Issue 49

S.A.G. Pereira et alii, Frattura ed Integrità Strutturale, 49(2019) 412-428; DOI: 10.3221/IGF-ESIS.49.40 425 Four-point bending - crack path with 2D elements Fig. 14 shows a graphic comparison between the crack path obtain in laboratory and the one obtained with the software. The pre-crack of specimens 4, 7 and 9 had a slight initial inclination, since the process of making the pre-crack is manual, which implies that it is not totally controllable. So, two simulations were carried out, one in which the pre-crack was as obtained in the process of making the pre-crack (red curve), and another with the nominal geometry (green curve). Three-point bending - crack path with 2D elements At this point the comparison between the crack paths in the case of 3-point and mixed-mode bending is presented. In the case of pure mode I, the propagation is not presented since it takes place at 0 degrees, as expected. Figure 15 : a) Specimen 3PB-9, b) Specimen 3PB-10. For both test specimens there is a good agreement between the simulated and experimental paths, although it was not possible to obtain a longer propagation using XFEM models, Fig. 15. Four-point bending - crack path with 3D elements Fig. 16 shows a comparison between crack paths for specimen 4. Both the 2D and the 3D simulations show a good agreement with the experimental path, for the early stages of propagation, although the 3D seems to culminate in a more consistent prediction of the crack path. Figure 16 : Specimen 4, 2D and 3D.