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Oregui, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author), Moraal, J. (author)In railway tracks, short wave rail surface defects give rise to high wheel-rail dynamic forces and noise. Having a better insight into short wave defect occurrence could lead to development of adapted maintenance methods or track design to delay or avoid defect, so that the high short wave defect related maintenance costs may be reduced. As part...conference paper 2011
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Oregui, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)Rail joints have a shorter service life than most other railway track components. The discontinuity between rail ends turns the rail joint into a weak spot, and consequently, into a track component demanding more frequent maintenance measures, which result in high maintenance costs. Moreover, difficulties are often found when assessing the...conference paper 2012
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Yang, Z. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)This paper presents a full finite element (FE) interaction model of wheel-track to study the wheel-rail impact noise caused by squat. The wheel, the rail and some other track components are modeled with finite elements in three dimensions, where necessary and appropriate. Realistic contact geometry, including geometric irregularity (squat) in...conference paper 2013
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Yang, Z. (author), Rahimi, S. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)This paper presents a full finite element (FE) model of wheel-track interaction to study the wheel-rail impact noise excited by an insulated joint (IJ). The integration is performed in the time domain with an explicit central difference scheme. The vibratory behaviour of the track and wheel model are respectively validated with hammer test and...conference paper 2014
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Molodova, M. (author), Li, Z. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author)This paper presents an automatic method for detecting railway surface defects called “squats” using axle box acceleration (ABA) measurements on trains. The method is based on a series of research results from our group in the field of railway engineering that includes numerical simulations, the design of the ABA prototype, real-life...journal article 2014
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Qian, Z. (author), Deng, X. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)The rolling contact of elastic bodies (upper body and lower body) can be analyzed with the Hertz theory and the Kalker’s model. It is generally believed that the width of the contact area should be much smaller than the characteristic size of each elastic body, to ensure that the half-space assumption is valid. However the definition of “much...conference paper 2014
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Naeimi, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)A new small–scale test rig developed for rolling contact fatigue (RCF) investigations in wheel–rail material. This paper presents the scaling strategy of the rig based on dimensional analysis and mechanical modelling. The new experimental rig is indeed a spinning frame structure with multiple wheel components over a fixed rail-track ring,...conference paper 2014
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Naeimi, M. (author), Li, Z. (author), Petrov, R.H. (author), Dollevoet, R.P.B.J. (author), Sietsma, J. (author), Wu, J. (author)The substantial similarity of fatigue mechanism in a new test rig for rolling contact fatigue (RCF) has been investigated. A new reduced-scale test rig is designed to perform controlled RCF tests in wheel-rail materials. The fatigue mechanism of the rig is evaluated in this study using a combined finite element-fatigue prediction approach. The...conference paper 2014
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Yang, Z. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)The precise mechanism which activates squeal, especially flange squeal has not been fully explained. The complex non-Hertzian contact and the broad-band high frequency feature bring great challenges to the modelling work of flange squeal. In this paper, an explicit integration finite element method is presented to simulate the dynamic curving...conference paper 2015
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Naeimi, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)A numerical model of wheel-track system is developed for nucleation of squat-type fatigue cracks in rail material. The model is used for estimating the angles of squat cracks in three dimensions. Contact mechanics and multi-axial fatigue analysis are combined to study the crack initiation mechanism in rails. Nonlinear material properties, actual...conference paper 2015
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Oregui, M. (author), Molodova, M. (author), Nunez, A. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)This paper presents a feasibility study to determine if the health condition of Insulated Rail Joints (IRJs) can be assessed by examining their dynamic response to impact excitation. First, a reference dynamic behavior is defined in the frequency domain of 50-1200 Hz based on field hammer test measurements performed on a IRJ baseline (i.e., a...journal article 2015
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Naeimi, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author), Wu, J. (author), Petrov, R.H. (author), Sietsma, J. (author)The coupled mechanical–thermal behaviour of wheel and rail materials under rolling contact is studied to determine the temperature rise due to the frictional heat. The wheel–rail frictional rolling contact problem is solved using the three–dimensional finite element (FE) method. The FE model considers the wheel tread–rail top contact with...conference paper 2015
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Jamshidi, A. (author), Faghih Roohi, S. (author), Nunez, Alfredo (author), Babuska, R. (author), De Schutter, B.H.K. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)This paper develops a defect-based risk analysis methodology for estimating rail failure risk. The methodology relies on an evolution model addressing the severity level of rail surface defect, called squat. The risk of rail failure is assessed by analyzing squat failure probability using a probabilistic analysis of the squat cracks. For this...conference paper 2016
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Li, Z. (author), Zhao, X. (author), Dollevoet, R.P.B.J. (author)A methodology for the determination of a critical size of surface defects, above which RCF can initiate, has been developed and demonstrated with its application to the passive type of squats under typical Dutch railway loading conditions. Such a methodology is based on stress evaluation of transient rolling contact at the defects, for which...journal article 2016
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Burgelman, N.D.M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)When a train runs through a turnout or a sharp curve, high lateral forces occur between the wheels and rails. These lateral forces increase when the couplers between the wagons are loaded in compression, i.e., a rear locomotive pushing a train or a front locomotive braking a train. This study quantifies these effects for a train that begins...journal article 2016
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Oregui Echeverria-Berreyarza, M. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)This paper presents a sensitivity analysis of railpad parameters on vertical railway track dynamics, incorporating the nonlinear behavior of the fastening (i.e., downward forces compress the railpad whereas upward forces are resisted by the clamps). For this purpose, solid railpads, rail-railpad contact and preloaded springs are defined in a...journal article 2016
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Shen, C. (author), Wei, Z. (author), Burgelman, N.D.M. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)Though numerical models based on multi-body dynamics (MBD) are often used to simulate the vehicle-track interaction at crossing impact, their relative capabilities and accuracy were not discussed. This paper aims to investigate the influence of wheelset flexibility on the result of crossing impact simulation in the frequency range 0–500 Hz. Two...conference paper 2016
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Oregui Echeverria-Berreyarza, M. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author), Carroll, R (author), Dollevoet, R.P.B.J. (author)Rail joints are a weak component in railway tracks because of the large impact and wheel-rail contact forces. Every train passage contributes to the deterioration of rail joints, causing visible (e.g. battered rails) and invisible (e.g. loose bolts) damages. The invisible damage cannot be detected by the commonly performed visual inspection,...journal article 2016
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- Jamshidi, A. (author), Nunez, Alfredo (author), Molodova, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author) conference paper 2016
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Wu, J. (author), Petrov, R.H. (author), Naeimi, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author), Sietsma, J. (author)White etching layer (WEL) is a frequently observed microstructural phenomenon in rail surface, formed during dynamic wheel/rail contact. It is considered as one of the main initiators for rolling contact fatigue cracks. There are several hypotheses for the formation mechanism of WEL. However, due to the complicated wheel/rail contact...journal article 2016