o:2936 Oscilacije kompozitnih nanostruktura primenom teorija višeg reda Vibration of composite nanostructures by using higher-order theory : doctoral dissertation sr In this doctoral dissertation, the oscillatory characteristics of nanobeams and nanotubes were analyzed, considering the influence of various parameters on the change in the fundamental circular frequency, critical temperature, and critical fluid flow velocity. The dynamic equations were derived using Hamilton's principle, and analytical and numerical methods were applied to solve them. Special attention was given to structures made of functionally graded materials, which are significant due to their variable mechanical properties. Using Eringen's lower- and higher-order nonlocal theory, as well as strain gradient theory, mathematical models of the studied structures were presented. The change in the fundamental circular frequency with temperature variation was analyzed. Special emphasis was placed on the change in the fundamental circular frequency, critical temperature, and critical fluid flow velocity, with changes in the volume fraction exponent, lower- and higher-order nonlocal parameters, and the length scale parameter, allowing for a deeper understanding of nonlocal effects on the change in the fundamental circular frequency. It was demonstrated that the nonlocal parameter and length scale parameter affect material stiffness differently, and thus have different impacts on the change in the circular frequency of nanostructures. The influence of the geometric coefficient on the change in the circular frequency of a non-uniform nanotube was considered. In the case of the non-uniform nanotube, the fluid flow velocity is expressed as a function of the geometric coefficient, allowing for the analysis of the change in the critical fluid flow velocity through the non-uniform nanotube with the variation of the geometric coefficient. Biografija autora: list. 218-219. Bibliografija: list. 211-217. Datum odbrane: 27.03.2025. Theoretical and applied mechanics 91552100 168161289 91552101 8752 2025-06-23T09:29:55.053Z 45 no 46 Nikola, 1991- Despenić 60401673 2025 63 mentor Goran, 1970- Janevski 14286439 2025 63 član komisije Ivan R., 1979- Pavlović 60353801 2025 63 član komisije Vladimir, 1983- Stojanović 22545255 2025 63 član komisije Damir, 1981- Mađarević 19844967 2025 63 član komisije Aleksandar M., 1988- Tomović 28363367 2025 [14], 222 str. 5205818 http://phaidrani.ni.ac.rs/o:2936 no yes 12 2025-06-23T09:29:55.320Z 70 oscilacije, kružna frekvencija oscilovanja, nano-strukture, nelokalna teorija, nelokalna teorija gradijenta deformacije, nano-grede, nano-cevi, funkcionalno gradijentni materijali, kritična temperatura, kritična brzina strujanja fluida vibration, circular frequency, nanostructures, nonlocal theory, nonlocal strain gradient theory, nanobeams, nanotubes, functionally graded materials, critical temperature, critical fluid velocity 621.3.018:[539.32:539.216(043.3) T 210 1738 18A04 18A0403 2025