Crack Paths 2009

100

0.5 )

. m

a

(M P

increasing in notch depth

T RSpecimen

90

s s , o u g h n e F r a c t u r e T

a/w=0.4, 0.5,0.6

Linear Fit

80

70

-130

-125

-120

-115

-110

-105

Tef,c(MPa)

diagram for the case of roman tile specimens and for notch aspect

Figure 5.

cef c T K , , − ρ

ratio

ta/ = 0.4; 0.5; 0.6.

Computing the stress distribution ahead of the notch tip leads to the following

results. The parameter A3 is practically equal to zero until a/t= 0.3. For larger value of

a/t, negative values of A3 increase, and the approximation given by Eq. 7 is no longer

valid. In this case, fracture toughness transferability needs two parameters (T and A3)

for values of a/t >0.3.

All experimental assessment points ( cefcTK,,,ρ) for 4 specimen types are

summarized in Fig. 6.

120

S E N T

)

Pa. m

100

T R

( M

80

C T

arcto ,

Increasing in Notch depth

Failure Material Curve (Exp. Resu ts)

60

Intensit y F

Kρ,c=-0.0694 Tρ,c+77.2873

D C B

40

N o t c h S t r e s s

C T (Exp.), a/w =0.3,0.5

S E N T(Exp.) ,a/w =0.5

20

T R (Exp.), a/w =0.4,0.5,0.6

D C B (Exp.), a/w =0.5

0

-300

-200

-100

0

100

T-stress,

Tρ,c (MPa)

Figure 6.

cef c T K , , − ρ

material master curve for X52pipe steel.

210