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  • 101.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering.
    Identification of rail contribution to pass-by noise by a modified wave signature extraction (WSE) method2018Ingår i: INTER-NOISE and NOISE-CON Congress and Conference Proceedings, Institute of Noise Control Engineering , 2018, s. 617-625Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The present paper explores a modified version the wave signature extraction (WSE) method [1], whose aim is to separate the rail contribution to the pass-by noise of railway vehicles. The method requires a line microphone array parallel to the rail, and two accelerometers on the rail in the ver- tical and lateral direction. The motivation for this work is the need to separate the rail contribution to the pass-by noise of railway vehicles. The WSE method [1] is based on the wavenumber domain filtering of pass-by data measured with a microphone array located in the near-field of the rail. The filter design does not require a priori information of the structural properties of the rail, since the required information is obtained from array pressure data and rail vibration data before and after the train passes in front of the array. The filter is such that it extracts the dispersion plot branches of the first family of horizontal and vertical bending waves (moving band-pass filter). Although the comparison with TWINS simulation data provides very promising results, there are discrepancies at the higher frequencies, possibly due to the onset of new bending wave families. Therefore in the present paper we propose a modified filtering procedure, where a bank of band-pass and low-pass filters are used instead, and the results are compared to the original WSE implementation and the TWINS simulation data. We show that the results in the higher frequency range are improved with respect to the original WSE implementation.

  • 102.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering.
    On modified wavenumber filters for rail contribution estimations2018Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 144, s. EL286-EL289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This brief communication exposes an overview of various wavenumber filters to separate the rail contribution to pass-by noise via the wave signature extraction method [Zea, Manzari, Squicciarini, Feng, Thompson, and Lopez Arteaga, J. Sound Vib. 409, 24–42 (2017)]. It has been found that the originally proposed filters underesti- mate the rail noise at frequencies above 1.6 kHz due to the presence of higher-order wave families that is unaccounted for. The goal of this let- ter is thus to propose and examine different filter functions that can cap- ture such waves, and to assess whether the rail contribution estimations can be improved.

  • 103.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering.
    Simplified wave signature extraction method for rail contribution estimations2018Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The present paper investigates a modified implementation of the wave signature extraction (WSE) method [1], whose aim is to separate the rail contribution to the pass-by noise of railway vehicles. The method requires a line microphone array parallel to the rail, and two accelerometers on the rail in the vertical and lateral direction. The motivation for this work is the need to separate the rail contribution to the pass-by noise of railway vehicles. The WSE method [1] is based on the wavenumber domain filtering of pass-by data measured with a microphone array located in the near-field of the rail. The filter design does not require a priori information of the structural properties of the rail, since the required information is obtained from array pressure data and rail vibration data before and after the train passes in front of the array. The filter is such that it extracts the dispersion plot branches of the first family of horizontal and vertical bending waves (moving band-pass filter). Although the comparison with TWINS simulation data provides very promising results, there are discrepancies at the higher frequencies, possibly due to the onset of new bending wave families. Therefore in the present paper we assess the performance of a simplified WSE method, where a moving low-pass filter is used instead, and the results are compared to the original WSE implementation and the TWINS simulation data. We show that the results in the higher frequency range are improved with respect to the original WSE implementation.

    [1] Zea et al. Journal of Sound and Vibration 409, pp. 24–42, 2017

  • 104.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Single layer planar near-field acoustic holography for compact sources and a parallel reflector2016Ingår i: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 380, s. 129-145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We consider the problem of planar near-field acoustic holography (PNAH) and introduce a new reconstruction method that can be used to process single layer pressure measurements performed in the presence of a reflective surface that is parallel to the measurement plane. The method is specially tailored for compact sources, or for problems in which the scattered field due to the source can be neglected. The approach consists in formulating a seismic model (WRW model) in wavenumber–space and employ it for sound source reconstructions. The proposed method is validated with numerical and experimental data, and, although the most accurate results are obtained when an estimate of the surface impedance is known beforehand, we show that it can substantially improve the reconstruction performance with respect to that of free-field PNAH.

  • 105.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Single-layer array method to reconstruct extended sound sources facing a parallel reflector2017Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 141, nr 5, s. 3984-3984Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    The accuracy of sound field reconstruction methods with single-layer microphone arrays is subject to the room or enclosure in which the measurements take place. Thus, the authors recently introduced a single-layer method that can be employed to reconstruct compact sources in the presence of a reflecting surface that is parallel to the array. Now the authors propose a method conceived for extended planar sources such as baffled plates facing a parallel reflector. The method is based on a wavenumber-domain function describing the propagation paths between the source, the reflector and the array. The free-space sound field radiated by the source is then recovered by means of a regularized inversion of the propagation function. Numerical simulations are performed in order to assess the method's performance and potential for source reconstructions. The results are promising and point towards future experimental validation.

