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Railway sleeper vibration measurement by train-borne laser Doppler vibrometer and its speed-dependent characteristics

Zeng, Y. (author), Nunez, Alfredo (author), Li, Z. (author)

A train-borne laser Doppler vibrometer (LDV) directly measures the dynamic response of railway track components from a moving train, which has the potential to complement existing train-borne technologies for railway track monitoring. This paper proposes a holistic methodology to characterize train-borne LDV measurements by combining computer...

journal article 2024

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Vertical dynamic measurements of a railway transition zone: a case study in Sweden

Unsiwilai, S. (author), Shen, C. (author), Zeng, Y. (author), Wang, L. (author), Nunez, Alfredo (author), Li, Z. (author)

This study presents a measuring framework for railway transition zones using a case study on the Swedish line between Boden and Murjek. The final goal is to better understand the vertical dynamics of transition zones using hammer tests, falling weight measurements, and axle box acceleration (ABA) measurements. Frequency response functions ...

journal article 2024

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Measuring transfer functions of track structures in a test rig with laser Doppler vibrometer and accelerometers on a moving vehicle

Zeng, Y. (author), Nunez, Alfredo (author), Li, Z. (author)

A transfer function (TF) is an effective representation of the load-response relationship of railway track structures. To fill the gap in measuring track structure TFs over a wide frequency range from a moving vehicle, we develop a TF measurement system and the associated TF estimation methodology. Accelerometers are utilized to estimate the...

journal article 2024

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Multiple-axle box acceleration measurements at railway transition zones

Unsiwilai, S. (author), Wang, L. (author), Nunez, Alfredo (author), Li, Z. (author)

This paper presents a methodology for monitoring transition zones using responses of multiple-axle box acceleration (multi-ABA) measurements. The time–frequency characteristics of the vertical ABA signals from four wheelsets are analyzed. The major contributions are as follows. (1) We propose four key performance indicators (KPIs) to quantify...

journal article 2023

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An Interpretable Method for Operational Modal Analysis in Time-Frequency Representation and Its Applications to Railway Sleepers

Zeng, Y. (author), Shen, C. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), Zhang, Weihua (author), Li, Z. (author)

Operational modal analysis (OMA) enables the identification of modal characteristics under operational loads and conditions. Traditional frequency-domain methods cannot directly capture modal changes over time, while existing time-frequency representations are not sufficiently interpretable due to spurious modes and implicit parameter design....

journal article 2023

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Rail wear rate on the Belgian railway network: a big-data analysis

Vernaillen, T. (author), Wang, L. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

This paper presents a big data-based analysis of the rail wear of the whole Belgian railway network measured in 2012 and 2019. Wear rates are reported, discussed, and quantitatively formulated as functions of critical factors in terms of curve radius, annual tonnage (rail age), high rail in curves, an average from both rails in straight...

journal article 2023

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Speckle noise reduction for structural vibration measurement with laser Doppler vibrometer on moving platform

Zeng, Y. (author), Nunez, Alfredo (author), Li, Z. (author)

Speckle noise is a major problem for structural vibration measurements with Laser Doppler vibrometer on moving platform (LDVom) due to its highly random, frequent, and broadband nature, especially at high speeds. This paper develops a new post-processing framework to reduce speckle noise based on a case study of LDVom measurements on railway...

journal article 2022

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Mechanism of short pitch rail corrugation: initial excitation and frequency selection for consistent initiation and growth

Li, Z. (author), Li, S. (author), Zhang, P. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author)

This paper proposes a new hypothesis for the formation process of short pitch rail corrugation. An FE wheel-track dynamic model is utilized to verify the hypothesis by reproducing corrugation initiation and consistent growth. It is found longitudinal compression modes are responsible for corrugation initiation with necessary initial...

journal article 2022

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Vibration modes and wave propagation of the rail under fastening constraint

Zhang, P. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author)

This paper investigates three-dimensional (3D) rail vibrations under fastening constraint up to 5000 Hz and provides insights into rail vibration control by fastening parameters. A methodology is proposed, including experimental investigation and numerical simulations of rail vibrations. Three steps are considered: 1) experimental investigation...

