PSI - Issue 23

I.O. Sinev et al. / Procedia Structural Integrity 23 (2019) 565–570 I.O. Sinev/ Structural Integrity Procedia 00 (2019) 000 – 000

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Fig.3. The growth curve of the relative area of the damaged surface S * of samples with a notch (1-3), for which stress concentration factor σ α ~ 2.9; sample with stress concentrators (4), σ α ~ 1.1; and a smooth sample (5) depending on the relative deformation in a static loading.

4. Conclusion

Characteristics reflecting the damage accumulation kinetics at different stages of samples fracture with different geometry from steels with different structures are evaluated. It is shown that the kinetics of damage accumulation is determined by the concentration k -criterion, which characterizes the degree of damage and is a function of both deformation at an applied stress and the coefficient of strain hardening of the material. Decrease in the k -criterion at testing steel with higher strain hardening coefficient is a consequence of intense plastic deformation in the early stages of its development and earlier microcrack formation. A decrease in the stress concentration leads to a later formation of surface microcracks in the plastic deformation zone, a quantitative reduction in the fraction of the surface occupied by microcracks and to later start of the defect merging process.

Acknowledgements The study was supported by the Russian Science Foundation (project №19 -19-00674).

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