PSI - Issue 50

Andrey Yu. Fedorov et al. / Procedia Structural Integrity 50 (2023) 83–90 A.Yu. Fedorov et al. / Structural Integrity Procedia 00 (2023) 000–000

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The result of the test is the tearing force required to break the adhesion bond. Tensile strength is calculated by the formula:

F A

(2)

,

σ =

where F is the maximum breaking force, A is the specimen area. All tests were carried out on the SHIMADZU universal testing machine of AGS-X series. To determine the tearing strength for each material, 3 specimens were tested. The loading rate was 1 mm / min. The results of measurement were processed in accordance with regional standard GOST R 8.736–2011. The arithmetic mean of measured values is

n i = 1

1 n

¯ x =

x i ,

(3)

where x i is the i -th measurement result, n is the number of measurements. Mean-square deviation is calculated by the formula: ¯ S = n i = 1 ( x i − ¯ x ) 2 n − 1 .

(4)

The results of tests are shown in Table 2.

Table 2. Results of the adhesive strength tests. Material No.

Specimen area

Breaking force

Tensile strength

Average tensile

A ,mm 2

F , N

σ ,MPa

strength σ

a ,MPa

1 2 3 1 2 3 1 2 3 1 2 3

361.3 361.9 361.1 364.1 363.4 382.6 362.6 362.8 361.5 361.3 361.9 361.1

171.8 245.6 297.7

0.5 0.7 0.8 0.5 0.1 0.3

Rubber adhesive

0.7 ± 0.2

180.8

Silicone sealant

37.1 98.6

0.3 ± 0.2

5488.9 5297.1 6321.8

15.1 14.6 17.5

Epoxy resin

15.7 ± 1.5

171.8 245.6 297.7

0.5 0.7 0.8

P1000 material

0.7 ± 0.2

According to the results of tests, it can be concluded that epoxy resin when separating from ebonite demonstrates the highest adhesive strength, and among the materials with a Poisson’s ratio close to 0.5, such is the P1000 material. These materials will be used in further experiments.

3.3. Determination of elastic moduli of materials

A tensile test was used to determine the elastic modulus of materials. The modulus of elasticity was determined in accordance with the regional standard GOST 9550–81 using the following formula:

( F 2 − F 1 ) · l 0 A 0 · ( ∆ l 2 − ∆ l 1 ) ,

(5)

E =

where F 2 is the load corresponding to the upper limit of relative elongation, F 1 is the load corresponding to the lower limit of relative elongation, l 0 is the base of the extensometer, A 0 is the initial cross-sectional area of the specimen,