Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load

Critical velocities are investigated for an infinite Timoshenko beam resting on a Winkler-type elastic foundation subjected to a harmonic moving load. The determination of critical velocities ultimately comes down to discrimination of the existence of multiple real roots of an algebraic equation wit...

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Main Authors: Bin Zhen, Wei Luo, Jian Xu
Format: Article
Language:English
Published: Wiley 2014-01-01
Series:Shock and Vibration
Online Access:http://dx.doi.org/10.1155/2014/848536
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author Bin Zhen
Wei Luo
Jian Xu
author_facet Bin Zhen
Wei Luo
Jian Xu
author_sort Bin Zhen
collection DOAJ
description Critical velocities are investigated for an infinite Timoshenko beam resting on a Winkler-type elastic foundation subjected to a harmonic moving load. The determination of critical velocities ultimately comes down to discrimination of the existence of multiple real roots of an algebraic equation with real coefficients of the 4th degree, which can be solved by employing Descartes sign method and complete discrimination system for polynomials. Numerical calculations for the European high-speed rail show that there are at most four critical velocities for an infinite Timoshenko beam, which is very different from those gained by others. Furthermore, the shear wave velocity must be the critical velocity, but the longitudinal wave velocity is not possible under certain conditions. Further numerical simulations indicate that all critical velocities are limited to be less than the longitudinal wave velocity no matter how large the foundation stiffness is or how high the loading frequency is. Additionally, our study suggests that the maximum value of one group velocity of waves in Timoshenko beam should be one “dangerous” velocity for the moving load in launching process, which has never been referred to in previous work.
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spelling doaj-art-97e4bc9374e64686b1eda023cfbf53d22025-08-20T02:10:07ZengWileyShock and Vibration1070-96221875-92032014-01-01201410.1155/2014/848536848536Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving LoadBin Zhen0Wei Luo1Jian Xu2School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, ChinaCollege of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, ChinaSchool of Aerospace Engineering and Mechanics, Tongji University, Shanghai 200092, ChinaCritical velocities are investigated for an infinite Timoshenko beam resting on a Winkler-type elastic foundation subjected to a harmonic moving load. The determination of critical velocities ultimately comes down to discrimination of the existence of multiple real roots of an algebraic equation with real coefficients of the 4th degree, which can be solved by employing Descartes sign method and complete discrimination system for polynomials. Numerical calculations for the European high-speed rail show that there are at most four critical velocities for an infinite Timoshenko beam, which is very different from those gained by others. Furthermore, the shear wave velocity must be the critical velocity, but the longitudinal wave velocity is not possible under certain conditions. Further numerical simulations indicate that all critical velocities are limited to be less than the longitudinal wave velocity no matter how large the foundation stiffness is or how high the loading frequency is. Additionally, our study suggests that the maximum value of one group velocity of waves in Timoshenko beam should be one “dangerous” velocity for the moving load in launching process, which has never been referred to in previous work.http://dx.doi.org/10.1155/2014/848536
spellingShingle Bin Zhen
Wei Luo
Jian Xu
Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load
Shock and Vibration
title Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load
title_full Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load
title_fullStr Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load
title_full_unstemmed Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load
title_short Analysis of Critical Velocities for an Infinite Timoshenko Beam Resting on an Elastic Foundation Subjected to a Harmonic Moving Load
title_sort analysis of critical velocities for an infinite timoshenko beam resting on an elastic foundation subjected to a harmonic moving load
url http://dx.doi.org/10.1155/2014/848536
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AT jianxu analysisofcriticalvelocitiesforaninfinitetimoshenkobeamrestingonanelasticfoundationsubjectedtoaharmonicmovingload