Registration Number
0221U103891,
0116U004194
, R & D reports
Title
Development of physical principles of local approach to quasi-brittle fracture of structural alloys
popup.stage_title
Head
Kotrechko Sergiy , Доктор фізико-математичних наук
Meshkov Yuriy , Доктор технічних наук
Registration Date
26-02-2021
Organization
Institute of Metal Physics. G.V. Kurdyumov of the National Academy of Sciences of Ukraine
popup.description2
The main factors have been found that govern the level of local stress of brittle fracture initiation, Sf, and which are the reason for stochastic nature of this mechanical characteristic. It is ascertained that Sf dependence on both local plastic strain and temperature values is due to the effect of the crack nuclei number (CN), which are formed in the "process zone" in the vicinity of the stress raiser, on it magnitude. It is shown that both Sf dependence on the value of local plastic strain and essential non-uniformity of distribution of the latter within the "process zone" ahead of stress raisers result in the influence of local plastic strain gradient on Sf. The specific feature of influence of the grain structure inhomogeneity on Sf is established, which is caused by localisation of the region of brittle fracture initiation inside of extremely small volumes in the vicinity of stress raiser. This effect is purely stochastic in nature, and it "mitigates", to some extent, the "negative" influence of the heterogeneity of the grain structure on Sf.
Both the proposed concept of "critical strength level" Rc, at which structural alloy failures in a brittle way under non-uniform force fields due to stress raisers, and the technique for experimental determination of this characteristic are of key application importance. The fundamental significance of the results obtained is that they enabled to ascertain key features of brittle fracture initiation in structural alloys under the strongly non-uniform force fields created by stress raisers, and to show the role of structural state of metal in fracture under above conditions. The applied significance of the results is because they lay theoretical foundations for engineering calculations for resistance to brittle fracture of structural elements under stress concentration and allow formulating requirements for a set of mechanical properties of structural alloys, at which maximum level of structural strength is reached.
Product Description
popup.authors
Zimina Galina P.
Zatsarna Olexandra V.
Kyslyuk Viktor V.
Ovsyannikov Olexsandr V.
Polushkin Yuriy O.
Soroka Kateryna F.
Stetsenko Natalya M.
Shiyan Artur V.
popup.nrat_date
2021-02-26
