Issue 48

C. E. Cruz Gonzalez et alii, Frattura ed Integrità Strutturale, 48 (2019) 530-544; DOI: 10.3221/IGF-ESIS.48.51 534 The surface energy was 48.32 and 53.02 J.m -2 for cleaned steel and anodized aluminum , respectively. After the substrate surface finishing was completed, the adheren t s were bonded and cured considering 12.7 and 50.0 mm overlap length. Bond-line thickness is one of the important factors in adhesive joint because a thin bond-line is preferred over a thick one. The above due to the stress concentration at the corners of the joint is lesser in a thinner bond-line. In order to control bond-line thickness, glass beads (diameter of 0.180 mm) were added by manufacturer for MP55420 and Betamate 120 adhesives. On the contrary, metallic shims (0.180 mm in thickness) were positioned along the test coupon for the DC-80 adhesive. After curing, test coupons were sawed and then machined until the specimen final dimensions were reached (25.4×101.6×adherend thickness in mm) and thicknesses of adhesive layer were measured (by means of an optical comparator) and the average was determined (0.180 mm). Five specimens were prepared in order to fulfill aforementioned standard. Tab. 1 summarizes the configurations in this experiment. Overlap length (mm) Adhesive Adherend 1 Thickness (mm) Adherend 2 Thickness (mm) 12.70 DC-80 AA6061 T6, 6.4 mm Dual phase steel, 2.90 mm Betamate 120 MP55420 50.00 DC-80 Betamate 120 MP55420 Table 1: Configurations used in this experiment. Fig. 2 shows coupon and specimen used for this study. As can be noted, Fig. 2 depicts the original plate configuration (before bonding and after cleaning procedure), in such the testing coupon after curing where test specimens where outlined before cutting. Finally, the Fig. 2 red inset depicts the standard test specimen for single lap shear according to ASTM D1002 [18]. Figure 2: Test coupon adhesive bonding fixture and ASTM D1002 [18] test specimen.