Issue 48

C. E. Cruz Gonzalez et alii, Frattura ed Integrità Strutturale, 48 (2019) 530-544; DOI: 10.3221/IGF-ESIS.48.51 538 adhesive (Fig. 8b) and MP55420 adhesive test specimens (Fig. 8c) reached a 100 % cohesive failure. It means that for latters, the crack runned thorugh the adhesive bond-line. On the other hand, the DC-80 test specimens showed that the crack runned through the adhesive bond-line and it´s interface. As can be noted from Fig. 8a), the adhesive spew fillets remained upon the surface, suggesting that it was the crack origin. Since, the edge of the lap joint was the higher stress zone, a fractographic analisis with scanning electron microscope was conducted. Overlap (mm) Whöler model Log N f = A  S a + B Basquin model Log N f = A  Log S a + B A B Std Dev A B Std Dev 12.7 DC80 -1.0716 7.4349 0.976 -7.019 7.3927 0.1513 50.0 -0.3534 7.6551 2.926 -5.887 10.366 0.1511 12.7 Betamate 120 -0.5743 6.7718 0.9377 -3.695 6.7221 0.1527 50.0 -0.1802 7.129 3.443 -3.942 9.1617 0.1526 12.7 MP55420 -1.3595 7.7687 0.6968 -5.905 6.6818 0.1523 50.0 -0.4350 7.7293 1.5101 -4.253 7.9596 0.1512 Table 3: Coefficient of Whöler and Basquin models for adhesive joins in fatigue (S [kN]). Figure 5: a) and b) 6061-T6 DC-80 adhesive bonded joint with 12.7 mm overlap length Wholer and Basquin graphs, c) and d) Wholer and Basquin graphs for 6061-T6 DC-80 adhesive bonded joint with 50.0 mm.