Dispersional dependences and peculiarities of energy transfer by flexible waves in a beam lying on a generalized elastic base

Author details
  • Mechanical Engineering Research Institute – Branch of Federal Research Center A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russian Federation; National Research Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russian Federation
  • Mechanical Engineering Research Institute – Branch of Federal Research Center A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russian Federation
  • Mechanical Engineering Research Institute – Branch of Federal Research Center A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russian Federation
  • Mechanical Engineering Research Institute – Branch of Federal Research Center A.V. Gaponov-Grekhov Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod, Russian Federation

Abstract

The dynamics of a Bernoulli – Euler beam lying on an elastic foundation is considered. A generalized model of an elastic foundation is selected, which includes two independent bedding coefficients: the stiffness of the foundation for tensile-compression deformation and for shear deformation. Unlike the classical elastic foundation model (Winkler's model), the generalized model takes into account the distribution capacity of the soil, i.e. its property to settle not only under the loaded area, under the foundation, but also near it. The beam is considered to be infinite. Such idealization is permissible if optimal damping devices are located on its boundaries, that is, the parameters of the boundary fixation are such that the perturbations falling on it will not be reflected. This makes it possible to consider the beam model without taking into account the boundary conditions, and consider vibrations propagating along the beam as traveling bending waves. The influence of a two-constant elastic foundation on the parameters of a bending wave propagating in a beam is studied. It is shown that with an increase in the shear stiffness of the elastic base, waves with the same wavenumber (i.e., waves of the same length) will have a higher frequency, higher phase and group velocities. For the system under consideration, the energy transfer equation is written in divergent form. It is shown that the average rate of energy transfer is equal to the group velocity of the flexural wave. The equality of these velocities serves as an additional factor indicating the internal physical consistency of the model of bending vibrations of a beam lying on a generalized elastic foundation.

Keywords

beamgeneralized elastic foundationflexural wavedispersionenergy transfer.

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Article information

Published
23 June 2023
Issue date
23 June 2023
Issue
No. 2 (2023)
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