Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions

Abstract Functionally graded materials have broad engineering applications including mechanical engineering, electronics, chemistry, and biomedical engineering. One notable advantage of such materials is that their stiffness distribution can be optimized to avoid stress concentration. A novel approa...

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Main Authors: János Lelkes, Bendegúz Dezső Bak, Tamás Kalmár-Nagy
Format: Article
Language:English
Published: Nature Portfolio 2024-02-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-024-52860-4
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author János Lelkes
Bendegúz Dezső Bak
Tamás Kalmár-Nagy
author_facet János Lelkes
Bendegúz Dezső Bak
Tamás Kalmár-Nagy
author_sort János Lelkes
collection DOAJ
description Abstract Functionally graded materials have broad engineering applications including mechanical engineering, electronics, chemistry, and biomedical engineering. One notable advantage of such materials is that their stiffness distribution can be optimized to avoid stress concentration. A novel approach for solving the equations describing the longitudinal vibration of functionally graded rods with viscous and elastic boundary conditions is proposed. The characteristic equation of the system is derived for the solution of the undamped case for the constant stiffness rod. Then, a homotopy method is applied to compute the eigenvalues and mode shapes of graded rods for viscoelastic boundary conditions. The changes of the eigenvalues and mode shapes as function of the damping parameters are investigated. The optimal damping of the system is computed. It is shown that the qualitative behavior depends on the relation between the actual damping and the optimal damping of the system. The energy density distribution of graded rods is also discussed. An energy measure, the mean scaled energy density distribution is introduced to characterize the energy distribution along the rod in the asymptotic time limit. The significance of such a measure is that it reveals how the energy tends to distribute along the rod. It is shown that the energy distribution can be manipulated by changing the damping parameters. Qualitative changes depending on the relation between the actual damping and the optimal damping are highlighted.
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spelling doaj.art-9b2aa930f46e488b9ebfb6589fc306412024-03-05T18:55:40ZengNature PortfolioScientific Reports2045-23222024-02-0114111610.1038/s41598-024-52860-4Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditionsJános Lelkes0Bendegúz Dezső Bak1Tamás Kalmár-Nagy2Department of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and EconomicsDepartment of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and EconomicsDepartment of Fluid Mechanics, Faculty of Mechanical Engineering, Budapest University of Technology and EconomicsAbstract Functionally graded materials have broad engineering applications including mechanical engineering, electronics, chemistry, and biomedical engineering. One notable advantage of such materials is that their stiffness distribution can be optimized to avoid stress concentration. A novel approach for solving the equations describing the longitudinal vibration of functionally graded rods with viscous and elastic boundary conditions is proposed. The characteristic equation of the system is derived for the solution of the undamped case for the constant stiffness rod. Then, a homotopy method is applied to compute the eigenvalues and mode shapes of graded rods for viscoelastic boundary conditions. The changes of the eigenvalues and mode shapes as function of the damping parameters are investigated. The optimal damping of the system is computed. It is shown that the qualitative behavior depends on the relation between the actual damping and the optimal damping of the system. The energy density distribution of graded rods is also discussed. An energy measure, the mean scaled energy density distribution is introduced to characterize the energy distribution along the rod in the asymptotic time limit. The significance of such a measure is that it reveals how the energy tends to distribute along the rod. It is shown that the energy distribution can be manipulated by changing the damping parameters. Qualitative changes depending on the relation between the actual damping and the optimal damping are highlighted.https://doi.org/10.1038/s41598-024-52860-4
spellingShingle János Lelkes
Bendegúz Dezső Bak
Tamás Kalmár-Nagy
Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
Scientific Reports
title Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
title_full Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
title_fullStr Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
title_full_unstemmed Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
title_short Vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
title_sort vibrations and energy distribution in inhomogeneous rods with elastic and viscous boundary conditions
url https://doi.org/10.1038/s41598-024-52860-4
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AT bendeguzdezsobak vibrationsandenergydistributionininhomogeneousrodswithelasticandviscousboundaryconditions
AT tamaskalmarnagy vibrationsandenergydistributionininhomogeneousrodswithelasticandviscousboundaryconditions