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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observation and by the presence of dramatic drops of the loading force. Figure 2 c , d shows the exterior of the device for testing at room temperature and in the climate chamber.

Table 1. The composition of the adhesives based on the ED-20 epoxy diane resin

Curing conditions

Mass ratio resin: curing agent

Composition number

Curing agent

Temperature, °C

Time, h

Polyamidepolyamine (PAPA) Diethylenetriamine (DETA)

Composition 1

10 : 3

25

24

Composition 2

10 : 1

25

24

a

b

c

d

Fig. 2. The pattern of joining the specimens for the Brazilian test (a); experiment scheme (b); the exterior of the test facility for testing at room temperature (c) and with the use of a climate chamber (d)

3. Results

The experiments resulted in data from the loads P max corresponding to the moments of failure for specimens with both adhesive layer materials (Fig. 3 a , b ) at +25 °C and 50 °C and from the visible shear at +50 °C. Note here that, at +50 °C, the adhesive epoxy layer behaves as a viscous material, and there is often no specimen separation into parts, but there is shearing of the layer between the two metal parts (Fig. 4). This phenomenon has yet to be studied in more detail; however, we can suppose that it is associated with the recovery (self-healing) of the adhesive bond destroyed by shear under the combined effect of normal compressive stresses and temperature.