| 1. |
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| 2. |
- Bergman, Penny, 1982, et al.
(author)
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Perceptual validation of auralized heavy-duty vehicles
- 2015
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In: Euronoise 2015. ; , s. 769-774
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Conference paper (peer-reviewed)abstract
- Auralization is a valuable tool when evaluating the effect of traffic noise on people. The present study focuses on the validation of auralization of heavy-duty vehicles with a diesel engine. To capture the characteristics of the diesel engine a granular approach has been used. The granular approach has proven to be successful in a previous validation test examining two microphone positions around a still-standing truck. In the present study a granular approach was used to achieve pass-by noise at an artificial listening position alongside a Volvo truck (experiment 1) and pass-by noise inside an apartment (experiment 2). The aim of experiment 1 was to determine the number of interpolated sets of grains needed, in order to create a perceptually valid auralized signal. The results were used in the auralization of pass-by noise in an apartment in experiment 2. 20 and 15 participants respectively rated original recordings and auralized signals on four different attributes: realism, annoyance, and emotional response measured by valence and arousal. The results of both experiments suggest that auralizations of heavy-duty vehicles are successful and usable. It further indicates that what distinguish the auralized signals from the original recordings is mostly the arousal responses.
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| 3. |
- Fabre, François, et al.
(author)
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Sound Radiation from Railway Wheels including Ground Reflections: A half-space formulation for the Fourier Boundary Element Method
- 2021
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 493
-
Journal article (peer-reviewed)abstract
- Current models for the acoustic radiation from railway wheels assume free field radiation. However, slab tracks are increasingly used for new railway lines. The acoustically hard surface of those tracks makes a re-evaluation of the free field assumption relevant, as such a surface can affect the radiation efficiency of an acoustic radiator. The wheel as the acoustic radiator is most conveniently described in a cylindrical coordinate system, thus making use of its axisymmetry. While this is a viable solution for the structural vibrations, for instance by using the curved Waveguide Finite Element formulation, the axisymmetry breaks when including a reflective plane in the calculation of the acoustic radiation. A convenient method to include an infinitely large, reflective plane is by using half-space Green’s functions in combination with the Boundary Element method. This method can be formulated in cylindrical coordinates using the Fourier series BEM (FBEM). However, the FBEM has not yet been combined with half-space Green’s functions. This paper provides a half-space formulation for the FBEM, which enables e.g. the evaluation of sound radiation of railway wheels over reflective surfaces. Finally, it is shown that the assumption of free field radiation for railway wheels is valid, as there is no major contribution of the reflective plane to the radiation efficiency of the wheel. The developed method is validated against laboratory measurements as well as analytical models.
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| 4. |
- Garcia-Andrés, Xavier, et al.
(author)
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REDUCING ROLLING NOISE IN RAILWAY WHEELS WITH CONSTRAINED LAYER DAMPING TREATMENTS CONSIDERING COMPREHENSIVE VISCOELASTIC MODELS
- 2023
-
In: Proceedings of the International Congress on Sound and Vibration. - 2329-3675.
-
Conference paper (peer-reviewed)abstract
- In this work, the reduction of radiated sound power of a railway wheel incorporating a constrained layer damping treatment is modelled and studied in detail. Such vibration control mechanism consists of an arrangement of a viscoelastic material between a constraining layer and the wheel web, and has been proven as an effective method of reducing rolling noise. The modelling of these devices presents many challenges due to the non-linear and frequency-dependent nature of the viscoelastic material behaviour, as well as the interaction between the wheel and the different layers of material. Thus, the model developed in the present work considers the viscoelastic behaviour of the polymer through a number of material models that include the frequency dependence of the main properties, such as the Burgers and Zener approaches. The variation of radiated rolling noise for a wheel with different configurations of constrained layer damping is later compared, analysing their suitability for minimising sound radiation.
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| 5. |
- Grau, Loïc, et al.
(author)
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Influence of the ground/structure interaction on the calculation of the force at the wheel/rail contact
- 2016
-
In: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 2086-2097
-
Conference paper (peer-reviewed)abstract
- The prediction of ground vibration from railway traffic represents a major challenge for railway operators, especially with regard to the increasing number of new lines built close to residential buildings. In this context, it becomes essential to have a model that accounts on the one hand for ground/structure interaction and on the other hand for wheel/rail interaction. In this paper, such a model is developed by combining two existing models. The model for ground/structure interaction, SIPROVIB, is an analytical model of a slab with Kirchhoff-Love hypothesis coupled to the ground in 3D. The model for wheel/rail interaction is a computationally efficient time-domain model, where vehicle and track are represented by pre-calculated Green's functions. The wheel/rail contact is modelled as 3D, non-linear and non-Hertzian. Both models are combined by replacing the track Green's function by a Green's function representing the ground and slab coupled to a simplified rail model. Numerical results showed that the influence of slab and ground on the dynamic wheel/rail contact forces increases for thinner slabs and softer grounds, but is generally of secondary importance. Deviations in contact force did not exceed 2 dB for frequencies up to 200 Hz. © 2016, German Acoustical Society (DEGA). All rights reserved.
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| 6. |
- Kropp, Wolfgang, 1959, et al.
(author)
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The application of dither for suppressing curve squeal
- 2019
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In: Proceedings of the International Congress on Acoustics. - 2226-7808 .- 2415-1599. ; 2019-September, s. 1551-1558
-
Conference paper (peer-reviewed)abstract
- Curve squeal is a highly disturbing tonal sound generated by vehicles like railways, metros or trams, when negotiating a sharp curve. The probability that squeal occurs increases with reduced curve radius of the track. Curve squeal noise is attributed to self-excited vibrations caused by stick/slip behaviour due to lateral creepage of the wheel tyre on the top of the rail. With respect to the enormous number of the rolling stock units and the long lifetime of waggons there is an urgent need for a cheap and simple retrofitting measure to reduce curve squeal. The main objective of the paper is therefore to investigate the potential to reduce curve squeal by means of active control in the form of dither in an efficient and robust way. Dither control has been applied in the field of mechanical engineering for systems including non-linear components. There it has been shown to suppress self-excited oscillations very efficiently. The control is an open loop control. It consists in adding a forced vibration to the vibrational system. The demand on this additional signal is that it is higher in frequency than the friction-induced response. From a physical point of view, dither control modifies the effective friction characteristic.