journal article 2021

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Multimodal dispersive waves in a free rail: Numerical modeling and experimental investigation

Zhang, P. (author), Li, S. (author), Nunez, Alfredo (author), Li, Z. (author)

In this paper, we present a solution method based on finite element (FE) modeling to predict multimodal dispersive waves in a free rail. As well as the modal behaviors and wavenumber-frequency dispersion relations, the phase and group velocities of six types of propagative waves are also derived and discussed in detail in the frequency range...

journal article 2021

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High-Precision Detection Method for Structure Parameters of Catenary Cantilever Devices using 3D Point Cloud Data

Liu, Wenqiang (author), Liu, Zhigang (author), Li, Qiao (author), Han, Zhiwei (author), Nunez, Alfredo (author)

This article proposes an automatic high-precision detection method for structure parameters of catenary cantilever devices (SPCCDs) using 3-D point cloud data. The steps of the proposed detection method are: 1) segmenting and recognizing the components of the catenary cantilever devices, 2) extracting the detection plane and backbone...

journal article 2020

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Multi-criteria evaluation of wheel/rail degradation at railway crossings

Wei, Z. (author), Nunez, Alfredo (author), Liu, Xiubo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

This study evaluates the degradation of wheels and rails at railway crossings. The evaluation method is composed of 1) finite element simulation of dynamic wheel/crossing interaction and 2) multi-criteria analysis of wheel/rail degradation in terms of yield behavior, rolling contact fatigue (RCF) and wear. With the aid of this method, we...

journal article 2020

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Method for evaluating the performance of railway crossing rails after long-term service

Wei, Z. (author), Nunez, Alfredo (author), Boogaard, M.A. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

In this paper, we present a method for evaluating the performance of railway crossing rails after long-term service. The method includes 1) 3D profile and hardness measurements; 2) finite element simulation of wheel/rail interaction; and 3) numerical prediction of rail degradation. We conducted a case study on a crossing that had been in service...

journal article 2018

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A decision support approach for condition-based maintenance of rails based on big data analysis

Jamshidi, A. (author), Hajizadeh, S. (author), Su, Z. (author), Naeimi, M. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), De Schutter, B.H.K. (author), Li, Z. (author)

In this paper, a decision support approach is proposed for condition-based maintenance of rails relying on expert-based systems. The methodology takes into account both the actual conditions of the rails (using axle box acceleration measurements and rail video images) and the prior knowledge of the railway track. The approach provides an...

journal article 2018

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An integrated approach for characterizing the dynamic behaviour of wheel-rail interaction at crossings

Wei, Z. (author), Boogaard, M.A. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

This paper describes an approach for characterizing the dynamic behavior of the vehicle/track interaction at railway crossings. In the approach, we integrate in situ axle box acceleration (ABA) measurements with roving-accelerometer hammer tests to evaluate the influence of train speed, train moving direction (facing and trailing directions),...

journal article 2018

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Evaluating degradation at railway crossings using axle box acceleration measurements

Wei, Z. (author), Nunez, Alfredo (author), Li, Z. (author), Dollevoet, R.P.B.J. (author)

In this paper, we investigate the capability of an axle box acceleration (ABA) system to evaluate the degradation at railway crossings. For this purpose, information from multiple sensors, namely, ABA signals, 3D rail profiles, Global Positioning System (GPS) and tachometer recordings, was collected from both nominal and degraded crossings....

journal article 2017

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Robust and predictive fuzzy key performance indicators for condition-based treatment of squats in railway infrastructures

Jamshidi, A. (author), Nunez, Alfredo (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

This paper presents a condition-based treatment methodology for a type of rail surface defect called squat. The proposed methodology is based on a set of robust and predictive fuzzy key performance indicators. A fuzzy Takagi-Sugeno interval model is used to predict squat evolution for different scenarios over a time horizon. Models including...

journal article 2017

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New insights into the short pitch corrugation development enigma based on 3D-FE dynamic vehicle-track coupled modelling in frictional rolling contact

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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A big data analysis approach for rail failure risk assessment

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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Health condition monitoring of insulated joints based on axle box acceleration measurements

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