PSI - Issue 77

C.F.F. Gomes et al. / Procedia Structural Integrity 77 (2026) 95–102 Gomes et al. / Structural Integrity Procedia 00 (2026) 000–000

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follows a linear trend for all adhesives. The AV138 demonstrates the highest strength, surpassing the 2015 by approximately 15% and outperforming the 7752 by 43%. When L O increases from 20 to 40 mm, the P m trend remains linear for the 2015, whereas the AV138 and 7752 exhibit an inflection point. The peak P m value observed at L O =40 mm was approximately 56,489.2 N for joints using the 2015. At this length, the 2015’s P m was 10% higher than that of the AV138 and 40% above the 7752. Fig. 5 (c) presents the P m findings for DIN 55Si7 steel joints as L O varies for the three adhesives. In this scenario, the results exhibit uniform trends, as the increase in P m remains linear across all cases. Throughout the examined L O range, the AV138 consistently emerges as the most effective adhesive, followed by the 2015 and finally the 7752. 3.4. Failure energy The adhesive joint’s ability to dissipate energy is crucial to ensure a reliable connection. The failure energy ( U ) is the amount of energy dissipation up to failure. U was obtained from the load-displacement ( P- δ ) curves generated in Abaqus ® as the area under each P- δ curve. Fig. 6 displays U for the different adherends, L O , and adhesives.

(a)

(b)

(c)

Fig. 6. U as a function of L O and different adhesives for a) AW 6082-T651 aluminum; b) CFRP, and c) DIN 55Si7 steel adherends.

For the aluminum adherends (Fig. 6 a), the AV138 and 7752 showed similar behavior, with slightly higher U for the AV138. For L O =20 mm, U for AV138 and 2015 were nearly identical (difference of only 1%). At L O =40 mm, the AV138 reached 8.75 J, whereas the 7752 peaked at only 4.49 J, a 49% difference. Notably, the 2015 exhibited a sudden increase in U beyond L O =20 mm, due to adherend plasticization, with a sharp rise to 33.2 J at L O =40 mm. From L O =10 to 40 mm, the AV138 and 7752 recorded increases of 285% and 353%, respectively. For the CFRP tubular joints (Fig. 6 b), among the three adhesives, the 2015 exhibited the highest U , reaching 10.38 J at L O =40 mm, a 47% increase over the AV138. The AV138 showed intermediate U across all L O levels, increasing from 1.55 J at L O =10 mm to 7.07 J at L O =40 mm (a 356% increase). The 7752 displayed lower and more stable values, with U at L O =10 mm corresponding to 48% of the AV138, decreasing to 42% at L O =40 mm. For the steel adherends (Fig. 6 c), the 2015 showed a linear increase with L O : a 100% rise from 10 to 20 mm and a 299% increase from 20 to 40 mm. The AV138 demonstrated a declining growth rate beyond L O =20 mm. The highest U was recorded for the 2015 at L O =40 mm (10.60 J), 73% higher than the AV138 at the same L O . The 7752 consistently showed the lowest U values throughout the study. Overall, the highest U were obtained by aluminum (especially for the plasticized geometry), followed by the steel, and lastly CFRP.