PSI - Issue 47

Zoltán Bézi et al. / Procedia Structural Integrity 47 (2023) 646–653 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

652

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previously presented model. Since the real situation differs from the plane strain, 86% of the cross-section of the specimen was used in the calculation, which in this case was 21.7 mm.

Fig. 8. 2D FEM model created for VCCT showing the finer mesh on the highlighted detail.

As with GTN model, a model of the unloads has been constructed and evaluated against the standard, and J integral values have been extracted directly from the simulation. The evaluation was carried out for both initial crack sizes, Figure 9 compares the J integral values from the test for the 23.8 mm crack with the results from the VCCT model based on the standard. The results for the other crack size, for which the results extracted directly from the VCCT model in accordance with the standard calculations, are shown in Fig. 9.b. a b

Fig. 9. VCCT model results (a) VCCT results comparison with test (b) J integral from standard calculation and directly from simulation.

The fracture toughness results obtained so far are summarized in Table 2.

Table 2. Fracture toughness results from different models and test. Data from Data analyses

Fracture Toughness [kJ/m 2 ]

Difference [%]

Test

ASTM E1820-20 ASTM E1820-20 ASTM E1820-20

338.18 325.77 345.73 346.32

-

Simulation with GTN parameters

-3.7 +2.2

Simulation with VCCT Simulation with VCCT

Simulation

+2.4 Uncertainty in J ic is less than 4 %.