Issue 68

B. Spisák et alii, Frattura ed Integrità Strutturale, 68 (2024) 296-309; DOI: 10.3221/IGF-ESIS.68.20

In the simulations, it was found that the small-size specimens (mini SENB, mini CT) were more sensitive to geometric dimensions and also to the size and shape of the pre-cracking, which were not present in the normal-size specimens.

Figure 11: Fracture surface (left) and force-COD diagram (right) of mini SENB test specimens.

Figure 12: Fracture surface (left) and force-COD diagram (right) of normal SENB test specimens.

I MPLEMENTATION OF THE MODIFIED VCCT METHOD FOR THE SIMULATION OF SENB SPECIMENS

Built-up of 2D finite element model n order to determine the goodness of fit of the developed model, a 2D finite element model of the normal-size SENB specimen was constructed. The VCCT method requires a predefined crack path limited to the element boundaries. The modified finite element model of the standard SENB test specimen is illustrated in Fig. 13. A 2D plane-strain model with linear four-node elements was used in the simulations, while the rollers were assumed to be perfectly rigid. A displacement in the vertical direction was given at the center of each of the two pins, while the displacement in the horizontal direction was fixed. Finally, to ensure that the model could not move in the direction perpendicular to the force, gripping along the plane of symmetry of the specimen was applied at the nodes as illustrated in Fig. 13. The mesh of the mini SENB specimen was generated the same way as it was already introduced in case of the normal SENB and it is shown in Fig. 14. Experience has shown that for small specimens, contact surfaces should be taken into account as they have a large influence on the results obtained. If the loading is applied along a point, the application of the damage model will cause locally large deformations at the point of contact during the calculation, which will damage the material at this location, essentially I

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