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| 7. |
- Kropp, Wolfgang, 1959, et al.
(author)
-
The application of dither to mitigate curve squeal
- 2021
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 514
-
Journal article (peer-reviewed)abstract
- Curve squeal is a highly disturbing tonal sound generated by rail vehicles like trains, metros or trams, when negotiating a sharp curve. The probability that squeal occurs increases with reduced curve radius of the track. Curve squeal noise is attributed to self-excited vibrations caused by stick/slip behaviour due to lateral creepage of the wheel tyre on the top of the rail. With respect to the large number of rolling stock units and the long lifetime of vehicles, there is an urgent need for a cheap and simple retrofitting measure to reduce curve squeal. Therefore, main objective of this paper is to investigate the potential to reduce curve squeal by means of active control in the form of dither in an efficient and robust way. Dither control has been applied in the field of mechanical engineering for systems including non-linear components. There it has been shown to suppress self-excited oscillations very efficiently. The control is an open-loop control. It consists in adding a forced vibration to the vibrational system. A time-domain model has been applied to investigate the mechanisms behind self-excited vibrations leading to curve squeal at the squealing noise rig at Chalmers University of Technology. The analysis showed, that in the presence of constant friction, the coupling between lateral and vertical direction is the driving mechanism for building up self-excited vibrations. Based on this insight, the potential of dither has been investigated. For the case considered here dither has the potential to reduce the overall kinetic energy on the wheel by more than 10 dB and on the rail by more than 20 dB. Further optimisation of dither forces with respect to the radiated sound power might increase this potential.
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| 8. |
- Maglio, Michele, 1993, et al.
(author)
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Railway wheel tread damage and axle bending stress – Instrumented wheelset measurements and numerical simulations
- 2022
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In: International Journal of Rail Transportation. - : Informa UK Limited. - 2324-8386 .- 2324-8378. ; 10:3, s. 275-297
-
Journal article (peer-reviewed)abstract
- A combination of instrumented wheelset measurements and numerical simulations of axle bending stresses is used to investigate the consequences of evolving rolling contact fatigue (RCF) damage on a passenger train wheelset. In a field test campaign, stresses have been monitored using a wheelset with four strain gauges mounted on the axle, while the evolution of wheel tread damage (out-of-roundness) has been measured on regular occasions. The strain signals are post-processed in real time and stress variations are computed. Based on a convolution integral approach, the measured wheel out-of-roundness has been used as input to numerical simulations of vertical dynamic wheelset–track interaction and axle stresses. Simulated and measured axle stresses are compared for cases involving combinations of low or high levels of rail roughness and the measured levels of RCF damage. The study enhances the understanding of how wheel tread damage and track quality influence axle stress amplitudes.
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| 9. |
- Maglio, Michele, 1993, et al.
(author)
-
Wheel–rail impact loads and axle bending stress simulated for generic distributions and shapes of discrete wheel tread damage
- 2021
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 502
-
Journal article (peer-reviewed)abstract
- Wheel–rail impact loads generated by discrete wheel tread irregularities may result in high dynamic bending stresses in the wheelset axle, leading to a decrease in component life and an elevated risk for fatigue failure. In this paper, a versatile and cost-efficient method to simulate the vertical dynamic interaction between a wheelset and railway track, accounting for generic distributions and shapes of wheel tread damage, is presented. The wheelset (comprising two wheels, axle and any attached equipment for braking and power transmission) and track with two discretely supported rails are described by three-dimensional finite element (FE) models. The coupling between the two wheel‒rail contacts (one on each wheel) via the wheelset axle and via the sleepers is considered. The simulation of dynamic vehicle–track interaction is carried out in the time domain using a convolution integral approach, while the non-linear wheel–rail normal contact is solved using Kalker’s variational method. Wheelset designs that are non-symmetric with respect to the centre of the axle, track support conditions that are non-symmetric with respect to the centre of the track, as well as non-symmetric distributions of tread damage on the two wheels (or irregularities on the two rails) can be studied. Time-variant stresses are computed for the locations in the wheelset axle which are prone to fatigue. Based on Green’s functions for stress established using the wheelset FE model, this is achieved in a post-processing step. An extensive parametric study has been performed where wheel–rail impact loads and axle stresses have been computed for different distributions and sizes of tread damage as well as for different train speeds.
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| 10. |
- Nielsen, Jens, 1963, et al.
(author)
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Wheel–Rail Impact Loads, Noise and Vibration: A Review of Excitation Mechanisms, Prediction Methods and Mitigation Measures
- 2021
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 3-40, s. 3-40
-
Book chapter (other academic/artistic)abstract
- Railway noise and ground-borne vibration induced by wheel–rail impact loads are generated by discrete wheel/rail surface irregularities or local deviations in the nominal wheel–rail contact geometry. On the running surface of a rail, a discrete irregularity can be inherent to the railway design, for example at crossings or insulated joints. On the wheel or rail, the irregularity could also be the result of surface damage due to rolling contact fatigue cracking or a consequence of wheel sliding without rolling. This review describes the mechanisms of wheel–rail impact generated by wheel flats, rail joints and crossings. These can be a source of locally increased noise and vibration levels and increased annoyance, as well as of damage to vehicle and track components. The wheel–rail excitation at such irregularities, as indicated by the vertical wheel centre trajectory, leads to an abrupt change of momentum, potentially causing a momentary loss of wheel–rail contact followed by an impact on the rail. The resulting loading is a transient and often periodically repeated event exciting vibration in a wide frequency range with most of the energy concentrated below about 1 kHz. For the numerical prediction of high-magnitude transient loading and situations potentially leading to loss of contact, a non-linear wheel–rail contact model is required, implying that the simulation of contact force is carried out in the time domain. To avoid the need for large, computationally expensive models, a hybrid approach has been developed in which the time history of the contact force is transformed into an equivalent roughness spectrum; this is used as input to frequency-domain models for the prediction of noise and vibration. Since the excitation mechanism is similar to that for rolling noise, the same types of measures to mitigate wheel and track vibration can be applied. However, the main priority should be to control the irregularity by design and regular maintenance.
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| 11. |
- Pieringer, Astrid, 1979, et al.
