Issue 31

C.L. dos Santos et alii, Frattura ed Integrità Strutturale, 31 (2015) 23-37; DOI: 10.3221/IGF-ESIS.31.03 30 Tension/ Compression Shear L R / T LR RT LT Experimental strength values [MPa] 40–98 4.2–9.4 14–16 2.4–4.5 14–16 Adopted yield stresses [MPa] Central Member 80 6.1 12.8 3.6 12.8 Side Member Table 3 : Experimental strength properties and adopted yield values for Pine wood: same constants set used for both wood members [29]. Tension/ Compression Shear L R / T LR RT LT Experimental strength values [MPa] 40–98 4.2–9.4 14–16 2.4–4.5 14–16 Adopted yield stresses [MPa] Central Member 90 5.3 12.8 4.1 14.4 Side Member 85 5.3 11.2 3.2 11.2 Table 4 : Experimental strength properties and adopted yield values for Pine wood: distinct constants used for each wood member [29]. Even though the better description of non-linear response of joint, the elasto-plastic simulations are not able to simulate the initiation and propagation of cracks responsible for sudden load drop observed in the joint testing. Therefore, the plasticity modelling strategy is important to describe the ductile behaviour characterizing the joint, but further enhancements are required to deal with brittle features of the failure modes. Cohesive zone damage models can be used to simulate the brittle cracking occurring in the side members of the T-connection under investigation. In this paper, the use of both plasticity and cohesive zone damage models will be explored including their association. Figure 7 : Strength – relative displacement relation for pure modes (adapted from [19]). The ANSYS ® code [19] includes the possibility for cohesive zone damage modelling which can be used to simulate crack propagation at predefined interfaces that can experience decohesion. Consequently, this approach requires the definition of interfaces which can be modelled using interface elements or contact elements. The implementation of the cohesive damage model was performed, in this study, using contact elements. The cohesive damage law adopted was the linear one as defined by Alfano and Crisfield [30]. The damage law for pure fracture modes (I and II) is shown in Fig. 7, where max,i  represents the onset damage stresses ( max,I  : maximum tensile stresses; max,II  : maximum shear stresses). The

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