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Sound files supporting the PhD thesis "Modelling Railway Rolling Noise"
No full textThis dataset includes supplementary sound files for the PhD thesis:
C Knuth, Modelling Railway Rolling Noise, University of Southampton, Faculty of Engineering and Physical Sciences, 2025
This dataset contains the sound files produced using the numerical models developed during the PhD candidature (2020 - 2025) for listening to synthesised railway rolling noise signals and impulse responses of the railway track. The simulations were carried out by combining the FE model of a rotating railway wheelset with a 2.5D FE/BE model of the railway track in a rolling noise prediction scheme for roughness excitation. Overall 28 sound files are included as .wav files and structured in the folders of the supplemented .zip file. The folders contain the following files:
- Impulse response of the rail and sleepers (sound pressure at the receiver for a vertical unit force on the rail head) at distances 0, 25 m and 50 m from the forcing position
- Simulated pass-by rolling noise signals of a single wheel on a single rail and the sleepers excited by the rail for a speed of 160 km/h
- Simulated pass-by rolling noise signals of a wheelset (two wheels) on both rails and the sleeper excited by the two rails for a speed of 160 km/h
- Simulated pass-by rolling noise signals of four wheelsets on both rails and the sleeper excited by the two rails for a speed of 160 km/h
- Measured pass-by noise signal of the train for a speed of 160 km/h
- Simulated pass-by rolling noise signals of a train (16 wheelsets on both rails and the sleeper excited by the rails) for a speed of 160 km/h for replicating the measurement
- Measured pass-by noise signal of the train for a speed of 80 km/h
- Simulated pass-by rolling noise signals of a train (16 wheelsets on both rails and the sleeper excited by the rails) for a speed of 80 km/h for replicating the measurement
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Modelling railway rolling noise
No full textRailways are a vital component of modern transportation systems and play a crucial role in achieving climate goals as an environmentally friendly means of travel. One key challenge for a shift to rail is railway noise. It arises from various sources, with rolling noise being the most significant at conventional train speeds. Existing prediction tools rely on various simplifications that potentially limit their accuracy. This thesis therefore aims to overcome this by developing a comprehensive simulation tool for rolling noise predictions by combining state-of-the-art numerical models of the wheel and the track, capable of accurate calculations up to high frequencies. Neglecting wheel rotation or simplifying it as a moving load is a commonly found modelling assumption. To investigate this effect, a rotating axisymmetric Finite Element model of the wheel has been developed. Results show that resonances in the frequency response of the rotating wheel split into two distinct peaks, with the separation depending on the mode type and train speed. These peaks correspond to co- and counter-rotating waves that do not have fixed nodal lines around the wheel circumference. In contrast, in a non-rotating wheel, these peaks do not separate, leading to standing waves with fixed nodal lines and partial decoupling of vibrations. Simplifying rotation by a moving load approximation only partially captures the peak separation.Using a Timoshenko beam to model the rail neglects cross-section deformation, which may be important, particularly at high frequencies. Therefore, a 2.5D Finite Element rail model has been implemented and coupled to an equivalent continuous support. The track frequency responses are analysed for different forcing conditions. It is shown that the vibration transmitted along the rail consists of several waves that dominate at different frequencies and distances from the excitation position, depending on the forcing location on the rail and the direction of the force. These waves include cross-section deformation as frequency increases and introduce vertical/lateral coupling due to torsion, which is not seen in a Timoshenko beam model. The 2.5D FE track model showed a good agreement with measurements in terms of the frequency responses and track decay rates.The rotating wheel model was coupled to an analytical model to calculate the sound radiation, while a 2.5D Boundary Element model of the track has been implemented for accurate high-frequency calculations that capture the effects of rail cross-section deformation. By introducing an interpolation method, calculation times are reduced by a factor of over 100, enabling efficient calculations of rail and sleeper sound power. It is shown that cross-section deformation can increase the sound power by over 10 dB for excitation with a vertical force. Larger differences occur for lateral forcing conditions, as the Timoshenko beam model does not account for rail torsion and foundation eccentricity. The sound radiation from the sleepers is modelled as a discrete set of radiators, showing that, in comparison with a rigidly vibrating sleeper, a flexible sleeper can increase sound power around the sleeper resonance frequencies. This is more relevant in a track with a stiffer rail pad, that increases the rail-on-pad resonance beyond the first few modal sleeper frequencies.The developed wheel and track models are coupled in an interaction model for roughness excitation, allowing for the vertical, lateral, longitudinal