Issue 31

C.L. dos Santos et alii, Frattura ed Integrità Strutturale, 31 (2015) 23-37; DOI: 10.3221/IGF-ESIS.31.03 35 of results shown in Fig. 14 reveals a significant improvement in the numerical response, both in terms of ductility and ultimate loads prediction. The simulations assuming elastic-plastic behaviour in all wood members only produced a slight global strength reduction, confirming the little plastic deformation verified in the side members. However, the global response based in this simulation resulted in a better approximation with respect to the experimental data. A local peak was observed in the resulting P-d curves, which is due to the crack initiation. With respect to the crack configuration (see Fig. 15a), the “elastic-plastic with cohesive (1)” approach resulted in a corner crack, similarly to the crack observed with the simulation presented in Fig. 12, but lower opening displacement values were observed (Fig.15b). The “elastic-plastic with cohesive (2)” resulted in an approximately central crack in the side member (see Fig. 16a). In this case, the central nodes were the first ones to reach the rupture strength, starting the process zone at this location (see Fig. 16b). For this case, the complete nodes separation was not verified before unstable crack growth. (a) (b) Figure 15 : Elastic-plastic model in the centre member + elastic and cohesive damage model in the side member: (a) crack opening displacement; (b) stress-displacement relation at the nodes situated in the interface on the hole surface. (a) (b) Figure 16 : Elastic-plastic model for both members + cohesive damage in the side member: (a) crack opening displacement; (b) stress- displacement relation at the nodes situated in the interface on the hole surface. C ONCLUSIONS n experimental and numerical characterization of the mechanical behaviour of a type of doweled wood joints was investigated. In this particular case, the investigation was carried out over a T-joint with a central member loaded along the longitudinal or grain direction and the side member loaded perpendicularly to the grain direction. The tested T-joint exhibited both ductile and brittle failure modes. While the failure at side wood members corresponded to brittle failure modes, the failure at the central member corresponded to ductile failure modes. The application of EC5 rules allowed accurate predictions of the ultimate loads even considering that EC5 rules used for this calculation does not A