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Wyszukujesz frazę "sound transmission loss" wg kryterium: Temat

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    Wyświetlanie 1-6 z 6
    Tytuł:
    Using MLS methods in laboratory measurement of airborne sound insulation
    Autorzy:
    Mleczko, Dominik
    Powiązania:
    https://bibliotekanauki.pl/articles/2146652.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    sound insulation
    sound transmission loss
    MLS method
    izolacyjność akustyczna
    izolacyjność akustyczna od dźwięków powietrznych
    metoda MLS
    Opis:
    Following the requirements of ISO 10140, to determine the acoustic insulation, measurements of the sound pressure levels in the source (L1) and receiving (L2) rooms and the reverberation time measurements in the receiving room (T) should be performed. However, the standard does not indicate the measuring signal to be used for the measurements. Various measurement methods can be used, including the use of the broadband noise or MLS method. The article examines the influence of the applied measurement methodology on the determined spectra of acoustic insulation and the weighted sound reduction index Rw. The total uncertainty of determining the acoustic insulation properties and partial uncertainties in determining L1, L2 and T were also calculated. The analysis of the obtained results allows concluding that the applied measurement method has no significant impact on the obtained acoustic insulation values, and the obtained measurement differences may rather be the result of an insufficient sample size.
    Źródło:
    Vibrations in Physical Systems; 2021, 32, 2; art. no. 2021205
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparative analysis of the acoustic properties of granular materials determined with the use of impedance tube
    Autorzy:
    Kosała, Krzysztof
    Powiązania:
    https://bibliotekanauki.pl/articles/24202011.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    granular materials
    sound absorption coefficient
    sound transmission loss
    materiały ziarniste
    współczynnik pochłaniania dźwięków
    strata transmisji dźwięku
    Opis:
    The results of acoustic property tests for six types of granular materials: perlite, vermiculite, active coconut carbon, rubber granulates, pumice and wood chips, which can be used in noise protection structures, are shown in the article. The characteristics of the normal incidence sound absorption coefficient and the normal incidence sound transmission loss for material specimens with seven thicknesses in the range of 10-100 mm were determined based on the results of experimental tests carried out with the use of an impedance tube. The relationships between the first resonant absorption frequencies and the thicknesses of material specimens were determined. Single-number indices for the tested materials, in the form of the weighted sound absorption coefficients, were determined. Subsequently, dependencies of these indices on the surface mass of the tested materials were determined. The research showed that three materials, perlite, vermiculite and active coconut carbon, were distinguished among the examined granules with the best sound-absorbing and sound-insulating properties. Active coconut carbon had the best sound-insulating properties among the granular materials tested.
    Źródło:
    Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022321
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental study and prediction of insertion loss of acoustical enclosures
    Autorzy:
    Kosała, Krzysztof
    Majkut, Leszek
    Olszewski, Ryszard
    Powiązania:
    https://bibliotekanauki.pl/articles/2146558.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    acoustical enclosures
    prediction of insertion loss
    sound transmission loss
    obudowy akustyczne
    predykcja tłumienności wtrąceniowej
    tłumienność przesyłania dźwięku
    Opis:
    The article presents the results of an experimental study and calculations, using theoretical models, of the insertion loss of acoustical enclosures. The research used a developed prototype stand for testing acoustical enclosures. The sound power levels of the source without and with the enclosure, needed to determine the insertion loss, were determined by the approximate method in accordance with standard requirements. To calculate of the insertion loss for enclosures with sound absorbing and insulating walls, a known calculation model using the transmission loss of baffles was used. A new calculation model for enclosures with sound insulating walls is proposed in the article.