and spin degrees of freedom, and used to calculate rolling noise in terms of sound power in the frequency domain. The effects of some common modelling assumptions are quantified by comparing the current model with simplified track, wheel, and interaction models. The rolling noise calculations show that rail cross-section deformation increases the rail sound power by up to 6 dB at high frequencies in one-third octave band resolution. This increase is more relevant in a track with a soft rail pad, where the rail contribution remains significant in comparison with the wheel, even at high frequencies. A Timoshenko beam is therefore less suitable, in general, to predict rail sound radiation accurately. The sound power of the rotating wheel has up to 8 dB difference in one-third octave bands compared with the non-rotating wheel. The overall wheel sound power is increased by 2-3 dB at common train speeds if rotation is included. A moving load approximation reduces this difference to about 0.5 dB, making this a reasonable modelling simplification. Further, it is found that including coupling in the interaction model in longitudinal and spin direction yields small changes of up to 0.5 dB in wheel or rail sound power compared with only including vertical and lateral coupling.Finally, a sound propagation model has been introduced which allows the pass-by synthesis of rolling noise produced by a set of wheels moving along the track above a ground represented by an acoustic impedance. This enabled a comparison with measured pass-by noise to validate the model. The comparison showed the model can accurately predict the temporal evolution of rolling noise. The overall A-weighted level is predicted within up to 1 dB accuracy. In the one-third octave bands from 400 Hz to 8 kHz, the noise was underestimated by 2.6 dB and 2.2 dB on average for train speeds of 160 km/h and 80 km/h. Further validations of the full rolling noise model are desirable to determine the range of its applicability and confirm its robustness
An engineering approach for estimating the radiation efficiency of orthogonally stiffened plates
No full textA systematic investigation of the sound radiation of orthogonally stiffened plates is presented using a numerical procedure that combines the finite element method with the Rayleigh integral. Results are computed for plates with different numbers of stiffeners, stiffener depth, and plate thickness to investigate the dependence on the most important parameters. Differences are seen in the radiation efficiency of stiffened plates compared with unstiffened panels. In the monopole region, the result depends on the type of mode that dominates the response. For excitation within a bay, the radiation efficiency is reduced to that of a single bay if the stiffeners are stiff enough. If excited on a stiffener, the plate tends to radiate sound over its full surface area. In the short-circuiting region, on average, the radiation efficiency is equal to that of a smaller bay-sized panel with clamped edges, regardless of the excitation position. Results from the systematic study of 120 numerical cases are used to develop asymptotic formulae for the radiation efficiency of stiffened plates based on existing formulae for unstiffened panels. For all tested configurations, the average difference between the formulae and the numerical calculations was 0.3 dB over the whole frequency spectrum, with a standard deviation of ±1.5 dB. Between the frequency bands, the mean value varied between −2 and 3 dB, with a standard deviation of up to ±1.5 dB in the monopole region and a larger variation of up to ±5 dB in the short-circuiting region
Data supporting the article "An efficient model for predicting the sound radiation from a railway rail accounting for cross-section deformation"
No full textThis dataset contains the numerical data used to produce Figures 5-23 of the publication, some of which are divided into sub-figures from (a)-(c). </span
An efficient numerical model for the sound radiation from a supported rail
No full textIn this work, the sound radiation of a supported rail is investigated using a numerical 2.5D Finite Element model that is coupled with a 2.5D Boundary Element model. The vibration of the track is modelled by coupling the infinite rail to an equivalent continuous double-layer support and is used as input for calculating the consequent sound radiation. An interpolation method that allows for a quick solution of the boundary element calculations is proposed and validated by comparison with an analytical solution, showing differences less than 0.1 dB. The assembled model is used for calculating the sound radiation from the rail in terms of sound power per unit squared force applied to the rail head in vertical and lateral directions for three different rail configurations. The transfer functions obtained can be used in rolling noise calculations. The proposed interpolation method allows calculations that are more than 100 times faster than the regular procedure for the case considered
Data supporting the article: An engineering approach for estimating the radiation efficiency of orthogonally stiffened plates
No full textChristopher Knuth, Giacomo Squicciarini, David Thompson (2023) Dataset supporting the article: An engineering approach for estimating the radiation efficiency of orthogonally stiffened plates. Published in ASME Journal of Vibration and Acoustics
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An efficient model for predicting the sound radiation from a railway rail accounting for cross-section deformation
