Issue 49

M. Hadj Miloud et alii, Frattura ed Integrità Strutturale, 49 (2019) 630-642; DOI: 10.3221/IGF-ESIS.49.57 639 Figure 8 : Global comparison between experimental data and numerical results. Figure 9 : FE model and geometry of the experimental CT25 specimen. D UCTILE TEAR ON CT SPECIMEN Experiment he tear tests were carried out on an Instron-type hydraulic test machine at room temperature on CT specimens pre- cracked (Fig. 9). The test was conducted to reach a ratio a/W ≈0.5, with ‘ a’ the crack length and ‘ W’ the specimen width. The CT specimen was pre-cracked by fatigue. After pre-cracking, except one, the specimens were grooved laterally with a depth of 2.5 mm on each side to guide the crack propagation and to have the most rectilinear crack path possible [30]. The tests were carried out under the following experimental conditions: • Notch opening speed 0.1 mm/min, • Opening interval of the notch 0.1 mm. During the test, the loading and the opening of the crack lips were recorded simultaneously. The displacement was measured using a blade extensometer located between the two fixed blades at the front of the specimen [7]. Numerical model The tear test, described previously, is modeled using the FE software Abaqus/Explicit. In order to compare the numerical results with the experimental data of Ref. [7], the same geometry of the specimen (Fig. 9) is modeled in Cartesian coordinates. 0% 5% 10% 15% 20% 25% 30% 35% 0 1 2 3 4 5 6 7 Cost function Number of Iterations Cost function of GTN Ident with Predifined σ(ε) Cost function of GTN Ident with Voce Cost function of GTN Ident with Ludwik T Symmetry condition / Y Free area (pre-crack) Affined mesh in crack propagation zone Loading (W) a