PSI - Issue 41

A.E.S. Pinheiro et al. / Procedia Structural Integrity 41 (2022) 60–71 Pinheiro et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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evaluation errors, although these also exist, as shown previously in Section 3.1. On the other hand, the GY model was accurate for L O =40 mm, giving  P m =7.5%, but an error of 24.1% was found for L O =20 mm. The CZM method is the most suitable between all studied techniques, obtaining  P m of 2.4% for L O =20 mm and 4.7% for L O =40 mm (over predictions in both cases). CZM is based on both stress and fracture toughness concepts and, as proved in previous works (Rocha and Campilho 2018), it can be applied for a wide range of adhesive types. 3.2.2. Araldite ® 2015 Fig. 8 reports  P m of the analytical methods and the FEM compared with the experimental results, for L O = 20 mm and L O = 40 mm and the 2015. Table 6 quantifies the obtained data.

50

0

20

30

40

 P m [%]

-50

-100

L O [mm]

N-H

P&C-MPSC P&C-MSSC

FEM-MPSC FEM-MSSC

GY

FEM-CZM

P&C-MPSC+MSSC FEM-MPSC+MSSC

Fig. 8.  P m between the predictions and experimental results for the 2015.

Table 6. Summary of  P m [%] for the 2015 and both L O . L O [mm] 20

40

N-H

-63.7 -86.4 -63.7 -86.4 -49.4 -61.8 -61.8 9.5

-73.9 -90.5 -73.9 -90.5 -63.8 -72.6 -72.6 4.2

P&C-MPSC P&C-MSSC

P&C-MPSC+MSSC

GY

FEM-MPSC FEM-MSSC

FEM-MPSC+MSSC

FEM-CZM

6.1

2.9

Fig. 8 shows yet again that the CZM approach provides the best approximation, and accurate results, while the GY approach provides identical results. In line with the AV138, the other methods cannot accurately capture P m . The detailed analysis of Table 6 depicts under predictions for the continuum mechanics-based methods in the range of 49.4% and 86.4% for L O =20 mm, and 63.8% and 90.5% for L O =40 mm. Identically, the models of Pugno and Carpinteri, and Nayeb-Hashemi et al. models give identical  P m for the MSSC. Additionally, the high  P m are mostly caused by the inadequacy of the evaluated criteria, reinforced by this adhesive’s ductility. Due to these characteristics, the GY model presents a 9.5% offset (under prediction) to the average experimental P m , while for L O =40 mm the difference is only 4.2%. The CZM remains as the most accurate method for this adhesive, with small errors for L O =20 mm (6.1%) and L O =40 mm (2.9%). 3.2.3. SikaForce ® 7752 The final comparison, for the 7752, is presented in Fig. 9, for all prediction methods, together with the quantitative P m and  P m in Table 7.