  • 106.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering.
    Sound field separation for planar sources facing a parallel reflector2019Ingår i: Applied Acoustics, ISSN 0003-682x, Vol. 149C, s. 181-191Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We consider the problem of separating and reconstructing the sound field radiated by a planar source, e.g. a vibrating plate, that faces a parallel reflector. For this purpose we propose a Fourier-based technique to process near-field microphone array measurements that are performed on a single plane between the plate and the reflector. A closed-form expression is derived in the wavenumber domain to recover the free-space sound field radiated by the plate. The fundamental assumption is that the plate scatters sound in a locally-reacting fashion. Overall, provided the admittances of the plate and the reflecting surface are known, the results demonstrate that it is possible to recover the free-field sound radiated by the plate with a reasonable accuracy.

  • 107.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering.
    Space-variant sound field separation with linear microphone arrayManuskript (preprint) (Övrigt vetenskapligt)
  • 108.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Manzari, Luca
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering, The Netherlands.
    Squicciarini, Giacomo
    University of Southampton, ISVR.
    Thompson, David
    University of Southampton, ISVR.
    Separation of track contribution to pass-by noise by near-field array techniques2016Ingår i: Proceedings of the 22nd International Congress on Acoustics, 2016Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A technique to separate the track noise contribution is proposed based on identifying and extracting the track signature from the pass-by noise information measured with a microphone array relatively close to the track. Separation of the contributions of the vehicle and the track in the pass-by noise spectra is a challenging task, which is currently addressed by a combination of direct and indirect measurements and model predictions. Due to the uncertainties in the separation of the track contribution, whether a vehicle will comply with regulations during certification tests is still very much track dependent. Therefore, accurate means to identify the track contribution to the pass-by noise are needed. In this paper we propose to make use of the fact that in a wide frequency range the track is a distributed source that radiates plane waves at a given angle with respect to the track. By measuring the sound field close to the track with a microphone array, the wavenumber spectrum of the radiated sound can be determined. For the track contribution this wavenumber spectrum is tonal and therefore sparse. We make use of this property to design filters that extract the track contribution to the total pass-by noise. This is illustrated with simulations and experiments. 

  • 109.
    Zea, Elias
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Manzari, Luca
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Squicciarini, Giacomo
    University of Southampton, Institute of Sound and Vibration Research.
    Feng, Leping
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Thompson, David
    University of Southampton, Institute of Sound and Vibration Research.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Eindhoven University of Technology, Department of Mechanical Engineering.
    Wavenumber-domain separation of rail contribution to pass-by noise2017Ingår i: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 409, s. 24-42Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to counteract the problem of railway noise and its environmental impact, passing trains in Europe must be tested in accordance to a noise legislation that demands the quantification of the noise generated by the vehicle alone. However, for frequencies between about 500 Hz and 1600 Hz, it has been found that a significant part of the measured noise is generated by the rail, which behaves like a distributed source and radiates plane waves as a result of the contact with the train's wheels. Thus the need arises for separating the rail contribution to the pass-by noise in that particular frequency range. To this end, the present paper introduces a wavenumber–domain filtering technique, referred to as wave signature extraction, which requires a line microphone array parallel to the rail, and two accelerometers on the rail in the vertical and lateral direction. The novel contributions of this research are: (i) the introduction and application of wavenumber (or plane–wave) filters to pass-by data measured with a microphone array located in the near-field of the rail, and (ii) the design of such filters without prior information of the structural properties of the rail. The latter is achieved by recording the array pressure, as well as the rail vibrations with the accelerometers, before and after the train pass-by. The performance of the proposed method is investigated with a set of pass-by measurements performed in Germany. The results seem to be promising when compared to reference data from TWINS, and the largest discrepancies occur above 1600 Hz and are attributed to plane waves radiated by the rail that so far have not been accounted for in the design of the filters.

  • 110. Zhou, H.
    et al.
    Lopez-Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. Eindhoven University of Technology, Netherlands.
    Nijmeijer, H.
    Broadband planar nearfield acoustic holography based on one-third-octave band analysis2016Ingår i: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 109, s. 18-26Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Planar nearfield acoustic holography (PNAH) is usually based on narrow-band, single frequency analysis, which is time consuming when the source behavior over a broad frequency range is of interest, as is the case with many industrial sources. In this paper a method, broadband planar nearfield acoustic holography based on one-third-octave band analysis (BPNAH), is described. Data relating to the complex band pressure on the hologram is obtained by combining the root-mean-square pressure corresponding to a one-third-octave band with the phase of the pressure corresponding to a single frequency line. Numerical simulations and measurements show that the BPNAH method allows a significant reduction in processing time, while keeping a similar accuracy to the conventional reconstruction, which is based on the summation of frequency by frequency in the corresponding band. As a simple, time-saving and robust technique, the BPNAH method is particularly well adapted to industrial studies.

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