    Źródło:
    Vibrations in Physical Systems; 2020, 31, 2; art. no. 2020209
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental tests of the acoustic properties of sound-absorbing linings and cores of layered baffles
    Autorzy:
    Kosała, Krzysztof
    Powiązania:
    https://bibliotekanauki.pl/articles/2146647.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    sound transmission loss
    sound absorption coefficient
    insertion loss
    baffles
    mineral wool
    izolacyjność akustyczna od dźwięków powietrznych
    współczynnik pochłaniania dźwięku
    tłumienie przepustowe
    przegrody
    wełna mineralna
    Opis:
    The article presents the results of research on the acoustic properties of materials used as sound-absorbing linings and cores in baffles of anti-noise protection. Using an impedance tube the spectral characteristics of the normal incidence sound absorption and sound transmission loss indices of 12 specimens of mineral wool with different density and thickness were determined. From these characteristics, the single-number weighted sound absorption coefficient αw and the sound reduction index Rw were calculated. To calculate the value of the Rw index on the basis of surface mass of the mineral wool specimen, a new formula was proposed. The insertion loss of an acoustic enclosure with one, two and three-layer walls with dimensions of 0.7×0.7 m, containing mineral wool, was determined. The best efficiency was achieved for the enclosure made of walls of layers: mineral wool, placed on the sound source side, steel plate and aluminium plate.
    Źródło:
    Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021107
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sound transmission loss calculation for metamaterial plate using combined analytical and numerical approach
    Autorzy:
    Chojnacka, Klara
    Kras, Aleksander
    Kamisiński, Tadeusz
    Powiązania:
    https://bibliotekanauki.pl/articles/24201968.pdf
    Data publikacji:
    2022
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    locally resonant structures
    metamaterials
    sound transmission loss
    simulations
    diffuse field
    struktury miejscowo rezonujące
    metamateriały
    strata transmisji dźwięku
    symulacje
    pola rozproszone
    Opis:
    In recent years acoustic metamaterials are broadly investigated in many different fields of acoustics and one of them is noise and vibration mitigation. The solution with highest potential are locally resonant metamaterials (LRS), which by creation of band gap effect in flexural wave propagation in structure improve its Sound Transmission Loss (STL). Standard STL simulation procedures can be fully analytical or numerical. Analytical solution, when it comes to metamaterial modelling, is fast but it does not take into consideration metamaterial geometry. On the other hand numerical solution even when considering small part of periodic structure, is time consuming and can generate numerical errors related for example to the mesh. In this work combined analytical - numerical method is analysed as the alternative for STL calculation. This method can be a substitute for basic simulation procedures concerning vibro-acoustic metamaterials, since the simulations results are comparable and it is less time consuming method. Formulas and simulation procedure for the presented method are described and compared with analytical and numerical simulation results as well as with STL measurement results.
    Źródło:
    Vibrations in Physical Systems; 2022, 33, 3; art. no. 2022314
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modeling of sound power transmission within duct systems
    Autorzy:
    Strek, Tomasz
    Powiązania:
    https://bibliotekanauki.pl/articles/2146600.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Poznańska. Instytut Mechaniki Stosowanej
    Tematy:
    transmission loss
    finite element method
    dimensionless acoustic equations
    sound power
    izolacyjność akustyczna
    metoda elementów skończonych
    moc akustyczna
    Opis:
    External boundaries of acoustic devices can channel sound propagation, and in some cases can create buildup or attenuation of acoustic energy within a confined space. In this paper, it is proposed an efficient practical numerical method (based on FEM) of calculation of attenuation of sound power transmission through ducts. The method shows its viability by presenting the reasonably consistent anticipation of the experimental result. One can observe the mechanical behaviour of the duct’s medium for lower frequencies (high transmission loss) and wave behaviour for higher frequencies (small or zero attenuation). The authors proved that mechanical vibrations of medium reduce the possibility of acoustic energy transmission in duct systems. The radiation impedance for the duct is calculated as well.
    Źródło:
    Vibrations in Physical Systems; 2020, 31, 3; art. no. 2020320
    0860-6897
    Pojawia się w:
    Vibrations in Physical Systems
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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