PSI - Issue 2_A

Toshiyuki Meshii et al. / Procedia Structural Integrity 2 (2016) 704–711 Toshiyuki Meshii and Kenichi Ishihara / Structural Integrity Procedia 00 (2016) 000–000

708

5

4. Result of EP-FEA P - V diagrams obtained from EP-FEA are shown in Fig. 5. Solid line in the Fig. 5 shows V calculated from the elastic compliance given in ASTM E1820. Here, P s is the load P corresponding to J s : the predicted minimum J , described later. As shown in Fig. 5, the linear slope of the FEA result was very close to the linear P - V relationship calculated from the equations given in ASTM E1820. It was also noted that P s s for 0.5T SE(B) and 1T CT are close to the deviation point from the linear slope. The relationships between  22 measured at 4  t on the x 1 axis  22d and J FEA calculated from P - V diagram for each load step are shown in Fig. 6. From Fig. 6, it is clear that  22d shows convergence tendency for increasing J FEA . There is not a definite method to determine the convergence value of  22d , i.e.,  22c , hence we applied the method described below, which could be effectively applied to 102 SE(B) specimens manufactured from steel from the decommissioned Shoreham RPV, was chosen. For the actual method for the convergence judgement, first, an i -th  22d defined as  22d i and  22d which obviously converged define as  22d0 . S n is defined as below

1 2

1    i     n

   





2

(1)

n S







i

d

d0





and J at the value of S n / S n +1 is equal to 0.9999 is defined as J s : the predicted minimum fracture toughness. By using this method the values of J s were predicted 15.6 N/mm for 0.5T SE(B) specimen and 11.5 N/mm for 1T CT specimen as shown in Table 1.

0 2.5 5 7.5 10 12.5 15

0 10 20 30 40 50 60 70 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 P [kN] V LL,FEA [mm] FEA Ps ASTM

P [kN]

FEA Ps ASTM

0

0.2

0.4

0.6

0.8

V g,FEA [mm]

(a) 0.5T SE(B) (b) 1TCT Fig. 5 P - V diagram obtained from EP-FEA compared with the linear relationship predicted by the elastic compliance given in ASTM E1820.

5

5

4

4

3

3

σ 22d / σ YS

σ 22d / σ YS

2

2

FEA Js

FEA Js

1

1

15.6

11.5

0

0

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80 90 100

J [N/mm]

J [N/mm]

(a) 0.5T SE(B) (b) 1TCT Fig. 6 Convergence of  22d measured at the specimen mid-plane with increasing J

Table 1 Predicted minimum J c : J s 0.5T SE(B)

1T CT

 22d0 (MPa) J s (N/mm)

1633 15.6

1694 11.5