Damage evolution around white etching layer during uniaxial loading

Jessop, Casey; Ahlström, Johan; Persson, Christer; Zhang, Yubin

doi:10.1111/ffe.13044

Cited by 7 publications

(7 citation statements)

References 25 publications

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“…The constitutive models presented in Section 3 and the homogenization methods in Section 4 are implemented as user defined subroutines in Abaqus [71]. These are used in thermo-mechanical FE-simulations of a laser heating experiment performed in [58,72]. Experimental results are phase transformations and residual stresses which are compared against simulation results.…”

Section: Thermo-mechanical Simulation Of Laser Pulse Induced White Et...mentioning

confidence: 99%

“…In the laser heating experiment [58,72], martensitic spots, so called white etching layers (WEL), are induced on the surface of pearlitic R260 rail steel by laser heating a small spot above austenitization temperature for 1 second. As the heat-pulse is short, the surrounding material is still close to room temperature, whereby heat diffusion causes rapid cooling and effectively quenches the austenite to form a thin disk of martensite.…”

Section: Laser Heating Experiments and Residual Stress Measurementsmentioning

confidence: 99%

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Homogenization based macroscopic model of phase transformations and cyclic plasticity in pearlitic steel

Andersson

Ahlström

Ekh

et al. 2022

Journal of Thermal Stresses

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In this contribution macroscopic modeling of phase transformations and mechanical behavior of low alloy steels are developed and investigated. Such modeling is of importance in simulations of transient thermo-mechanical processes which can cause phase transformations, examples from the railway industry include train braking induced frictional heating as well as rail grinding and welding operations. We adopt a modeling approach which includes phase transformation kinetics and individual constitutive models for the phases in combination with different homogenization methods. Algorithmic implementations of the isostrain, isostress and selfconsistent homogenization methods are presented and demonstrated in finite element simulations of a laser heating experiment. Stress field results from the different homogenization methods are compared against each other and also against experimental data. The importance of including transformation induced plasticity in the modeling is highlighted, as well as the multi-phase stages of the heating and cooling.

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Section: Thermo-mechanical Simulation Of Laser Pulse Induced White Et...mentioning

confidence: 99%

Section: Laser Heating Experiments and Residual Stress Measurementsmentioning

confidence: 99%

Homogenization based macroscopic model of phase transformations and cyclic plasticity in pearlitic steel

Andersson

Ahlström

Ekh

et al. 2022

Journal of Thermal Stresses

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“…Digital Image Correlation (DIC) is often employed in mechanical testing to calculate the strain fields. With this method, a crack is detected by the strain concentration due to it opening and thus before it can be observed on the unloaded surface [9]. DIC can also be used to find cracks in concrete structures, see Mohan and Poobal[17] for an overview.…”

Section: Introductionmentioning

confidence: 99%

“…DIC uses differences between two images to detect cracks. Jessop et al [9] used the difference between the undamaged and the damaged states. In this paper, however, we consider the difference between two images at different load levels.…”

Section: Introductionmentioning

confidence: 99%

In-field railhead crack detection using digital image correlation

Meyer¹,

Gren²,

Ahlström³

et al. 2021

Preprint

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A significant challenge for railway infrastructure managers is to know when and how to maintain rails. Often, the critical missing information is the current health status, in particular information about rail cracks. Therefore, a new method for rail crack detection is proposed. By utilizing a train-mounted camera system, a single measurement train can monitor a large rail network. The system uses Digital Image Correlation (DIC) to measure the strain fields due to rail bending caused by the measurement train. Promising results are obtained under laboratory conditions. The identified cracks are correlated to the actual crack network, characterized by serial-sectioning microscopy. Furthermore, finite element simulations show the method's high sensitivity to crack depths. Knowing the crack depths enable infrastructure managers to optimize the rail maintenance.

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“…Yuvarlanma temas yorulmasına (RCF), kabuklanma ve soyulma problemlerine demiryolu endüstrisinde yaygın olan rastlanılmaktadır. Tekerlekler ve raylar arasındaki yuvarlanma temasından tekrarlanan yüklerin uygulanması, malzemenin en üst katmanında ciddi plastik deformasyona [24] neden olur, bu da sonunda yorgunluk hasarı bir sınırı aştığında çatlak oluşumuna yol açar [25]. RCF ve aşınma arasında optimum çözümlerin bulunmasında ray teker malzemelerinin mikroyapı kararlılığının sağlanması çatlakların önlenmesi için önemlidir [26][27][28].…”

Section: Introductionunclassified

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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Damage evolution around white etching layer during uniaxial loading

Cited by 7 publications

References 25 publications

Homogenization based macroscopic model of phase transformations and cyclic plasticity in pearlitic steel

Homogenization based macroscopic model of phase transformations and cyclic plasticity in pearlitic steel

In-field railhead crack detection using digital image correlation

Metalografik İncelemelerle Ray Yüzeyindeki Soyulmaların Nedeninin Araştırılması

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