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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7

Table 6. The results of tensile test results for ebonite specimens with V-notches. Specimen type Test

Curve number on the graph

Maximum breaking force F , N

With V-notch not filled

a b

1 1 2 3 4 5 6

3867 3604 7846 9111 3967 4145 4129

with material

With V-notch filled

a

with epoxy

With V-notch filled with P1000 material

b

F

, kN

b

а

F

, kN

10

5

3

4

4

7.5

1

1 4 6 5

2

6 5

3

4

2 3

5

2

1

1

2.5

1

0

0

w

w

, mm

, mm

00.511.522.53

0 1 2 3 4 5 6 7

Fig. 3. Graph of the tensile force F versus stroke of the traverse w : curve 1 is for the specimen with unfilled V-shaped notch; a) curves 2 , 3 are for the V-shaped notch filled with epoxy resin; b) curves 4 , 5 , 6 are for the V-shaped notch filled with P1000 material.

4. Conclusion

The tensile tests were carried out with the aim to evaluate the e ff ectiveness of reducing the stress concentration near the V-shaped notch by filling it with a certain material, whose Poisson’s ratio is close to 0.5 and the elastic modulus is much lower than that of the base material. The elastic moduli of ebonite, epoxy resin and P1000 material were determined experimentally. The elastic moduli of epoxy resin and ebonite are of the same order, and the elastic modulus of P1000 material is three orders of magnitude lower than that of ebonite. In the course of tensile tests, it was found that filling a V-shaped notch with a material the elastic modulus of which is of the order of the ebonite elastic modulus (epoxy resin), causes a significant increase in the ultimate load (over 50%) compared to the ultimate load for a specimen with unfilled V-shaped notch. When the notch was filled with a material whose elastic modulus is three orders of magnitude lower than that of the base material, the increase in the ultimate load was 15%. An extended series of experiments is planned for other ratios of V-shaped notch depths and for fillers with the elastic moduli two and three orders of magnitude lower than that of the base material.

Acknowledgements

The work was funded by the Russian Foundation for Basic Research and the Perm Territory (project number 20-41-596007).