Research On Sound Absorption Properties Of Perforated Panel Resonant Sound Absorber

Noise pollution is more serious.Reducing noise at low frequency is difficult.Staying prolonged in environment of high noise pressure level can deduce a health hazard.A low frequency noise can be dissipated by the perforated panel resonant absorber.So mode and absorption properties of the perforated panel resonant absorber are studied in this research.Firstly,using the finite element software COMSOL,the perforated panel resonant absorber of free vibration is modeled and the properties of its resonant frequencies are obtained.Secondly,by simulation calculation,the normal-incidence model of the perforated panel resonant absorber forced by a plane wave is modeled.And based on a transfer function method,the absorption coefficient is calculated.The influences of the perforation arrangement,the perforation ratio,the perforation radius,the panel thickness and the cavity depth on absorption properties of the perforated panel resonant absorber are studied.Finally,using the transfer function method in impedance tubes,the normal-incidence absorption coefficient of the perforated panel resonant absorber are measured.By the experiments,the influences of above parameters on absorption properties of the perforated panel resonant absorber are studied.The simulation results and the experiments results are coincident.And four conclusions are drawn through the simulations and the experiments:(1)The resonant frequencies is independent of perforations arrangement type,increase by perforation ratio,and reduce by the radius of the resonator neck,the length of the resonator neck or the depth of air pace;(2)The absorption coefficient peaks is independent of the perforation arrangement,increase by the increase of the panel thickness and reduce by increasing the perforation ratio,the perforation diameter and the the cavity depth;(3)The absorption bandwidth has nothing to do with the perforation arrangement and the cavity depth,increases by increasing the perforation ratio,and reduce by increasing the diameter of the perforation and the panel thickness.(4)In a interested band from 50 to 6400 Hz,if the cavity depth reach a limit,the numbers of resonant frequencies are more than one,including the Helmholtz resonant frequency(the first resonant frequency).