Detection of Damage in Rail Head by using Safe Method

Teidj, Sara; Driouach, Abdellah; Khamlichi, Abdellatif

doi:10.14738/tmlai.54.3325

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Let us consider an elastic waveguide with waves propagating along the direction x 3 with the wave number k and frequency u. The cross-section of the waveguide is in the plane ðO; x 1 ; x 2 Þ The equation of motion is written [8]:…”

Section: Propagation Of Guided Elastic Waves In a Railmentioning

confidence: 99%

Mathematical modeling on the propagation of guided elastic waves

Teidj¹

2020

International Review of Applied Sciences and Engineering

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The main cause of train derailment is related to transverse defects that arise in the railhead. These consist typically of opened or internal flaws that develop generally in a plane that is orthogonal to the rail direction. Most of the actual inspection techniques of rails relay on eddy currents, electromagnetic induction, and ultrasounds. Ultrasounds based testing is performed according to the excitation-echo procedure [1]. It is conducted conventionally by using a contact excitation probe that rolls on the railhead or by a contact-less system using a laser as excitation and air-coupled acoustic sensors for wave reception. The ratio of false predictions either positive or negative is yet too high due to the low accuracy of the actual devices. The inspection rate is also late; new numerical method has been developed in this context: The semi-analytical finite element method SAFE. This method has been applied in the case of anisotropic media [2], composite plates [3] and media in contact with fluids [4]. This method has been used successfully for several structures and especially in the case of beams of any cross-section such as rails that are the subject of this work and we were interested in wave propagation in waveguides of any arbitrary cross-section in the case of beams or rails.

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Section: Propagation Of Guided Elastic Waves In a Railmentioning

confidence: 99%

Mathematical modeling on the propagation of guided elastic waves

Teidj¹

2020

International Review of Applied Sciences and Engineering

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Metalografik İncelemelerle Ray Yüzeyindeki Soyulmaların Nedeninin Araştırılması

Uğur¹,

Davut²,

Bacaci³

2020

European Journal of Science and Technology

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Railways are increasingly used for passenger and freight transportation worldwide. This increased traffic causes more quick and frequent formation of defects on train tracks. In this study, rail sets used in Bursa province, that had been reported to experience rapid wear and scaling, were examined. The rail sets were manufactured from R260 steel and the problem occurs more frequently on curves. For comparison, rail sets from straight lines were also examined. After visual examination, specimens from gauge and field corner regions were taken and prepared for metallographic examination. The microstructure of the specimens was examined under optical and scanning electron (SEM) microscopes. Moreover, Vickers micro-hardness tests were also performed. Micro-chemical analyses were performed using an energy dispersive X-ray spectroscopy (EDS) system attached to the SEM. For macro-chemical analysis, an optical emission spectrometer (OES) was used. The cross section of the rails was macro-etched for macro-examination. The results show that the microstructure of the rails is composed of 100% pearlite. On the other hand, the pearlitic structure degenerates at parts of the rail which are under loading. Due to severe plastic deformation, the pearlitic structure changes into a fiber-like structure composed of sub-micron ferrite and cementite. Those degenerated pearlitic regions have higher hardness due to strain hardening and cause crack initiation. Those cracks can then grow into inner sections of the rail easily due to the presence of non-metallic inclusions in the microstructure. Iron oxide particles were found in the vicinity of cracks; which indicate that cracks do not grow rapidly, they rather grow in time according to usage and atmospheric conditions. The examinations revealed that the wear, cracks and scaling problems were formed due to rolling contact fatigue (RCF). The presence of inclusions enhanced the growth of RCF-cracks and later cause "shelling". In order to delay or prevent this problem, using higher strength rails at critical locations such as curves, controlling and rating the non-metallic inclusions in accordance with the international standards, checking the lubrication and maintenance strategies of rails and wheels, working on optimization of rail-wheel contact characteristics are recommended. The last recommendation involves developing a sustainable model by identifying technical limitations of the line and cruise depending on vehicle characteristics.

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Detection of Damage in Rail Head by using Safe Method

Cited by 2 publications

References 5 publications

Mathematical modeling on the propagation of guided elastic waves

Mathematical modeling on the propagation of guided elastic waves

Metalografik İncelemelerle Ray Yüzeyindeki Soyulmaların Nedeninin Araştırılması

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