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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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A Simulation Study on Characterizing Transfer Functions of Railway Tracks Using Train-Borne Laser Doppler Vibrometer

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

Due to train load and aging, the dynamic properties of railway tracks degrade over time and deviate over space, which should be monitored to facilitate track maintenance decisions. A train-borne laser Doppler vibrometer (LDV) can directly measure track vibrations in response to the moving train load, which can be potentially applied to large...

conference paper 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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A multiple spiking neural network architecture based on fuzzy intervals for anomaly detection: a case study of rail defects

Phusakulkajorn, W. (author), Hendriks, J.M. (author), Moraal, J. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author), Nunez, Alfredo (author)

In this paper, a fuzzy interval-based method is proposed for solving the problem of rail defect detection relying on an on-board measurement system and a multiple spiking neural network architecture. Instead of outputting binary values (defect or not defect), all data will belong to both classes with different spreads that are given by two fuzzy...

conference paper 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

document

Special issue of Wear on Contact Mechanics 2018

Li, Z. (author), Berg, Mats (author), Fletcher, David (author), Meehan, Paul (author), Nunez, Alfredo (author)

Editorial

contribution to periodical 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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Smart technology solutions for the NeTIRail-INFRA case study lines: Axle box acceleration and ultra-low cost smartphones

Nunez, Alfredo (author), Popa, Tudor (author), Anghel, Lucian Emmanuel (author), Hendriks, J.M. (author), Moraal, J. (author), Buretea, Laurentiu Dorin (author), Paragreen, Jon (author), Miron, Berbece (author), Gheorghe, Draghici (author), Campean, Mihail (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

In this paper, we present preliminary results on the development of smart technology solutions for lower density railway lines. The goal is to reach a cost effective inspection and asset management to minimize maintenance<br/>interventions time/cost without dedicated inspection vehicles. The proposed methods include axle box acceleration...

conference paper 2018

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Smart technology solutions for the NeTIRail-INFRA case study lines: Axle box acceleration and ultra-low cost smartphones

Nunez, Alfredo (author), Popa, Tudor (author), Anghel, Lucian Emmanuel (author), Hendriks, J.M. (author), Moraal, J. (author), Buretea, Laurentiu Dorin (author), Paragreen, Jon (author), Miron, Berbece (author), Gheorghe, Draghici (author), Campean, Mihail (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

Results on the development of smart technology solutions for lower density<br/>railway lines are presented. The goal is to reach a cost effective inspection and<br/>asset management to minimize maintenance interventions time/cost without<br/>dedicated inspection vehicles. The proposed methods in this paper include: 1) axle box acceleration...

poster 2018

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Preface

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

contribution to periodical 2018

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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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Rail Condition Monitoring using Axle Box Acceleration Measurements: Defect detection in the Netherlands and Romania

Nunez, Alfredo (author), Hendriks, J.M. (author), Moraal, J. (author), Ramirez Fonseca, I. (author), Dollevoet, R.P.B.J. (author), Li, Z. (author)

In this paper we discuss rail condition monitoring based on axle box acceleration (ABA) measurements. We present three case studies. The first one in The Netherlands, the detection of local defects with different severity levels (squat A, squat B and squat C) is analysed. The second case from the Faurei testing ring in Romania, the detection of...

conference paper 2018