PSI - Issue 50

N. Mullahmetov Maksim et al. / Procedia Structural Integrity 50 (2023) 200–205 Mullahmetov Maksim N. et al./ Structural Integrity Procedia 00 (2022) 000 – 000

202

3

where σ y( ρ ) - is the stress function as a function of the distance from the top of the sample notch, σ 0 - is the ultimate strength of the strip sample, L - is the critical distance. The critical distance can be defined:

2

   

   

σ K

1 π

th

,

L



0

where K th - threshold value of stress intensity. For the experiments, STEF structural fiberglass samples were prepared. The geometry of the samples used is shown in figure 2.

Fig. 2. Geometry and dimensions of the samples used . Uniaxial tensile tests were carried out on a universal electromechanical testing system Instron 5882 (100 кН ) (fig. 3). For all tested specimens, the loading rate was set to 2 mm/min.

Fig. 3. (a) Instron 5882