Identification of Bending Modes of Vibration in Rails by a Laser Doppler Vibrometer on a Moving Platform

Kaynardağ, Korkut; Battaglia, Giuseppe; Ebrahimkhanlou, Arvin; Pirrotta, Antonina; Salamone, Salvatore

doi:10.1007/s40799-020-00401-9

Cited by 8 publications

(3 citation statements)

References 26 publications

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“…In simulation studies, train‐borne LDVs are used to identify bridge mode shapes (OBrien & Malekjafarian, 2016) and estimate transfer functions of track structures (Zeng, Núñez, et al., 2023). In experimental studies, train‐borne LDVs measure rail vibrations to identify rail bending modes (Kaynardag et al., 2021) and detect welds (Kaynardag et al., 2023).…”

Section: Introductionmentioning

confidence: 99%

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

Zeng,

Núñez,

2024

Computer aided Civil Eng

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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‐aided approaches and real‐life measurements. The focus is on the speed‐dependent characteristics because the train speed affects the intensity of railway sleeper vibrations and the intensity of speckle noise, which further affects the quality and usability of the measured signals. First, numerical models are established and validated to simulate sleeper vibrations and speckle noise separately. Then, a vibration–noise separation method is proposed to effectively extract speckle noise and structural vibrations from LDV signals measured at different speeds. The parameters of the separation method are tuned using simulation signals. The method is then validated using laboratory measurements in a vehicle‐track test rig and applied to field measurements on a railway track in Rotterdam, the Netherlands. Further, the speed‐dependent characteristics of train‐borne LDV measurement are determined by analyzing the competition between sleeper vibrations and speckle noise at different speeds. Simulation and measurement results show that an optimal speed range yields the highest signal‐to‐noise ratio, which varies for different track structures, measurement configurations, and operational conditions. The findings demonstrate the potential of train‐borne LDV for large‐scale rail infrastructure monitoring.

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Section: Introductionmentioning

confidence: 99%

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

Zeng,

Núñez,

2024

Computer aided Civil Eng

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“…In a simulation study [11], train-borne LDVs are used to identify the mode shapes of a bridge. In an experimental study [12], a train-borne LDV is used to identify the rail bending modes.…”

Section: Introductionmentioning

confidence: 99%

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

Zeng

Núñez

2023

Lecture Notes in Civil Engineering

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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-scale rail infrastructure monitoring. This paper characterizes track structures as a distributed system by estimating transfer functions between the wheel-rail force and the response of each sleeper measured by a train-borne LDV. A challenge with this technique is that a train-borne LDV measures only a fragment of the response for each sleeper while the train load is moving. To investigate the feasibility of this technique and the influence of key factors, we perform numerical simulations using a vehicle-track model and analyze the estimation performance through comparison with simulated impact hammer tests. We find that the transfer function estimated under a moving excitation is close to but noisier than that estimated under an impact load. Partial measurement affects the estimation performance significantly, and a wider sleeper provides a better estimate and a higher frequency resolution. Train speed is a crucial factor for a train-borne LDV system. As the vehicle speed increases, the estimation performance gets better at high frequencies but worse at low frequencies.

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“…This system is designed to incorporate two LDVs attached vertically on a moving rail car. Initial field tests of the system were carried out at the Technology Transfer Center Transportation Technology Center Inc. in Colorado to demonstrate the feasibility of recording rail vibrations using an LDV placed on a moving rail car ( 26 ).…”

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confidence: 99%

Numerical Simulations to Examine the Interaction of Train-Induced Guided Waves With Transverse Cracks

Kaynardağ

Yang

Salamone

2022

Transportation Research Record: Journal of the Transportation R

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This paper presents the results of a numerical study aimed at investigating the propagation of guided waves generated by train wheels on rails. The particular application of interest is to exploit such waves for the identification of transverse cracks located in the rail head. The research presented is part of an ongoing project aimed at developing a non-contact damage detection system based on laser Doppler vibrometer measurements. In this study, numerical simulations were carried out using three rail models. The first two models consisted of a transverse crack whose size is 20% and 10% of the rail head cross-section (RHC), respectively. The third model consisted of the same crack size as the first model, but it was designed to be longer before and shorter after the location of the crack compared with the first model. The goal of this model was to examine the location where the effect of cracks on the waves first appeared. To acquire train-induced guided waves to use in the simulations, an accelerometer was placed under a rail head, and propagating waves were recorded during the passage of an operating train. Afterward, on each rail model, the location of excitation and two measurement points were shifted forward over the rail to replicate the movement of the defect detection system. Two damage functions were used to examine the change in wave propagation caused by cracks, while a multi-dimensional damage index consisting of the damage functions was used to identify the location of the crack (20% of RHC).

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Identification of Bending Modes of Vibration in Rails by a Laser Doppler Vibrometer on a Moving Platform

Cited by 8 publications

References 26 publications

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

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

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

Numerical Simulations to Examine the Interaction of Train-Induced Guided Waves With Transverse Cracks

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