| 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. |
- 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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| 4. |
- 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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| 5. |
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| 6. |
- Pieringer, Astrid, 1979, et al.
(författare)
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Curve squeal of rail vehicles: Linear stability analysis and non-linear time-domain simulation
- 2016
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Ingår i: Civil-Comp Proceedings. - 1759-3433. ; 110
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Pieringer, Astrid, 1979, et al.
(författare)
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Investigation of railway curve squeal using a combination of frequency- and time-domain models
- 2016
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Ingår i: Proceedings of the 12h International Workshop on Railway Noise (IWRN12), Terrigal, Australia, September 12-16. ; , s. 444 - 451
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Konferensbidrag (refereegranskat)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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| 8. |
- Pieringer, Astrid, 1979, et al.
(författare)
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Investigation of railway curve squeal using a combination of frequency- and time-domain models
- 2018
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Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; 139, s. 83-95, s. 83-95
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Bokkapitel (övrigt vetenskapligt/konstnärligt)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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| 9. |
- Pieringer, Astrid, 1979, et al.
(författare)
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Modelling of railway curve squeal including effects of wheel rotation
- 2015
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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 10. |
- Zenzerovic, Ivan, 1988, et al.
(författare)
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An engineering time-domain model for curve squeal: Tangential point-contact model and Green's functions approach
- 2016
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 376, s. 149-165
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Tidskriftsartikel (refereegranskat)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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| 11. |
- Zenzerovic, Ivan, 1988, et al.
(författare)
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Influence of spin creepage and contact angle on curve squeal: A numerical approach
- 2018
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 1095-8568 .- 0022-460X. ; 419, s. 268-280
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Tidskriftsartikel (refereegranskat)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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| 12. |
- Zenzerovic, Ivan, 1988, et al.
(författare)
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Towards an engineering model for curve squeal
- 2015
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Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1612-2909 .- 1860-0824. ; 126, s. 433-440
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Tidskriftsartikel (refereegranskat)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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