PSI - Issue 13

Igor Golovnev et al. / Procedia Structural Integrity 13 (2018) 1632–1637 Author name / Structural Integrity Procedia 00 (2018) 000–000

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Additional analysis of the dependence of the maximal dispersion change on time and atomic plane number shows that the number of the plane with the maximal dispersion differs from the number of the rightmost plane (it is 100 in this system) and varies with time (Fig. 6). For clarity, Fig. 7 demonstrates the dependence of the maximal dispersion of the atomic plane in the nano-sized rod on time, as the nano-sized rod is under the cyclic extension и , and the dispersion of the right atomic plane (the 100 th ) in the same physical system at the same time instants. Evident that the maximal dispersion exceeds almost twice the dispersion of the right plane, though their growth in time is quite proportional.

Fig.6 Number of the atomic plane with the maximal dispersion on the external loading time

Fig.7 Dispersion of the atomic plane in the cut-off structure versus time after the external loading beginning. The black line is the maximal dispersion of the atomic plane, the grey line is the rightmost plane dispersion

Thus, both dispersion values can be used as the criterion of the fracture beginning on the atomic level. Then let us consider the planes with the maximal dispersion instead of the utmost planes. For the more fundamental physical analysis, it is interesting to compare the maximal dispersions of the atomic planes at certain instants of the external loading cutoff and the dispersions of the same atomic planes after the cooling of the disturbed nano-sized rod. These data give the specified physical criterion of the defect occurrence beginning in the nanostructure on the atomic level (crystal structure failure beginning). The increasing dispersion of the atomic plane with the maximal dispersion in the cooled disturbed nano-sized rod is a sign, as compared to the dispersion of the same plane at the instant of the external loading cutoff (Fig. 8).

Fig.8 Maximal dispersion of the atomic plane in the nano-sized rod versus time after the cyclic extension beginning: the black line – the instan t of the external loading cutoff, the grey line – in the disturbed structure after the external loading cutoff and nano-sized rod cooling.