(author)
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A fast time-domain model for wheel/rail interaction demonstrated for the case of impact forces caused by wheel flats
- 2008
-
In: 7th European Conference on Noise Control 2008, EURONOISE 2008; Paris; France; 29 June 2008 through 4 July 2008. - 2226-5147. ; , s. 2643-2648
-
Conference paper (peer-reviewed)abstract
- The prediction of impact forces caused by wheel flats requires the application of time-domain models that are generally more computationally demanding than are frequency-domain models. In this paper, a fast time-domain model is presented to simulate the dynamic interaction between wheel and rail, taking into account the non-linear processes in the contact zone. Track and wheel are described as linear systems using impulse-response functions that can be precalculated. The contact zone is modelled by non-linear contact springs, allowing for loss of contact. This general model enables the calculation of the vertical contact forces generated by the small-scale roughness of rail and wheel, by parametric excitation on a discretely supported rail and by discrete irregularities of rail and wheel. Here, the model is applied to study the excitation caused by wheel flats by introducing a flat on a rotating wheel whose profile in the contact zone is updated in every time step. To demonstrate the functioning of the model, simulation results are compared to field measurements of impact forces and a brief parameter study is presented.
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| 12. |
- Pieringer, Astrid, 1979
(author)
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A numerical investigation of curve squeal in the case of constant wheel/rail friction
- 2014
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 333:18, s. 4295-4313
-
Journal article (peer-reviewed)abstract
- Curve squeal is commonly attributed to self-excited vibrations of the railway wheel, which arise due to a large lateral creepage of the wheel tyre on the top of the rail during curving. The phenomenon involves stick/slip oscillations in the wheel/rail contact and is therefore strongly dependent on the prevailing friction conditions. The mechanism causing the instability is, however, still a subject of controversial discussion. Most authors introduce the negative slope of the friction characteristic as a source of the instability, while others have found that squeal can also occur in the case of constant friction due to the coupling between normal and tangential dynamics. As a contribution to this discussion, a detailed model for high-frequency wheel/rail interaction during curving is presented in this paper and evaluated in the case of constant friction. The interaction model is formulated in the time domain and includes the coupling between normal and tangential directions. Track and wheel are described as linear systems using pre-calculated impulse response functions that are derived from detailed finite element models. The nonlinear, non-steady state contact model is based on an influence function method for the elastic half-space. Real measured wheel and rail profiles are used. Numerical results from the interaction model confirm that stick/slip oscillations occur also in the case of constant friction. The choice of the lateral creepage, the value of the friction coefficient and the lateral contact position on the wheel tread are seen to have a strong influence on the occurrence and amplitude of the stick/slip oscillations. The results from the interaction model are in good qualitative agreement with previously published findings on curve squeal.
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| 13. |
- Pieringer, Astrid, 1979, et al.
(author)
-
A time-domain model for coupled vertical and tangential wheel/rail interaction - a contribution to the modelling of curve squeal
- 2012
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Tokyo : Springer Japan. - 1612-2909 .- 1860-0824. ; 118, s. 221-229
-
Conference paper (peer-reviewed)abstract
- Lateral forces due to frictional instability are seen as the main reason for the occurrence of curve squeal. Predicting squeal requires thus to describe the high-frequency wheel/rail interaction during curving including the coupling between vertical and lateral directions. In this article, a time-domain approach is presented which includes both vertical and lateral forces and takes into account the non-linear processes in the contact zone. Track and wheel are described as linear systems using pre-calculated impulse response functions. The non-linear, non-steady state contact model is based on an influence function method for the elastic half-space, includes a velocity-dependent friction coefficient and accounts for surface roughness. First results from the interaction model demonstrate the functioning of the approach.
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Pieringer, Astrid, 1979, et al.
(author)
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Acoustic monitoring of rail faults in the German railway network
- 2021
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 242-250
-
Book chapter (other academic/artistic)abstract
- The early detection of rail surface defects such as squats, poor welds, or wheel burns is important to prevent further rail deterioration. In this paper, a methodology for acoustic monitoring of squats in the German railway network is proposed based on the measurement of axle box acceleration (ABA) on the DB noise measurement car (SMW) and the previously developed numerical model WERAN for wheel/rail interaction. Specific characteristics of squats in the ABA signals are determined with the model and verified by pass-by measurements combined with direct geometry measurements of the squats. Based on these re- sults, a logistic regression classifier is devised for the detection of squats in the measured ABA signals of the SMW. Trained with simulated and measured data, the classifier identifies all of the known severe squats and 87% of the known light squats in the measured test data.
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| 18. |
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| 19. |
- Pieringer, Astrid, 1979, et al.
(author)
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Curve squeal of rail vehicles: Linear stability analysis and non-linear time-domain simulation
- 2016
-
In: Civil-Comp Proceedings. - 1759-3433. ; 110
-
Journal article (peer-reviewed)abstract
- Railway curve squeal arises from self-excited vibrations during curving. In this paper, a combination of a frequency-and a time-domain approach for curve squeal is applied in order to compare and evaluate the two different approaches. In the frequency-domain, linear stability is investigated through complex eigenvalue analysis. The time-domain model is based on a Green's functions approach and uses a convolution procedure to obtain the system response. To ensure comparability, the same submodels are implemented in both squeal models. The wheel model includes a single flexible wheel and accounts for inertia effects due to rotation adopting Eulerian coordinates. The track is modelled using the moving element method technique corresponding to a finite element mesh that travels with the vehicle speed. Coulomb's law with a constant friction coefficient is applied to model the local friction characteristics in the contact zone. The frictional instability arises due to geometrical coupling. The rolling contact model applied is Kalker's variational method in the time domain and a linearized version of this method in the frequency domain. Conditions similar to those of a curve on the Stockholm metro exposed to severe curve squeal are studied with both squeal models. The influence of the wheel-rail friction coefficient and the direction of the resulting creep force on the occurrence of squeal is investigated for vanishing train speed. The results of both models show similar tendencies, but differ in the predicted squeal frequencies.
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| 20. |
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| 21. |
- Pieringer, Astrid, 1979, et al.
