Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure

In this paper, a new type of one-degree-of-freedom pure nonlinear oscillator with a time variable degree of nonlinearity is introduced. Namely, the degree of the nonlinearity in the restitution force is not a constant but a ‘slow time’ variable function. The mathematical model is a second-order nonl...

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Main Authors: L. Cveticanin, M. Zukovic
Format: Article
Language:English
Published: MDPI AG 2023-09-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/11/18/3958
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author L. Cveticanin
M. Zukovic
author_facet L. Cveticanin
M. Zukovic
author_sort L. Cveticanin
collection DOAJ
description In this paper, a new type of one-degree-of-freedom pure nonlinear oscillator with a time variable degree of nonlinearity is introduced. Namely, the degree of the nonlinearity in the restitution force is not a constant but a ‘slow time’ variable function. The mathematical model is a second-order nonlinear differential equation with time-variable parameters. An approximate solving procedure based on the method of time-variable amplitude, frequency and phase is developed. It is found that the vibration properties depend on initial conditions and the degree of time-variable function. The theoretical results are tested on almost linear, cubic and high-degree nonlinear oscillators. According to theoretical considerations, the process of aging in fiber-reinforced polymer composite structure is investigated. It is found that the amplitude and the frequency of vibration of the reinforced polymer structure decrease over time. The result is in good agreement with already published experimental data. The additional conclusion of the research is that the oscillator model suggested in the paper is suitable for the prediction of mechanic properties of the polymer structure in aging and also in similar destructive processes.
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spelling doaj.art-957853d8e68d4335b8b2d23f192a6ff62023-11-19T11:49:57ZengMDPI AGMathematics2227-73902023-09-011118395810.3390/math11183958Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite StructureL. Cveticanin0M. Zukovic1Faculty of Technical Sciences, University of Novi Sad, 21000 Novi Sad, SerbiaFaculty of Technical Sciences, University of Novi Sad, 21000 Novi Sad, SerbiaIn this paper, a new type of one-degree-of-freedom pure nonlinear oscillator with a time variable degree of nonlinearity is introduced. Namely, the degree of the nonlinearity in the restitution force is not a constant but a ‘slow time’ variable function. The mathematical model is a second-order nonlinear differential equation with time-variable parameters. An approximate solving procedure based on the method of time-variable amplitude, frequency and phase is developed. It is found that the vibration properties depend on initial conditions and the degree of time-variable function. The theoretical results are tested on almost linear, cubic and high-degree nonlinear oscillators. According to theoretical considerations, the process of aging in fiber-reinforced polymer composite structure is investigated. It is found that the amplitude and the frequency of vibration of the reinforced polymer structure decrease over time. The result is in good agreement with already published experimental data. The additional conclusion of the research is that the oscillator model suggested in the paper is suitable for the prediction of mechanic properties of the polymer structure in aging and also in similar destructive processes.https://www.mdpi.com/2227-7390/11/18/3958aging in fiber-reinforced polymer compositeanalytic solving procedureAteb functionnonlinear oscillatortime-variable nonlinearitymarine industry
spellingShingle L. Cveticanin
M. Zukovic
Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure
Mathematics
aging in fiber-reinforced polymer composite
analytic solving procedure
Ateb function
nonlinear oscillator
time-variable nonlinearity
marine industry
title Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure
title_full Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure
title_fullStr Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure
title_full_unstemmed Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure
title_short Oscillator with Time-Variable Degree of Nonlinearity: Theory and Application in Aging of Polymer Composite Structure
title_sort oscillator with time variable degree of nonlinearity theory and application in aging of polymer composite structure
topic aging in fiber-reinforced polymer composite
analytic solving procedure
Ateb function
nonlinear oscillator
time-variable nonlinearity
marine industry
url https://www.mdpi.com/2227-7390/11/18/3958
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AT mzukovic oscillatorwithtimevariabledegreeofnonlinearitytheoryandapplicationinagingofpolymercompositestructure