No full textThe track is the main contributor to railway rolling noise below 2 kHz. In this frequency range it is usually acceptable to represent the rail vibration using a Timoshenko beam. At higher frequencies, however, cross-section deformation occurs in the rail, which requires more complex track models. In this paper a vibroacoustic 2.5D Finite Element and Boundary Element model of a continuously supported rail is implemented for studying the effect of cross-section deformation on sound radiation. A novel interpolation strategy is developed to significantly reduce the solution time by interpolating element coefficient vectors. Results are calculated for vertical or lateral excitation applied to the rail head and comparisons are made with a Timoshenko beam model in which the cross-section remains undeformed. For vertical excitation, the sound power from both models is identical below 3 kHz, while for lateral excitation, the Timoshenko beam has differences of up to 25 dB below 200 Hz owing to the missing rail torsion and foundation eccentricity. Above 3 kHz for vertical excitation and from 1 kHz for lateral excitation, higher-order waves contribute to the sound power, causing an underestimation of up to 15 dB if the cross-section deformation is neglected. The calculated transfer functions of rail sound power per unit squared force are incorporated in a rolling noise prediction model that includes vertical and lateral dynamics. The results show that the Timoshenko beam rail underestimates the rail sound power by up to 5 dB in comparison with the 2.5D rail model in one-third octave bands.<br/
Railway rolling noise synthesis using a numerical modelling approach
No full textRolling noise is the major source of noise in railways at conventional train speeds. It is radiated by vibration of the wheel and track excited by the combined wheel and rail surface roughness [1]. Rolling noise prediction models such as TWINS (Track-Wheel Interaction Noise Software) [2] are principally designed to predict sound power accurately in the frequency domain, combining numerical and analytical methods. In the EU project Acoutrain [3], a sound propagation model was developed for modelling the temporal evolution of the sound pressure level during train pass-by. The wheel and track were simplified to moving point sources based on the sound power predicted from TWINS and simplified directivities. Models for the auralization of railway noise were implemented by Pieren et al. [4, 5] or Theyssen [6]. In this paper, a new numerical model based on the TWINS approach is employed for the synthesis of pass-by rolling noise signals using state-of-the-art wheel and track models that allow accurate calculations up to high frequencies
The effect of wheel rotation on the rolling noise predictions
No full textThe effect of the wheel rotation on its sound radiation in rolling noise predictions is investigated. The wheel response is modelled using a finite element model that can account for the different effects introduced by rotation and together with TWINS the radiated sound power is determined. Noise and vibration data are compared over a range of typical train speeds, between a stationary wheel, a rotating wheel where rotation is replaced by a moving load, and a rotating wheel that also includes the inertial forces. Compared with the most complete model, differences in the wheel sound power level of up to 6 dB in one-third octave bands are found if the stationary wheel is used instead. The differences remain below 2 dB for speeds up to 500 km/h if the rotation is approximated with a moving load. In terms of the total A-weighted sound power level of the wheel, the stationary wheel underestimates the noise by up to 3 dB, while the differences are less than 1 dB for a moving load. Generally, the differences introduced by the approximate representations of the wheel rotation are smaller than the uncertainties that are in-evitable in rolling noise predictions. The results show that in rolling noise predic-tions for usual train speeds the wheel rotation is sufficiently well approximated by a moving load, which is the method implemented in TWINS
Data supporting the article "Effects of rotation on the rolling noise radiated by wheelsets in high-speed railways"
No full textThis dataset supporting the article:
C Knuth, G Squicciarini, D Thompson, L Baeza,
Effects of rotation on the rolling noise radiated by wheelsets in high-speed railways, Journal of Sound and Vibration, Volume 572, 2024,
118180, ISSN 0022-460X,
https://doi.org/10.1016/j.jsv.2023.118180
This dataset contains the numerical data used to produce the Figures 2-12 of the publication, some of which are divided into sub-figures from (a)-(c).
-It is separated into 15 Microsoft Excel files (.xls), one for each sub-figure.
-The x- and y- data are stored as a matrix in the sheet, where the first column always corresponds to the x-data and the remaining to the y-data of the individual lines shown in the figure.
-A description is available in each sheet, that refers the data to the corresponding line in the figure.
-In Figure_5.xls three sheets are used because of the length of the data, where sheet 1 corresponds to frequencies from 10-3340 Hz, sheet 2 to 3340.1-6670 Hz, and sheet 3 to 6670.1-10000 Hz.
-In the ZIP file the data is organised in excel files by figures.
The simulations were carried out by combining the rotating wheelset model developed in this paper with the Track Wheel Interaction Noise Software (TWINS).
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