(author)
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Investigation of railway curve squeal using a combination of frequency- and time-domain models
- 2016
-
In: Proceedings of the 12h International Workshop on Railway Noise (IWRN12), Terrigal, Australia, September 12-16. ; , s. 444 - 451
-
Conference paper (peer-reviewed)abstract
- Railway curve squeal arises from self-excited vibrations during curving. In this paper, a frequency- and a timedomainapproach for curve squeal are compared. In particular, the capability of the frequency-domain model topredict the onset of squeal and the squeal frequencies is studied. In the frequency-domain model, linear stabilityis investigated through complex eigenvalue analysis. The time-domain model is based on a Green's functionsapproach and uses a convolution procedure to obtain the system response. To ensure comparability, the samesubmodels are implemented in both squeal models. The structural flexibility of a rotating wheel is modelled byadopting Eulerian coordinates. To account for the moving wheel‒rail contact load, the so-called moving elementmethod is used to model the track. The local friction characteristics in the contact zone is modelled inaccordance with Coulomb's law with a constant friction coefficient. The frictional instability arises due togeometrical coupling. In the time-domain model, Kalker's non-linear, non-steady state rolling contact modelincluding the algorithms NORM and TANG for normal and tangential contact, respectively, is solved in eachtime step. In the frequency-domain model, the normal wheel/rail contact is modelled by a linearization of theforce-displacement relation obtained with NORM around the quasi-static state and full-slip conditions areconsidered in tangential direction. Conditions similar to those of a curve on the Stockholm metro exposed tosevere curve squeal are studied with both squeal models. The influence of the wheel-rail friction coefficient andthe direction of the resulting creep force on the occurrence of squeal is investigated for vanishing train speed. Results from both models are similar in terms of the instability range in the parameter space and the predictedsqueal frequencies.
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| 22. |
- Pieringer, Astrid, 1979, et al.
(author)
-
Investigation of railway curve squeal using a combination of frequency- and time-domain models
- 2018
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 83-95
-
Book chapter (other academic/artistic)abstract
- Railway curve squeal arises from self-excited vibrations during curving. In this paper, a frequency- and a time-domain approach for curve squeal are compared. In particular, the capability of the frequency-domain model to predict the onset of squeal and the squeal frequencies is studied. In the frequency-domain model, linear stability is investigated through complex eigenvalue analysis. The time-domain model is based on a Green’s function approach and uses a convolution procedure to obtain the system response. To ensure comparability, the same submodels are implemented in both squeal models. The structural flexibility of a rotating wheel is modelled by adopting Eulerian coordinates. To account for the moving wheel–rail contact load, the so-called moving element method is used to model the track. The local friction characteristics in the contact zone are modelled in accordance with Coulomb’s law with a constant friction coefficient. The frictional instability arises due to geometrical coupling. In the time-domain model, Kalker’s non-linear, non-steady state rolling contact model including the algorithms NORM and TANG for normal and tangential contact, respectively, is solved in each time step. In the frequency-domain model, the normal wheel/rail contact is modelled by a linearization of the force-displacement relation obtained with NORM around the quasi-static state and full-slip conditions are considered in the tangential direction. Conditions similar to those of a curve on the Stockholm metro exposed to severe curve squeal are studied with both squeal models. The influence of the wheel-rail friction coefficient and the direction of the resulting creep force on the occurrence of squeal is investigated for vanishing train speed. Results from both models are similar in terms of the instability range in the parameter space and the predicted squeal frequencies.
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| 23. |
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| 24. |
- Pieringer, Astrid, 1979, et al.
(author)
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Investigation of the dynamic contact filter effect in vertical wheel/rail interaction using a 2D and a 3D non-Hertzian contact model
- 2011
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In: Wear. - : Elsevier BV. - 0043-1648. ; 271:1-2, s. 328-338
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Journal article (peer-reviewed)abstract
- Rolling noise is excited by the roughness of the wheel/rail running surfaces. The contact patch acts as a filter attenuating the excitation at wavelengths that are short in comparison with its length. Additionally, the excitation depends on the variations in roughness profile height across the width of the contact. While most available wheel/rail interaction models include the contact filter effect by roughness pre-processing, a time-domain model is presented in this paper that includes the contact filter effect dynamically by an appropriate two-dimensional (2D) or three-dimensional (3D) non-Hertzian contact model. The 2D contact model is based on a Winkler bedding, while wheel and rail are locally approximated by elastic half-spaces in the 3D contact model. The wheel/rail interaction model is applied to evaluate the contact filter effect for different sets of roughness data measured in several parallel lines. It is found that the 3D contact model gives, as a general tendency, a contact force level several dB lower than the 2D model. The differences increase with a decrease in correlation between the roughness on parallel lines and vary significantly with the choice of roughness line in the 2D model.
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| 25. |
- Pieringer, Astrid, 1979, et al.
(author)
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Model-based estimation of rail roughness from axle box acceleration
- 2022
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In: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 193
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Journal article (peer-reviewed)abstract
- Monitoring rail roughness in the railway network allows directing grinding actions to where they are needed to reduce rolling noise and large wheel/rail forces. To be able to measure rail roughness on a large scale, indirect measurements onboard railway vehicles have to be carried out. Existing methods use either axle box acceleration (ABA) or under-coach noise measurements to monitor the rail roughness indirectly. The two main challenges with rail roughness estimation from vibroacoustic signals measured onboard vehicles are to separate wheel and rail roughness and to take into account varying track dynamics in the railway network. Both questions have not yet been addressed sufficiently. In this paper, an enhanced method for estimating rail roughness from ABA is presented. In contrast to all existing methods in the literature, the presented method operates in the time domain. A time-domain method has the advantage that the spatial variations of roughness become visible and paves the way for the detection of localized defects such as squats or deteriorated welds. The method is based on a previously developed time-domain model for high-frequency wheel/rail interaction and estimates the time series of the roughness from the time series of ABA. In a first step, the time series of the contact force is calculated from the axle box acceleration using a Least Mean Square algorithm for source identification. In a second step, the combined wheel/rail roughness is obtained from the contact force based on a non-linear Hertzian contact model and a convolutional approach to determine wheel and rail displacement. Separation of wheel and rail roughness is possible by cycle-averaging the contact force over a distance corresponding to the wheel perimeter and performing the second step separately for the part of the contact force originating from the wheel and the rail roughness, respectively. The method was tested for simulated ABA obtained from measured wheel and rail roughness. In the relevant wavelength range from 0.5 m to 5 mm, the rail roughness could be estimated with good accuracy for known track dynamics. Overall, deviations in 1/3-octave bands between estimated and actual roughness were below 1 dB. Only for low rail roughness, higher deviations of less than 2.6 dB occurred around the pinned-pinned resonance frequency. Uncertainties in the track parameters affect the roughness estimation, where the most critical parameter is the rail pad stiffness. A deviation of 20% in rail pad stiffness leads to deviations in the rail roughness of up to 3.5 dB in single 1/3-octave bands. The results illustrate the need to extend the method for the simultaneous extraction of track parameters and roughness from measured axle box acceleration.
