| 1. |
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| 2. |
- Bergman, Penny, 1982, et al.
(författare)
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Perceptual validation of auralized heavy-duty vehicles
- 2015
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Ingår i: Euronoise 2015. ; , s. 769-774
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Konferensbidrag (refereegranskat)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. |
- Eriksson, Olle, 1967-, et al.
(författare)
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Survey of Curve Squeal Occurrence for an Entire Metro System
- 2024
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Ingår i: Noise and Vibration Mitigation for Rail Transportation Systems. - : Springer. - 9789819978519 - 9789819978526 ; 14th International Work-shop on Railway Noise, IWRN 2022, s. 483-490
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Bokkapitel (refereegranskat)abstract
- The current work presents a statistical analysis based on data collected during approximately 1.5 years of regular operation by two vehicles equipped with an on-board noise monitoring system on the Stockholm metro. Data covers 379,776 passages through 143 curves with radii up to 1000 m. Binary logistic regression is used to investigate the importance of curve radius, vehicle speed, relative humidity, air temperature, rail grinding and vehicle individual on curve squeal. Curve squeal occurrence shows an inverse proportionality with respect to curve radius. This trend is particularly pronounced for curve radii below 600 m. The two vehicles accounted for in the study show differences in propensity to generate squeal. The influence of temperature and relative humidity, and their interaction, on curve squeal is described by an estimated response surface. Results show the occurrence of curve squeal to increase after rail grinding. No strong relationship between curve squeal occurrence and vehicle speed is identified.
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| 4. |
- Fabre, François, et al.
(författare)
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Sound Radiation from Railway Wheels including Ground Reflections: A half-space formulation for the Fourier Boundary Element Method
- 2021
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 493
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Tidskriftsartikel (refereegranskat)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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| 5. |
- Garcia-Andrés, Xavier, et al.
(författare)
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REDUCING ROLLING NOISE IN RAILWAY WHEELS WITH CONSTRAINED LAYER DAMPING TREATMENTS CONSIDERING COMPREHENSIVE VISCOELASTIC MODELS
- 2023
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Ingår i: Proceedings of the International Congress on Sound and Vibration. - 2329-3675.
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Konferensbidrag (refereegranskat)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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| 6. |
- Grau, Loïc, et al.
(författare)
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Influence of the ground/structure interaction on the calculation of the force at the wheel/rail contact
- 2016
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Ingår i: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 2086-2097
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Konferensbidrag (refereegranskat)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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| 7. |
- Kropp, Wolfgang, 1959, et al.
(författare)
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The application of dither for suppressing curve squeal
- 2019
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Ingår i: Proceedings of the International Congress on Acoustics. - 2226-7808 .- 2415-1599. ; 2019-September, s. 1551-1558
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Konferensbidrag (refereegranskat)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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| 8. |
- Kropp, Wolfgang, 1959, et al.
(författare)
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The application of dither to mitigate curve squeal
- 2021
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 514
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Maglio, Michele, 1993, et al.
(författare)
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Railway wheel tread damage and axle bending stress – Instrumented wheelset measurements and numerical simulations
- 2022
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Ingår i: International Journal of Rail Transportation. - : Informa UK Limited. - 2324-8386 .- 2324-8378. ; 10:3, s. 275-297
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Maglio, Michele, 1993, et al.
(författare)
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Wheel–rail impact loads and axle bending stress simulated for generic distributions and shapes of discrete wheel tread damage
- 2021
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 502
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Tidskriftsartikel (refereegranskat)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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