PSI - Issue 41

A.R.F. Soares et al. / Procedia Structural Integrity 41 (2022) 48–59 Soares et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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equipment was fixed in the UTM, where the positioning of each specimen in the respective test configuration consists of fixing the specimen to the MMB equipment by calibrated pins with a safety lock. The specimens should remain horizontally levelled (Fig. 9) until the beginning of each test, regardless of the test configuration.

Fig. 9. Representative photograph of the specimen levelling process.

Each test is started through the computer, connected to the universal testing machine, and simultaneously the chronometer is activated to help the photographic register during the test. In case of an early total rupture of the adhesive, the test is considered terminated. Fig. 10 shows the final appearance of a test specimen after the test conclusion.

Fig. 10. Representative photograph of a completed trial.

4.4. Data analysis

Fig. 11 shows two examples of the failure modes that occurred in the tests performed, showing a cohesive failure in the adhesive in both cases since both failure surfaces are covered by adhesive. This failure mode occurs when the bond between the adhesive and the adherends’ is stronger than the internal adhesive’s strength, which constitutes the recommended mode of failure.

Fig. 11. Photograph representative of the failure mode that occurred in the tests.