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| 26. |
- Pieringer, Astrid, 1979, et al.
(author)
-
Modelling of railway curve squeal including effects of wheel rotation
- 2015
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1612-2909 .- 1860-0824. ; 126, s. 417-424
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Journal article (peer-reviewed)abstract
- Railway vehicles negotiating tight curves may emit an intense high-pitch noise. The underlying mechanisms of this squeal noise are still a subject of research. Simulation models are complex since they have to consider the non-linear, transient and high-frequency interaction between wheel and rail. Often simplified models are used for wheel and rail to reduce computational effort, which involves the risk of oversimplifications. This paper focuses on the importance to include a rotating wheel instead of a stationary wheel in the simulation models. Two formulations for a rotating wheel are implemented in a previously published wheel/rail interaction model: a realistic model based on an Eulerian modal coordinate approach and a simplified model based on a rotating load and moving Green's functions. The simulation results for different friction coefficients and values of lateral creepage are compared with results obtained for the stationary wheel. Both approaches for the rotating wheel give almost identical results for the rolling speed considered. Furthermore, it can be concluded that a model of a stationary flexible wheel is sufficient to simulate curve squeal.
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| 27. |
- Pieringer, Astrid, 1979
(author)
-
Modelling of wheel/rail interaction considering roughness and discrete irregularities
- 2008
-
Licentiate thesis (other academic/artistic)abstract
- The interaction between wheel and rail is the predominant source of noise emission from railway operations in a wide range of conventional speeds. On the one hand, this wheel/rail noise concerns rolling noise and impact noise caused by the vertical interaction excited by roughness and discrete irregularities of the wheel/rail running surfaces, respectively. On the other hand, it concerns squeal noise generated by the tangential interaction. While a well-established frequency-domain model is available for the prediction of rolling noise, likewise successful models do not yet exist for the prediction of impact noise and squeal noise. The overall aim of this thesis is to develop a model for the vertical wheel/rail interaction induced by roughness and discrete irregularities. The inclusion of tangential interaction is a subject of future work. In order to include the non-linearities in the contact zone, the interaction model presented in this thesis is formulated in the time domain. Wheel and track models are represented by Green’s functions, which leads to a computationally efficient formulation and allows inclusion of detailed non-Hertzian contact models. The first contact model considered is a two-dimensional (2D) model consisting of a bedding of independent springs. This model uses a simplified wheel and rail geometry and takes into account one line of wheel/rail roughness in the rolling direction. The second contact model is a three-dimensional (3D) model based on an influence-function method for the elastic half-space. This model considers the real three-dimensional wheel and rail geometry and includes the roughness in several parallel lines. In the thesis, the interaction model using both the 2D and the 3D contact models is applied to simulate the wheel/rail interaction caused by parametric excitation on a discretely supported rail and by wheel/rail roughness. The results indicate that the application of the 3D contact model is preferable when the degree of correlation between roughness across the width of the contact is low, although more simulations should be carried out before drawing a final conclusion. The interaction model using the 2D contact model is applied to simulate impact forces caused by wheel flats and shows encouraging agreement with field measurements.
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| 28. |
- Pieringer, Astrid, 1979
(author)
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On the modelling of wheel/rail noise
- 2013
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In: AIA-DAGA 2013 Conference on Acoustics, Meran, Italy, March 18-21, 2013.
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Conference paper (peer-reviewed)
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| 29. |
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| 30. |
- Pieringer, Astrid, 1979, et al.
(author)
-
The influence of contact modelling on simulated wheel/rail interaction due to wheel flats
- 2014
-
In: Wear. - : Elsevier BV. - 0043-1648. ; 314:1-2, s. 273-281
-
Journal article (peer-reviewed)abstract
- Most available wheel/rail interaction models for the prediction of impact forces caused by wheel flats use a Hertzian spring as contact model and do not account for the changes in contact stiffness due to the real three-dimensional wheel flat geometry. In the literature, only little information is available on how this common simplification influences the calculation results. The aim of this paper is to study the influence of contact modelling on simulated impact forces due to wheel flats in order to determine the errors introduced by simplified approaches. For this purpose, the dynamic wheel/rail interaction is investigated with a time-domain model including a three-dimensional (3D) non-Hertzian contact model based on Kalker's variational method. The simulation results are compared with results obtained using a two-dimensional (2D) non-Hertzian contact model consisting of a Winkler bedding of independent springs or alternatively a single non-linear Hertzian contact spring. The relative displacement input to the Hertzian model is either the wheel profile deviation due to the wheel flat or the pre-calculated vertical wheel centre trajectory. Both the 2D model and the Hertzian spring with the wheel centre trajectory as input give rather similar results to the 3D model, the former having the tendency to slightly underestimate the maximum impact force and the latter to slightly overestimate. The Hertzian model with the wheel profile deviation as input can however lead to large errors in the result. Leaving aside this contact model, the correct modelling of the longitudinal geometry of the wheel flat is actually seen to have a larger influence on the maximum impact force than the choice of contact model.
