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Wave propagation in railway tracks at high frequencies

Wave propagation in railway tracks at high frequencies
Wave propagation in railway tracks at high frequencies

In order to understand long range wave propagation in railway tracks, it is re- quired to identify how far vibrations can travel along a rail. To answer this question, the main wave types that propagate along rails and their attenuation characteristics are determined as a function of frequency. In this work the effective wave types and their decay rates are investigated for frequencies up to 80 kHz. Two numerical methods, the conventional finite element method and the wave- number finite element method, are utilized to predict the predominant wave types and their decay rates for a rail on a continuous foundation. From these simulations, the waves that are measurable on various regions of the rail cross-section are identi- fied. Also, to improve the simulated results, the frequency dependent damping loss factor of a rail has been measured up to 80 kHz on several short rail samples. The predominant wave types predicted have been validated by experiments performed on a short test track. The measured group velocities present very good agreement with the predicted ones so that it is identified which wave types predominantly prop- agate in various regions of the rail cross-section. Another measurement has been performed on an operational track to validate the simulated decay rates. In this experiment, train-induced rail vibrations were acquired for several trains running over a long section of rail. The measured decay rates are presented for comparison with the output of the simulations and good agreement is. found between them. A feasibility study is carried out of wave reflection and transmission due to cracks in rails. These are estimated for various cracks of progressively larger size by means of numerical simulation. Through this simulation, the relative efficiency of various incident and reflected waves for detecting defects in rails is determined.

University of Southampton
Ryue, Jungsoo
06336056-2b9b-4620-9c4a-f2cbd602ab3e
Ryue, Jungsoo
06336056-2b9b-4620-9c4a-f2cbd602ab3e

Ryue, Jungsoo (2008) Wave propagation in railway tracks at high frequencies. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

In order to understand long range wave propagation in railway tracks, it is re- quired to identify how far vibrations can travel along a rail. To answer this question, the main wave types that propagate along rails and their attenuation characteristics are determined as a function of frequency. In this work the effective wave types and their decay rates are investigated for frequencies up to 80 kHz. Two numerical methods, the conventional finite element method and the wave- number finite element method, are utilized to predict the predominant wave types and their decay rates for a rail on a continuous foundation. From these simulations, the waves that are measurable on various regions of the rail cross-section are identi- fied. Also, to improve the simulated results, the frequency dependent damping loss factor of a rail has been measured up to 80 kHz on several short rail samples. The predominant wave types predicted have been validated by experiments performed on a short test track. The measured group velocities present very good agreement with the predicted ones so that it is identified which wave types predominantly prop- agate in various regions of the rail cross-section. Another measurement has been performed on an operational track to validate the simulated decay rates. In this experiment, train-induced rail vibrations were acquired for several trains running over a long section of rail. The measured decay rates are presented for comparison with the output of the simulations and good agreement is. found between them. A feasibility study is carried out of wave reflection and transmission due to cracks in rails. These are estimated for various cracks of progressively larger size by means of numerical simulation. Through this simulation, the relative efficiency of various incident and reflected waves for detecting defects in rails is determined.

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Published date: 2008

Identifiers

Local EPrints ID: 466395
URI: http://eprints.soton.ac.uk/id/eprint/466395
PURE UUID: 2a8b66d1-f4eb-482c-88ff-87d3f79c7e97

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Date deposited: 05 Jul 2022 05:14
Last modified: 16 Mar 2024 20:40

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Author: Jungsoo Ryue

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