PSI - Issue 65

Sergey Smirnov et al. / Procedia Structural Integrity 65 (2024) 263–268 Sergey Smirnov, Irina Veretennikova, Dmitry Vichuzhanin / Structural Integrity Procedia 00 (2024) 000–000

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4

а

b

Fig. 3. The load P max as dependent on the angle α for compositions 1 ( a ) and 2 ( b )

Fig. 4. Shear of the adhesive layer in testing at +50 °C

It follows from the loading diagrams shown in Fig. 5 a – e that all the obtained strain dependences of the loading force have a qualitatively identical behavior, this being indicative of the fact that the strain is mainly affected by the epoxy matrix material. From the very beginning, the loading diagrams have an irregular oscillating behavior. In Stukhlyak et. al. (2014) it is attributed to the appearance of local strains and successive microcracking in the adhesive layer. However, the oscillation frequency is different depending on the test temperature; namely, it is higher in testing at 50 °C than at positive temperatures. The value of the failure load P max differently depends on the test temperature and the tilt angle α for adhesive compositions 1 and 2. For the specimens with the adhesive layer of composition 1, the values of P max are about identical and depend on the value of the angle α only slightly at all the studied temperatures. For the specimens with with the adhesive layer of composition 2, at positive temperatures and α = 0, the achieved values of P max are half as high as at 50 °C. The load P max increases with the angle α, but the increase is much more rapid at 50 °C. The strength of the adhesive joints differs as follows: at positive test temperatures, the failure load is higher for all the angles α, but at 50 °C, the values are higher for composition 2, and they increase with the angle α.