PSI - Issue 36

Valeriy Kharchenko et al. / Procedia Structural Integrity 36 (2022) 145–152 Valeriy Kharchenko, Eugene Kondryakov, Andriy Kravchuk et al. / Structural Integrity Procedia 00 (2021) 000 – 000

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Fig. 5. Shear stress (a) and fracture plastic strains (b) as a functions of the shear strain rate. Fig. 6 shows the loading diagrams for the specimens of steel 20 cut in different directions. With an increase of the shear zone length for specimens in the longitudinal direction, the duration of the plastic yield zone increases as compared with the specimens in the transverse direction. Thus, the loading diagrams are almost identical for the specimens in different directions. The most significant differences are observed in the specimens with side grooves (Fig. 6(d)), where the duration of the plastic yield zone in the specimens in the longitudinal direction is almost 200 μs more as compared with the specimens in the transverse direction. Fig. 7 shows the loading diagrams for specimens of steel 20 with different chamfer radii R = 0.25 and 0.5 mm. An increase in chamfers radius should reduce the stress concentration, and therefore postpone strain localization. However, this effect is observed only for the specimens with a shear zone length L = 4 mm (Fig.7(c)). Also in these specimens with an increase of chamfer radius, the maximum force increases by 25%. In specimens with a shear zone length L = 1 mm (Fig.7(a)) and 2 mm (Fig.7(b)), the chamfer radius practically does not affect the results.

Fig. 6. Loading diagrams F(t) for the specimens with shear zone length L = 1 mm (a), 2 mm (b), 4 mm (c) and with side grooves (d) from steel 20 cut in longitudinal and transverse directions.