PSI - Issue 2_A

1980 6

Alberto Sapora et al. / Procedia Structural Integrity 2 (2016) 1975–1982 Sapora et al. / Structural Integrity Procedia 00 (2016) 000–000

1.2

1

0.8

K If / K Ic , K IIf / K Ic

0.6

0.4

mode I mode II

0.2

τ +

τ

−

0

−1 −0.8 −0.6 −0.4 −0.2

0 0.2 0.4 0.6 0.8 1

Dimensionless T−stress, τ

Fig. 4. T -stress effects on FFM failure loads for pure mode I and mode II loading conditions.

0

τ +

τ −

−10

−20

−30

−40

θ c (deg)

−50

−60

−70

mode I mode II

−80

−90

−1 −0.8 −0.6 −0.4 −0.2

0 0.2 0.4 0.6 0.8 1

Dimensionless T−stress, τ

Fig. 5. T -stress effects on FFM critical kinking angle for pure mode I and mode II loading conditions.

In order to improve FFM predictions (Sapora and Mantic, 2016), from an equivalent point of view, one could consider the following modified ERR in the energy balance:

G = G I + γ G II .

(8)