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| 31. |
- Pieringer, Astrid, 1979
(author)
-
Time-domain modelling of high-frequency wheel/rail interaction
- 2011
-
Doctoral thesis (other academic/artistic)abstract
- The interaction between wheel and rail is the predominant source of noise emission from railway operations in a wide range of conventional speeds. On the one hand, this wheel/rail noise concerns rolling noise and impact noise caused by the vertical interaction excited by roughness and discrete irregularities of the wheel/rail running surfaces, respectively. On the other hand, it concerns squeal noise generated by the tangential interaction due to frictional instability. The aim of this thesis is to develop a model for the combined vertical and tangential wheel/rail interaction induced by roughness, discrete irregularities or frictional instability. This is the main step in the formulation of a combined prediction model for the three different types of wheel/rail noise, which can be used as a design tool for noise reduction. In order to include the non-linearities in the contact zone, the interaction model presented in this thesis is formulated in the time domain. Wheel and track models are represented by Green’s functions, which leads to a computationally efficient formulation and allows the inclusion of detailed contact models. A two-dimensional (2D) vertical contact model consisting of a bedding of independent springs, and a three-dimensional (3D) vertical and tangential model based on an influence-function method for the elastic half-space, are considered. Non-Hertzian and transient effects are taken into account. In the thesis, the vertical interaction model has been applied for excitation by wheel/rail roughness and by wheel flats. In the former case, the model has been validated against existing established models. In the latter case, encouraging agreement with field measurements has been found. Results from simulations carried out with both the 2D and the 3D contact models for excitation by detailed measured roughness data indicate that significant errors may occur in the calculated contact forces, when the 3D roughness distribution is represented by the roughness on only one longitudinal line. The errors increase with a decrease in roughness correlation across the width of the contact. Frictional instabilities during curve negotiation have been investigated with the combined vertical/tangential interaction model. For both a constant friction law and a friction curve falling with the sliding velocity, stick/slip oscillations were observed. While the model is not yet considered completely reliable in the case of a falling friction curve due to the possibility of multiple solutions, the results in the case of constant friction are in good qualitative agreement with previouslypublished findings on curve squeal.
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| 32. |
- Theyssen, Jannik, 1991, et al.
(author)
-
A time-domain model for railway rolling noise
- 2023
-
Conference paper (other academic/artistic)abstract
- The poster presents a modelling approach for railway rolling noise prediction developed at Chalmers during a recent PhD project. Rolling noise, which is caused by the roughness-excited vibration of the wheel and the track, is the dominant noise source in a wide range of vehicle speeds. The presented modelling approach is based on the time-domain, non-linear contact model WERAN. The model has been extended with a numerically efficient description of the structural vibration of the wheel and the track based on moving Green's functions. Further, efficient models for the sound radiation from the wheel and track were developed and implemented, again using a Green's functions approach. The Green's functions are computed using combinations of the Waveguide Finite Element method (2.5D FE), the Wavenumber domain Boundary Element Method (WBEM / 2.5D BE), the Fourier domain BEM (FBEM), and spherical harmonics equivalent sources. This model provides a physics-based, time-domain description of the radiated sound based on the combined roughness between the wheel and the rail. There are several possible applications for a time-domain rolling noise model, for example in component design, condition monitoring, and, by auralising the noise, as an effective tool for communication with a broader public.
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| 33. |
- Theyssen, Jannik, 1991, et al.
(author)
-
Calibration and validation of the dynamic response of two slab track models using data from a full-scale test rig
- 2021
-
In: Engineering Structures. - : Elsevier BV. - 1873-7323 .- 0141-0296. ; 234
-
Journal article (peer-reviewed)abstract
- For the development of accurate and reliable simulation models, the procedure of calibration and validation against measurement data is essential. In this paper, a finite element model and a waveguide finite element model of a slab track are calibrated and validated against hammer impact measurement data from a full-scale test rig. The finite element model is three-dimensional, where the rails are modelled as Rayleigh–Timoshenko beams and the concrete slab and support layer are modelled using linear shell elements. In the waveguide finite element model, a constant track cross-section described by two-dimensional finite elements is assumed, and the vibration in the direction perpendicular to the cross-section is described by propagating waves that are decaying exponentially. Measured frequency response functions (FRFs) are compared with the corresponding calculated FRFs from the two modelling approaches. The calibration is conducted in two steps using (i) a parameter study and (ii) a genetic algorithm. For multiple excitation positions and sensor locations, both calibrated models capture the trend of the Single-Input Multiple-Output measurements with rather small deviations compared to the overall dynamic range. This implies that both models can successfully represent the dynamic response of the test rig and can be considered as validated.
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| 34. |
- Theyssen, Jannik, 1991, et al.
(author)
-
Efficient calculation of the three-dimensional sound pressure field around a railway track
- 2022
-
Journal article (other academic/artistic)abstract
- The wavenumber domain Boundary Element method (or 2.5D BE) is well suited for calculating the acoustic sound field around structures with a constant cross-section along one dimension, such as noise barriers or railway tracks. By expressing the sound field along this dimension in the wavenumber domain, the numerical model is reduced from a 3D model to a 2D model at each wavenumber. A consequence of the required discrete Fourier domain representation is that the sound field is represented by periodically repeating sections, of which only one section is physically meaningful. The resolution and the number of required wavenumbers increase with this section's desired length and spatial discretization. Describing the sound field adequately to auralising the sound field without disturbing artefacts requires a large number of wavenumbers (and thus 2D BE computations), which is not feasible for large geometries. Here, a method is introduced that allows the calculation of the 3D sound field by solving a single 2D BE problem for a dense frequency spectrum and interpolating at a higher wavenumber. The calculation efficiency is further increased by pre-calculating the acoustic transfer functions between each BE surface element and receiver positions. Combining these two methods allows the efficient calculation of the 3D sound field. The numerical approach is validated compared to a standard 2.5D BEM calculation and an analytical model. Pre-calculated transfer functions to calculate the sound radiation from railway tracks are presented and made available online.
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| 35. |
- Theyssen, Jannik, 1991, et al.
(author)
-
Efficient calculation of the three-dimensional sound pressure field around a slab track
- 2024
-
In: Acta Acustica. - 2681-4617 .- 1022-4793. ; 8
-
Journal article (peer-reviewed)abstract
- The wavenumber domain Boundary Element (2.5D BE) method is well suited to calculate the acoustic sound field around structures with a constant cross-section along one dimension, such as noise barriers or railway track. By expressing the sound field along this dimension in wavenumber domain, the numerical model is reduced from a 3D model to 2D model at each wavenumber. A consequence of the required discrete Fourier domain representation is that the sound field is represented by periodically repeating sections, of which only one section is physically meaningful. The resolution and the number of required wavenumbers increases with the desired length and spatial discretisation of this section. Describing the sound field adequately to auralise the sound without disturbing artefacts requires a large number of wavenumbers (and thus 2D BE computations), which is not feasible for large geometries. Here, a method is introduced that allows the calculation of the 3D sound field by solving a single 2D BE problem for a dense frequency spectrum and interpolating at higher wavenumbers. The calculation efficiency is further increased by precalculating the acoustic transfer functions between each BE surface element and receiver positions. Combining these two methods allows for efficient calculation of the 3D sound field around acoustically rigid structures such as slab tracks. The numerical approach is validated by comparison with a standard 2.5D BEM calculation and an analytical solution. Precalculated transfer functions to calculate the sound radiation from railway track, which are made available online, are illustrated. An example application is presented.
