Technical gazette, Vol. 27 No. 6, 2020.
Original scientific paper
https://doi.org/10.17559/TV-20190704100439
Oscillator with Hyperbolically Variable Inertia
Zvonko Rakarić
orcid.org/0000-0001-6223-6519
; University of Novi Sad-Faculty of Technical Sciences, Department of Mechanics, Trg Dositeja Obradovića 6, 21000 Novi Sad-Serbia
Boris Stojić*
orcid.org/0000-0001-8344-1466
; University of Novi Sad-Faculty of Technical Sciences, Department of Mechanization and Design Engineering, Trg Dositeja Obradovića 6, 21000 Novi Sad-Serbia
Abstract
Novel oscillator model is introduced whose kinetic energy is inversely proportional to the generalized coordinate. System is referred to as "Oscillator with Hyperbolically Variable Inertia" (OHVI), since its inertia undergoes hyperbolic growth. Concept of comparison of free OHVI with the behaviour of simple harmonic oscillator (HO) via contraction and deformation of a 3D energy surface is introduced. Analysis of phase orbits and fixed point is performed. Obtaining an exact analytical solution for motion of free OHVI is shown. Main features of the system are demonstrated by numerical experiment performed for kinematically excited OHVI using appropriate mechanism design. It is shown that OHVI has an exact solution in the form of Jacoby elliptic function. Also, phase orbits of OHVI show characteristic oval ("egglike") shape. Motiontime histories and amplitude-frequency (AF) characteristics for forced oscillations were determined. Analysis of solutions for free system indicates possibility of realization of oscillatory system that has very long period i.e. low natural frequency. Comparison of system behaviour with typical nonlinear oscillator with restoring force of hardening type was carried out. Presented analysis shows that such system can be successfully applied for attenuation of low frequency vibrations or their detection.
Keywords
energy surface contraction; harmonic excitation of support; nonlinear oscillator; singular inertial coefficient; super-attenuation
Hrčak ID:
248219
URI
Publication date:
19.12.2020.
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