreover, analysis of the specimen which initial seam height ratio is 0.2, we can know that for the specimen with a relatively small initial seam height ratio, its fracture characteristics is affected by the maximum-tensile-stress failure, and has a certain shear failure role. Compared with other groups, the role of splitting tensile failure is relatively small, so the crack propagation of specimen is inadequate and the subcritical crack propagation length is smaller.

30

. P ini

25

. P un

20

P /kN

15

10

5

0,1

0,2

0,3

0,4

0,5

a 0 / H

Fig.9 Curves of P ini and P un along with a 0 / H

250

200

.

150

a c

.

∆ a c

100

mm

50

0

0,1

0,2

0,3

0,4

0,5

a 0 / H

Fig.10 Curves of c a and

c a  along with a 0 / H