PSI - Issue 72

L.A.S. Maia et al. / Procedia Structural Integrity 72 (2025) 43–51

48

30

60

DP8005+AV138 RTV106+AV138 DP8005+XNR6852

12.5 mm 37.5 mm 25 mm 50 mm

48.22

25

50

20

40

36.94

15

27.28

30

26.05

P m [kN]

P [kN]

20.66

18.84

10

17.41

20

14.51

14.28

10.84

5

8.48

10

6.95

0

0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

12.5

25

37.5

50

a)

b)

L O [mm]

δ [mm]

Fig. 4. Numerical P -  curves for the DP8005+AV138 combination (a) and P m for the various adhesive combinations (b) as a function of L O . The P -  curves for the DP8005+AV138 combination (Fig. 4 (a)) show a P m increase with L O , in parallel to an increase in the failure displacement ( δ max ). The DSLJ configuration with the best performance is DP8005+XNR6852E-2, followed by DP8005+AV138, which shows slightly better results than RTV106+AV138. From Fig. 4 (b) it is possible to observe an increase of P m with the increase of L O and this is valid for all the adhesive combinations. Table 5 lists E f for the DSLJ and different L O , estimated by the area under the P -  curve. The calculation was carried out in the R ® software together with RStudio ® for graphical visualization and to enable easier data import. There is an increase in E f with L O , due to the greater amount of adhesive used to absorb the impact, which in turn results in a longer impact and displacement time until failure. In the DP8005+AV138 combination with L O =50 mm, the elastic limit of the adherends was exceeded, resulting in a plastic deformation of 0.051%. In the RTV106+AV138 combination, the RTV106 adhesive is highly flexible and in the DP8005+AV138 combination the DP8005 adhesive is not only flexible but also has higher E f . This statement can be corroborated since the RTV106+AV138 combination shows lower E f than the RTV106+AV138 combination. For the RTV106+AV138 combination, the elasticity limits were not exceeded, and therefore no plastic deformation took place. The DP8005+XNR6852E-2 combination is the one with the highest E f , which is to be expected as the XNR6852E-2 adhesive was developed for impact applications and, consequently, presents the highest toughness. Additionally, for this combination of adhesives, there was plastic deformation of the adherends for L O =37 .5 and 50 mm (0.056% and 0.2%, respectively). Due to the low plasticity values, plastic deformation does not influence P m for the DP8005+XNR6852E-2 combination as was also the case of the DP8005+AV138.

Table 5. Influence of L O on E f .

Adhesive combination

Difference [%]

L O [mm]

E f [J]

12.5

2.09 4.47 7.62 0.98 1.79 3.13 4.89 4.35 8.99 11.09 16.19 26.00

-

25

+113.9 +264.6 +430.6 +82.7 +219.4 +398.9 +106.7 +272.2 +497.7 - -

DP8005+AV138

37.5

50

12.5

25

RTV106+AV138

37.5

50

12.5

25

DP8005+XNR6852E-2

37.5

50

3.3. Overlap length effect

The t P influence on P m is presented. The considered t P were 1, 2, 3 e 4 mm, while L O was kept constant (25 mm). The strategy adopted for analyzing the stress distribution in the previous section was also followed for this study. Fig. 5 presents  xy (a) and  y stress distributions (b) for the DP8005+AV138 combination as a function of t P .