The invention relates to the field of light-rail sound absorption, in particular to a sound absorbing device used for the U-beam
composite structure of the
light rail. The sound absorbing device comprises a sound absorbing device body, the sound absorbing device body is composed of a microporous plate,
tin foil, sound absorbing cotton, a cavity and a bottom plate from outside to inside, the surface of the microporous plate is provided with micropores spaced, the
tin foil is closely attached above the sound absorbing cotton, spaced projections are arranged on the bottom plate, and the height of the projections is identical with the height of the cavity. The sound absorbing device is of
composite structure, the microporous plate is an aluminum
alloy pore plate or an inorganic pore plate, the bottom plate is molded by PVC (
polyvinyl chloride)
alloy materials by a
vacuum casting process. The sound absorbing device is filled with the sound absorbing cotton (with
noise reduction coefficient larger than or equal to 0.88), and is specially designed from the aspects of flow resistance of an acoustic panel absorber,
porosity,
structure factor, thickness, density, surface material treatment and mounting, advantages of various single materials can be sufficiently given into play, high, medium and
low frequency broad-spectrum
noise is reduced, and the sound absorbing device has the advantages of simplicity, convenience, attractive appearance and practicality.