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| 36. |
- Theyssen, Jannik, 1991, et al.
(author)
-
On the efficient simulation of pass-by noise signals from railway wheels
- 2023
-
In: Journal of Sound and Vibration. - 1095-8568 .- 0022-460X. ; 564
-
Journal article (peer-reviewed)abstract
- The article presents an approach for calculating pass-by sound pressure radiated from railway wheels in the time domain using moving Green's functions. The Green's functions are obtained by using Finite Element (FE) and Boundary Element (BE) methods in the frequency domain, subsequent inverse Fourier transform, followed by convolution with a time series of rolling contact forces to obtain the pass-by time signals. However, traditional BE methods are computationally expensive due to the low structural damping of the wheel, necessitating a high frequency resolution. To overcome this issue, a modal approach is introduced in which the pass-by sound radiated by each wheel mode is calculated separately. This approach incorporates the dynamic response of the wheel in the time-domain processing and thus reduces the cost of the BE solution. A modal source signal is introduced to describe the excitation of each mode at each time step. The sound field radiated by unit modal amplitudes is calculated in BE and subsequently approximated by spherical harmonic (SH) equivalent sources, which allows for efficiently calculating acoustic transfer functions for varying relative positions of the wheel and a stationary receiver. Convolution of the source signal with the moving acoustic transfer function produces the pass-by pressure signal. The article investigates the directivity of the radiation from each mode and finds that most modes, including those with dominant radial deflection, radiate in mostly axial direction at high frequencies. Modes that dominate the pass-by pressure level are identified, both in frequency bands and with respect to the relative positioning of the wheel to the receiver. Finally, it is found that an SH expansion order of approximately 30 is required to satisfy the employed error measures, although lower orders may suffice for an auralisation of the signal.
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| 37. |
- Theyssen, Jannik, 1991, et al.
(author)
-
The Influence of Track Parameters on the Sound Radiation from Slab Tracks
- 2021
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 90-97
-
Book chapter (other academic/artistic)abstract
- The influence of track parameters on the sound radiation has so far mainly been studied for ballasted tracks. The increasing usage of slab tracks in new railway lines worldwide makes a review of these parameters relevant. In this paper, the structural vibrations of rail and slab are evaluated based on two waveguide finite element models that are coupled in a finite number of positions. This discretely supported rail is compared to a rail on a continuous support. The sound radiation from rail and slab is evaluated based on a wavenumber boundary element method. The slab and rail contributions are evaluated separately. It is found that comparable to ballasted tracks, the rail pad stiffness has a large influence on the radiated sound power. For a continuously supported rail, the total sound power is reduced and the rail pad stiffness is less influential.
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| 38. |
- Theyssen, Jannik, 1991, et al.
(author)
-
The low-noise potential of low-vibration track
- 2021
-
Conference paper (other academic/artistic)abstract
- High-speed railway lines worldwide are increasingly built using slab-track technology, in which a reinforced concrete slab replaces the supporting function of traditional ballast and sleepers. The increased use, no longer limited to tunnels and bridges, is partly due to their lower maintenance, compact construction, and potential for effective isolation against ground-borne vibrations. However, rolling noise on slab tracks typically shows higher levels of noise radiation compared to ballasted tracks. There is an apparent conflict between ground-borne vibration and noise: The stiffness of the rail support determines if the vibrational energy is transmitted into the ground, exciting ground-borne vibrations, or stays in the rail, leading to higher noise radiation. In this work, a slab track construction type called low-vibration track is adapted such that both low vibrations and low noise radiation can be achieved without compromising. This is made possible by tuning the inertia of this system's booted sleeper and its surrounding elasticity to provide a low support stiffness at low frequencies and a high stiffness in the range where the rail has a high radiation efficiency. It is found that the track decay rate, an indicator for the radiated noise from the rail, can be increased significantly above 300 Hz.
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| 39. |
- Theyssen, Jannik, 1991, et al.
(author)
-
Towards auralization of pass-by noise from railway wheels: Sensitivity to the lateral contact position
- 2023
-
In: Proceedings of Forum Acusticum. - 2221-3767. ; , s. 5621-5628
-
Conference paper (peer-reviewed)abstract
- Railway rolling noise is typically described in equivalent pass-by noise levels. However, this descriptor does not always sufficiently correlate with the perceived annoyance of, for example, tonal components or transient effects. An auralisation of such effects allows researching this correlation. The wheels are a main contributor to the overall noise level above about 1 kHz. The low damping of the wheels leads to a strong modal behavior. Typically, modes with a strong axial response to a vertical excitation in the wheel-rail contact dominate the radiated sound. The lateral position of this contact point on the wheel tread, and thus the modal excitation, is therefore an important parameter in an auralisation. However, the exact contact location varies due to the lateral oscillation of the wheelset during running. This paper presents a computationally efficient, time-domain prediction model for the sound pressure produced by one wheel as it passes a stationary track-side position. The model makes use of pre-calculated acoustic transfer functions of each mode, which allow an evaluation of the modal contributions to the track-side sound pressure. The sensitivity of these modal contributions on the lateral contact position is analyzed.
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| 40. |
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| 41. |
- Torstensson, Peter, 1981, et al.
(author)
-
Simulation of rail roughness growth on small radius curves using a non-Hertzian and non-steady wheel-rail contact model
- 2012
-
In: 9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, CM 2012; Chengdu; China; 27 August 2012 through 30 August 2012. ; , s. 223-230
-
Conference paper (peer-reviewed)abstract
- A time-domain model for the prediction of long-term rail roughness growth on small radius curves is presented. Both lowfrequency vehicle dynamics due to curving and high-frequency vehicle-track dynamics excited by short-wavelength rail irregularities are accounted for. The influence of non-Hertzian and non-steady effects in the wheel-rail contact model on rail wear is studied. The model features a refined contact detection algorithm that accounts for wheelset yaw angle as well as surface irregularities and structural flexibilities of wheelset and rail. The development of corrugation on a small radius curve is found to be highly influenced by the wheel-rail friction coefficient. For vehicle speed 25 km/h and friction coefficient 0.3, predictions of long-term roughness growth on the low rail generated by the leading wheelset show decreasing magnitudes in the entire studied wavelength interval. For friction coefficient 0.6, roughness growth is found at several wavelengths. The corresponding calculation for the high rail contact indicates no roughness growth generated by the trailing wheelset independent of friction coefficient. The importance of accounting for the phase between the calculated wear and the present rail irregularity is demonstrated.
