PSI - Issue 31

G. Kastratović et al. / Procedia Structural Integrity 31 (2021) 127 – 133 G. Kastratovi ć et al. / Structural Integrity Procedia 00 (2019) 000–000

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(a) (b) Fig. 4. (a) Stress-strain diagrams for tested specimens (tensile test); (b) Tensile test specimens’ fracture.

Results of the three-point bending tests are presented in Tab. 6 and Fig 5(a).

Table 6. Three-point bending test results (Elastic modulus E F , force P, Normal bending stress σ s , deflection δ and strain ε). Test bars, n=5 Efc [GPa] P [daN] σ s [MPa] δ [mm] ε [%]

KC-4 KC-5 KC-6 KC-7 KC-8

9.32 11.10 11.02 11.42 10.58 10.69 0.82 7.65

32.82 34.78 34.59 35.58 32.30 34.01 1.39 4.09

252.46 267.54 266.08 273.69 248.46 261.65 10.70 4.09

15.40 14.01 14.16 14.03 13.79 14.28 0.64 4.49

3.27 2.96 2.99 2.96 2.91 3.02 0.14 4.79

MV SD CV [%]

(a) (b) Fig. 5. (a) Stress-strain diagrams for tested specimens (three-point bending); (b) Bending test specimens’ fracture.

Fig. 5(a) shows that specimen KC-4 “produced” considerable deviation in strain values compared to other specimens (similarly to K-2 specimen in tensile experiment). By omitting the values obtained with K-4, the following mean values are obtained: E F = 11.03 GPa, R m = 263.94 MPa, and ε = 2.95%. The fractured specimens can be seen in Fig. 5(b). Fractures occurred in the middle of the specimens, as expected.