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Li, S. (author), Li, Z. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author)A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine the system responses in terms of vibration...journal article 2017
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Jamshidi, A. (author), Faghih Roohi, S. (author), Hajizadeh, S. (author), Nunez, Alfredo (author), Babuska, R. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author), De Schutter, B.H.K. (author)Railway infrastructure monitoring is a vital task to ensure rail transportation safety. A rail failure could result in not only a considerable impact on train delays and maintenance costs, but also on safety of passengers. In this article, the aim is to assess the risk of a rail failure by analyzing a type of rail surface defect called squats...journal article 2017
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Naeimi, M. (author), Li, Z. (author), Petrov, R.H. (author), Sietsma, J. (author), Dollevoet, R.P.B.J. (author)A new downscale test rig is developed for investigating the contact between the wheel and rail under impact-like loading conditions. This paper presents the development process of the setup, including review and synthesis of the potential experimental techniques, followed by scalability, mechanical and operational analysis of the new setup. The...journal article 2017
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Molodova, M. (author), Oregui Echeverria-Berreyarza, M. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)This paper presents a health condition monitoring system for insulated rail joints (IRJs) based on axle box acceleration (ABA) measurements. The ABA signals from all the wheels of the measuring train are processed to extract those characteristics that better represent the quality of the IRJ. Then, different indicators are used for damage...journal article 2016
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Yang, Z. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)By considering real wheel and track geometry and structures, as well as their coupled interaction, an explicit finite element method is applied to simulate the transition of wheel–rail rolling from single-point tread contact to two-point tread-flange contact. The evolutions of the contact position, stress magnitude and direction, adhesion–slip...journal article 2016
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- Naeimi, M. (author), Li, Z. (author), Dollevoet, R.P.B.J. (author) poster 2016
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Burgelman, N. (author), Li, Z. (author), Dollevoet, R. (author)This paper investigates the effect of the calculation of the longitudinal location of a wheel rail contact point on the wheelset’s motion in a vehicle dynamic simulation. All current vehicle dynamic software programs assume that the contact between wheel and rail takes place in the vertical plane through the wheelset’s rolling axis. However,...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
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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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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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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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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)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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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), 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