Issue 41

M.F. Funari et alii, Frattura ed Integrità Strutturale, 41 (2017) 524-535; DOI: 10.3221/IGF-ESIS.41.63 533 In Fig. 9 the interfacial tractions across the two cohesive interfaces, i.e. Adhesive-Steel ( as ) and Adhesive-Frp ( af ), for different time steps of the delamination process, are reported. At first, in Fig.9(a), the distribution of the interfacial traction forces is presented for the status A of the zoom reported in Fig. 7a and 8a, which basically corresponds to the peak load of the quasi-static branch. It represents the stage just before the initiation of the debonding process, in which all layers are still bonded together. However, at the point A, the non-linear response of the cohesive adhesive-steel interface shows how the interfacial normal and tangential tractions tend to zero. This reflects the initiation of the dynamic debonding failure. In Figs. 9b-d, the representation of the evolution of the dynamic debonding, in terms of interfacial traction, has been reported for different lengths of the debondend region. In particular, the results are referred to the points B, C, D of the zoom reported in Figs. 7a-8a, in which the debonding lengths of adhesive-steel region are equal to 25, 50 and 75mm, respectively. Figure 7 : Comparisons in terms of loading curve for different thickness of the FRP strip (a) ; Comparisons in terms of time histories of the debonding front speed for different thickness of the FRP strip (b) . Figure 8 : Comparisons in terms of loading curve for different thicknesses of the adhesive layer (a) ; Comparisons in terms of time histories of the debonding front speed for different thickness of the adhesive layer (b) . It is worth noting that the af does not debond but it is able to provide interfacial tractions between the mathematical layers (Fig. 9). Finally, the consistency of the proposed model has been investigated also in terms of computational efforts. In