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| 42. |
- Torstensson, Peter T, 1981, et al.
(author)
-
Simulation of rail roughness growth on small radius curves using a non-Hertzian and non-steady wheel–rail contact model
- 2014
-
In: Wear. - : Elsevier BV. - 0043-1648. ; 314:1-2, s. 241-253
-
Journal article (peer-reviewed)abstract
- A time-domain model for the prediction of long-term growth of rail roughness (corrugation) on small radius curves is presented. Both low-frequency vehicle dynamics due to curving and high-frequency vehicle–track dynamics excited by short-wavelength rail irregularities are accounted for. The influence of non-Hertzian and non-steady effects in the wheel–rail contact model on rail wear is studied. The model features a contact detection method that accounts for wheelset yaw angle as well as surface irregularities and structural flexibilities of wheelset and rail. The development of corrugation on a small radius curve is found to be highly influenced by the wheel–rail friction coefficient. For vehicle speed 25 km/h and friction coefficient 0.3, predictions of long-term roughness growth on the low rail show decreasing magnitudes in the entire studied wavelength interval. For friction coefficient 0.6, roughness growth is found at several wavelengths. The corresponding calculation for the high rail contact of the trailing wheelset indicates no roughness growth independent of friction coefficient. The importance of accounting for the phase between the calculated wear and the present rail irregularity is demonstrated.
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| 43. |
- Torstensson, Peter, 1981, et al.
(author)
-
Towards a model for prediction of railway tread brake noise
- 2014
-
In: The ISMA conference on Noise and Vibration Engineering (ISMA2014), 15 - 17 September 2014, Leuven. - 9789073802919 ; , s. 3543-3556
-
Conference paper (peer-reviewed)abstract
- A model for complex linear stability analysis of railway tread brakes has been developed. It accounts forinertial effects due to wheel rotation as well as damping provided by tangential wheel–rail contact forces.Kinematic constraint equations are used to model the normal brake–wheel contact. For a brake–wheelfriction coefficient higher than 0.2, unstable vibrations develop for several system eigenmodes in thefrequency range above 6 kHz. The required level of brake–wheel friction at onset of instability isinfluenced by the wheel profile and the tangential wheel–rail contact damping. The present workconstitutes the first step in the development of a prediction model for railway tread brake noise.
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| 44. |
- Zenzerovic, Ivan, 1988, et al.
(author)
-
An engineering time-domain model for curve squeal: Tangential point-contact model and Green's functions approach
- 2016
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 376, s. 149-165
-
Journal article (peer-reviewed)abstract
- Curve squeal is a strong tonal sound that may arise when a railway vehicle negotiates a tight curve. In contrast to frequency-domain models, time-domain models are able to capture the nonlinear and transient nature of curve squeal. However, these models are computationally expensive due to requirements for fine spatial and time discretization. In this paper, a computationally efficient engineering model for curve squeal in the time domain is proposed. It is based on a steady-state point-contact model for the tangential wheel/rail contact and a Green's functions approach for wheel and rail dynamics. The squeal model also includes a simple model of sound radiation from the railway wheel from the literature. A validation of the tangential point-contact model against Kalker's transient variational contact model reveals that the point-contact model performs well within the squeal model up to at least 5 kHz. The proposed squeal model is applied to investigate the influence of lateral creepage, friction and wheel/rail contact position on squeal occurrence and amplitude. The study indicates a significant influence of the wheel/rail contact position on squeal frequencies and amplitudes. Friction and lateral creepage show an influence on squeal occurrence and amplitudes, but this is only secondary to the influence of the contact position.
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| 45. |
- Zenzerovic, Ivan, 1988, et al.
(author)
-
Influence of spin creepage and contact angle on curve squeal: A numerical approach
- 2018
-
In: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 419, s. 268-280
-
Journal article (peer-reviewed)abstract
- Curve squeal is a loud tonal sound that may arise when a railway vehicle negotiates a tight curve. Due to the nonlinear nature of squeal, time-domain models provide a higher degree of accuracy in comparison to frequency-domain models and also enable the determination of squeal amplitudes. In the present paper, a previously developed engineering time-domain model for curve squeal is extended to include the effects of the contact angle and spin creepage. The extensions enable the evaluation of more realistic squeal cases with the computationally efficient model. The model validation against Kalker's variational contact model shows good agreement between the models. Results of studies on the influence of spin creepage and contact angle show that the contact angle has a significant influence on the vertical-lateral dynamics coupling and, therefore, influences both squeal amplitude and frequency. Spin creepage mainly influences processes in the contact, therefore influencing the tangential contact force amplitude. In the combined spin-contact angle study the spin creepage value is kinematically related to the contact angle value. Results indicate that the influence of the contact angle is dominant over the influence of spin creepage. In general, results indicate that the most crucial factors in squeal are those that influence the dynamics coupling: the contact angle, wheel/rail contact positions and friction.
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| 46. |
- Zenzerovic, Ivan, 1988, et al.
(author)
-
Towards an engineering model for curve squeal
- 2015
-
In: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1612-2909 .- 1860-0824. ; 126, s. 433-440
-
Journal article (peer-reviewed)abstract
- Curve squeal is a strong tonal noise that may arise when a railway vehicle negotiates a curve. The wheel/rail contact model is the central part of prediction models, describing the frictional instability occurring in the contact during squeal. A previously developed time-domain squeal model considers the wheel and rail dynamics, and the wheel/rail contact is solved using Kalker’s nonlinear transient CONTACT algorithm with Coulomb friction. In this paper, contact models with different degree of simplification are compared to CONTACT within the previously developed squeal model in order to determine a suitable contact algorithm for an engineering curve squeal model. Kalker’s steady-state FASTSIM is evaluated, and, without further modification, shows unsatisfying results. An alternative transient single-point contact algorithm named SPOINT is formulated with the friction model derived from CONTACT. Comparing with the original model results, the SPOINT implementation results are promising and similar to results from CONTACT.
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