PSI - Issue 33

R.F.P. Resende et al. / Procedia Structural Integrity 33 (2021) 126–137 Resende et al. / Structural Integrity Procedia 00 (2019) 000 – 000

134

9

is only moderate, the P m - L O curve is far from being proportional. Nonetheless, L O is a highly influencing parameter on the joint behavior and overall strength.

30

24

18

P m [kN]

12

6

0

0

12.5

25

37.5

50

L O [mm]

2015 Exp

2015 GY

Fig. 7. Experimental P m and GY prediction vs. L O plot.

Table 4 shows the average P m for the joints bonded with the adhesive Araldite ® 2015 and the respective percentile improvement (  P m ), calculated between consecutive L O , i.e., between a given L O and the one immediately below. Results shown in the table reveal a gradually diminishing  P m for higher P m , and that the highest P m improvement takes place between L O =12.5 and 25 mm (66.8%). Also, between L O =12.5 and 50 mm (limit values tested), the improvement is 152.3%, which is noteworthy and reveals some plasticization ability of this particular adhesive.

Table 4. P m and  P m vs. L O values.

L O [mm]

12.5

25

37.5

50

Average P m [N]

5520.5

9207.7

12116.8

13927.9

-

66.8

31.6

15.0

 P m [%]

In the meshless simulations, only cohesive failures of the adhesive layer were equated, because this was the only observed failure mode in the experiments. Fig. 8 presents peel (a) and shear stresses (b) at the overlap region at P m considering L O =12.5 mm and the EDP yield criterion. For both stress components, the loci of highest stress concentrations are the overlap edges of the adhesive layer, which are thus considered as the failure onset locations taking place when the respective continuum mechanics-based failure criterion is met.

Fig. 8. Normalized peel (a) and shear stresses (b) at P m for L O =12.5 mm and the EDP yield criterion. Left side of the adhesive layer is shown.